β-​D-​Glucopyranoside, (3β,​12β)​-​12-​hydroxy-​20-​[(O-​β-​D-​xylopyranosyl-​(1→3)​-​O-​β-​D-​glucopyranosyl-​(1→6)​-​β-​D-​glucopyranosyl)​oxy]​dammar-​24-​en-​3-​yl 2-​O-​β-​D-​glucopyranosyl-