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Review Article
Necroptosis, an immunogenic programmed cell death, drives inflammatory diseases, neurodegeneration, ischemia-reperfusion injury, and cancers. Natural products regulate RIPK1/3-MLKL pathway, oxidative stress, and mitochondrial dysfunction to exert therapeutic potentials against necroptosis-associated diseases. This review explores their mechanisms and clinical potential for developing necroptosis-related therapies.
Necroptosis is a genetically regulated form of necrotic cell death initiated by diverse signals, including death receptor ligands, which activate the receptor-interacting protein kinases 1/3 (RIPK1/3) and mixed-lineage kinase domain-like pseudokinase (MLKL) pathway. Necroptosis plays a pivotal role in the pathophysiology of inflammatory diseases, ischemia/reperfusion injury, and neurodegenerative disorders.
Therapeutically inhibiting necroptosis holds promise for these conditions, driving significant interdisciplinary interest, particularly from researchers in biology and medicinal chemistry. In addition to synthetic necroptosis inhibitors, numerous natural products have been identified as inhibitors of necroptosis, demonstrating promising therapeutic potential in various diseases.
This review aims to elucidate the established and emerging molecular mechanisms underlying necroptosis as well as its contribution to human diseases. The therapeutic effects and mechanistic insights of natural products in inhibiting necroptosis and associated diseases are further summarized, with particular emphasis on their regulatory roles in the RIPK1/3-MLKL signaling pathway, oxidative stress modulation, and mitochondrial dysfunction. These progresses are expected to not only facilitate the design and development of natural products-based necroptosis modulators, but also promote the clinical application of natural product-derived therapies for necroptosis-associated diseases.
Cell death is essential for maintaining organismal homeostasis. Programmed cell death (PCD) is an actively triggered process regulated by multiple genetic mechanisms, serving not only as an essential step for tissue differentiation and development but also as the primary strategy for hosts to eliminate damaged, infected, or redundant cells. Although apoptosis was long regarded as the principal PCD pathway, emerging research has revealed additional regulated cell death mechanisms, including necroptosis, pyroptosis, and ferroptosis, all classified as forms of regulated necrosis1. Laster et al. first discovered that tumor necrosis factor-α (TNF-α) not only induces apoptosis but also triggers necrosis characterized by "balloon-like" plasma membrane blebbing2. In 2000, Holler et al., identified that Fas, a transmembrane glycoprotein of the TNF receptor (TNFR) superfamily, triggers caspase-8-independent cell death through receptor-interacting serine/threonine-protein kinase 1 (RIPK1)3. In 2005, Yuan and colleagues established the term necroptosis for TNF-α-induced, caspase-8-deficient cell death4. Morphologically, necroptosis is characterized by organelle swelling, plasma membrane rupture, cellular lysis, and loss of intracellular contents, exhibiting necrotic-like changes1. The resultant membrane breach results in the release of intracellular contents, eliciting potent inflammatory responses. This immunogenic cell death mechanism operates as a double-edged sword in host defense: while effectively neutralizing pathogens, it concurrently risks collateral tissue damage. Pathologically, necroptosis participates in a variety of pathological processes such as ischemia-reperfusion (I/R) injury, infectious and non-infectious inflammation, and neurodegenerative diseases1,3,5. Given its pivotal role in disease pathogenesis, necroptosis modulation represents a clinically promising therapeutic approach1,3,5,6.
Natural products have been regarded as a cornerstone of drug discovery, delivering abundant vital therapeutic molecules for over a century7,8. Currently, about 50% of approved drugs are derived directly or indirectly from natural products7,8, and this traditional advantage remains prominent in necroptosis regulators research. Despite the development of various synthetic small-molecule inhibitors of necroptosis9, natural products and their derivatives remain a hot focus in necroptosis regulation studies due to their structural diversity and high biocompatibility8. Recently, a series of naturally derived small-molecules have been identified as inhibitors of necroptosis, demonstrating unique therapeutic potential in complex pathological processes including infectious inflammation, non-infectious inflammation, neurodegenerative diseases, and I/R injury. More importantly, the discovery of these natural necroptosis inhibitors not only provides novel lead compounds for disease treatment, but also reveals new targets for necroptosis inhibition, offering innovative approaches to overcome existing therapeutic limitations. Although several natural necroptosis inducers have been developed, necroptosis exhibits dual pro- and anti-tumor effects in cancer development, which are largely dependent on tumor heterogeneity and microenvironmental complexity6. Therefore, this review primarily focuses on the anti-necroptotic effects of natural compounds. However, comprehensive systematic reviews delineating the therapeutic advancements of natural products in the management of necroptosis-associated diseases remain conspicuously absent in current literature. Herein, this paper focused on three core aspects: (1) the molecular mechanisms of necroptosis and its role in disease pathogenesis; (2) the inhibitory effects of natural compounds on necroptosis and their molecular mechanisms and functional targets; and (3) the therapeutic potential of these natural products for related diseases. By integrating recent advances in natural-derived necroptosis modulators, this review not only establishes theoretical foundations for the development and utilization of natural products but also provides critical translational insights for designing novel necroptosis-targeted therapies.
