Objective: A number of Indian medicinal plants have been used for thousands of years in a traditional system of medicine. Hemidesmus indicus is an important member of the Asclepiadaceae family. It is an endemic to the southern Western Ghats, India. The aim of the study was to investigate the free radical scavenging activity of H. indicus. Methods: The aqueous and methanol leaf extracts of H. indicus were assayed for radical scavenging activity, using the stable free radical 2,2-diphenyl- 1-picryl-hydrazyl-hydrate and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid). Results: The results revealed that the IC50 values of aqueous extract of H. indicus were found to be higher than that of the other solvent extracts. The free radical scavenging activity of the plant extracts may be due to the presence of phytoconstituents. Conclusion: In all the methods, the aqueous extract has exhibited the good scavenging activity and this arises that the plant has a potential antioxidant agent.

To evaluate the rhizosphere soils and ten medicinal herbs polluted soils were tested for the association of arbuscular mycorrhizal fungi and determined the impact of the physico chemical factors in relation to the quantitative and qualitative assessment of AM fungi in polluted soils. Forty species of AMF belonging to five genera such as Glomus, Acaulospora, Gigaspora, Sclerocystis and Scutellospora were recorded and identified. Glomus fistulosum was noticed as the moist dominant in the polluted. In the non-polluted soils,all the plant species were colonized with AM fungi. Where as in polluted soils, eight herb species only were colonized and the percentage of root colonization was less.

The present study on the influence of disturbance in the dominated grassland near Bharathiar University, Coimbatore was studied over a period of one year from September, 2014 to August, 2015. The study was made during three seasons such as winter, summer and rainy so as to find out the seasonal changes as influenced by disturbance. The studied grassland is a semi-arid community containing most number of mesophytes with few xerophytes. To study the impact of disturbance, two sites such as undisturbed and disturbed ones spread over an area of 10 and 12 ha respectively were selected in the grassland. The floristic analysis showed that the undisturbed community was registered with 71 species and the disturbed community with 51 species. The family, Poaceae was represented by the high number of 14 and 13 species respectively in undisturbed and disturbed communities. Of the 71 species encounted, a sizablenumber of 66 species (92 %) harbour medicinal uses. It indicates that the study site was a potential habitat of medicinal plants with wide diversity. The quantitative ecological characters have been varied widely between the two sites due to the influence of disturbance. The resource apportionment for various species present in both study sites indicates that the grass, Brachiaria ramosa shared higher amount of resources than any other species present in the communities. The study suggested that the studied Brachiaria ramosa dominated grassland near Bharathiar University must be given conservation priority to protect the valuable medicinal species.

In the present research work was to examine the possible antioxidant activities of the aqueous and ethanol leaf extract of Rhinacanthus nasutus (Linn.) Kurz. DPPH, Hydroxyl radical scavenging and reducing power assays were employed. The results showed that the DPPH activity of aqueous and ethanol leaf extract at the dose of 50μg/ml has exhibited in 63.81±0.013 and 79.36±0.028 inhibition with an IC50 value of 21.39 and 29.41μg/ml. The highest Hydroxyl radical scavenging activity showed aqueous and ethanol leaf extract at the dose of 50μg/ml has exhibited in 96.18±0.029 and 121.23±0.081 inhibition with an IC50 values of 30.19and 41.39μg/ml, the reducing power assay aqueous and ethanol leaf extract showed the 0.59 and 0.71 absorption at 700 nm extract at the dose of 50μg/ml suggested that promising antioxidant activity of crude aqueous and ethanol extract could be used as a source of natural antioxidants of R. nasutus and needs further studies to bring new natural products into pharmaceutical industries.

The methanolic rhizome extract of A. calcarata was evaluated for its antibacterial activities against five bacterial strains Pseudomonas aeuroginosa, Proteus vulgaris, Salmonella paratyphi, Bacillus thurungiensis and Staphylococcus faccealis. The extract has inhibited all the tested bacterial species with different manner at various concentration. However the higher level zone of inhibition in 400 (mg/ml) is significant against all the above said bacterial strains of these Salmonella paratyphi. Based on the present study it can be conculuded that the plant rhizome possess potent anti bacterial activity.