Comparative Hepatoprotective Effects of Flavonoids-rich Fractions from Flowers and Leaves of Penthorum chinense Pursh in vitro

Ethnopharmacological relevance: Penthorum chinense Pursh is a traditional Miao ethnomedicine rich in bioactive components, widely recognized for its hepatoprotective properties. However, the hepatoprotective effects of its flowers and leaves have not been individually elucidated.

Aims of the study: The objective of this study was to isolate and purify flavonoids-rich fractions from the flowers (PFF) and leaves (PLF) of P. chinense, and to assess their potential protective effects against oxidative, alcohol-induced, and free fatty acid (FFA) induced injury in hepatic cells.

Materials and methods: The P. chinense flowers and leaves flavonoids-rich fractions were extracted by the method optimized by response surface methodology, and the extracts were subsequently purified using petroleum ether and microporous column. The physical characteristics and component composition of PFF and PLF were analyzed by FT-IR and UPLC-MS/MS. The hepatoprotective activities of PFF and PLF were evaluated by the alcohol, H₂O₂, and FFA-induced hepatocyte injury cellular model in vitro. The protective effects of PFF and PLF on the hepatic cells were evaluated by assessing cell apoptosis rate, enzymes activities, mitochondrial membrane potential, and mRNA expression in relevant signaling pathways.

Results: The results revealed that PFF was mainly composed of pinocembrin, quercitrin and quercetin, while PLF was predominantly composed of quercetin, pinocembrin, and kaempferol and their derivatives. PFF and PLF exhibited distinct effects on increasing the cell proliferation rate, regulating the MDA, GOT and GPT levels, and modulating the mRNA expression in apoptosis and antioxidant pathways in alcohol damaged LO2 cells. PFF exhibited superior efficacy in reducing cell apoptosis in alcohol-damage cells compared to PLF. Both PFF and PLF alleviated mitochondrial stress in H₂O₂-induced LO2 cells. Additionally, the PFF and PLF attenuated lipid accumulation and activated mRNA expressions in PPARα/ACOX1/CPT-1 lipid metabolism pathways, as well as Nrf2/ARE oxidative stress pathways.

Conclusion: This study compared the hepatoprotective activities of flavonoids-rich fractions purified from the flowers and leaves of P. chinense. The results contribute to the enhanced development and utilization of various parts of P. chinense aimed at medical and health food applications.