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Molecular mechanisms of necroptosis
From a genetic perspective, programmed necrosis is regulated by a multi-gene network, with its phenotype shaped by genetic background, cellular lineage, and pathological microenvironment1,3. In the absence of apoptotic signals, stimulation of death receptors by homologous ligands can trigger necroptosis, such as TNF-α/TNFR, Fas ligand/FAS, and TNF-related apoptosis-inducing ligand (TRAIL)/death receptor 4/5 (DR4/5)1,6. TNFα/TNFR-mediated necroptosis is the most extensively characterized10. TNF-α binding induces TNFR1 homotrimerization, which recruits TNFR1-associated death domain protein (TRADD), TNF receptor associated factor 2 (TRAF2), cellular inhibitor of apoptosis proteins 1/2 (cIAP1/2), and RIPK1 to form membrane-bound Complex I11. This complex activates transforming growth factor-beta-activated kinase 1 (TAK1), TANK-binding kinase 1 (TBK1), and inhibitor of nuclear factor kappa-B kinases (IKKs), resulting in nuclear factor kappa-B (NF-κB) pathway activation. Ubiquitination of RIPK1 by E3 ligases and cIAP1/2 ultimately promotes NF-κB activation and cell survival11,12. Upon second mitochondria-derived activator of caspases (SMAC)-mediated inhibition of cIAP1/2, RIPK1 remains non-ubiquitinated. This triggers RIPK1 dissociation from the membrane, enabling its recruitment of Fas-associated death domain protein (FADD) and caspase-8 to assemble cytoplasmic Complex IIa. The complex subsequently initiates caspase-8-dependent activation of caspase-3, culminating in apoptotic cell death13. Upon caspase-8 inhibition, activated RIPK1 recruits RIPK3 to form Complex IIb, known as necrosome14. The necrosome then triggers RIPK3-mediated phosphorylation of mixed lineage kinase domain-like protein (MLKL), promoting MLKL oligomerization and plasma membrane translocation15. The resultant membrane permeabilization initiates necroptotic cell death (Figure 1). Notably, necroptosis exhibits dual inflammatory amplification: RIPK3 directly activates nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome16, while MLKL-mediated membrane disruption provides additional NLRP3 assembly signals and releases mitochondrial DNA to activate the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway17,18, thereby exacerbating inflammatory responses.
Besides the canonical necroptosis pathways, alternative signaling routes can initiate this programmed cell death modality19. In caspase-deficient cells, viral double-stranded RNA (dsRNA) activates Toll-like receptor 3 (TLR3) or bacterial lipopolysaccharide (LPS) engages TLR4, promoting TRIF (TIR-domain-containing adapter-inducing IFNβ) association with RIPK3 to induce necroptosis20. Furthermore, viral Z-DNA/Z-RNA is recognized and activated by Z-DNA binding protein 1 (ZBP1), facilitating its interaction with RIPK3 to induce necroptosis21. Moreover, interferon-γ promotes necrosome formation and MLKL activation through interferon alpha/beta receptor 1 (IFNAR1)-mediated transcriptional regulation22. Recently, several studies have demonstrated that extracellular stimuli, including calcium overload, osmotic stress, heat shock, and drug exposure, can induce necroptosis. Specifically, cytoplasmic calcium accumulation initiates necroptosis by promoting RIP1 phosphorylation via Ca²⁺/calmodulin-dependent kinase II (CaMKII)23. Osmotic stress directly activates RIPK3 kinase through solute carrier family 9 member 1 (SLC9A1)-mediated cytoplasmic pH elevation24, whereas heat shock induces ZBP1 activation via heat shock transcription factor 1 (HSF1)25, thereby triggering RIPK3 phosphorylation and subsequent MLKL recruitment and phosphorylation (Figure 1). Furthermore, mitochondrion also plays pivotal roles in necroptosis through three key mechanisms: (1) RIPK3 may promote necroptosis activation by stimulating mitochondrial reactive oxygen species (ROS) generation26; (2) RIPK3 can induce oxidative stress and mitochondrial dysfunction in renal tubular epithelial cells (TECs) via upregulation of NADPH oxidase 4 (NOX4) and inhibition of mitochondrial complexes I/III, thereby triggering necroptosis27; (3) phosphoglycerate mutase 5 (PGAM5) regulates necroptosis through dynamin-related protein 1 (Drp1)-mediated mitochondrial hyper-fission28.
Necroptosis and human diseases:
Generally, apoptosis manifests as an immunologically silent cell death process29, in stark contrast to the highly immunogenic nature of necroptosis characterized by plasma membrane rupture6. This catastrophic membrane failure triggers the uncontrolled release of cytoplasmic damage-associated molecular patterns (DAMPs), including high mobility group box 1 (HMGB1), ATP, and nucleic acids, which serve as potent pro-inflammatory mediators. Although this mechanism facilitates immune cell recruitment to sites of infection or injury, promoting pathogen elimination and tissue regeneration, unregulated necroptotic signaling can precipitate severe pathological consequences. Excessive DAMPs spillage leads to hyperactivation of myeloid cells (particularly macrophages and microglia), initiating a self-perpetuating cycle of pro-inflammatory cytokine production and progressive cell death30. This inflammatory cascade ultimately results in substantial organ damage, with documented involvement in diverse pathological states ranging from inflammatory/autoimmune disorders to neurodegenerative conditions and I/R injury1,3,5,6,30,31 (Figure 2).
Neurodegenerative diseases
Alzheimer's disease (AD) and Parkinson's disease (PD) are two common neurodegenerative disorders characterized by significant neuronal death and upregulated RIPK1/3-MLKL signaling in affected brain regions32,33. Genetic ablation of MLKL has been found to attenuate dopaminergic neuron degeneration in PD models34, while pharmacological inhibition of RIPK1 or MLKL similarly protects against neuronal necroptosis in AD models35. Furthermore, in both superoxide dismutase 1 (SOD1) glycine 93-alanine (G93A) mutant transgenic mice and human amyotrophic lateral sclerosis (ALS) patient samples, RIPK1/RIPK3-mediated axonal degeneration emerges as a shared pathological hallmark, strongly implicating necroptosis as a pivotal driver of ALS progression36. Moreover, mutations or loss of optineurin (OPTN) activate the RIPK1/3-MLKL signaling pathway, thereby promoting ALS pathogenesis. Notably, inhibition of RIPK1 kinase activity has been shown to alleviate disease symptoms in ALS mouse models36. Similarly, necroptosis has been implicated as a significant contributor to the pathogenesis of Huntington's disease37. Collectively, RIPK1/RIPK3/MLKL-mediated necroptosis pathway exacerbates neural death and injury, positioning this signaling axis as a compelling therapeutic target for neurodegenerative disorders33.
