Background: Liver cells are particularly susceptible to mitochondrial dysfunction due to external stimuli, leading to excess reactive oxygen species (ROS) and redox imbalance. The aim of this study was to extract and purify the polyphenolic fractions of Mallotus peltatus (Geiseler) Mull. Arg. and evaluate their potential protective effect against H ₂ O ₂ ‐induced oxidative stress injury in hepatocytes. Methods: The extraction process of polyphenols in MPMA was optimized by the response surface method. Then, we purified the crude extracts with macroporous resin HPD600 to obtain MPMAP‐I, MPMAP‐II, and MPMAP‐III. The physical properties and component composition of the samples were analyzed by FT‐IR and UPLC‐MS/MS. An in vitro H ₂ O ₂ ‐induced oxidative stress injury model in hepatocytes was established to investigate the protective effect of MPMAP‐I on L02 cells. The effect was assessed by measuring cell survival rate, enzyme activities, intracellular ROS levels, cell apoptosis rate, mitochondrial membrane potential, and the mRNA expression of related signaling pathways. Results: The results showed that the optimized extraction conditions of MPMA were 60% ethanol, 140 min, 85°C, and liquid‐to‐solid ratio of 30 mL/g. All three purified fractions contained different polyphenols (such as kaempferol 3‐O‐sophoroside, corilagin, and cirsiliol) and had great antioxidant activities. MPMAP‐I treatment could increase the activities of SOD, CAT, and GPx in H ₂ O ₂ ‐induced L02 cells, reduce the content of MDA, the activities of transaminases, the production of intracellular ROS, and the rate of cell apoptosis, and restore mitochondrial function. Furthermore, these effects might be related to the inactivation of the Bcl2/Bax/caspase‐3 apoptotic pathway and the activation of the Nrf2/γ‐GCL antioxidant pathway. Conclusion: Our study provided a theoretical basis for the protective effect of MPMA polyphenols on liver injury, which is helpful to improve the development and application of MPMA in medicine and healthcare products.

In China, Pyracantha fortuneana has been consumed as a nutritious plant to improve indigestion. In the current study, the main chemical composition of P. fortuneana fruits was extracted and analysed for composition. Free fatty acids (FFA)-induced normal human hepatic L02 cells were used to construct a high-fat cell model, and lipid deposition in Caenorhabditis elegans was induced by a high concentration of glucose to study the anti-hyperlipidemic effects of the main components. The results showed that the flavonoid content of PFF (P. fortuneana Flavonoid Fractions) was 80.28%, and it contained various flavonoids such as epicatechin, isoquercetin, rutin, quercetin, and myricitrin, while the saponin content of PFS (P. fortuneana Saponin Fractions) was 74.4%, and it contained saponins such as shionone, crategolic acid, and ursolic acid. PFF and PFS significantly reduced the content of lipid droplets in high-fat L02 cells, inhibited mitochondrial membrane potential decline, regulated the fat accumulation by up-regulating the relative mRNA expression levels in the Nrf2/ARE signaling pathway, as well as the CPT-1 and SIRT1 genes in lipid metabolism. Meanwhile, both PFF and PFS significantly reduced lipid deposition, reactive oxygen species (ROS) levels, malondialdehyde (MDA) content, and catalase activity in C. elegans. In summary, our results indicated that the flavonoids and saponins of P. fortuneana are potential natural products in antihyperlipidemic effect.

This study characterized the basic structure of partridge tea leaves polysaccharides and comparatively analyzed the in vitro lipid-lowering activity of total partridge tea polysaccharide (PTPS) and its two purified homogeneous fractions, namely PTPS-I (13,560 Da) and PTPS-III (30,935 Da). In terms of structural composition, PTPS-I and PTPS-III share identical monosaccharide types but differ significantly in monosaccharide proportions, glycosidic linkages and backbone structures. In vitro experiments demonstrated that PTPS, PTPS-I, and PTPS-III could effectively reduce intracellular lipid levels and oxidative stress in free fatty acids (FFA)-injured L02 cells and alleviate the decline of mitochondrial membrane potential in damaged hepatocytes. At the high concentration of 400 μg/mL, PTPS-III showed a superior effect in reducing triglyceride (TG) content compared with the other two samples, with the value reaching 0.31 ± 0.024 mmol/mg prot. Additionally, 400 μg/mL PTPS markedly decreased total cholesterol (TCHO) content and enhanced superoxide dismutase (SOD) activity, which were 0.55 ± 0.039 mmol/mg prot and 29.92 ± 0.22 μmol/mg prot, respectively. PTPS-I of 400 μg/mL significantly reduced malondialdehyde (MDA) content to 1.31 ± 0.288 μmol/mg prot and inhibited the decline of mitochondrial membrane potential (MMP) by 9.67%. The three polysaccharide fractions could elevate the mRNA expression of Nrf2, NQO1 and HO-1 in the Nrf2/HO-1 signaling pathway and the gene expression of PPARα, CPT-1 and ACOX1 in the lipid metabolism pathway, and ultimately regulate lipid accumulation in L02 cells. This study validated the in vitro antilipid activities of partridge tea leaves polysaccharide and provided fundamental data for research on its bioactivity and functional components. Further in vivo assays and mechanism exploration will be conducted to evaluate its potential application in fatty liver intervention product development.