Phytochemical Screening and Antibacterial Evaluation of Conventional Antibiotics, Garlic and Ginger on Isolates from Fish Pond Water Samples in Awka, Anambra State, Nigeria

Abstract

Medicinal plants are used by almost 80% of the world’s population for their basic health care because of their low cost and ease in availability. In the last few decades, many bacteria have continued to show increasing resistance against current antibiotics.
 Aim: In this study, phytochemical screening and antibacterial effects of conventional antibiotics, garlic and ginger on test isolates from fish pond water samples were evaluated between May-November, 2019.
 Methods: Standard methods for phytochemical screening and antibacterial analysis were employed.
 Results: The results showed that amongst the antibiotics used for susceptibility test, Amoxicilin (30 µg) was mostly resisted by all the bacterial isolates except Staphylococcus aureus, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella typhi while erythromycin (10 µg) was unable to inhibit Bacillus subtilis. Ciprofloxacin (10 µg) and pefloxacin (10 µg) inhibited the growth of all the isolates except Pseudomonas aeruginosa. The test isolates showed variable susceptibility to the garlic and ginger extracts (ethanol, methanol and hot water). The extracts inhibited the isolates in descending order; ginger ethanol > ginger methanol > garlic methanol > ginger hot water > garlic ethanol > garlic hot water. Vibrio parahaemolyticus, Vibrio cholerae and Staphylococcus aureus showed little resistant to the extracts while these extracts showed better activity on Klebsiella pneumoniae and Proteus mirabilis. Synergistic effect of garlic and ginger (500mg/ml) inhibited the growth of all the isolates with ethanol extracts having the highest zone diameter (29 mm) on Klebsiella pneumoniae and Proteus mirabilis while hot water extracts had the least zone of inhibition (18 mm) on Acinetobacter calcoaceticus and Vibrio parahaemolyticus. The minimum inhibitory and bactericidal concentration for ethanol, methanol and hot water extracts ranged from 31.25mg/ml to 62.5mg/ml and 62.5mg/ml to 125mg/ml respectively.
 Conclusion: The outcomes of susceptibility experiment depicted that ethanol and methanol extracts of garlic and ginger (each alone and in combination) showed more inhibitory effect than aqueous extracts and also the combination of ethanol, methanol and aqueous extracts resulted in inhibitory effect greater than each of the extracts when used singly. The use of ginger and garlic for control of fish pathogens appears to be justified.

Phytochemical profile and antioxidant activity of various solvent extracts of two varieties of ginger and garlic

“…Aqueous extracts of garlic had a statistically similar high alkaloid quantity; (12.67 and 13.02%) in local and hybrid garlic; the alkaloid concentration was lowest in acetone extracts of local and hybrid garlic (6.30 and 6.66%, respectively). Alkaloid concentration was in the range reported for other spices: pepper (13.44%), ginger (11.21%), and 2.54% in garlic [ 59 ]; 15.38 and 11.32% in ginger and garlic [ 60 ]; 0.15 and 0.012 mg AE/g for ginger and garlic [ 61 ]. Variations are attributed to the difference in the method of testing, as the previous study employed a spectrophotometric method.…”

“…Whereas, saponins were not detected in acetone and ethanol extracts of the hybrid garlic. In a previous study, absolute methanol, ethanol extracts, and hot water extracts of ginger contained saponins; organic solvent extracts of garlic contained saponins; while the hot water extracts did not contain saponins [ 60 ]. This is contrary to previous reports in which moderate quantities were reported for ginger while high quantities were reported for garlic extracts [ 62 ].…”

“…In garlic, acetone extracts of both varieties and ethanol extracts of hybrid garlic contained large quantities of terpenoids. In a previous study, terpenoids were detected in both organic solvent and aqueous extracts of ginger and garlic [ 60 ]. However, terpenoids concentration was higher in garlic than in ginger extracts [ 64 , 61 ].…”