Cardio-cerebrovascular diseases
Necroptosis-associated proteins have emerged as therapeutic targets for various cardio-cerebrovascular diseases, including myocardial injury, atherosclerosis, stroke, and abdominal aortic aneurysm (AA). Clinical observations demonstrate elevated levels of RIPK3 and MLKL in patients with unstable carotid atherosclerosis, along with phosphorylated MLKL detection in advanced atherosclerotic plaques38. Furthermore, low-density lipoprotein (LDL) has been shown to promote the transcription and phosphorylation of RIPK3 and MLKL, while RIPK1 inhibitor Necrostatin-1 attenuates plaque instability in apolipoprotein E (ApoE)-/- mice38. Moreover, RIPK3 knockout significantly reduces myocardial infarction area and inflammation in I/R mice, exhibiting long-term cardioprotective effects23,39. Similarly, in abdominal AA pathogenesis, upregulated RIPK3 expression is observed predominantly in medial smooth muscle cells (SMCs). RIPK3 overexpression induces SMC necroptosis, whereas RIPK3 deficiency suppresses the expression of pro-inflammatory genes and AA progress40. Additionally, Degterev et al found that necroptosis drives delayed brain injury after stroke, with Necrostatin-1 reducing infarct volume4. Notably, RIPK1/3 activation triggers brain inflammation, while RIPK3/MLKL knockout promotes microglial switch from pro-inflammatory M1 to protective M2 phenotypes41. This evidence positions necroptosis as a fundamental pathological driver in cardio-cerebrovascular disorders, thereby providing a foundation for novel therapeutic strategies.
Respiratory disease
Acute lung injury (ALI) is an acute diffuse lung disorder caused by infection, trauma, or shock, marked by alveolar-capillary damage, pulmonary edema, and severe hypoxia, potentially progressing to acute respiratory distress syndrome (ARDS)42. Emerging evidence demonstrates that necroptosis plays a central role in ALI pathogenesis. Staphylococcus aureus virulence factors, including α-hemolysin, activate RIPK1/3-MLKL signaling to induce alveolar macrophage necroptosis, while RIPK1 inhibition or RIPK3 knockout attenuates pulmonary inflammation in murine models43. Similarly, LPS triggers macrophage necroptosis via ZBP1 activation44. Influenza A virus induces necroptosis in alveolar macrophages through the RIPK1/3-MLKL pathway, correlating with elevated mRNA expression of RIPK1/3 and MLKL in influenza patients45. Beyond macrophages, alveolar epithelial cells (AECs) are also susceptible to necroptosis. LPS exposure promotes mitochondrial citrate accumulation, facilitating FUN14 domain-containing protein 1/Drp1 interaction-induced mitophagy while aberrantly activating RIPK1/3-MLKL pathway, both contributing to AECs necroptosis46,47. In cecal ligation and puncture (CLP)-induced sepsis mice, RIPK3 deficiency reduces release of DAMPs and pro-inflammatory cytokines, thereby alleviating ALI48. Beyond ALI, necroptosis contributes to chronic pulmonary disorders. Elevated RIPK3 and MLKL phosphorylation is observed in chronic obstructive pulmonary disease (COPD) patients, while RIPK3 or MLKL deficiency prevents cigarette smoke (CS)-induced airway inflammation and reduces CS-related remodeling and emphysema49. These findings suggest necroptosis-driven pathological damage to macrophages and AECs is a critical regulatory mechanism in pulmonary disorders, highlighting its therapeutic potential.
Liver diseases
Liver diseases, including infectious hepatitis, alcoholic liver disease (ALD), metabolic dysfunction-associated fatty liver disease (MAFLD), drug-induced injuries, and hepatic fibrosis, represent major global health challenges. Despite their diverse etiologies, these conditions share common pathogenic features: sustained cell death and inflammation50. Although hepatocytes naturally lack RIPK3 and are theoretically resistant to necroptosis51, clinical and preclinical evidence suggests its pathological involvement in liver diseases. In MAFLD patients, hepatic TNF-α, RIPK3, and p-MLKL levels are significantly elevated. Similarly, high-fat diet (HFD)- or methionine-choline-deficient (MCD) diet-fed mice show upregulated hepatic RIPK3 and MLKL expression, while RIPK3 knockout attenuates MCD diet-induced liver injury, steatosis, and oxidative stress52. Paradoxically, RIPK3 deficiency exacerbates steatosis and inflammation in MAFLD mice53. In ALD, both patients and chronic ethanol-fed mice exhibit elevated hepatic RIPK3 expression without RIPK1 alterations. Although RIPK3 knockout mitigates ethanol-induced steatosis and damage, RIPK1 inhibitor Necrostatin-1 does not show protective effect54. In acetaminophen (APAP)-induced liver injury mice, despite observed RIPK1 phosphorylation and Necrostatin-1 reducing ROS production, RIPK1 inhibition's protective effect may rely more on anti-inflammatory mechanisms than cell death suppression55. Ramachandran et al. identified RIPK3 as an early mediator of APAP-induced hepatocyte necrosis in mice, with its inhibition or knockout reducing necrotic death potentially through suppression of downstream NLRP3 inflammasome activation56. Furthermore, the liver comprises diverse cell populations, such as hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, and hepatic stellate cells, each of which plays distinct and even opposing roles in the pathogenesis of different liver diseases. Consequently, using a global RIPK3 knockout strategy, as opposed to conditional ablation in specific cell types, may obscure its precise functional contributions in particular disease contexts. This limitation likely contributes to contradictory outcomes observed across disparate liver disease models. Given these contradictory findings, whether necroptosis occurs in the liver and its contribution to liver disease pathogenesis remains controversial.
