Ethno-Medico-Botanical Studies and Antibacterial Activity of Some Indigenous Ethno-Medicinal Plants Alleged to Cure Scabies in Irulars in Western Ghats, South India

The study area, Siruvani Hills, in Coimbatore district is a continuous range of the Western Ghats mountains included in the Nilgiri Biosphere Reserve. Irulars or Irulas are the predominant tribal sect inhabiting Siruvani Hills. In the present study solvent and aqueous extracts of five selected ethno-medicinal plants traditionally used by Irulas to cure scabies were screened for antibacterial activity. The selected plants are Clematis gouriana (Ranunculaceae), Clerodendrum viscosum (Verbenaceae), Dodonaea viscosa (Sapindaceae), Shorea roxburghii (Dipterocarpaceae) and Toddalia asiatica (Rutaceae). The plant extracts were prepared with solvents, hexane, chloroform, ethylacetate, acetone, methanol and distilled water. The solvent and aqueous extracts thus obtained were screened for antibacterial activity using bacteria, Escherichia coli, Klebsiella pneumonia, Salmonella typhimurium, Staphylococcus aureus and Pseudomonas aeruginosa.

Among the investigated plants, Clematis gouriana was found to exhibit the greatest inhibition effect against the tested organisms by registering a mean value of zone of inhibition 12.13mm followed by Shorea roxburghii (8.56mm) and Clerodendrum viscosum (6.21mm). However Clematis gouriana exhibited nil inhibition activity against E.coli except with hexane extract. Though Shorea roxburghii exhibited an inhibition zone of 8.56mm the mean value was found out to be low.

The least antimicrobial inhibition effect was recorded for Dodonaea viscosa(1.78mm) followed by Toddalia asiatica (0.18mm). Therefore, from the above said results Clematis gouriana, Clerodendrum viscosum and Shorea roxburghii appear to be the most promising ethno-medicinal plants for treating scabies. Phytochemical studies reveal that these plants possess bioactive compounds like glycosides, steroids, terpenoids and volatile oils which might confer antibacterial activity on these plants.