Abstract:
The genus Ocimum comprises therapeutically important medicinal plants which are heavily
used in traditional systems of medicine. Although this genus has a great value for its
medicinal properties, available information on Sri Lankan grown Ocimum species is
scattered or lacking. Therefore, the present study was undertaken to investigate significant
pharmacognostic aspects of seven Ocimum morphotypes grown in Sri Lanka by means of
physicochemical parameters, phytochemical constituents and bioactivity. Phytochemical
and physicochemical studies were conducted as per WHO guidelines. Brine shrimp toxicity
assay was conducted as per Michel et al., 1956. Results revealed that the physicochemical
parameters were within the range accepted by the WHO guidelines. The phytochemical
screening test revealed the presence of secondary metabolites such as flavonoids,
alkaloids, saponins, tannins, steroidal glycosides in all Ocimum morphotypes tested. Thin
layer chromatographic profiles after spraying with three spray reagents, vanillin-sulfuric,
ferric chloride and anisaldehyde-sulfuric exhibited the presence of different chemical
compounds at different Rf values. Some Rf values were common to all morphotypes while
some exhibited distinguishing spots with different Rf values, 0.59 for vanillin-sulfuric, 0.57
and 0.71 for ferric chloride and anisaldehyde-sulfuric respectively. All morphotypes
exhibited a certain toxicity. The findings of the current study are of vital importance for
quality control and standardization of Ocimum species.
Keywords: Morphotype, pharmacognosy, Ocimum, phytochemicals, physico-chemicals,
thin layer chromatography
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