Tsaokoflavanols A1-J1: Flavanol-fatty alcohol hybrids with HPL inhibitory activity from Amomum tsao-ko.

ABSTRACT

Ten previously undescribed compounds were isolated from the fruits of Amomum tsao-ko (Zingiberaceae), including nine undescribed flavanol-fatty alcohol hybrids (1-6, 10-11, 13), and a flavanol-monoterpenoid hybrid (14), along with seven known flavanol hybrids (7-9, 12, 15-17). The structures of these compounds were determined using various analyses, such as HRESIMS, 1D/2D NMR, and ECD calculations. In terms of biological activity, compounds 1, 2, 5, and 6 exhibited inhibitions of human pancreatic lipase (HPL), with IC50 values ranging from 0.017 to 0.193 mM. Some of these values were found to be stronger than that of the positive control, orlistat (IC50, 0.067 mM). Molecular docking studies were also conducted to investigate the interactions between these compounds and HPL. The docking simulations revealed the importance of the orientation of the 3,4-dihydroxyphenyl in binding with HPL. Additionally, compound 9 demonstrated cytotoxicity against HepG2, with a CC50 value of 14.96 ± 0.62 µM as determined by the MTT assay. Flow cytometry analysis indicated that compound 9 induced apoptosis in HepG2 cells. Western blot results showed an up-regulation of apoptosis-related proteins, such as p53 protein, Bax and Caspase-3 proteins, while the expression of Bcl-2 protein was down-regulated.