Phenols and triterpenoids from an ethyl acetate extract of the bark of Calophyllum pisiferum

Abstract

Calophyllum is among the largest genera in the Guttiferae family and is widely distributed across tropical regions. Its wood is known for its strength and durability, making it a popular choice for construction and boat building. Moreover, several species within the genus are traditionally used for medicinal purposes. C. pisiferum is one of 15 species of the Calophyllum genus found in Vietnam. Despite its widespread occurrence, this species remains largely understudied globally. To date, only one study has chemically investigated the plant’s root, which led to the isolation of 13 compounds, including 7 xanthones and 6 coumarins. Some of these compounds have shown cytotoxic activity against MCF-7 breast cancer cells and MDA-MB-231 human breast adenocarcinoma cells. The aim of this study was to investigate the chemical constituents of an ethyl acetate extract of the bark of C. pisiferum collected from Phu Quoc National Park. The dried and ground bark was subjected to extraction using n-hexane and ethyl acetate solvents through Soxhlet extractors. The recovery of the solvents produced the n-hexane extract and the ethyl acetate extract. Repeated column chromatography over silica gel, RP-18, and Sephadex LH-20 on the ethyl acetate extract led to the isolation of five compounds. The structures of these compounds were determined by using NMR and HRESIMS spectroscopy, with a comparison of the spectral data to literature values. The identified compounds included three phenols, calofolic acid D (1), curcumin (2), bisdemethoxycurcumin (3), and two triterpenoids, glutinol (4) and friedelin (5). This marks the first time these compounds have been discovered in C. pisiferum, contributing to a deeper understanding of the potential pharmacological applications of this plant species.