Antimicrobial activity and brine shrimp toxicity of propolis collected from various regions of Tanzania

Abstract

Background: Propolis has been traditionally used in many countries for management of various health conditions and many previous studies have shown that it has many biological activities, including antimicrobial activity and cytotoxicity. However, not much has been studied with regard to Tanzanian propolis; hence this study reports biological activity of propolis collected from 8 regions of Tanzania. Objectives: The purpose of this study was to evaluate the antimicrobial activity and potential cytotoxicity of propolis samples collected from various regions of Tanzania. Metet hods: Ethanolic extracts of 28 propolis samples collected from 8 regions in Tanzania were evaluated for antimicrobial activity against Gram +ve bacteria, Gram -ve bacteria and fungi, using the broth microdilution method, through which minimum inhibitory concentrations were determined. Brine shrimp lethality test was done using Artemia salina nauplii, as a preliminary indication of potential anticancer activity. Results: Out of 28 tested propolis samples, 21 exhibited antimicrobial activity on one or more microorganisms at the tested concentrations, with MICs of 1.25 – 5.0 mg/ml. Fourteen out of 28 samples were found to be toxic on brine shrimps, with a sample from Singida region being the most toxic. Conclusion: Propolis samples from various regions of Tanzania demonstrated antimicrobial activity on some microorganisms, indicating that they are a potential source of antimicrobial agents. Some samples also exhibited brine shrimp toxicity; implying that they may also be toxic on cancer cells and thus, may be a potential source of anticancer agents. They may also be a source of compounds with other biological activities.