Abstract
As part of an effort to search for extracts and compounds with new antimicrobial efficacy to fight against bacterial resistance, the antibacterial activity of Rauvolfia caffra var. caffra (Sond.), a plant of family Apocynaceae used in Traditional Medicine in Tanzania, was investigated. Ethanol, methanol and water extracts from leaf, stem and root barks were tested against three species of bacteria namely Escherichia coli (ATCC 25922) (Gram -ve), Staphylococcus aureus (ATCC 25923) (Gram +ve) and Enterococcus faecalis (ATCC 51299) (Gram +ve) using Agar-well diffusion assay method and minimum inhibitory concentration on Mueller-Hinton Agar plates. The extracting solvents were removed by vacuo evaporator to obtain gummy-like extracts. This was then dissolved in dimethylsulfoxide (10% DMSO). The DMSO without plant extracts was used as a negative control whereas Gentamicin® as the standard antibiotic was used as a positive control. The Zone of Inhibition (ZOI) measured in mm and Relative Inhibitory Zone Diameter (RIZD) was calculated. Results showed that R. caffra exhibited antimicrobial inhibitory activity at a range of 1.25 to 5.0 mg/ml with activity most prominent with methanol extract (ZOI of 28.33± 0.33 mm and RIZD of 95% for S. aureus; and ZOI of 26.66 ± 0.33 mm for E.coli and 19.0 ± 0.57 mm for E. faecalis at P< 0.05). To characterize further, the alkaloid from the root bark was extracted according to the standard procedure. The antioxidant activity of the alkaloids and ethanolic extracts was determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and reducing capacity assays. The results indicated that alkaloid fraction of the root and 80% ethanolic extracts of stem bark exhibited high antioxidant activity. The phytochemical analysis indicated that R. caffra is rich in alkaloids, anthraquinones, anthocyanoides, flavonoids, saponins, tannis and reducing sugars. This study provides supportive evidence that methanol and ethanol extracts of R. caffra can be used as herbal medicine in control of E.coli, S. aureus and E. faecalis.
Highlights
The increasing resistance of bacteria and fungi to currently marketed antimicrobial agents is becoming a world-wide medical problem (World Health Organization [WHO], 2004)
As part of an effort to search for extracts and compounds with new antimicrobial efficacy to fight against bacterial resistance, the antibacterial activity of Rauvolfia caffra var. caffra (Sond.), a plant of family Apocynaceae used in Traditional Medicine in Tanzania, was investigated
A general trend shows that methanolic root bark extracts (RBMe) was more effective against all the three tested pathogens with values of 28.33± 0.33 mm, 26.66 ± 0.33 mm and 19.0 ± 0.57 mm against S. aureus, E. coli and E. faecalis, respectively.This was followed by stem bark ethanolic extracts (SBEt)
Summary
The increasing resistance of bacteria and fungi to currently marketed antimicrobial agents is becoming a world-wide medical problem (World Health Organization [WHO], 2004). Antimicrobial resistance has increased both severity of infectious disease and mortality rates from certain infections. This has necessitated studies on potential source of additional effective, safe and cheap antimicrobial alternatives, and plants are one of these sources that have not been exhaustively utilized. Plants have ability to synthesize a wide variety of chemical compounds such as alkaloids, glycoside, saponins, resins, lactose and essential oils (Soraya, 2011). Many of these phytochemicals have beneficial effects on a long term human health and may be used to effectively treat human disease (Lai & Roy, 2004)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
