Abstract

Abstract Because of the need to source biologically active products from plants, this paper reports the chemical compounds, anti-nociceptive and anti-inflammatory activities of essential oils hydrodistilled from the leaves and stem bark of Turnera diffusa Wild (Passifloraceae). The essential oils were separately isolated using hydrodistillation of the pulverized (360 g of leaf and 316 g of stem bark) materials in an all-glass Clevenger- type apparatus and characterized by GC-FID and GC-MS. The hot plate method was used to determine the anti- nociceptive property while the anti-inflammatory activity was established using the Carrageenan induced paw edema model. The yields of the essential oils were 0.19% (v/w, yellow, leaf) and 0.28% (v/w, colorless, stem bark), calculated on a dry weight basis. The leaf oil consists mainly of β-caryophyllene (43.7%) and germacrene B (21.3%) while geranial (50.7%) and neral (33.6%) were the main constituents of the stem bark oil. In our study, we found that the essential oils of T. diffusa (100, 200, and 400 mg/kg) exhibited an anti-nociceptive effect at all observation periods at a significance of p<0.001 for both the leaves and stem bark. The essential oil from the stem bark showed high anti-inflammatory activity (p<0.001) at the 1st to the 4th h for all the essential oil doses while the leaves of T. diffusa inhibited inflammation up to the 3rd h post-treatment, but were non-significant at the 4th h for all doses. The results indicate the potential of the essential oils in pain-relieving activities.