Research Article published by the European Journal of Medicinal Plants
Aims: To evaluate the antibacterial activity of Tetradenia riparia crude extracts against
Escherichia coli, Staphylococcus aureus and Enterococcuss faecalis. The phytochemicals
that are responsible for the bioactivity were also screened.
Study Design: In vitro assay of antibacterial properties.
Place and Duration of Study: Samples were collected from Njari village at Uru North in
Moshi district located in north eastern Tanzania. Extraction and phytochemical analyses
were conducted at the College of Pharmacy and Nutrition, University of Saskatchewan,
Saskatoon, Canada. Antimicrobial assay was carried out at Department of Microbiology,
Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
between March 2013 and August 2013.
Methodology: Agar well diffusion test was used to determine antimicrobial activity of the
plant extracts. Ethanol, methanol, hexane and distilled water were used as extracting solvents. These extracting solvents were removed by vacuo evaporator. The resulting
concentrated gummy-like materials were dissolved in Dimethysulfoxide (10% DMSO).
Chemical tests were used to determine the group of phytochemicals present in the
sample extracts.
Results: Sensitivity testing results indicated that S. aureus was found to be more
sensitive than E. coli and E. faecalis. Tetradenia riparia methanolic extracts from the root
were the most active with zone of inhibition values of 29.33±0.88mm, 21.33±0.33mm and
20.0±1.0mm in diameter against S. aureus, E. faecalis and E. coli respectively. The
relative inhibitory zone diameter (RIZD) was calculated. The highest percentage values of
relative inhibition zone diameter of 84±5.06% (S. aureus) and 76±6.86% (E. coli) were
demonstrated by T. riparia root methanolic extracts. However, T. riparia leaf and root
extracts using hexane as well as leaf extracts using water did not show any antibacterial
activity against E. faecalis. Root methanolic and ethanolic extracts demonstrated the
minimum inhibitory concentrations ranging from 1.25mg/ml to 5.00mg/ml. Phytochemical
screening of crude extracts from leaf and root of T. riparia revealed the presence of
alkaloids, flavonoids, phenolics, saponins, tannins and sterols.
Conclusion: The study findings suggest likelihood of designing and developing
potentially active antibacterial drug from T. riparia. Further studies should concentrate on
the investigations of not only leaf but also the root part of the plant.