In vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plants against gastro intestinal bacterial pathogens.

Abstract

The thesis entitled “in vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plant against gastro intestinal bacterial pathogenes” was carried out in the Microbiology division of Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, during 2018-2019 academic years.The objective of the study was Screening of medicinal plant extracts for anti infective property against gastro intestinal bacterial pathogens and identification of lead compounds, targeted efficacy testing of selected compounds against FtsZ proteins through in vitro and in silico approaches, demonstrating the effect of the compounds identified on virulence factors and bio-film formation of enteropathogens. Diarrhoeal diseases remain a leading cause of preventable death, especially among children under five in developing countries. Acute watery diarrhoea mainly affecting children of developing countries that results in dramatic dehydration and it is most dangerous in the very young. Enterotoxigenic Escherichia coli or Vibrio cholerae are most common causative agent of acute watery diarrhoea. Diarrhoea also cause huge economic burden on people of impoverished countries. There is need for novel anti-infective agents that can prevent disease and economic burden of diarrhoea. Developing countries are rich source of traditional knowledge and natural resources. These resources can be channelized to develop novel anti-diarrhoeal agents that can prevent emergence and dissemination of gastrointestinal pathogen including drug-resistant strains. Many diarrhoeal diseases are known to be treated with herbal remedies throughout the history of humankind. Even today, plant materials continue to play a major role in primary health care as therapeutic remedies in many developing countries. For centuries, many secondary metabolites present in leaves are found to have an outstanding role in medical world. Most of these compounds belong to alkaloids, flavonoids, terpenoids, steroids, saponins, quinones, coumarin and tannins. Leafs and roots are been extensively used in folk and modern medicine for treating various diseases. 105 We have explored anti-infective activity of the leaf and roots ethanol extract of five medicinal plants Moringa oleifera, Bixa orellana, Persicaria glabra, Pimenta dioica and Homonia riparia against enteropathogens like E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. Among these extractes hot ethanol extracts of persicaria glabra exhibited antibacterial activity against gastrointestinal pathogens such as E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. It also induced filamentation of Bacillus subtilis 168 which is an indication of cell division inhibition. The active compound present in persicaria glabra extract was identified to be querecetin, this compound can be used to develop novel anti-diarrhoeal agents.