Studies on Leaf Extract on Bacterial Strains associated with Human Infections

Bachelor Thesis from the year 2022 in the subject Biology - Micro- and Molecular Biology, grade: 3.21, Obafemi Awolowo University, language: English, abstract: This paper is about studies on leaf extract of "Napoleona vogelii" on bacterial strains associated with human infections. "Napoleona vogelii" is most commonly used in herbal preparations to cure wounds, burns, fever, pneumonia, syphilis, and staphylococcal infections. This work was carried out to determine the antimicrobial effectiveness of the extract from "Napoleona vogelii" leaves on some bacterial strains. The leaves of "Napoleona vogelii" were collected and air dried until constant weight of the sample was achieved. The sample was grounded into fine powder and extracted using methanol and sterile distilled water solution in the ratio 3:2 (v/v) for 96 hours with regular agitation. The supernatant was filtered and concentrated in vacuo using a rotary evaporator to expel the methanol, and the aqueous part was then lyophilized to obtain the crude extract. The antimicrobial activity of the crude extract was tested against some selected bacterial strains using agar well diffusion method. Streptomycin was used as positive control. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined using standard methods. The mean diameter of the zones of inhibition exhibited by the plant extract against the bacterial strains ranged between 13 mm to 17 mm, while the diameter of zones of inhibition exhibited by streptomycin ranged from 14 mm to 25 mm. The MIC value was between 1.09 mg/ml and 17.5 mg/ml while the MBC value ranged between 2.19 mg/ml and 17.5 mg/ml. The phytochemical screening of the plant extract showed the presence of tannins, saponins, flavonoids, alkaloids, terpenoids, cardiac glycosides, and carbohydrate. In conclusion, the extract obtained from "Napoleona vogelii" leaves exhibited appreciable antibacterial activity against the test organisms