Evaluation Of The Laxative, Antioxidant And Antimicrobial Activities Of Vernonia Amygdalina:- Obi, Ijeoma C

ABSTRACT xi Vernonia amygdalina, a wildly growing plant has been reported to possess a number of medicinal properties. The purpose of the present study was to evaluate the laxative, antioxidant and anti-microbial activities of ethanol extracts ofleaf of Vernonia amygdalina. Fourteen Wistar albino rats of seven groups with 2 animals each were used for the laxative study. Group I which served as the negative control received 0.5mg/kg of normal saline. Group II which served as the positive control received lOmg/kg of Ducolax, the rest ofthe groups (Groups III — VII)received 2000, 1000, 500, 250, 125 mg/kg of the extract respectively. The values were expressed as mean±standard deviation. The laxative effects were 2000mg/kg extract (0.55±0.71), lOOOmg/kg extract (0.40±0.14*), 500mg/kg extract (0.50±0.14*), 250mg/kg extract (0.30±0.14*), 125mg/kg extract (0.35±0.07*). 0.5ml normal saline (0.60±0.14**), lOmg/kg ducolax (standard drug) 1.00±0.14*. The result showed that there was a significant (p<0.05) reduction in the faecal weight of the groups that received extracts of Vernonia amygdalina when compared with the untreated group (Group 1), greater activity was observed at 250mg/kg concentration as compared with the standard drug (Ducolax lOmg/kg). Agar well diffusion method was used to carry out the antimicrobial activity of ethanol leaf extract of Vernonia amygdalina. The extract at different concentrations (1000, 500, 250, 125, 62.5 and 31.25mg/ml) significantly (P<0.05) inhibited the growth of selected pathogenic organisms. The extract had greater antimicrobial activity at lOOOmg/ml on S. aureus (42.5±0.71). It moderately inhibited K. pneumonia (33.00±0.71), P. aeruginosa (32.50±0.71), S'. pneumonia (30.50±0.71) and S. typhi (30.50±0.71). The least inhibition was observed for E. coli (22.50±0.71) compared to the standard antibiotic Ciprofloxacin 500mg/ml (50.5±0.71). DPPH percentage scavenging activity ofthe extract was in the range (0.00±0.00 - 85.00±0.00) and standard (97.67±0.58), antilipid peroxidation percentage inhibition activity of the extract was in the range (2.33±2.08 - 86.33±6.51) and standard (99.00±0.00). nitric oxide percentage scavenging activity of the extract was in the range (20.00±7.21 -7.00±1.73) and standard (98.00±0.00). The minimum inhibitory concentration (MIC) for S. typhi was 250mg/ml, E. coli 125mg/ml, P. aeruginosa 125mg/ml, S. aureus 125mg/ml, K. pneumonia 500mg/ml and S', pneumonia 250mg/ml. the extract of Vernonia amygdalina showed a significant (P<0.05) DPPH scavenging activity, antilipid peroxidation activity and nitric oxide scavenging activities at 200mg/kg, lOOmg/kg, 50mg/kg, 25mg/kg and 12mg/kg compared to that ofthe control (vitamin C). The result obtained shows that the leave of Vernonia amygdalina can be used as a laxative, treatment of pathogenic infections and as an antioxidant agent in the prevention of pathological conditions caused by oxidative stress produced by free radicals in the body