In vitro antimicrobial synergism within plant extract combinations from three South African medicinal bulbs

• Published in: Journal of ethnopharmacology Vol. 139; no. 1; pp. 81 - 89
• Main Authors: Ncube, B., Finnie, J.F., Van Staden, J.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 06.01.2012
• Subjects: Allium; Anti-Bacterial Agents - pharmacology; Antifungal Agents - pharmacology; Antimicrobial; Antimicrobial activity; Antimicrobial agents; antimicrobial properties; Bulbs; Candida albicans; Candida albicans - drug effects; Chemotherapy; Drug Synergism; Extract combination; Gram-negative bacteria; Gram-Negative Bacteria - drug effects; Gram-Positive Bacteria - drug effects; Hypoxis; Hypoxis hemerocallidea; Infectious diseases; Interaction; leaf extracts; Leaves; Liliaceae; Medicinal plants; Medicine, African Traditional; Microbial Sensitivity Tests; Phytochemical; Plant extracts; Plant Extracts - pharmacology; Plant Leaves; Plant Roots; Plants, Medicinal; South Africa; Staphylococcus aureus; synergism; Synergy; traditional medicine; South Africa; Antimicrobial; FIC; MIC; Interaction; EtOH; MFC; ATCC; INT; DCM; CFU; YM; PE; Extract combination; Synergy; MH; Phytochemical
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2011.10.025

Independent and various extract combinations of Tulbaghia violacea, Hypoxis hemerocallidea and Merwilla plumbea indicates that extract combinations involving ethanol and DCM extracts has better anticandidal activity than any other combination and independent extracts respectively. Tulbaghia violacea, Hypoxis hemerocallidea and Merwilla plumbea are used in South African traditional medicine for the treatment of some infectious diseases and other ailments. The study aimed at investigating the antimicrobial efficacies of independent and various within-plant extract combinations of three medicinal bulbs to understand the possible pharmacological interactions. Bulb and leaf extracts of the three medicinal plants, independently and in combinations, were comparatively assessed for antimicrobial activity against two Gram-positive and two Gram-negative bacteria and Candida albicans using the microdilution method. The fractional inhibitory concentration indices (FIC) for two extract combinations were determined. At least one extract combination in each plant sample demonstrated good antimicrobial activity against all the test organisms. The efficacies of the various extract combinations in each plant sample varied, with the strongest synergistic effect exhibited by the proportional extract yield combination of PE and DCM extracts in Merwilla plumbea bulb sample against Staphylococcus aureus (FIC index of 0.1). Most extract combinations demonstrated either a synergistic, additive or indifferent interaction effect against the test bacteria with only a few exhibiting antagonistic effects. The observed antimicrobial efficacy and synergistic interactions indicate the beneficial aspects of combination chemotherapy of medicinal plant extracts in the treatment of infectious diseases.