Withanolides from the active extract of Physalis angulate and their anti-hepatic fibrosis effects

Ethnopharmacological relevance: Physalis angulata L., a traditional Chinese medicine called "Kuzhi" in China, was used traditionally to treat liver diseases (eg. icterus, hepatitis) as well as malaria, asthma, and rheumatism. Aim of the study: Our study aimed to investigate the withanolides with anti-hepatic fibrosis effect from P. angulate. Materials and methods: Withanolides were obtained from the EtOH extract of P. angulate by bioassay-molecular networking analysis-guided isolation using column chromatography and normal/reversed-phase semipreparative HPLC. The structures of new withanolides were elucidated by combinations of spectroscopic techniques with NMR and ECD calculations. MTT cell viability assay, AO/EB staining method, cell wound healing assay, ELISA and Western blot experiments were employed to evaluate the anti-hepatic fibrosis activity and to uncover related mechanism. Molecular docking analysis and cellular thermal shift assay were used to evaluate and verify the interaction between the active withanolides and their potential targets. Results: Eight unreported withanolides, withagulides A-H (1-8), along with twenty-eight known ones were obtained from P. angulate. Withanolides 6, 9, 10, 24, 27, and 29-32 showed marked anti-hepatic fibrosis effect with COL1A1 expression inhibition above 50 %. Physalin F (9), the main component in the active fraction, significantly decreased the TGF beta 1-stimulated expressions of collagen I and alpha-SMA in LX-2 cells. Mechanism study revealed that physalin F exerted its anti-hepatic fibrosis effect via the PI3K/AKT/mTOR signaling pathway. Conclusion: This study suggested that withanolides were an important class of natural products with marked antihepatic fibrosis effect. The main withanolide physalin F might be a promising candidate for hepatic fibrosis treatment. The work provided experimental foundation for the use of P. angulate to treat hepatic fibrosis.