Toxicology studies and antibacterial activities of the ethyl acetate extract of Piliostigma reticulatum

Abstract

The ethyl acetate extract of Piliostigma reticulatum was evaluated for its antibacterial activity against pathogenic clinical bacteria (Shigella dysenteriae, Escherichia coli, Streptococcus pyogenes and Staphylococcus aureus) using the agar well diffusion method. The comparative antibacterial effect was also investigated using standard antibiotics. Multiple antibiotic resistance index was determined using standard methods. The phytochemical components of the plant were also investigated. The in-vivo acute toxicity study was carried out on cell lines of Wister rat. The phytochemical screening was carried out. The antibacterial test showed the plant extract to be active against all the test organisms at 100mg/ml with zones of inhibition of 20 mm, 16 mm, 18 mm and 16 mm against S. dysenteriae, E. coli, S. pyogenes and S. aureus respectively. The antibiotic sensitivity test showed E. coli to have 61% susceptibility, while S. pyogenes had 23% and S. aureus had 7.6% susceptibility while S. dysenteriae had 100% resistance. MAR index revealed all the test bacteria to a have a high level of resistance to standard antibiotics. Phytochemical components include alkaloids, glycosides, steroids, phenol, tannin and saponin. Toxicology studies showed no mortality, no changes in the physical appearances, tremor or salivating. The rats appeared active after treatment as compared with the control with no apparent loss of weight. The biochemical analysis also revealed no significant difference in data obtained as compared to the control. Haematological parameters also showed no significant differences in values as compared to the control. There were obvious organ damages as observed in the histological gross assessment of the cross section of the organ (kidney, liver and intestine) which include gross distortion of the architecture, haemorrhaging, and congestion of vessels. However, tolerance on the part of the experimental animals prevented mortality and physical manifestation of organ damage. The result thus obtained in this work evidenced that P. reticulatum is toxicologically safe and biologically active against test organisms and hence be considered as a candidate in antibacterial drug formulation.