Browsing by Author "Oguntoye, S.O."
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Item Effects of Seasonal Variation on Chemical Constituents and Insecticidal Activity of Leaf Essential Oil of Citrus limonium(Nigerian Society of Biochemistry and Molecular Biology, 2015) Usman, L.A; Olanipekun, B.E; Ismaeel, R.O.; Oguntoye, S.O.; Ojumoola, A.OLeaves (500g) of Citrus limonium harvested in the morning (7.00 am) during dry and rainy seasons were separately hydrodistilled and yielded 0.46 and 0.30 % (w/w) of essential oils. GC and GC-MS analysis revealed that the oils obtained from dry and rainy season harvests were predominated by monoterpenoids (84.2% and 77.2%). The most abundant constituent of the oils from dry and rainy season harvests was; limonene (17.9% and 15.3%). Other principal constituents of the oils were; β-pinene (8.0% and 1.5%), terpinolene (7.0% and 7.1%), citronellal (12.9% and 8.3%), carveol (8.0% and 9.0%), neral (7.9% and 8.5%). citronellol (4.4% and 5.9%) and β-caryophyllene (3.3% and 5.2%). Contact toxicity bioassay was used to investigate the insecticidal activity of the oils against Callosobruchus maculatus. Irrespective of the season of harvest the oils were active against the insect. Interestingly, oils from the two harvests had comparable activity against the adult C. maculatus. Hence, seasonal variation has no significant effect on insecticidal activity of the oil on the postharvest insect pest.Item Phytochemical screening, Antimicrobial and Antioxidant activities of crude extracts of Scenecio abyssinicus flower(Faculty of Pharmaceutical Sciences, University of Ilorin, 2018) Egharevba, G.O.; Dosumu, O.O.; Oguntoye, S.O.; Njinga, N.S.; Abdulmumeen, H.A.; Adebayo, M.A.B.With the emergence of more resistant pathogenic micro-organisms against synthetic antibiotic, it is pertinent to search for plant extracts with broad spectrum antimicrobial compounds from folklore medicine. The n-hexane, ethyl acetate and methanolic extract of Senecio abyssinicus flower were investigated for their phytochemical composition, antimicrobial and antioxidant activities. Standard methods, disk diffusion method and 2, 2-diphenyl-2-picryl-hydrazyl free radical (DPPH.) were used to determine the phytochemical composition, the antimicrobial activity and the in-vitro antioxidant activity respectively. The flower was found to contain alkaloids, flavonoid, saponins, tannins, anthraquinones and steroids. The antibacteria linvestigation of the n-hexane, ethyl acetate and methanolic extracts of Senecio abyssinicus flower inhibited the growth of Staphyloccocus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa at concentrations between 50 and 200mg/ml. The ethyl acetate extract exhibited higher intrinsic antifungal properties on Candida albicans, Aspergillus niger, Rhizopus stolon, and Pneumonae notatum. Only the methanol extract acted as hydrogen/electrons donor or scavenger of radicals with IC50 of 46.24 μg/mL while that of Ascobic acid (standard) was found to be 12.24 μg/mL.Item Production and characterization of biodiesel using palm kernel oil, fresh and recovered from spent bleaching earth(Green Wave Publishing of Canada, 2014) Aladetuyi, A.; Olatunji, G.A.; Ogunniyi, D.S.; Odetoye, T.E.; Oguntoye, S.O.Palm kernel oil (PKO) was recovered from spent bleaching earth with a yield of 16 %, using n-hexane while the fresh oil was extracted from palm kernel with n-hexane and a yield of 40.23% was obtained. These oils were trans-esterified with methanol under the same reaction conditions: 100 oC, 2 h reaction time, and oil-methanol ratio of 5:1 (w/v). The cocoa pod ash (CPA) was compared with potassium hydroxide (KOH) as catalyst. The percentage yields of biodiesel obtained from PKO catalysed by CPA and KOH were 94 and 90%, respectively. While the yields achieved using the recovered oil catalysed by CPA and KOH were measured at 86 and 81.20 %. The physico-chemical properties of the biodiesel produced showed that the flash point, viscosity, density, ash content, percentage carbon content, specific gravity and the acid value fell within American Society for Testing and Materials (ASTM) specifications for biodiesel. The findings of this study suggest that agricultural residues such as CPA used in this study could be explored as alternatives for KOH catalyst for biodiesel production.