STUDIES ON PHYTOCHEMICAL SCREENING, ANTIOXIDANT ACTIVITY AND EXTRACTION OF ACTIVE COMPOUND (SWERTIAMARIN) FROM LEAF EXTRACT OF ENICOSTEMMA LITTORALE.

Objective: The objective of the study was to evaluate the phytochemical constituents, total phenol, total terpenoid, antioxidant activity and HPLC analysis of swertiamarin compound from the leaf extract of Enicostemma littorale.Methods: Preliminary screening involved the qualitative methods to detect the presence of terpenoids, flavonoids, phenols, tannins, steroids, quinones, saponins, cardiac glycosides and alkaloids. Total phenol and terpenoid contents were quantitatively estimated.  Total phenolic content was estimated by folin-ciocalteau method. In vitro antioxidant activity of petroleum ether, chloroform, acetone, aqueous and ethanol extracts was evaluated by studying 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity using standard procedure. The leaf extract was screened for major metabolite namely swertiamarin compound using HPLC.Results: The phytochemical analysis of leaf extract of E. littorale revealed the presence of significant secondary metabolites such as steroids, quinones, cardiac glycosides, saponins, tannins, phenols, flavonoids, terpenoids and alkaloids. The total phenol and terpenoid content in leaf extract were found to be 16.32 mg GAE /g and 71.0 mg /g respectively. The acetone leaf extract of E. littorale had showed significant radical scavenging activity. The results of High Performance Liquid Chromatography analysis in the leaf extract of E. littorale proved the presence of the active principle namely swertiamarin.Conclusion: It can be concluded that E. littorale leaf extract can be used as a potent source of natural antioxidant and thus could prevent many free radical mediated diseases. The validated HPLC method can be used for a routine quality control analysis. Key words: Enicostemma littorale, antioxidant activity, phenols, terpenoids,                    phytochemical screening.Â

A transcontinental comparison of the diversity and composition of tropical forest understory herb assemblages

Although tropical forests are renowned for their high plant diversity, to date there has been no global quantitative evaluation of the local species richness of terrestrial forest herbs in tropical forests. In this paper, richness and composition of terrestrial herb assemblages is compared in tropical forests of America, Africa and South East Asia. We established 86 non-continuous transects of 445 m each. Herb species richness was analysed and compared to six environmental parameters using minimal adequate regression models and simultaneous autoregressive models. At the global scale, we found a close relationship between herb species richness and temperature parameters, with no differences between continents. The subdivision into three main taxonomic groups (ferns, monocots, dicots) showed that each group has distinct relations to environmental factors and differences in richness between continents. Most of the 72 families found have pantropical distributions but 12, 11, and 16 families were significantly over-represented in America, Africa, and Asia, respectively. Although total species richness was closely related to climatic factors, ferns, monocots and dicots were represented by distinct sets of families with varying species richness on each continent. Which species are found at a given site may thus reflect group-specific evolutionary and historical factors

Liana diversity and the future of tropical forests

Lianas contribute substantially to the total species richness of tropical forests, accounting for up to a quarter of the woody plant diversity. However, liana diversity is intrinsically linked with forest condition and consequently is altered by human-induced forest modifications. Multiple environmental drivers including forest fragmentation, logging and climate change are impacting tropical forests; the extent and degree of their effects will likely define future global liana diversity