Two new polyhydroxylated urs-12(13)-ene pentacyclic triterpenes namely 2α, 3α, 19α, 20β, 23-pentahydroxyurs-12-en-28-oic acid (1) and 1β, 2α, 3α, 5, 19α, 24-hexahydroxyurs-11(12), 20(30)-dien-28-oic acid (2) were isolated from the stem bark of Manilkara pellegriniana together with seven known compounds: ursolic acid 3, 1β-hydroxyeucaphic acid 4, β-Amyrin acetate 5, taraxerol 6, taraxerol acetate 7, 3α-spinasterol 8, and spinasterone 9. In addition, the chemical investigation of another specie of the same genus, M. argentea afforded six known compounds: 3β,6α,19α,23-tetrahydroxyurs-12-en-28-oic acid 10, 2α-hydroxyursolic acid 11, garbanzol 12, 3α-spinasterol glucoside 13, 3,5,7,4′,5′-pentahydroxyflavan 14, and (+)-proto-quercitol 15. Their structures were established from spectral data, mainly HRESIMS, 1D NMR and 2D NMR and by comparison with literature data. The cytotoxicity activities of compounds 1 and 2 as well as doxorubicin were evaluated on four cancer cell lines. Compound 1 had significant cytotoxic effect towards SPC212 lung cancer cells with IC50 value of 0.52 μM.

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