Intestinal diseases
Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis (UC), is a chronic intestinal inflammatory disorder characterized by intestinal epithelial cell death and inflammatory cell infiltration57. Clinical studies show elevated RIPK3 and p-MLKL levels with reduced E-cadherin expression in pediatric IBD patients58. Intestinal mucosal barrier injury facilitates bacterial translocation, triggering macrophage activation and inflammation59. Pharmacological inhibition of RIPK1 enhances E-cadherin, occludin, and Zonula occludens-1 expression in dextran sodium sulfate (DSS)-induced colitis, thereby restoring epithelial homeostasis60. Notably, Lee and colleagues found elevated expression of necroptosis-related molecules in CD4+ T cells from UC patients. RIPK3 inhibition not only blocks necroptosis but also suppresses Th17 differentiation, reducing pro-inflammatory cytokine levels in both UC patients' peripheral blood monocytes and DSS-induced colitis mice61. In addition to IBD, necrotizing enterocolitis and heatstroke-associated intestinal injury are also linked to necroptosis. Both necrotizing enterocolitis patient tissues and heatstroke-related intestinal injury mice demonstrate significant upregulation of necroptosis pathway proteins. Necrostatin-1 effectively inhibits necroptosis and alleviates intestinal damage62. These findings indicate that necroptosis drives pathological progression in diseases like IBD by disrupting intestinal epithelial integrity and immune homeostasis, providing a theoretical basis for novel therapeutic strategies.
Renal diseases
Acute kidney injury (AKI), a rapid-onset renal dysfunction syndrome caused by sepsis, nephrotoxins, hemorrhage, I/R, and urinary obstruction, is mainly defined by elevated serum creatinine or oliguria63. Emerging evidence demonstrates that necroptosis is closely linked to AKI pathophysiology. In I/R-induced AKI models, RIPK3/MLKL-dependent necroptosis activation occurs in proximal TECs. RIPK3 knockout or RIPK1 inhibition effectively prevents TECs death, inflammatory infiltration, and fibrosis64. Beyond I/R injury, necroptosis also contributes to cisplatin-induced AKI. Cisplatin-induced AKI is alleviated by RIPK3 knockout in mice, and Xu et al. showed reduced proximal tubule damage in MLKL-knockout mice65. In folate-induced AKI, despite the elevated RIPK3 and MLKL in renal tissue, early-stage AKI is not effectively protected by RIPK3 or MLKL knockout. However, late-stage AKI involves TNF-related weak inducer of apoptosis (TWEAK)/Fn14-dependent necroptosis, which is ameliorated by RIPK3 or MLKL deficiency or RIPK1 inhibition66. Notably, in sepsis-induced AKI, RIPK3 drives tubular damage through NOX4 induction, mitochondrial dysfunction, and oxidative stress, independently of MLKL67. Similar to AKI, necroptosis has also been identified in chronic kidney diseases (CKD). For example, subtotal nephrectomy in mice induces necroptosis characterized by upregulated RIPK1/3 expression at 8 weeks post-surgery, significantly alleviated by Necrostatin-168. Therefore, necroptosis drives tubular injury and inflammation, serving as a critical pathogenic mechanism in both acute and chronic kidney injury induced by ischemia or nephrotoxic drugs.
Cancers
The role of necroptosis in cancer is dualistic, exerting both tumor-suppressive and tumor-promoting effects. On one hand, as an immunogenic form of cell death, necroptosis can eliminate tumor cells and activate anti-tumor immunity, offering a potential therapeutic strategy against apoptosis-resistant tumors. On the other hand, necroptosis may impair antitumor immunity by killing immune cells, thereby facilitating cancer progression3,6. Similarly, necroptosis also exhibits a dual role in tumor metastasis69. During early stages, tumor cell-induced necroptosis of endothelial cells enhances vascular extravasation, while MLKL knockout or RIPK1 inhibition effectively suppresses metastasis in nasopharyngeal carcinoma70, lung cancer, and melanoma71. Paradoxically, several chemotherapeutics trigger tumor cell necroptosis and immunogenic death, inhibiting pancreatic cancer progression72. Notably, necroptosis-related molecular expression displays tumor-specific heterogeneity: RIPK1 is upregulated in glioblastoma and lung cancer correlating with poor prognosis73,74, whereas RIPK3 and MLKL are frequently downregulated in breast cancer and colorectal cancer75,76. Consequently, tumor heterogeneity endows necroptosis with both tumor-suppressive and tumor-promoting effects, thereby offering novel therapeutic perspectives for precision oncology across diverse tumor types.
Other diseases
Beyond the aforementioned diseases, necroptosis is also implicated in the pathogenesis of multiple disorders. For instance, pharmacological inhibition of RIPK1 reduced pancreatic cell death in caerulein-induced pancreatitis mice77. However, Boonchan et al. demonstrated that RIPK3- or MLKL-deficient mice exhibited exacerbated pancreatic edema and inflammation78. In psoriasis, an autoimmune skin disease, MLKL and RIPK1/3 showed significant expression in epidermal tissues from patients. Inhibition of RIPK1 or MLKL attenuated necroptosis both in vitro and in vivo, markedly reducing inflammation in imiquimod (IMQ)-induced psoriasiform dermatitis models79. These findings suggest that targeting necroptosis may offer novel therapeutic strategies for acute pancreatitis and psoriasis.
