Antibacterial and genotoxic activity of Bixa orellana, a folk medicine and food supplement against multidrug resistant clinical isolates

Worldwide rapid spread of multi drug resistance among the community as well as healthcare associated bacterial infections has impaired the current antimicrobial therapy, warranting the search for other alternatives. The current study aimed to find the antibacterial activity of hydro-ethanolic extract of Bixa orellana, the seed of which is frequently used as a food supplement. Multidrug resistant strains isolated from various outbreaks and sporadic cases of infectious diseases in various parts of the country like A&N Islands, Karnataka, Assam and Odisha were included in the study. The plant extract was tested for minimum inhibitory concentration (MIC) assay, synergistic activity, DNA damage, chemical constituent profiling using Gas Chromatography-Mass spectrometry (GC-MS). The zone of inhibition of the extract ranged from 13 to 25 mm and the MIC ranged from 512 to 2048 mu g/mL against these pathogens. All the strains were initially resistant to ampicillin, however in combination with the plant extract, the MIC was reduced to 2-10 folds. DNA damage assay exhibited the cell damage capability against all these pathogens. The genotoxic effect of the plant extract was also established for the first time in the current study in B. orellana. GC-MS analysis of hydro-ethanolic extract from leaves of B. orellana showed the presence of 40 compounds which had not been previously reported from this plant. The present study demonstrates the antibacterial activity of a hydro-ethanolic extract from the leaves of B. orellana against multi-drug resistant pathogens alone and in combination with an antibiotic.