Phytochemistry of Calophyllum inophyllum L. and Calophyllum teysmannii Miq. and their biological activities

The genus Calophyllum is consisted of 180-200 species of evergreen trees which are widely distributed in Asia and Africa. This genus is popularly known for their bioactive compounds such as terpenoids, xanthones and coumarins. The need of new drugs are on the rise due to the discovery of various new diseases. Besides, the development of drug resistant diseases also makes drug discovery research significant. Hence, natural products research is important as they provide new templates in the field of drug discovery. Detailed studies were carried out chemically and biologically on the stem bark of two selected plants species, Calophyllum inophyllum and Calophyllum teysmannii. A total of two terpenoid compounds and five xanthones were isolated from the n-hexane and chloroform crude extracts of Calophyllum inophyllum respectively. The terpenoids are friedelin (82) and stigmasterol (83) whereas the xanthones are caloxanthone A (23), caloxanthone B (24),caloxanthone C (43), pyranojacareubin (6) and macluraxanthone (5). On the other hand, a total of two xanthones were isolated from the n-hexane and methanol crude extracts of Calophyllum teysmannii correspondingly namely ananixanthone (29) and β-mangostin (84). The structures of the acquired compounds were elucidated by analyzing the spectroscopic data such as 1D NMR, 2D NMR, IR, and MS. Structural modifications on the parent compound ananixanthone (29) afforded four other new synthesized xanthone derivatives namely ananixanthone monoacetate (85), ananixanthone diacetate (86), 5-methoxyananixanthone (87), and 5-O-benzylananixanthone (88). Their structures were concluded through comparison with the parent compound’s NMR spectra. The crude extracts of both the plants were subjected to toxicity test against LPS stimulated RAW264.7 cells. The results indicated that only chloroform crude extract of Calophyllum inophyllum exhibited a promising result with an IC50 value of 14.81±0.0417 μg/mL. However, the rest of the crude extracts