Chemical Composition, Anti-Inflammatory and Analgesic Activities of Extracts and Fractions of Vitex negundo

Abstract

This study aims to determine chemical components and demonstrate the anti-inflammatory and analgesic activities of Vitex negundo species native to the Philippines. Using high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), eleven compounds were tentatively identified from the iridoids, flavonoids, and phenolics group. The anti-inflammatory activity was determined by measuring the inhibition of proinflammatory enzymes, lipoxygenase (LOX), and cyclooxygenase (COX-2). For LOX inhibitory effect, crude methanol extract has an IC50 value of 440.9 µg/mL. Solid-phase extraction (SPE) fractionation results in IC50 values of 196.6 µg/mL and 150.0 µg/mL for the 50% methanol-water and 100% methanol fractions, respectively. The IC50 value of crude hexane extract is 519.7 µg/mL. SPE produced lower IC50 values; 397.5 µg/mL for 2% IPA-hexane fraction and 142.9 µg/mL for 50% IPA-hexane fraction. The inhibition against COX-2 was effective in the 100% methanol fraction with an IC50 of 34.27 μg/mL and 2% IPA-hexane with an IC50 of 6.57 μg/mL. SPE fractions demonstrated more potent anti-inflammatory effects via in-vitro inhibition of LOX for the 100% methanol-water and 50% IPA-hexane or COX-2 for the 100% methanol and 2% IPA-hexane. The analgesic action was evaluated using acetic acid-induced writhing in mice. The percentage inhibition of writhing at all dose levels of methanol and hexane extracts ranged from 90-96% (p<0.05). The SPE fractions from methanol extracts showed inhibition of 73-97% (p<0.05). Both extracts and fractions showed strong analgesic effects in an in-vivo animal model.