Chemical composition, in vitro antioxidant assessment and toxicity test of the essential oils of Bridelia ferruginea Benth

Bridelia ferruginea Benth is a plant usually found in Savannah regions, used in ethno-medicine for treatment of dysentery, elephantiasis, intestinal and bladder disorder. Chemical compounds present in the leaf, twig, stem bark, stem wood and root wood of Bridelia ferruginea essential oils, their antioxidant and toxicity assays are been reported. The essential oils were obtained by hydro-distillation and analysed by means of gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antioxidant assay was conducted using 1,1-diphenyl-2-picrylhydrazyl (DPPH) while the brine shrimp lethality test was carried out using Artemia salina eggs. Leaf, twig, stem bark, stem wood and root wood essential oils gave yields of 0.44%, 0.42%, 0.51%, 0.20% and 0.26% respectively. A total of eighty-two (82) compounds were identified in the five essential oils. Ethyl salicylate was the dominant constituent of the leaf essential oil (41.15%) while methyl salicylate was most abundant in the twig (33.33%) and stem bark (24.67%) essential oils. Stem wood oil contained ethyl salicylate (12.60%) while the root wood oil was composed mostly of 1-octadecene (18.53%). The antioxidant assay showed that stem bark had the most activity (53.12 mu g/mL) while the least activity was recorded for twig oil (1037.14 mu g/mL). The brine shrimp lethality test revealed that lethal concentration at 50% level (LC50) for leaf essential oil was non-toxic (74361.99 mu g/mL). Bridelia ferruginea is rich in antioxidants; significant amounts of monoterpenoids and sesquiterpenes in the essential oils support the use of the plants in ethno-medicine.