Indian Journal of Experimental Biology Vol. 41, April 2003, pp. 363-366 Antidiarrhoeal effects of methanolic root extract of Hemidesmus indicus (Indian sarsaparilla) - An in vitro and in vivo study Sarita Das, R Prakash & S Niranjali Devaraj* Department of Biochemistry & Molecular Biology, University of Madras, Guindy Campus, Chennai 600025, India Received 7 October 2002; revised 5 February 2003 Methanolic extract of H. indicus root (MHI) was screened for its antimicrobial activity against S. typhimurium, E. coli and S. flexneri, in vitro and in experimentally induced diarrhoea in albino rats, in vivo. MHI had an anti enterobacteriae effect as evident from agar well diffusion method and decrease in CFUlml in MHI treated LB broth culture. MHI inhibited the castor oil induced diarrhoea in rats as judged by a decrease in the amount of wet faeces in MHI-pretreated rats at a dose of 500-1500 mg/kg. The results indicated that MHI was more active than standard antidiarrhoeal drug, lomotil. Phytochemical tests revealed the main constituents as tannins, steroids, triterpenoids and carbohydrates. Present findings suggested that MHI might elicit an antidiarrhoeal effect by inhibition of intestinal motility and by its bacteriocidal activity. Diarrhoea and dysentery are the most common causes of mortality and morbidity in the developing countries. Though the disease is self-limiting, it becomes life threatening in the high-risk groups like young children, elderly and immune suppressed people. The members of Enterobacteriaceae are the causati ve organisms for watery diarrhoea, which sometimes can lead to serious microangiopathy and Hemolytic Uremic Syndrome (HUS)I, ultimately causing death. The situation be- comes worse due to the emergence of multi drug resis- tant strains of Enterobacteriaceae, due to their high mu- tation frequency and horizontal gene transfer 2 . S. typhimurium is a Gram-negative bacterium, transmitted through oral-feacal route that causes a variety of diseases from gastroenteritis in humans to typhoid fever in mice. Upon ingestion, it adheres to epithelium through its fimbriae. Salmonella induces degeneration of enterocyte microvilli 3 , followed by profound membrane ruffling due to exploitation of host cytoskeleton at bacteria-host cell contact area 4 , accompanied by profuse macropinocytosis, which leads to internalization of bacteria into non-phagocytic host cells 5 . Entire process completes within minutes. Salmonella resides in membrane bound vesicles and cytoskeleton returns to its original distribution 6 . Sev- eral chromosomal genes (inv/spa) involved in Salmo- nella invasion are clustered in a pathogenecity island, Salmonella Pathogenecity Island 1 (SPI 1)7, which encodes a type III secretion system and several viru- lence factors . *Correspondent author: niranjali@yahoo.com Hemidesmus indicus R. Br. (Asclepiadaceae) commonly called as anantamul, is a well known me- dicinal plant, widely used in Ayurveda, Siddha and Unani systems of medicine, for a variety of diseases, like rheumatism, leprosl, impotency and skin infec- tions. It is also known for its anti-snake-venom activ- ity 9 and as an effective cooling tonic. Roots of the plant are extensively used by diverse folklore and aboriginals of Orissa state, India for diarrhoea and dysenterylO-12 . Yet, there is no scientifically proven literature for its possible antidiarrhoeal efficacy, either in human or in animal studies. The present work was carried out to prove its potent antidiarrhoeal efficacy. Preparation of methanolic root extract of H. in- dicus (MHI) - Roots were collected from Karapalli and Hinjlicut villages of Orissa, India, in the month of October and November 2001, identified and authenti- cated by Dr S K Dash, Department of Botany, College of Pharmaceutical Sciences, Berhampur, Orissa. The shade dried, coarsely powdered root (70 g) was sub- jected to exhaustive Soxhlet extraction in methanol (250 ml) for 72 hr at 60°C which gave a mean yield of 15.3 % (Ref. 13). Bacterial cultures - For the present work, clinical isolates of Salmonella typhimuriuin, Shigella flexneri and Escherichia coli from CMC, Vellore and standard strains (MTCC 98, MTCC 1457 and MTCC 390) from Institute of Microbial Technology, Chandigarh, were used. A single colony was inoculated into LB medium (0.85 ml) and incubated at 37°C for 12 hr and 0.15 ml of sterile glycerol was added, mixed thor- oughly and stored at -70°C.