Chemical Qualities of Dried Rhizomes of Curcuma longa Linn. and the Antimicrobial Activities of its Extracts on Microorganisms Associated in Skin Infections

摘要

Rhizomes of Curcuma longa (Turmeric) purchased from local farmers in Ado Ekiti, Nigeria, were analysed for their nutritional, phytochemical and antimicrobial properties as well as the bioactive constituents of its essential oil. The dried rhizomes were found to be rich in energy, protein, carbohydrate and fat, with high concentrations of Ca2+, Fe2+, K-, PO42- and ascorbic acid but low levels of Zn2+, thiamine, niacin and riboflavin. Quantitative phytochemical analyses revealed high concentrations of alkaloids, tannins and saponins, moderate level of oxalate with low level of phytates and no detectable cyanogenic glycosides. Qualitative phytochemical analyses of the extracts of C. longa indicated that alkaloids, tannins and phenols were present in the acetone, methanol and ethanol extracts and saponin only in the ethanolic extract; while none of the tested phytochemicals were detected in the chloroform extract. Identification of the bio-active components of C. longa oil using GC-MS showed a total of 19 peaks. The identified compounds include beta-curcumene, Tumerone, Ar-tumerone, oleic acid and methoprene among others. The bacteria and fungi used in this study are organisms commonly found in association with skin infections. All the extracts showed high antimicrobial activities to the bacteria and fungi used. The methanol extracts however showed high superiority in antimicrobial activities, followed by the ethanol extract. In the time-kill kinetics of antimicrobial study of the extracts showed significant reduction in viable cell count within 48 hours. Results obtained in this study indicated that the extracts of C. longa rhizome possess pharmacologically active compounds that work synergistically against organisms associated with skin infections.