.beta.-D-Glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl 3-O-(6-deoxy-.alpha.-L-mannopyranosyl)-6-O-[(2E)-3-(3-hydroxy-4-methoxyphenyl)-1-oxo-2-propenyl]- AIDS-112622 AIDS112622 Plantainoside C