Naturally derived necroptosis inhibitors:
Necroptosis, a regulated form of cell death, not only maintains homeostasis but also plays pivotal roles in various disease pathogenesis. It exhibits Janus-faced effects in various diseases: inhibiting necroptosis contributes preserve to homeostasis and mitigates organ damage from inflammation, I/R, and toxicity3,5,6. Currently, numerous synthetic necroptosis inhibitors have been identified, including RIPK1 inhibitors (like Necrostatin-1, GSK2982772, and GSK3145095), RIPK3 kinase inhibitors (like GSK872, carfilzomib, and dabrafenib), and MLKL-targeted necrosulfonamide9. Significantly, a growing array of natural products has been identified as necroptosis inhibitors, demonstrating promising therapeutic potential in preclinical disease models. This review systematically summarizes and discusses the current advances in the inhibitory roles and molecular mechanisms of a total of 31 natural compounds in necroptosis regulation, while also exploring their health benefits in necroptosis-related diseases. Among them, there are 9 flavonoids (1-9): Baicalein (1), Cardamonin (2), Hesperetin (3), Luteolin (4), Luteolin-7-O-β-D-glucuronide (5), Morin hydrate (6), Oroxyloside (7), Wogonin (8), and Quercetin (9); 9 terpenoids (10-18): Paeoniflorin (10), Aucubin (11), Genipin (12), Artesunate (13), Tanshinone I (14), Kongensin A (15), Celastrol (16), Pristimerin (17), and Ursolic acid (18); 4 alkaloids (19-22): Aloperine (19), Aurantiamide (20), Neferine (21), and Piperlongumine (22); 5 phenols (23-27): Curcumin (23), Gallic acid (24), Resveratrol (25), Pterostilbene (26), and Theaflavin (27); and 4 additional compounds: Arctiin (28, lignin), Eleutheroside B (29, phenylpropanoid), Gambogic acid (30, xanthone), and Indole-3-carbinol (31, indole). Figure 3 depicts the chemical structure of the aforementioned natural products.
Flavonoids
Baicalin (1), the primary active component of Scutellaria baicalensis, is demonstrated to exert anti-inflammatory, antioxidant, and cytoprotective properties80. Huang et al. further demonstrated that baicalin significantly inhibited LPS plus pan-caspase inhibitor IDN-6556 or TNF-α combined with Smac mimetic (LCL-161) and IDN-6556 (TSI)-induced necroptosis, mitochondrial dysfunction, and ROS production in mouse bone marrow-derived macrophages (BMDMs) or J774A.1 cell lines, while effectively ameliorating caerulein-induced acute pancreatitis in mice. Mechanistic studies revealed that baicalin did not suppress TSI-induced RIPK1/3-MLKL phosphorylation but markedly inhibited MLKL oligomerization, thereby contributing to its necroptosis inhibition81. Besides acute pancreatitis, baicalin has been shown to alleviate dydrogesterone-induced unexplained recurrent abortion (URSA) in mice, with its mechanism linked to the suppression of Drp1-mitochondrial fission 1 protein (Fis1)-mediated excessive mitochondrial fission and necroptosis of endometrial stromal cells (ESCs)82. Additionally, Bai et al. found that baicalin's cardioprotective effect was associated with the inhibition of necroptosis in hypoxia-reoxygenation (H/R)-stimulated cardiac microvascular endothelial cells (CMECs), which was mainly mediated by phosphatidylinositol 3-kinase/protein kinase B (PI3K-AKT) activation and subsequent suppression of RIPK1/3-MLKL signaling83. Based on the above findings, it is proposed that the anti-necroptotic effect of baicalin serves as one of the fundamental mechanisms underlying its anti-inflammatory and cytoprotective properties. Previously, cardamonin (2), an active chalcone derived from Alpinia katsumadai, was found to significantly inhibit TNF-α plus SM-164 and z-VAD-FMK (TSZ)-induced necroptosis in HT29 human colon adenocarcinoma cells and L929 mouse fibroblast cells. Mechanistic investigations further demonstrated that cardamonin bound to RIPK1/3 kinases, suppressing TSZ-induced RIPK1/3 phosphorylation, necrosome assembly, and MLKL phosphorylation, thereby ameliorating epithelial barrier disruption and necroinflammation in DSS-induced colitis mice84. Intriguingly, cardamonin was found to suppress NLRP3 inflammasome activation85. Given that necroptosis induces NLRP3 activation via potassium efflux17, it is suggested that cardamonin-mediated NLRP3 inhibition may be partially attributable to its inhibition of necroptosis. Additionally, hesperetin (3), a bioactive flavonoid found in citrus fruits, was shown to alleviate DSS-induced colitis by inhibiting phosphorylation of RIPK3 and MLKL86. However, its precise molecular target remains to be elucidated.
