Synthesis of Trisaccharide of Incanosides from Caryopteris incana

Recent evidence has accumulated suggesting that free radicals are involved in many deterioration processes. They attack the unsaturated fatty acids in the biomembranes resulting in membrane lipid peroxidation, which is strongly connected with aging, carcinogenesis and atherosclerosis.[1] Free radicals also attack DNA and cause mutation leading to cancer.[2] Thus it is desirable to look for effective radical scavengers. In 1999, Gao et al.[3] isolated incanosides C, D and E from the whole plant of Caryopteris incana (THUNB.). These natural products were proved to exhibit good radical scavenging activities against DPPH radical and inhibitory activities against the oxidation of linoleic acid.[4] Herein, for the first time we report the synthesis of trisaccharide phenyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl-(1→2)-3,4-di-O-benzoyl-α-L-rhamno-pyranosyl-(1→3)-2-O-acetyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside (1), which is the common carbohydrate moiety of incanosides C, D and E.

Synthesis of Trisaccharide of Incanosides from Caryopteris incana

Recent evidence has accumulated suggesting that free radicals are involved in many deterioration processes. They attack the unsaturated fatty acids in the biomembranes resulting in membrane lipid peroxidation, which is strongly connected with aging, carcinogenesis and atherosclerosis.[1] Free radicals also attack DNA and cause mutation leading to cancer.[2] Thus it is desirable to look for effective radical scavengers. In 1999, Gao et al.[3] isolated incanosides C, D and E from the whole plant of Caryopteris incana (THUNB.). These natural products were proved to exhibit good radical scavenging activities against DPPH radical and inhibitory activities against the oxidation of linoleic acid.[4] Herein, for the first time we report the synthesis of trisaccharide phenyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl-(1→2)-3,4-di-O-benzoyl-α-L-rhamno-pyranosyl-(1→3)-2-O-acetyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside (1), which is the common carbohydrate moiety of incanosides C, D and E.