Abstract:
Ginger (Zingiber officinale) is a popular therapeutic agent in traditional medicine. In Sri Lanka, many cultivars of ginger are often used as a spice in cuisine and for Ayurvedic medicine. This study tested two widely grown cultivars of Z. officinale in Sri Lanka, Sri Lankan and Chinese, for their antimicrobial properties. Ethanol and aqueous extracts were obtained from their dried rhizomes. The antimicrobial activity of the extracts was tested using the agar-well diffusion method against three pathogenic bacterial strains: Staphylococcus aureus ATCC 25923, Salmonella typhi DSM 17058, and Escherichia coli ATCC 25922. The antimicrobial efficiency was assessed by measuring the clear zone diameter and controls (positive-chloramphenicol and negative-ethanol [95%]/distilled water). The Chinese cultivar showed the highest inhibition on S. typhi with both extracts (33.7 ± 1.53 mm-ethanol, 33.3 ±0.58 mm-aqueous). However, the effect of ethanol extract of Sri Lankan ginger against S. typhi (7.7 ± 1.15 mm) was comparatively less effective. The effect of ethanol extracts from both cultivars on S. aureus was moderate, showing inhibition zones of 16.3 ±0.58mm-Chinese cultivars and 12.0 ± 1.00 mm- Sri Lankan cultivars, respectively. The aqueous extracts of both cultivars were less effective against the target organisms, except for the Chinese cultivar against S. typhi. None of the extracts were effective against E. coli. In conclusion, both Z. officinale cultivars exhibited varying degrees of antimicrobial potential, with ethanol extracts showing stronger activity than the aqueous. The antimicrobial activity of the Chinese cultivar outperforms the Sri Lankan cultivar against target organisms, S. typhi and S. aureus.
