Effect of Plant Extract on Pathogens Isolated from Water Source

This study was designed to evaluate the effect of Aloe barbadensis Miller (Aloe vera) and Cymbopogon citratus (Lemongrass) extracts on pathogenic bacteria isolated from surface and ground water samples in Port Harcourt Metropolis. Samples of Aloe vera and Lemon grass were collected, pre-treated and extracted using n-hexane and ethanol respectively. The plant extracts were qualitatively and quantitatively assessed for their phytochemical properties using standard methods. Surface and ground water samples were collected and characterized for their physico-chemical and microbiological properties using standard methods. The pathogenic bacteria isolated from the water samples were subjected to antibacterial susceptibility tests using selected commercial antibiotics and the plant extracts respectively. Result revealed the presence of eight phytochemicals namely alkaloid, flavonoid, saponnin, tannin, glycoside, steroid, phenol and terpene in both hexane and ethanol extracts of the Lemongrass and Aloe vera with varying degrees. Four bacterial pathogens namely Streptococcus spp., Shigella spp., Pseudomonas spp. and Staphylococcus spp. were identified in the water samples. All of them were susceptible to both hexane and ethanol extracts of the Lemongrass and Aloe vera plants with zones of inhibition ranging from 10.2 mm to 14.5 mm and 16.7 mm to 20.9 mm and 4.2 mm to 9.5 mm and 6.7 mm to 11.2 mm, respectively. Commercial antibiotics such as Ciproflox, Streptomycin, Chloramphenicol and Cuntamycin were active against all the bacteria pathogens, with zones of inhibition ranging from 15.7 mm to 21.2 mm, 13.2 mm to 21.3 mm, 3.1 mm to 14.5 mm and 3.3 mm to 14.7 mm, respectively. The antibacterial action of ethanol extract of the Lemongrass on all four pathogens was comparable to that of commercial antibiotics such as Ciproflox, Streptomycin and Ofloxacin which also demonstrated higher antibacterial action on the pathogens. This study has revealed the usefulness of Aloe vera and Lemongrass plants in phyto-antibiotics and phyto-medicine.