BIOACTIVE NATURAL PRODUCTS FROM THE RHIZOMES OF AMPELOCISSUS GRANTII, CISSUS CRINITA AND CISSUS SOKODENSIS (VITACEAE)
BIOACTIVE NATURAL PRODUCTS FROM THE RHIZOMES OF AMPELOCISSUS GRANTII, CISSUS CRINITA AND CISSUS SOKODENSIS (VITACEAE)
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Date
2015-11
Authors
ALI, TIJJANI
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Abstract
Ampelocissus grantii (Baker and Planch), Cissus crinita (Planch) and Cissus sokodensis (Gilg and Brandt) are plants that belong to the family Vitaceae and are used in traditional medicine in northern Nigeria for the management of cancers and infectious diseases. The phytochemistry of these plants has not yet been reported. Therefore, the plants have been deemed desirable for phytochemical investigation to identify the possible active compounds that may be contributing to these medicinal therapies claimed by the people using them. The plants‟ rhizomes, after collection, identification, air-drying and pulverisation, were subjected to cold extraction (maceration) using hexane, dichloromethane (DCM), ethyl acetate (EtOAc) and methanol (MeOH). Crude extracts obtained were phytochemically screened and chromatographed, mainly by column chromatography on silica gel. Standard antimicrobial method was employed to determine the minimum inhibitory concentration (MIC) of both the crude extracts and the isolates using clinical bacteria and fungi isolates: Staphylococcus aureus, Bacillus subtilis (Gram positive bacteria), Escherichia coli, Pseudomonas aeruginosa (Gram negative bacteria), Crytococcus neoformans,Candida albicans, Candida tropicalis, Aspergillus niger (fungi).The pure compounds were analysed for structure elucidations, using spectroscopic techniques, majorly 1D and 2D NMR experiments. Preliminary phytochemical screening of the crude plant extracts revealed the presence of steroids, terpenoids, flavonoids, tannins, saponins in both Cissus sokodensis and Cissus crinita. In addition to these compounds, anthraquinones were present in Ampelocissus grantii. Results of antimicrobial studies showed moderate to good activity against the organisms tested. Generally both the crude extracts and the pure compounds isolated recorded higher activities against the fungi. The MIC values of the crude extracts against the fungi ranged from 25 μg/ml to 200 μg/ml, 25 μg/ml to 100 μg/ml and 12.5 μg/ml to 100 μg/ml for Ampelocissus grantii, Cissus crinita and Cissus sokodensis respectively. The highest activity was recorded from Cissus
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sokodensis’s methanol extract against Candida albicans (MIC: 12.5 μg/ml).The respective MIC value against the bacteria for Ampelocissus grantii, Cissus crinita and Cissus sokodensis ranged from 25 μg/ml to 200 μg/ml, 100 μg/ml to 200 μg/ml and 100 μg/ml to 200 μg/ml. Highest MIC was observed from Ampelocissus grantii ethyl acetate extract against Escherichia coli (25 μg/ml). The pure compounds recorded higher activity against both the fungi and the bacteria compared to the crude extracts. The antifungal activity (MIC: 6.25-50 μg/ml) of the pure compounds was higher than the antibacterial activity (MIC: 12.5-50 μg/ml). Highest activity (MIC: 6.25 μg/ml) was recorded against Candida albicans and Aspergillus niger. Nine chemical compounds were isolated from the plants: β-sitosterol, betulin, 15-hydroxymethyl-16-methylheptadecylferulate and 3-hydroxymethyl-5-methyl-16-oxoheptadecylferulate from Ampelocissus grantii, β-sitosterol, oleanolic acid and 2,3,5-trihydroxymethylbenzoate-4-methylene-α-D-glucopyranose from Cissus sokodensis and two, β-sitosterol and 2,3,5-trihydroxymethylbenzoate-α-D-glucopyranose from Cissus crinita. Four out of these compounds: 15-hydroxymethyl-16-methylheptadecylferulate, 3-hydroxymethyl-5-methyl-16-oxoheptadecylferulate, 2, 3, 5-trihydroxymethylbenzoate-4-methylene-α-D-glucopyranose and 2, 3, 5-trihydroxymethylbenzoate-α-D-glucopyranose, are novel. Literature has shown that all the known compounds isolated have anticancer properties; further the newly isolated molecules have moieties in their structures with anticancer potentialities. Hence, the studied plants contain compounds that have anticancer property. The presence of the compounds isolated suggests that the plants contain chemical compounds that could possess both anticancer and antimicrobial properties. Therefore, these compounds may have been responsible for the anticancer and antimicrobial effects the plants have been said to possess in ethnomedicine and hence the folklore usage of the plants in the management of cancers and bacterial/fungi diseases are said to be validated.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY (PhD) IN ORGANIC CHEMISTRY
DEPARTMENT OF CHEMISTRY
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
BIOACTIVE NATURAL PRODUCTS,, RHIZOMES,, AMPELOCISSUS GRANTII,, CISSUS CRINITA,, CISSUS SOKODENSIS,, (VITACEAE),