Novel tetrahydrofuran derivatives from Trigonostemon howii with their potential anti-HIV-1 activities

Abstract

A novel tetrahydrofuran derivative, trigonohowine (1), together with five known tetrahydrofuran derivatives (2–6), were isolated from the stems and leaves of Trigonostemon howii. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with the data reported in literature. Among them, trigonohowine (1) represents the first example of a new type of tetrahydrofuran derivative, possessing an unprecedented carbon skeleton containing 23 carbon atoms on the carbon skeleton and the known compouds (2–6) are rare tetrahydrofuran derivatives in the plant kingdom with various carbon skeletons. All isolated compounds were evaluated for their anti-HIV-1 activities. Compounds 1–6 showed significant anti-HIV-1 activities with EC50 ranged from 0.08 to 1.03 µM. These findings suggest that the discoveries of these tetrahydrofuran derivatives with significant anti-HIV-1 activities isolated from T. howii could be of great importance to the development of new anti-HIV agents.