Two new cycloartanes from the leaves of Combretum quadrangulare growing in Vietnam and their biological activities

• Main Authors: Huu-Hung Nguyen, Thi-Phuong Nguyen, Nguyen Tien Trung, Cam-Tu D. Phan, Thi-Bich-Ngoc Dao, Dinh-Tri Mai, Jirapast Sichaem, Ngoc-Hong Nguyen, Cong-Luan Tran, Thuc-Huy Duong
• Format: Article
• Language: English
• Published: Elsevier 2021-07-01
• Series: Arabian Journal of Chemistry
• Subjects: Combretaceae; Combretum quadrangulare; Cycloartane; Combretanones G and H; Cytotoxicity; Antiparasitic activity
• Online Access: http://www.sciencedirect.com/science/article/pii/S1878535221002045

Two new cycloartanes, combretanones G and H (1 and 2), were isolated from the leaves of Combretum quadrangulare. Their structures were elucidated by applying a set of spectroscopic methods, while their relative configurations were determined using DFT-NMR chemical shift calculations and subsequent assignment of DP4 probabilities. Compounds 1 and 2 are C-23/C-24 stereoisomers of the previously-reported euphonerin E. Both exhibited moderate cytotoxicity against three human cancer cell lines. Compound 2 was shown to be a potent antiparasitic. Our results confirm the traditional medicinal uses of Combretum quadrangulare in Vietnam.