Chemical constituents from the fruits of Vitex negundo var. cannabifolia and their biological activities in vitro

Chemical constituents from the fruits of Vitex negundo var. cannabifolia and their nitric oxide (NO) inhibitory and cytotoxic activities were investigated. The compounds were isolated and purified by various column chromatography, and their structures were identified by physiochemical properties and spectroscopic data. Thirteen lignans and six phenolic compounds were isolated from the CH2Cl2 extract of the fruits of V. negundo var. cannabifolia, respectively. Their structures were elucidated as 6-hydroxy-4-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaldehyde (1), vitedoin A (2), vitexdoin F (3), detetrahydroconidendrin (4), vitexdoin E (5), 4-oxosesamin (6), L-sesamin (7), (+)-beechenol (8), ligballinol (9), 2-(4-hydroxyphenyl)-6-(3-methoxy-4-hydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane (10), (-)-pinoresinol (11), balanophonin (12), thero-guaiacylglycerol-β-coniferyl aldehyde ether (13), trans-p-coumaryl aldehyde (14), coniferyl aldehyde (15), 5,7-dihydroxychromone (16), trans-3,5-dimethoxy-4-hydroxy-cinnamic aldehyde (17), frambinone (18), and alternariol 4-methyl ether (19). Compounds 8-10,14,18,19 were firstly isolated from Verbenaceae family, compound 13 was obtained from Vitex species, and 6,7,12,15-17 from V. negundo var. cannabifolia for the first time, respectively. The isolated compounds were evaluated for their anti-inflammatory and cytotoxic effects in vitro. Eight compounds (3,5,7,10,11,14,15,17) showed inhibition against NO production in LPS-stimulated RAW 267.4 cells (IC₅₀ in the range of 7.8-81.1 μmol•L⁻¹) and four compounds (1-4) showed cytotoxicity on HepG-2 cells (IC₅₀ in the range of 5.2-24.2 μmol•L⁻¹).