Luteolin (4) is a flavonoid compound abundantly found in medicinal plants such as Chrysanthemum indicum and celery, exhibiting anti-inflammatory and antioxidant properties. Recent study confirmed that luteolin mitigated dexamethasone-induced necroptosis in bone microvascular endothelial cells (BMECs) by suppressing the phosphorylation of RIPK1/3-MLKL signaling87. Furthermore, its analogue, luteolin-7-O-β-D-glucuronide (5), a flavonoid glycoside derived from Ixeris sonchifolia (Bge.) Hance was found to alleviate oxygen-glucose deprivation (OGD)-induced primary cortical neuronal injury and middle cerebral artery occlusion (MCAO)-induced cerebral ischemic damage in rats by inhibiting RIPK3 and MLKL protein expression88. Oroxyloside (6) is a flavonoid glycoside isolated from Scutellaria baicalensis, which significantly ameliorated APAP-induced acute liver injury in mice, potentially via partial inhibition of c-Jun N-terminal kinase (JNK)-mediated upregulation of RIPK3 and MLKL89. Morin hydrate (7), a natural flavonoid primarily isolated from the Moraceae family90, demonstrated efficacy in alleviating 3-nitropropionic acid-induced Huntington's disease in rats. This effect was achieved through inhibition of striatal TNF-α expression and phosphorylation of RIPK1/3 and MLKL, thereby contributing to its anti-inflammatory and chemoprotective properties37. Furthermore, wogonin (8), another active component of Scutellaria baicalensis, was able to attenuate cisplatin-induced necroptosis in HK2 human TECs and AKI in mice by binding to RIPK1, thereby suppressing RIPK1/3 expression and MLKL phosphorylation91. Additionally, the widely distributed flavonoid quercetin (9) obviously alleviated H/R-induced necroptosis in primary mouse cardiomyocytes and myocardial I/R injury in mice by activating Sirtuin 5 (SIRT5) deacetylase activity, leading to downregulation of DNA-activated protein kinase catalytic subunit (DNA-PKcs) and MLKL expression92. In addition to cardiomyocytes, oligodendrocytes are sensitive to necroptosis, which contributes to neurological deficit in spinal cord injury (SCI). Quercetin was found to inhibit oligodendrocyte necroptosis induced by M1 microglia via reducing RIPK3 expression and MLKL phosphorylation, thereby improving functional recovery after SCI93. Meanwhile, the previously widely reported anti-inflammatory effect of quercetin94, may also be closely related to its role in inhibiting necroptosis. These findings collectively highlight flavonoids as promising necroptosis inhibitors, though their tissue-specific mechanisms and clinical translatability require further exploration. In addition, the reported biological effects and molecular mechanisms of these necroptosis inhibitors sourced from natural flavonoids are summarized in Table 1.
Terpenoids
The pathogenesis of diabetic nephropathy is also associated with necroptosis activation. Paeoniflorin (10), the primary active monoterpene component from Paeonia lactiflora, alleviated high glucose-induced MPC5 mouse podocyte necroptosis by binding to TNFR1 and promoting its degradation, thereby inhibiting downstream RIPK1/3-MLKL activation, ultimately protecting against streptozotocin (STZ)-induced diabetic nephropathy in mice95. Furthermore, paeoniflorin was demonstrated to interact with tumor necrosis factor α-inducing protein 3 (TNFAIP3), a ubiquitin-editing enzyme, thereby promoting TNFAIP3-RIPK3 interaction. This interaction promotes TNFAIP3-RIPK3 complex formation, inhibits RIPK3 and MLKL phosphorylation, and ultimately alleviates cisplatin/lansoprazole-induced AKI in mice96. Meanwhile, aucubin (11), an active iridoid isolated from Eucommia ulmoides and Plantago asiatica, suppressed neuronal necroptosis by inhibiting RIPK1 and MLKL protein expression, contributing to the mitigation of lithium-pilocarpine-induced status epilepticus in rats97. Genipin (12) another iridoid mainly from Gardenia jasminoides, has been reported to exhibit hepato-protective effect, though its mechanism remained unclear. Seo et al. revealed that genipin exerted protective effects against LPS/D-galactosamine (GalN)-induced hepatic inflammatory injury by downregulating RIPK3 protein expression, inhibiting RIPK1/3 necrosome assembly, and suppressing MLKL phosphorylation, thereby attenuating NLRP3 inflammasome activation98. Artesunate (13), a sesquiterpene lactone derivative of artemisinin, has been approved for malaria treatment99. Lei et al. revealed that artesunate ameliorated cisplatin-induced AKI in mice by inhibiting phosphorylation of RIPK1/3-MLKL pro-necroptotic pathway and NF-κB p65 pro-inflammatory pathway. Notably, co-culture models of mouse TECs and LPS-exposed BMDMs confirmed that artesunate's inhibitory effect on TECs necroptosis and inflammation was mediated through Mincle protein suppression in BMDMs100.
Tanshinone I (14), a diterpenoid compound derived from Salvia miltiorrhiza Bunge (Danshen), has been identified as a cardioprotective agent. Zhou et al., further showed that tanshinone I effectively suppressed tert-butyl hydroperoxide (t-BHP)-induced necroptosis in rat H9c2 myocardial cells by inhibiting RIPK1/3-MLKL axis activation, thereby mitigating myocardial I/R injury in rats101. Moreover, Tanshinone I alleviated oxidative stress and mitochondrial dysfunction by activating the AKT-mediated nuclear factor erythroid 2 related factor 2 (Nrf2)-heme oxygenase-1 (HMOX1)/NAD(P)H: quinone oxidoreductase-1 (NQO1) antioxidant pathway, contributing to its anti-necroptotic and cardioprotective effects101. Furthermore, phenotypic screening identified the diterpenoid kongensin A (15) from Croton kongensis as a potent necroptosis inhibitor. Interestingly, kongensin A covalently bound to cysteine 542/420 (Cys542/420) of heat shock protein 90 (HSP90), selectively disrupting its chaperone function without affecting ATPase activity. This covalent mechanism specifically inhibited the activation of client kinase RIPK3 and subsequent phosphorylation of MLKL, thereby suppressing TSZ-induced necroptosis in HT29 cells102.
