Structural and stereochemical studies of five new pregnane steroids from the stem bark of Toona ciliata var. pubescens

Five new pregnane steroids, toonasterones A (1), B (2), (Z)-aglawone (3), (Z)-toonasterone C (4), and (E)-toonasterone C (5), were isolated from the stem bark of Toona ciliata var. pubescens. Their structures were elucidated by means of detailed spectroscopic (IR, MS, and 2D NMR) analysis, and the stereochemistry of 1 was secured by X-ray diffraction analysis. (Z)-aglawone (3) exhibited moderate inhibitory activity of protein tyrosine phosphatase 1B (PTP1B), a potential drug target for treatment of type-II diabetes and obesity, with an IC(50) value of 1.12 μg/mL.

Triterpenoids from the leaves of Toona ciliata

One new limonoid, toonaciliatone A (1), and one new tirucallane-type triterpenoid, toonaciliatine A (4), along with three known compounds, methyl-3beta-acetoxy-1-oxomelic-14(15)-enate (2), perforin A (3), and cholest-14-ene-3,7,24,25-tetrol-21,23-epoxy-21-methoxy-4,4,8-trimethyl-3-(3-methyl-2-butenoate) (5), were isolated from the leaves of Toona ciliata. The structures of the new compounds were established by spectroscopic methods.