Thesis (M.Sc.)--Chulalongkorn University, 2011

Phytochemical study of the stems of Diosyros collinsae Craib (family Ebenaceae) led to the isolation of four triterpenoids, namely friedelin, lupeol, betulin and betulinic acid, two stilbenoids, diptoindonesin D and diptoindonesin G, together with a mixture of β-sitosterol and stigmasterol. Identification of the isolated compounds has been accomplished by spectroscopic analyses, including UV, IR, MS and NMR, and comparison with previously reported data. Diptoindonesin G exhibited antimalarial activity against Plasmodium falciparum with an IC₅₀ value of 6.88 µg/ml as well as cytotoxic activity against human small-cell lung cancer (NCI-H187) and breast adenocarcinoma (MCF-7) cell lines with IC₅₀ values of 1.94 and 43.28 µg/ml, respectively. The present study provided the first evidence for the production of stilbenoids in Diospyros Species.