Based on the pivotal role of HSP90 in necroptosis regulation, several known natural HSP90 inhibitors may also exhibit anti-necroptotic activity. For instance, celastrol (16), the bioactive pentacyclic triterpenoid from Tripterygium wilfordii was found to inhibit the protein expression of RIPK3 and MLKL, thereby alleviating necroptosis and mitigating DSS-induced colitis in mice103. Furthermore, celastrol was found to inhibit TSI-induced necroptosis in J774A.1 cells and BMDMs via blocking mitochondrial dysfunction and phosphorylation of RIPK1/3 and MLKL, thereby reducing caerulein-induced acute pancreatitis mice104. Previous study revealed that celastrol disrupts the formation of HSP90-cell division cycle 37 homolog (CDC37) complex105, thereby inhibiting its ATPase activity and blocking its chaperone function for kinases such as RIPK3 and MLKL. Intriguingly, pristimerin (17), an analogue of celastrol, has also been shown to suppress TSZ-induced necroptosis in HT29 cells by inhibiting RIPK1/3-MLKL signaling activation, thereby ameliorating DSS-induced acute colitis in mice106. Pristimerin was reasonably speculated to potentially exert an anti-necroptotic effect through targeting HSP90. Additionally, ursolic acid (18), a ubiquitously distributed triterpenoid, has been found to inhibit necroptosis by suppressing expression of RIPK1 and phosphorylation of RIPK3 and MLKL. Ursolic acid also attenuated necroinflammation by inhibiting the HMGB1-TLR4-NF-κB pathway, thereby reducing OGD/reperfusion (OGD/R)-induced necroptosis in intestinal epithelial cells (IECs) and I/R-induced intestinal injury. Critically, ursolic acid-mediated anti-necroptotic activity was associated with its inhibition of signal transducer and activator of transcription 3 (STAT3) phosphorylation107. Taken together, these natural terpenoids demonstrate potent anti-necroptotic activity by directly or indirectly inhibiting the RIPK1/3-MLKL pathway, suppressing oxidative stress, and blocking STAT3 signaling, as summarized in Table 2.
Alkaloids
Alkaloids are a class of nitrogen-containing basic organic compounds predominantly found in nature, most of which possess anti-inflammatory and anti-tumor activities. Aloperine (19) is an anti-inflammatory alkaloid isolated from Sophora alopecuroides, exhibiting an obvious protective effect in LPS-induced ALI mice. Cui et al., found that aloperine suppressed LPS-induced phosphorylation of RIPK1/3 and MLKL and inhibited RIPK3 binding to pyruvate dehydrogenase complex (PDC) in MLE-12 mouse AECs, thereby blocking necroptosis, NF-κB activation, and ROS production, ultimately alleviating ALI108. Aurantiamide (20), an amide compound derived from Portulaca oleracea, exhibited a significant necroptosis inhibition in H/R- and LPS- stimulated HK2 cells, thereby mitigating AKI induced by I/R and sepsis. Mechanistically,aurantiamide exerted its function by binding to and inhibiting gastrin-releasing peptide receptor (GRPR), thereby suppressing both RIPK1/3-MLKL necroptotic pathway and NF-κB pro-inflammatory cascade109. Neferine (21), a bisbenzylisoquinoline alkaloid from Nelumbo nucifera, protects mice from DSS-induced colitis. Wu et al. further revealed that its anti-colitis effect was linked to inhibition of RIPK3 and MLKL phosphorylation as well as necroptosis110. Additionally, piperlongumine (22), the active alkaloid from Piper longum, effectively inhibited TSZ-induced necroptosis in HT29 cells and FADD-deficient Jurkat cells via blocking RIPK1 phosphorylation, thereby ameliorating TNF-α-induced systemic inflammatory response syndrome (SIRS) in mice111. Since piperlongumine demonstrates improvement in experimental colitis, ALI, and I/R injury112, which are associated with necroptosis, it is speculated that its anti-necroptotic activity may contribute to its therapeutic efficacy in these diseases. The biological activities and underlying molecular mechanisms of these natural necroptosis inhibitors derived from alkaloids are compiled in Table 3.
