Abstract:
Ocimum species have been used as an important medicinal herb, since ancient times but
no recorded scientific evidence on morphological variations and phytochemical
composition in Sri Lanka. Hence this study was conducted to determine the variation of
morphological characteristics, total polyphenol content, antioxidant activity, and essential
oil composition of three different Ocimum species namely; Ocimum
sanctum, Ocimum gratissimum and Ocimum americanum. Healthy and fresh leaves
of Ocimum plants were collected from Badulla and Welimada area. Morphological
differences in leaves, flowers, roots, stem, and seeds of three Ocimum species were
compared visually and recorded. Methanol extraction was performed using dried and
powdered leaf samples and analysed total polyphenol content and antioxidant activity for
three species using the Folin Ciocalteu reagent method and standard 2,2-diphenyl-1-
picrylhydrazyl radical scavenging activity respectively. Hydro distillation was done to
extract essential oils from Ocimum sanctum and Ocimum gratissimum and analysed by
using Gas Chromatography – Mass Spectrometry method. There were differences and
similarities between morphological characteristics among three species. The maximum
polyphenol content was recorded in Ocimum americanum and the minimum was recorded
in Ocimum sanctum. In determination of antioxidant activity, the highest half maximal
inhibitory concentration was recorded in Ocimum americanum and the lowest was
recorded in Ocimum gratissimum. There were differences in essential oil composition
between Ocimum sanctum and Ocimum gratissimum. It can be concluded that there is a
significant variation in morphological characteristics and phytochemical composition of
three different Ocimum species available in Sri Lanka.
Keywords: Antioxidant, Chromatography, Polyphenol, Scavenging, Spectrometry.
