Anti-nociceptive Property, Anti-inflammatory Activity and Constituents of Essential Oils from the Leaves and Stem Bark of Turnera diffusa Wild (Passifloraceae) Growing in Nigeria

Because of the need to source biologically active products from plants, this paper reportsthe chemical compounds, anti-nociceptive and anti-inflammatory activities of essential oils hydrodistilled fromthe leaves and stem bark of Turnera diffusa Wild (Passifloraceae). The essential oils were separately isolatedusing 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 pawedema model. The yields of the essential oils were 0.19 % (v/w, yellow, leaf) and 0.28 % (v/w, colorless, stembark), calculated on a dry weight basis. The leaf oil consists mainly of β-caryophyllene (43.7 %) and germacreneB (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 allobservation periods at a significance of p<0.001 for both the leaves and stem bark. The essential oil from thestem bark showed high anti-inflammatory activity (p<0.001) at the 1st to the 4th h for all the essential oil doseswhile the leaves of T. diffusa inhibited inflammation up to the 3rd h post-treatment, but were non-significant atthe 4th h for all doses. The results indicate the potential of the essential oils in pain-relieving activities