Cucurbitacin B 2-sulfate and cucurbitacin glucosides from the root bark of Helicteres angustifolia

A new sulfated cucurbitacin, cucurbitacin B 2-sulfate (1) and a new cucurbitacin glucoside, cucurbitacin G 2-O-beta-D-glucopyranoside (2) together with two known cucurbitacin glucosides, arvenin I and arvenin III were isolated from the root bark of Helicteres angustifolia. The structures of these compounds were established on the basis of spectroscopic and chemical evidence. These four compounds taste of strong bitterness. Compound 1 is a first sulfated cucurbitacin found in plants.