New polyglucopyranosyl and polyarabinopyranosyl of fatty acid derivatives from the fruits of Lycium chinense and its antioxidant activity

Four new compounds 3,4-dihydroxy benzoic acid 3-octadecanoyl-4-O-α-l-arabinopyranosyl (2a→1b)-2a-O-α-l-arabinopyranosyl-(2b→1c)-2b-O-α-l-arabinopyranoside (1), 2,6,10-trimethyl-n-dodec-2-en-1-oyl-1-O-α-l-arabinopyranosyl-(2a→1b)-2a-O-α-l-arabinopyranosyl-(2b→1c)-2b-O-α-l-arabinopyranosyl-(2c→1d)-2c-O-α-l-arabinopyranosyl-(2d→1e)-2d-O-α-l-arabinopyranosyl-(2e→1f)-2e-O-α-l-arabinopyranosyl-(2f→1g)-2f-O-α-l-arabinopyranoside (2), n-docos-9,12-dienoyl-α-d-glucopyranosyl-(2a→1b)-2a-O-α-d-glucopyranosyl-(2b→1c)-2b-O-α-d-glucopyranosyl-(2c→1d)-2c-O-α-d-glucopyranosyl-(2d→1e)-2d-O-α-d-glucopyranosyl-(2e→1f)-2e-O-α-d-glucopyranoside (3), β-d-glucopyranosyl-(2a→1b)-2a-O-β-l-arabinopyranosyl-(2b→1c)-2b-O-β-l-arabinopyranosyl-(2c→1d)-2c-O-β-l-arabinopyranosyl-(2d→1e)-2d-O-β-l-arabinopyranosyl-(2e→1f)-2e-O-β-l-arabinopyranoside (4) along with some know compounds, were isolated and identified from a methanol extract Lycium chinense fruits. Their structures were determined of the new compounds using one- and two-dimensional NMR spectroscopies in combination by IR, FAB/MS and HR-FAB/MS. The compounds 1–4 were investigated for the antioxidant potential using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and the phosphomolybdenum activity and the results demonstrate that the compounds (2 and 3) has potential as a natural antioxidant whereas the compound (4) exhibited moderate activity and the compound (1) exhibited weak antioxidant activity.