Comparative Study of Antibacterial Effects of Curcuma longa Linn. and Zingiber officinale Rosc. Rhizomes

Aims: To investigate and compare the antibacterial effect of Curcuma longa with Zingiber officinale rhizome ethanolic extracts against five bacterial species which include three gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis) and two gram-positive bacteria (Staphylococcus aureus andStreptococcus pyogenes).

Study Design: Activity directed antibacterial effect of C. longa and Z. officinale using in vitro methods.

Place and Duration of Study: Medicinal Plants Section, Bioresources Development Centre, Ogbomoso, Nigeria between March and September, 2016.

Methodology: The ethanolic extract was prepared by separately weighing 20, 40 and 60 g of powdered C. longa and Z. officinale into 100 mL of absolute ethanol. The antibiotic sensitivity test was carried out using a sensitivity disc impregnated with various antibiotics including Augmentin (AUG), Ampicillin (AMP), Ciprofloxacin (CIP), Ceptriaxome (CEP) and Ofloxacin (OFL).

Results: 40 and 60 g of C. longa and Z. officinale extracts significantly (P < 0.05) inhibited all the isolates (more effect was on S. pyogenes, S. aureus, E. coli, P. mirabilis followed by K. pneumoniae) when compared with 20 g. Also, 40 g of Z. officinale extract significantly (P< 0.05) inhibited the growth of S. pyogenes when compared with C. longa while 60 g of C. longa significantly (P < 0.05) inhibited the growth of P. mirabilis andK. pneumonia when compared with Z. officinale. The minimum inhibitory concentration of both extracts that inhibited E. coli and P. mirabilis was 1.3 g. CIP followed by CEP and OFL were active on all the bacteria used for this study. AUG was slightly active only on K. pneumonia while AMP was not active on any of the test organisms.

Conclusion: The result of this study showed that all the gram-positive bacteria used in this study were more sensitive to both C. longa and Z. officinale rhizomes ethanolic extracts as compared to the gram-negative bacteria.