Browsing by Author "Usman L. A."

Now showing 1 - 6 of 6
  • Item
    Chemical Constituents of Leaf Essential Oil of Cochlospermum planchonii (Hook Ef. x Planch) Grown in Nigeria
    (Nigerian Society of Biochemistry and Molecular Biology, Nigeria, 2013) Usman L. A.; Muhammed N. O.; Ameen O. M.; Ismaeel R. O.; Azeez G. O.
    Leaf essential oil of Cochlospermum planchonii was obtained by hydrodistillation. GC and GC/MS analysis of the oil revealed that, the oil was rich in sesquiterpenes(51.7%). Nonterpenic and monoterpenic compounds constituted 35.5 and 11.9% of the oil. The principal constituents of the oil were; methylcyclopentane (26.3%), caryophyllene (11.4%), germacrene-D (8.8%), caryophyllene oxide (6.5%), copaene (5.6%), 2 – methylpentane (5.0%), δ-cadinene (4.9%), β-myrcene (4.3%) and α – cadinol (4.0%).In all, terpinic compounds that are biologically active against disease causing organisms constituted 63.6% of the oil. With the predominant of this class of metabolite, the oil could serve as therapeutic agents for pathogenic diseases.
  • Item
    Effect of collection time on phytochemical profile and insecticidal activity of essential oil from leaf of Ocimum gratissimum grown in Nigeria
    (2017) Usman L. A.; Olatayo B. S.; Babarinde S. A.; Ismaeel R. O.; Ogundele V. A.
    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.
  • Item
    Effect of collection time on phytochemical profile and insecticidal activity of essential oil from leaf of Ocimum gratissimum grown in Nigeria
    (Nigerian Society of Experimental Biology, 2017) Usman L. A.; Olatayo B. S.; Babarinde S. A.; Ismaeel R. O.; Ogundele V. A.
    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.
  • Item
    Effect of harvesting time on phytochemical profile and antioxidant activity of essential oil from Citrus medica leaves
    (College of Natural Sciences, Al-Hikmah University, Ilorin, 2017) Usman L. A.; Ologunja S. O.; Ismaeel R. O.; Akolade J. O.; Olanipekun B. E.
    Leaves (500 g) of Citrus medica L. harvested at interval of three hours from 7.00 am to 7.00 pm on a day during dry season were separately hydrodistilled for three hours. Oil yields from the leaves ranged from 0.22 - 0.34%. GC and GC-MS analyses revealed the predominant of monoterpenoids (50.5 - 70.3%) in theoils. The percentage composition of sesquiterpenoids was in the range of 29.7 - 29.5%. The principal constituents of the oils were; ocimene (4.1 - 5.6%), D-limonene (13.5 - 19.8%), terpinene (10.8 - 17.9%), linalool (3.8 - 4.0%), citronellal (2.7 - 7.5%), terpinen-4-ol (1.2 - 8.7%), citronelol (10.1 - 13.7%), linalyanthranilate (2.5 - 9.3%), elemene (3.0 - 6.4%), bergamotene (4.1 - 6.6%), humulene (1.2 - 2.8%), caryophyllene (7.9 - 16.5%), bisabolene (3.6 - 5.2%). The oils were of D-limonene and terpinene chemotypes. Antioxidant activity assay on the oils revealed that they were biochemically active against DPPH radicals. The activity was concentration dependent with the oil from 7am harvest having the highest activity and lowest EC50. Hence, the plant may be used as an alternative to synthetic antioxidants.
  • 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, Nigeria, 2015) Usman L. A.; Olanipekun B. E.; Ismaeel R. O.; Oguntoye O. S.; Ojumoola, A. O.
    Leaves (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; ȕ-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 ȕ-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 Profile and Antioxidant Activity of Leaf Essential Oil of Laggera aurita (L.) Native to North-central Nigeria.
    (Nigerian Society of Biochemistry and Molecular Biology, 2022) Ismaeel R. O.; Usman L. A.
    Oxidative stress is involved in the pathogenesis of various diseases in humans. The stress is curtailed using synthetic antioxidants whose usage is linked to several side effects. Essential oils have been reported to possess antioxidant activity devoid of any side effect. Their activity is a function of the type of phytochemicals in the oils. The aim of this study is therefore to characterize and evaluate antioxidant activity of essential oil from the leaves of Laggera aurita growing in north-central Nigeria. Leaves (500g) of L. aurita were pulverized and subjected to hydrodistillation. The antioxidant activity of the oil was evaluated using DPPH radical scavenging assay with ascorbic acid as standard. The hydrodistillation yielded 0.07±0.02% (w/w) of essential oil. GC and GC-MS analysis of the oil show the presence of twenty-three phytochemicals that have β-caryophyllene (27.8%) as the most abundant compound. Other principal constituents of the oil were; β-sesquiphellandrene (12.4%), β-bisabolol (3.4), α- bisabolol (4.4%), α-copaene (9.4%) and calamenene (8.3%). Terpinen-4-ol (2.4%) and α- terpineol (5.7%) were the two monoterpenoids that constituted the oil. The oil scavenged DPPH radical with IC50 of 57.13 μl/ml. The activity of the oil was lower than that of ascorbic acid (IC50= 12.84 μl/ml). However, with the activity exhibited by the oil, it has potential to ameliorate oxidative stress, hence, may serve as alternative to synthetic antioxidants after clinical trials.