Flavonoid glycosides in Lepidium sativum seeds and their bioactivities

Twelve flavonoid glycosides including five undescribed ones, lepisativutimines Q-U, were isolated and identified from Lepidium sativum seeds. Acid hydrolysis followed by acetic derivatization and GC analysis were conducted to determine the absolute configurations for sugars. Lepisativutimine U and beitingxinhuangtong A were uncommon kaempferol 8-S-glycosides, and complete NMR data of beitingxinhuangtong A were provided for the first time. Mass fragmentation pathways of isolated compounds were deduced based on their MS/MS data, and characteristic mass fragmentation patterns were summarized. Lepisativutimine U and kaempferol-7-O-α-l-rhamnopyranoside exhibited weak anti-diabetic activity against PTP1B with IC₅₀ values of 60.58 ± 3.53 and 33.90 ± 2.89 μM, respectively, quercetin-7-O-α-l-rhamnopyranoside displayed significant anti-diabetic activity against α-glucosidase with an IC₅₀ value of 25.96 ± 0.30 μM, and kaempferol 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside and kaempferol-7-O-α-l-rhamnopyranoside showed weak inhibitory activity against NO release in LPS-induced RAW264.7 cells with IC₅₀ values of 92.28 ± 4.19 and 40.77 ± 1.50 μM, respectively.