Chemical constituents and cytotoxic activities from the root and the stem of Reevesia formosana

In our previous studies, we have reported 13 new cardenolide glycosides with potent cytotoxicities, reevesiosides A-I and epi-reevesiosides F-I from the root of Reevesia formosana (Sterculiaceae). Continuing investigation of the root and the stem of this species led to the isolation of three new lignanoids, reevesic acid, reevesilignan, and reevesiacoumarin, two new sesquiterpenes, reevesiterpenol A and reevesiterpenol B, one new triterpene, 3α,27-di-O-caffeoylbetulinic acid, along with 37 known compounds including nine lignanoids, eight triterpenes, six steroids, four sesquiterpenes, three coumarins, three cardenolide glycosides, two benzenoids, one proanthocyanidin, and Q10. Three additional known cardenolide glycosides, strophathojavoside, strophalloside, and ascleposide isolated from the root of this plant also displayed potent cytotoxicity against the MCF-7, NCI-H460, and Hep G2 cancer cell lines, with IC₅₀ values of 0.767 ± 0.031, 0.175 ± 0.011, and 0.649 ± 0.06; 3.456± 0.130, 0.62 ± 0.059, and 2.593 ± 0.132; 0.166 ± 0.015, 0.037 ± 0.002, and 0.374 ± 0.020µM, respectively. The new triterpene, 3α,27-di-O-caffeoylbetulinic acid isolated from the stem of this species showed a moderate cytotoxicity against NCI-H460 cancer cell line. The structures of these compounds were elucidated by spectroscopic techniques.

Keywords: Reevesia formosana, Sterculiaceae, Root, Stem, Cardenolide glycoside, Cytotoxicity