Phenols
Phenols are characterized as organic compounds containing one or more hydroxyl groups directly bonded to a benzene ring (aromatic ring) structure. Curcumin (23) is a natural polyphenol extracted from turmeric, known for its anti-inflammatory, antioxidant, and anticancer properties, as well as its application as a food coloring agent113. Zhang's team discovered that curcumin inhibited TSZ-induced necroptosis in HT29 cells and alleviated symptoms of SIRS in mice induced by TNF-α plus z-VAD-FMK, as well as DSS-induced colitis. Mechanistic analysis revealed that curcumin directly bound to RIPK3, suppressing its phosphorylation, necrosome formation, and MLKL phosphorylation114. This discovery offers a novel mechanistic insight into curcumin's anti-inflammatory effects. Gallic acid (24), a major active polyphenol found in Phyllanthus emblica and Chinese gallnuts, is recognized for its protective effects against liver injury induced by various stimuli115. Zhou et al showed that gallic acid effectively protected immortalized human hepatocytes LO2 from ethanol-induced damage by activating Nrf2 and inhibiting RIPK1/3-mediated necroptotic signaling116. Similarly, Liu et al, found that gallic acid also exhibited neuroprotective effects by suppressing RIPK1/3 expression and necroptosis in a rat model of LPS intracerebral injection-induced neuroinflammation117. Resveratrol (25), another renowned natural polyphenol present in grapes, berries, and nuts, is celebrated for its antioxidant, anti-inflammatory, and cardiovascular benefits118,119. Zhong's team revealed that anti-necroptotic mechanisms contributed to resveratrol-mediated cardioprotective effects. Mechanistically, resveratrol suppressed TNF-α, RIPK1/3 expression, and MLKL phosphorylation in H/R-challenged H9c2 cells, thereby inhibiting necroptosis in I/R-induced myocardial injury120. Furthermore, resveratrol-mediated anti-necroptotic action was contributed to its SIRT1 activation, thereby inhibiting RIPK1 acetylation and subsequent MLKL phosphorylation, eventually prevented age-related atrial fibrillation in rats121. Pterostilbene (26), a dimethylated resveratrol analogue found in grapes and berries, exhibits both antioxidant activity and hepatoprotective effects. Shao et al. proposed necroptosis participated in pterostilbene-mediated protective effect against alcoholic liver disease. Mechanically, pterostilbene inhibited necroptosis by upregulating SIRT2 expression, which suppressed expression and nuclear translocation of nuclear factor of activated T-cells 4 (NFATc4) and subsequent RIPK3 expression in ethanol-treated LO2 cells. Furthermore, pterostilbene-mediated RIPK3 inhibition also contributed to its anti-oxidant action via activating Nrf2-HMOX1/NQO1 pathway122. Theaflavin (27), a polyphenolic compound formed during black tea fermentation, serves not only as a key quality indicator of black tea but has also been confirmed to process numerous health benefits, including antioxidant, hypolipidemic, and cardiovascular protective properties123. Zhou et al, revealed that theaflavin effectively suppressed TSI-induced necroptosis in MPC5 podocytes and LPS/IDN-6556-induced necroptosis in BMDMs, thereby attenuating cisplatin-induced AKI in mice. Theaflavin-mediated necroptosis suppression was associated not only with its inhibition of RIPK1/3 ubiquitination and RIPK1/3-MLKL phosphorylation, but also involved alleviating mitochondrial dysfunction and ROS accumulation124. Furthermore, this anti-necroptotic activity may also underlie theaflavin's cardiovascular protective effects. Taken together, these natural phenols exhibit anti-necroptotic effects through suppressing RIPK1/3-MLKL signaling and activating Nrf2 pathway, which are summarized in Table 3.
Others
In addition to the major classes of natural products mentioned above, several other types of natural small molecules have also been reported to exhibit anti-necroptotic effects. For example, arctiin (28), a lignan compound abundant in burdock, is found to exert anti-inflammatory and antioxidant effects by inhibiting the NF-κB pathway125. A recent study revealed that arctiin significantly protected against I/R-induced myocardial injury, which was associated with its inhibition of cardiomyocyte necroptosis. Mechanistic studies further suggest that arctiin may bind to RIPK1 and MLKL, thereby suppressing activation of RIPK1/3-MLKL cascade induced by I/R126. Beyond I/R-induced myocardial injury, high-altitude hypoxia can also trigger severe myocardial damage, which is closely associated with necroptosis. The phenylpropanoid derivative eleutheroside B (29), isolated from Acanthopanax senticosus, was found to activate the Nrf2-HMOX1 antioxidant pathway, thereby reducing RIPK1/3 protein expression and MLKL phosphorylation, ultimately alleviating necroptosis in hypoxia-exposed H9c2 cells and high-altitude-induced myocardial injury rats127. Moreover, similar to celastrol, gambogic acid (30), a primary xanthone derivative from Garcinia hanburyi, is also capable of inhibiting HSP90's ATPase and markedly blocking TSZ-induced necroptosis in HT29 cells and DSS-induced colitis in mice. Mechanistically, gambogic acid did not affect the kinase activity of RIPK1/3 and MLKL but blocked their phosphorylation by targeting HSP90128. Additionally, indole-3-carbinol (31), an indole compound derived from cruciferous vegetables including cabbage, broccoli, and cauliflower, has been proven to mitigate colitis by inhibiting necroptosis and inflammatory responses in TSZ-incubated NCM460 human IECs. Unlike HSP90 inhibitors, indole-3-carbinol activated the aryl hydrocarbon receptor (AhR) to induce protein expression of cIAP1 and X-linked inhibitor of apoptosis (XIAP), promoting RIPK1 ubiquitination and preventing necrosome formation129. The collective evidence demonstrates that these natural compounds exert their anti-necroptotic effects through inhibition of the RIPK1/3-MLKL signaling pathway and activation of the Nrf2 antioxidant pathway, as documented in Table 3.
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Over the past two decades, sustained advancements in necroptosis research have revealed numerous natural compounds that demonstrate inhibitory effects on necroptosis across diverse experimental models. Since necroptosis is primarily mediated by RIPK1/3-MLKL signaling axis, mitochondrial dysfunction, and oxidative stress, most identified natural necroptosis inhibitors influence this pathway through direct or indirect regulation of key signaling proteins. For example, baicalin blocks MLKL oligomerization, while cardamonin ...
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The authors declare that they have no conflicts of interest. The authors disclose using an artificial intelligence language model (ChatGPT) only for language polishing in preparing this review manuscript. All outputs were thoroughly reviewed and edited by the authors. ChatGPT was strictly confined to improving linguistic clarity and expression, without involvement in idea generation, data analysis, interpretation, or conclusion drafting. The authors conducted all literature citations, evidence synthesis, and conclusions independently based on the referenced studies, ensuring both accuracy and compliance with academic standards. Thus, the use of ChatGPT was limited solely to language optimization, while the scientific content and intellectual contribution remain entirely the responsibility of the authors.
This work was supported by the Natural Science Foundation of Sichuan Province from Science and Technology Department of Sichuan Province (2024NSFSC0698) and Joint Innovation Fund of Health Commission of Chengdu and Chengdu University of Traditional Chinese Medicine (WXLH20243022 and WXLH202403103).
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