Phenolic glycosides from Nitraria sibirica leaves and their in vitro biological activities

Seventeen phenolic glycosides were isolated from the Nitraria sibirica. Their structures were identified by the spectroscopic data and comparison with literatures as isovanillyl alcohol-7-O-β-d-glucopyranoside (1), benzyl β-primeveroside (2), benzyl-O-β-d-glucopyranoside (3), 1-O-β-d-glucopyranosyl-4-(8-hydroxyethyl)-2-methoxyphenyl (4), dehydrosyringin (5), trans-ferulic acid-4-O-β-d-glucoside (6), cis-ferulic acid 4-O-β-d-glucopyranoside (7), glucosyringic acid (8), 1-O-feruloyl-β-d-glucoside (9), sachaloside VII (10), (3S, 5R, 6R, 7E, 9S)-megastigmane-7-ene-3-hydroxy-5,6-epoxy-9-O-β-d-glucopyranoside(11), 3-hydroxy-4,5-dimethoxybenzyl alcohol (12), pinoresinol 4-O-β-d-glucopyranoside (13), eucommin A (14), isoeucommin A (15), acanthoside (16), liriodendrin (17). All these compounds except compound 13 were isolated from the Nitraria genus for the first time. In bioactivity assays for all compounds, the compounds 8 and 15 were exhibited strong antioxidant activity (IC₅₀ = 18.11 and 16.29 μM respectively), while compounds 3 and 11 were exhibited strong PTP1B enzymatic inhibition (IC₅₀ = 6.97 and 11.76 μM, respectively). Furthermore, the compounds 10 and 17 were presented strong inhibitory capacities against Candida albicans (14.5 and 13.5 mm, respectively).

Nitraria sibirica; antibacterial; antidiabetic; antioxidant; phenolic glycosides.