Xanthones with pancreatic lipase inhibitory activity from the pericarps of Garcinia mangostana L. (Guttiferae)

Abstract

Bioactivity‐guided isolation of natural compounds from the pericarps of Garcinia mangostana, using a pancreatic lipase assay, led to the identification of 13 xanthones including α‐mangostin (1), β‐mangostin (2), γ‐mangostin (3), 1‐isomangostin (4), gartanin (5), garcinone D (6), 9‐hydroxycalabaxanthone (7), smeathxanthone A (8), tovophyllin A (9), 8‐ deoxygartanin (10), mangostanin (11), calocalabaxanthone (12), and 1,7‐dihydroxy‐3‐methoxy‐2‐(3‐methylbut‐2‐enyl) xanthen‐9‐one (13). The inhibitory activities of the isolated xanthones against pancreatic lipase were evaluated and α‐mangostin (1) was found to possess the most potent inhibitory activity (IC50 5.0 µM) in a non‐competitive manner, compared with the positive control, orlistat (IC50 3.9 µM).Practical applications: Pancreatic lipase is a key enzyme in lipid absorption. A total of 13 compounds were isolated from the pericarps of G. mangostana. Their structures were characterized by HRESI‐MS, and 1D and 2D‐NMR spectroscopic data. Our results show that all the isolates exhibited inhibitory activity against pancreatic lipase. Of the active xanthones, α‐mangostin displayed the most potent lipase inhibition, with an IC50 value of 5.0 μM. Furthermore, kinetic analysis of α‐mangostin was carried out. In the Lineweaver–Burk plot, the apparent Vmax values in the presence of 1, 2, 4, and 10 µM α‐mangostin were decreased compared with those without α‐mangostin, whereas the Km values of 4‐MU oleate with and without α‐mangostin were both close to 3.22 μM. Finally, it is evident that xanthone derivatives isolated from G. mangostana possess pancreatic lipase inhibitory activities.A total of 13 compounds are isolated from the pericarps of Garcinia mangostana. α‐Mangostin is found to possess the most potent lipase inhibitory activity.