Flavonol and drimane-type sesquiterpene glycosides of Warburgia stuhlmannii leaves

An investigation of methanolic extract of Warburgia stuhlmannii leaves has led to the isolation of two new drimane-type sesquiterpene glycosides characterized as mukaadial 6- O-β- d-glucopyranoside, mukaadial 6- O-α- l-rhamnopyranoside together with two other novel flavonol glycosides identified as 3′,5′- O-dimethylmyricetin 3- O-β- d-2″,3″-diacetylglucopyranoside and 3′- O-methylquercetin 3- O-β- d-2″,3″,4″-triacetylglucopyranoside. The known compounds; mukaadial, deacetylugandensolide, quercetin, kaempferol, kaempferol 3- O-α- l-rhamnopyranoside, quercetin 3- O-β- d-glucopyranoside, kaempferol 7- O-β- d-glucopyranoside, myricetin 3- O-α- l-rhamnopyranoside, quercetin 3- O-α- l-rhamnopyranoside, quercetin 3- O-sophoroside and isorhamnetin 3- O-β- d-glucopyranoside were also isolated from the same extract. The isolation and structure determination of two flavonol glycosides together with two drimane-type sesquiterpene glycosides including compound 1 from methanolic extract of Warburgia stuhlmannii leaves are described.