New cucurbitacin glycosides from Picrorhiza kurrooa

Abstract

From the roots of Picrorhiza kurrooa Royle and Benth., seven cucurbitacin glycosides have been isolated and structurally elucidated mainly by NMR and mass spectroscopy. Four of them (4, 5, 6, 7) are new and two, the 2-O-glycoside of cucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anosta-5, 23-diene-3,11,22-trione) and the 2-O-glucoside of 23,24 didydrocucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anost-5-ene-3, 11-22-trione) were so far not reported as constituents of this plant. The four new cucurbitacins could be identified as 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos ta-5, 23-diene-22-one, 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos t-5-ene-22-one, the 2-O-glucoside of cucurbitacin Q (25-acetoxy-2-beta-glucosyloxy-3,16,20-trihydroxy-9-methyl-19-n orlanosta-5, 23-diene-11,22-dione), and the 2-O-glucoside of deacetoxycucurbitacin B (2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norlanosta-5 , 24-diene-3,11,22-trione).