Evaluation of the Phytochemical content, Antioxidant and Antimicrobial Activity of Citrullus Lanatus (THUNB) seed method extract
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Date
2017-04
Authors
Ayoola, G.A.
Adeyemi, D.K.
Johnson, O.O.
Lawal, L.O.
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Publisher
Nigerian Journal of Scientific Research
Abstract
The objective of the present work is to evaluate the phytochemical content, in vitro antioxidant potential and antimicrobial activity of Citrullus lanatus seed methanol extract. The methanol seed extract was obtained by cold maceration method. Preliminary phytochemical screening was carried out using standard procedures. In-vitro anti-oxidant activity of the Citrullus lanatus seed extract was estimated by 2, 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and Ferric Reducing Antioxidant Power (FRAP) assay. Phytochemical screening showed the presence of reducing sugars, cardiac glycoside, steroidal ring, tannins, flavonoids and saponins while alkaloids and anthraquinones were absent. For DPPH assay, the percentage inhibition range from 0.31 – 9% for Citrullus lanatus seed extract 95.13 – 96.54% for ascorbic acid and 59.77 – 95.85 for alpha tocopherol. FRAP assay exhibited 110 μMFe 2+/g dry material for ascorbic acid and 23.5 μMFe 2+/g dry plant for Citrullus lanatus seed extract. The antimicrobial assay carried out by agar well diffusion method exhibited a potent activity against selected organisms, with the minimum inhibitory concentration for Gram positive bacteria range from 4.32-19.57 mg/ml, while for Gram negative bacteria range from 7.46-14.45 mg/ml and Candida albicans is 9.93 mg/ml. Klebsiella pneumonia was resistant to the seed extract. The results of this study shows that the methanol extract of Citrullus lanatus seed can be used as an easily accessible source of natural antimicrobial agents. However the results revealed that the extract does not possess potent antioxidant activity compared to ascorbic acid and alpha -tocopherol. This may be attributed to environmental factors such as temperature, UV light, solar radiation, soil nutrient and soil water availability which could have impact on the plant constituents.
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Keywords
Antimicrobial, antioxidant, Citrullus lanatus seed, phytochemical screening.