ABSTRACT

Dennettia tr1oeta/a G. Baker (Annonaceae) or "pepper fruit" is a well known Nigerian spicy medicinal plant. Phytochemical screening of the fruit of D.trietaIa revealed the presence of the following classes of compounds: saponin(1.44%) tannin (0.06%), alkaloid (0.24%) and phenolic compounds (0.03%). The work suggests that these substances are responsible for biological properties of the plant. Ethanolic extract of D. tri7.'etala inhibited the growth of gram negative bacteria and yeast but could not inhibit gram positive bacteria and mould. The work showed that D.trieta/a contained crude protein (15.31%), total carbohydrate (62%), crude fiber (9.84%), crude lipid (3.47%) and moisture (8.0%). It had the calorific value of (480.24g/cal) and mineral content comprised: calcium (1.80%), phosphorus (0.33%) and potassium (2.48%). Trace elements included iron (17.75% mg/kg), copper (0.78 mg/kg),zinc (2.30 mg/kg),lead (4.55 mg/kg) and cadmium (0.29 mg/kg). Chromium was not detected. D. tri7etala is a good source of vitamins: ascorbic acid (58.48 mg/bOg), riboflavin (0.56 mg/bOg), thiamine (0.12 mg/bOg) and niacin (10.08 mg/bOg). The ethanolic extract from its TLC contained five main components. The major component was isolated in a pure state after extensive chromatography. This was shown through infrared and nmr spectra as well as mass spectrometric evidence to be the phenathrene alkaloid, uvariopsine. This is the first report of isolation of uvariopsine from the family Annonaceae. Garcinia kola Heckel ("Guttiferae) or "Bitter kola" is a popular Nigerian medicinal plant. Bioactive chemical substances estimated to be available in the seed include phenols (0.11%), alkaloids (0.36%), tannins (0.26%), saponins (11.48%) and flavonoids (1.98%). The work suggests these substances to be responsible for the biological activities of the plant. C. kola was analyzed for proximate composition, vitamins and mineral. The investigation revealed that the sample contained crude protein (3.94%), fats/Oils (3.50%), carbohydrate (81.16%), crude fiber (10.40%), ash (1.0%) and moisture (4.0%). It had a calorific value of (371.90 g/cal). It also contained hydrocyanic acid (0.027mg/kg). Mineral content comprised: calciuni(0. 17%), magnesium (O.07%), Phosphorous (0.11%) and potassium (0.35%). Trace elements detected include: iron (13.50 mg/kg), copper (0.40 mg/kg) zinc (1.75 mg/kg), cadmium (0.40 mg/kg), lea (4.55 mg/kg), manganese (0.37 mg/kg) and cobalt (0.55 mg/kg). Chromium was not detected. The work also shows that C. Kola is a good source of ascorbic acid (23.10 mg/bOg), riboflavin (0.22 mg/bOg), thiamine (0.45 mg/bOg) and niacin (1.60 mg/bOg). From the ethanol extract was isolated a pure crystalline solid identified as the flavone glycoside- 4',5,7- trihydroxyllavanone rhamnoglucose (that is naringenin-5-rhamnoglucoside) from its spectral data. Ethanolic extract of C. kola exhibited antimicrobial activity against yeast, gram positive and gram negative bacteria but not mould.