Phytochemical constituents and some biological activities of selected medicinal plants from Ghana

Loading...
Thumbnail Image
Date
2017-01-19
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
In this study, three Ghanaian medicinal plants namely, Anopyxis klaineana (Pierre) Engl. (Rhizophoraceae), Hexalobus monopetalus (A. Rich.) Engl. & Diels (Annonaceae) and Landolphia heudelotti A. DC. (Apocynaceae), were investigated for some of their biological activities and phytochemical constituents. The methanol and ethyl acetate fractions of A. klaineana stem bark at 300 mg/kg inhibited peak inflammatory responses and total paw oedema by 62.40 ± 6.32 % and 49.10 ± 10.31 % respectively in the carrageenan induced paw oedema assay. The total phenolic content and antioxidant capacity of the crude methanol extract were determined to be 110.21 ± 10.15 mg/g (tannic acid equivalent) and 110.6 ± 11.15 mg/g (ascorbic acid equivalent) respectively. The extract also scavenged DPPH free radicals with IC50 of 2.71 ± 0.21 μg/mL. The ethyl acetate fraction showed antimicrobial activity against Staphylococcus aureus and Streptococcus pyogens with MIC of 312 μg/mL. The ethyl acetate fraction of H. monopetalus exhibited antimicrobial activity against S. pyogens and Bacillus subtilis with MIC of 312 μg/mL. The crude methanol extract was found to have a total phenolic content of 66.19 ± 21.15 mg/g (tannic acid equivalent) and scavenged DPPH free radicals with IC50 of 10.1 ± 1.26 μg/mL. The total antioxidant capacity was determined to be 77.1 ± 14.15 mg/g (ascorbic acid equivalent). The methanol fraction of L. heudelotti roots exhibited antimicrobial activity against S. pyogens and B. subtilis at 312 μg/mL. The total phenolic content and antioxidant capacity of the methanol extract were determined to be 98.14 ± 14.70 mg/g (tannic acid equivalent) and 108.8 ± 14.52 mg/g (ascorbic acid equivalent) respectively. The crude extract scavenged DPPH radicals with IC50 of 6.95 ± 0.81 μg/mL. Phytochemical investigation of A. klaineana stem bark led to the isolation and characterization of six limonoids, five tirucallane triterpenes and one protolimonoid.
Description
A Thesis Submitted in fulfilment of the requirement for the degree of Dctor of Philosophy To the Department of Pharmacognosy Faculty of Pharmacy and Pharmaceutical Sciences College of Health Sciences Kwame Nkrumah University of Science and Technology, 2016.
Keywords
Citation