ISOLATION AND CHARACTERIZATION OF BIOACTIVE COMPOUNDS FROM STEMBARK EXTRACT OF Uapaca pilosa Hutch
ABSTRACT
Uapaca pilosa isolation and characterization of bioactive compounds from stembark extract of uapaca pilosa hutch (Hutch.) a plant used in some parts of Africa in the treatment of dysentery, menstrual pain, fever, constipation, erectile dysfunction, skin infections, female sterility, pile, rheumatism, emetic, tooth-troubles and fatigue. The dried plant was extracted, the extract was subjected tophyto chemical investigation using standard method revealed the presence of alkaloids, flavonoids, anthraquinones, tannins, saponins, steroids, terpenoids and glycocides. Extensive silica gel column chromatography of the ethylacetate fraction of the stem bark extract, the most active of all the fractions, led to the isolation of two compounds GF1 and GF2. Their identities were determined by analysis of their spectral data using FTIR, 1D and 2D NMR. The structures of the compounds were supported by comparing their spectral data with the literature. GF1 was found to be betulin while GF2 was found to be beta-sitosterol. The antimicrobial screening of the crude extract and fractions using agar well diffusion method showed activity against Staphylococcus aureus, Shigella dysenteriae, Salmonella typhii, Bacillus subtilis and Escherichia coli. The Zone of Inhibition of theplant extract against selected microorganisms ranges from 13 mm to 17 mm against Staphylococcus aureus, 10 mm to 14 mm against Bacillus subtilis, 12mm to 15 mm against Shigella dysenteriae,15 mm to 18 mm against Escherichia coli and 10 mm to 11 mm againstSalmonella typhii. The MIC and MBC for the extract, fractions and isolated compounds were also determined. The range of Minimum Inhibitory concentration is between 6.25 mg/mL to 25 mg/mL for Staphylococcus aureus, 25 mg/mL for Shigella dysenteriae, 6.25 mg/mL for Bacillus subtilisand 12.50 mg/mL for Escherichia coli while the Minimum Bactericidal Concentration range between 12.50mg/mL for Staphylococcus aureus, 50 mg/mL for Shigella dysenteriae, 12.50 mg/mL for Bacillus subtilis and 25 mg/mL for Escherichia coli. This study on the stem bark extract from Uapaca pilosa, used traditionally in some parts of Africa as a medicinal plant for the treatment of various ailments has confirmed that it has antimicrobial activity against the microbes that cause some of these diseases.
