(3.BETA.,16.ALPHA.,21.BETA.,22.ALPHA.)-16,21,22,28-TETRAHYDROXYOLEAN-12-EN-3-YL O-6-DEOXY-.ALPHA.-L-MANNOPYRANOSYL-(1-3)-O-.ALPHA.-D-GALACTOPYRANOSYL-(1-4)-O-[.BETA.-D-GLUCOPYRANOSYL-(1-2)]-.ALPHA.-D-GLUCOPYRANOSIDURONIC ACID NSC250680