Effect of collection time on phytochemical profile and insecticidal activity of essential oil from leaf of Ocimum gratissimum grown in Nigeria
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Date
2017
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Abstract
Leaves (500g) of Ocimum gratissimum harvested at interval of three hours (7:00 am-7:00 pm) in a day were separately hydrodistilled for three hours. Oil yields from the leaves ranged from 0.33 - 0.94%. GC and GC-MS analyses revealed abundance of hydrocarbon monoterpenoids in the oils (47.6-67.9%). Principal constituents of the oils were; γ-terpinene (17.6 – 26.9), m-cymene (18.1–26.0%), thymol (18.3–32.6%), α-thujene (3.6–5.0%), β-myrcene (3.7-4.7%), β-selinene (2.7-8.2%) and β-caryophyllene (1.7-3.6). Fumigant toxicity and repellence bioassays of the oils revealed that the oils exhibited insecticidal properties against Callosobruchus maculatus. The oil from 10:00 am harvest demonstrated stronger efficacy than other oils. The LT50 {1.78 h} of the oil against C. maculatus was significantly lower than the oils from other harvests. Percentage mortality (83.33%) observed in the oil was significantly greater than the oil from other harvests. Percentage repellency (90.00%) observed in the oil was significantly greater than the PR of the oils from other harvests. With the insecticidal properties, the oils can be used as alternative to synthetic insecticide against Callosobruchus
maculatus.
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Keywords
Ficus capensis, antibacterial, folk medicine, igala, flash chromatography
Citation
Usman, L.A., Ismaeel, R.O., Rasheedah, S.F., Arowona, M.T., Bello, O.K. & Olanipekun, B.E. (2017). Phytochemical profile and antioxidant potential of essential oil from fresh and dried leaves of Ocimum gratissimum grown in north-central Nigeria. Nigeria Journal of Pure & Applied Sciences. 30(2): 3037 – 3048