Antimicrobial activity of stingless bee (Trigona sp.) propolis used in the folk medicine of Western Maharashtra, India

Ethnopharmacological relevance: Stingless bee (Trigona sp.) propolis is widely used in the folk medicine of Western Maharashtra, India to treat a variety of ailments. Aim of the study: To determine the chemical composition and evaluate the antimicrobial activity of Indian stingless bee propolis. Materials and methods: Chemical composition of the ethanolic extract of propolis (EEP) was determined by GC-MS analysis. A range of bacteria including multidrug resistant (MDR) cultures as well as a yeast strain was tested for antimicrobial activity using EEP. MIC, MBC, MFC, Kill curves and post agent effect (PAE) of the EEP were assessed using standard microbiological methods. Results: GC-MS analysis revealed that propolis contained 24 compounds (9 known and 15 newly reported). Many of these were known bioactive compounds, including antimicrobials. The MICs of EEP were in the range of 1.21-9.75 mu g/mL while the MBCs/MFC were between 2.43 and 19.5 mu g/mL. The time required to achieve 90% (1 log(10)) reduction in culture growth ranged between 1.06 and 3.53 h at their respective MIC values. PAE for all the cultures was >24 h. Conclusion: Indian stingless bee propolis has a complex nature with 24 chemical compounds. It has a potent broad-spectrum antimicrobial activity. The latter finding, in conjunction with other bioactive properties, could provide a scientific basis to its popular use in the Indian folk medicine. (c) 2012 Elsevier Ireland Ltd. All rights reserved.