NSC676790 Olean-12-en-28-oic acid, 3-.beta.-(6-methyl-.beta.-D-glucopyranuronosyloxy)-, [2-O-[4-O-[4-O-(.beta.-D-xylopyranosyl)- .beta.-D-xylopyranosyl]-6-deoxy-.beta.-D-gulopyranosyl]- .beta.-L-arabinopyranosyl] ester