Here we report the biochemical composition and antibacterial activities of the leaves and flowers of four Lantana camara (Verbanaceae) plants with yellow, lavender, red, and white flowers. Three out of the four plants showed almost similar carbohydrates and lipid compositions. The levels of carbohydrates (mg/g dry weight) in the flowers were comparatively higher than in the leaves and the lipids content was relatively higher in the leaves except L. camara lavender and white. In lavender L. camara the amount of the total carbohydrates was very low. Proteins extracted from the leaves and flowers were subjected to electrophoresis. Electrophoresis of leaf proteins revealed similarity among L. camara yellow, red, and white flowers while that of flowers proteins showed similarity between L. camara yellow, lavender, red, and white. Extracts of leaves and flowers obtained with ethyl acetate were studied for antibacterial activities. Leaf and flower ethyl acetate extracts exhibited considerable antibacterial activities against the bacteria used where the value of zone of inhibition ranged from 10-21 and 9-15 mm, respectively. For flower and leaf ethyl acetate extracts, the zone of inhibition (mm) measured ranged from 10-21 and 9-15 mm, respectively. Thus, the study of the biochemical parameters viz., lipids, carbohydrates and proteins has revealed similarity among the four different L camara. However, antibacterial activities vary from one L. camara to the other and also according to the type of tissue used.

Essential oils distilled from Cymbopogon species are of immense commercial value as flavors and fragrances in the perfumery, cosmetics, soaps, and detergents and in pharmaceutical industries. Two major constituents of the essential oil, geraniol and citral, due to their specific rose and lemon like aromas are widely used as flavors, fragrances and cosmetics. Citral is also used for the synthesis of vitamin A and ionones (for example, β-ionone, methyl ionone). Moreover, Cymbopogon essential oils and constituents possess many useful biological activities including cytotoxic, anti-inflammatory and antioxidant. Despite the immense commercial and biological significance of the Cymbopogon essential oils, little is known about their biosynthesis and regulatory mechanisms. So far it is known that essential oils are biosynthesized via the classical acetate-MVA route and existence of a newly discovered MEP pathway in Cymbopogon remains as a topic for investigation. The aim of the present review is to discuss the biosynthesis and regulation of essential oils in the genus Cymbopogon with given emphasis to two elite members, lemongrass (C. flexuosus Nees ex Steud) and palmarosa (C. martinii Roxb.). This article highlights the work done so far towards understanding of essential oil biosynthesis and regulation in the genus Cymbopogon. Also, based on our experiences with Cymbopogon species, we would like to propose C. flexuosus as a model system for the study of essential oil metabolism beyond the much studied plant family Lamiaceae.

Changes in the level of phenolics, flavonoids and proanthocyanidins with leaf positions were studied in L. camara twigs. Leaves at different positions (from apex to base) in a twig represented gradient increase in the leaf age, apical being the youngest leaves. The study showed that the fresh weight, dry weight and area of the leaves increased rapidly from I until IV position in a twig. Levels of phenolics remained unchanged from I to V leaf position, while a sharp increase in the levels of proanthocyanidins and flavonoids was observed during I to III leaf position which decreased markedly thereafter. At any leaf position in a twig, the level of proanthocynidin was higher than both phenolics and flavonoids, while the proportion of flavonoids was much higher than the phenolics. In fact, phenolics were present in very small amounts. In addition, antioxidant potential of leaves extracts was measured in terms of reducing and scavenging activity. The study revealed that extracts prepared from leaves present from I to III position exhibited significantly higher antioxidant activities than the leaves present from IV to V position. The study thus revealed that leaf positions (age) influence the level of secondary metabolites and thereby their antioxidant properties.

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