In vitro antimicrobial evaluation of two indigenous functional food-plants (Chenopodium album and Solanum nigrum) used in the Oliver Reginald (O.R.) Tambo district municipality of South Africa

摘要

Plants have long been the source of important products with nutritional and therapeutic properties. African indigenous functional food-plants such as Chenopodium album and Solanum nigrum may constitute important sources of phytochemical constituents for the synthesis of antimicrobial compounds against infectious organisms. The objective of this study was to determine the antimicrobial properties of C. album and S. nigrum leaves used as functional food-plants in the O.R. Tambo district municipality of South Africa. Organic and aqueous solvent-extracts of C. album and S. nigrum were tested against Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6051), Escherichia coli (25922) and Enterococcus faecalis (51299) using standard microbiological techniques. Ciprofloxacin was included in all the experimental runs as positive control antibiotic. The aqueous extracts of both plants were the most active with zones of inhibition diameters ranging from 0 - 20 mm and minimum inhibitory concentration (MIC50) values ranging from 0.63 - 10 mg/mL. The positive control antibiotic was highly active with zones of inhibition diameters ranging from 17 - 31 mm and MIC50 values from 0.0003 - 0.0005 mg/mL for all the bacteria tested. Both extracts were bactericidal with minimum bactericidal concentration (MBC) ranging from 2.5 - 20 mg/mL. From the results, it can be concluded that both plants possess compounds with antimicrobial properties, thus validating scientifically their use in traditional medicine. However, more studies to document the respective plant-principles responsible for antimicrobial activity of these plants would shed more light on their pharmacological properties.