Effects of Ultra-Violet, Red and Sun Light on the Stability of Phytochemicals, Antiradical and Antimicrobial Activity of Ocimum gratissimum Linn. (Lamiaceae).
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Date
2020-04-01
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Publisher
East and Central African Journal of Pharmaceutical Sciences.
Abstract
The content and stability of phenols, flavonoids, saponins and alkaloids in Ocimum
gratissimum upon exposure to sunlight, red and ultra-violet (UV) radiation over a
period of 168 h was investigated as well as the effect of irradiation on its antiradical
and antimicrobial activities. Total phenolic, flavonoids, saponins and alkaloid contents
were determined using standard methods while antiradical and antimicrobial analyses
were determined using 1,1-diphenyl-2-picrylhydrazyl and agar diffusion methods,
respectively. Exposure to sunlight significantly increased (p<0.05) the total phenolic
and alkaloid contents. Ultra-violet and sun light significantly decreased the total
flavonoid and saponin content, while all the three forms of radiation significantly
increased antiradical activity as well as antimicrobial activity against Staphylococcus
aureus. Red and UV light significantly increased the activity against S. aureus while
UV light increased activity against Escherichia coli. These findings suggest
photochemical instability with increased antiradical and antimicrobial activities of the
methanol extracts of O. gratissimum after irradiation.
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Keywords
Ocimum gratissimum, extract stability, sunlight, ultraviolet light, antimicrobial assay, antiradical activity