Drug Biotransformation Enzyme Interactions Studies with Curcumin, Curcumin analogues and other Plant-derived Components

Vermeulen, N.P.E. [Promotor]Commandeur, J.N.M. [Copromotor

Plasmodium falciparum: Assessment of Selectivity of Action of Chloroquine, Alchornea cordifolia, Ficus polita, and Other Drugs by a Tetrazolium-Based Colorimetric Assay

A tetrazolium-based colorimetric selective assay (MTT-based CSA) was developed to assess the selectivity of antimalarial drugs. This in vitro assay, unlike all others, measures the ability of drugs to indirectly protect red blood cells (RBCs) from Plasmodium-falciparum-induced destruction. Optimum incubation time and number of cells needed were 5 days and 23 × 106 RBCs per well, respectively. A parasitemia range of 0.375% to 3% was found to be suitable for this assay. The MTT-based CSA determined anti-P. falciparum strain DD2 activity of chloroquine at a higher 50% effective concentration (EC50) value (21.0 μg/mL) than the isotopic microtest (10.0 μg/mL). Artesunate and oxytetracycline achieved 90% effect against DD2 with minimal or no toxicity to RBCs. Against chloroquine sensitive strain 3D7, chloroquine and Alchornea cordifolia had EC50 values of 0.025 μg/mL and 4.9 μg/mL respectively, and selective index (SI) values of >2,000 and >69.4 μg/mL, respectively

PHENOTYPIC TRAITS AND CHEMICAL PROPERTIES OF JATROPHA CURCAS SEEDS FROM NORTHERN GHANA

This study was carried out to examine the physical features, proximate composition and oil quality of Jatropha curcas seeds from Nyankpala and Bole in the Northern Region of Ghana. The unit mass of J. curcas seed and kernel, length, width, breadth, geometric and arithmetic mean diameter, volume, bulk density, solid density and sphericity were considered. The physical properties of J. curcas seed and kernel between the two provinces were significantly different (p ≤ 0.05) with the exception of bulk density. The geometric features of seeds and kernel from Nyankapla were greater than those from Bole. Proximate composition of crude protein for Nyankpala and Bole was 21.67 ± 0.795 and 23.14 ± 0.781 respectively. Ether extract of J. curcas seeds from Bole (22.41± 2.98%) was significantly higher (p<0.05) than from Nyankapla (18.37± 2.14). Oil properties indicated stability and high saturation among the oil samples. The study reveals that variation in agro-climatic conditions of the two provinces influence the seed physical features. This finding will serve as useful data for the design and improvement of J. curcas seed and kernel processing machine and for the use of J. curcas seed meal as potential feed in animal husbandry

PHENOTYPIC TRAITS AND CHEMICAL PROPERTIES OF JATROPHA CURCAS SEEDS FROM NORTHERN GHANA

This study was carried out to examine the physical features, proximate composition and oil quality of Jatropha curcas seeds from Nyankpala and Bole in the Northern Region of Ghana. The unit mass of J. curcas seed and kernel, length, width, breadth, geometric and arithmetic mean diameter, volume, bulk density, solid density and sphericity were considered. The physical properties of J. curcas seed and kernel between the two provinces were significantly different (p ≤ 0.05) with the exception of bulk density. The geometric features of seeds and kernel from Nyankapla were greater than those from Bole. Proximate composition of crude protein for Nyankpala and Bole was 21.67 ± 0.795 and 23.14 ± 0.781 respectively. Ether extract of J. curcas seeds from Bole (22.41± 2.98%) was significantly higher (p<0.05) than from Nyankapla (18.37± 2.14). Oil properties indicated stability and high saturation among the oil samples. The study reveals that variation in agro-climatic conditions of the two provinces influence the seed physical features. This finding will serve as useful data for the design and improvement of J. curcas seed and kernel processing machine and for the use of J. curcas seed meal as potential feed in animal husbandry

CYTOTOXIC EFFECTS OF ALBIZIA ZYGIA (DC) J. F. MACBR, A GHANAIAN MEDICINAL PLANT, AGAINST HUMAN T-LYMPHOBLAST-LIKE LEUKEMIA, PROSTATE AND BREAST CANCER CELL LINES

Objective: The objectives of this study were to investigate the cytotoxic effects of extracts and fractions of Albizia zygia roots (AZR) on human T-lymphoblast-like leukemia (Jurkat), prostate cancer (LNCap) and breast cancer (MCF-7) cells and the apoptotic effect in Jurkat cells.Methods: Aqueous and hydroethanolic extracts were prepared and tested for cytotoxic effects on the cell lines using the tetrazolium-based colorimetric assay. Apoptosis induction was determined by DNA fragmentation, cell morphological changes, flow cytometric and mitochondrial membrane potential assays.Results: Both aqueous and hydroethanolic extracts were more cytotoxic to Jurkat cells than the other cell lines, with selective index (SI) values of 104.4 and 86.6, respectively. The SI values of the extracts on LNCap cells were 9.0 and 35.4, respectively. Some of the fractions were non-cytotoxic. Nevertheless petroleum ether fraction was cytotoxic towards MCF-7 cells with SI value of 2.4. The hydroethanolic extract exhibited apoptosis via induction of DNA fragmentation in Jurkat cells. Cell morphological changes were consistent with the extract-mediated cytotoxicity and DNA fragmentation. Flow cytometric and mitochondrial membrane potential assays also showed significant apoptotic induction confirming apoptosis by the AZR extract.Conclusion: This study has shown that AZR possesses anticancer activity by demonstrating a high selective toxicity against Jurkat cells. Furthermore, the hydroethanolic extract induced apoptosis in the Jurkat cells. Albizia zygia roots may be a source of novel compounds for the development of new anti-cancer agents.Keywords: Albizia zygia, Cancer cells, Cytotoxicity, Apoptosi

Antimycobacterial and cytotoxic activity of selected medicinal plant extracts

AbstractEthnopharmacological relevanceTuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants.Material and methodsThe microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96® AQueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis.ResultsResults of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3µg/mL against M. tuberculosis; Strain H37Ra (ATCC® 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient=0.8).ConclusionThe overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis

Effective Detection, Isolation and Characterization of Dakaramine from Ghanaian Axinella sp and Bioactivity

Abstract The Ghanaian sponge Axinella sp collected for the first time from the Gulf of Guinea yielded similar amounts of dakaramine (1), acetamide and a new hydroxylated acetate metabolite (2). The structures of these metabolites were elucidated by 1D and 2D NMR data interpretation. The halogens in dakaramine were detected by high performance liquid chromatography coupled with inductively coupled plasma and electrospray ionization mass spectrometry (HPLC-ICPMS/ESMS), a technique that allows for heteroatoms and metals in organic compounds to be detected specifically and with very high sensitivity. Cytotoxicity of dakaramine was assessed in vitro using two human cancer cell lines, human lymphocytic cell (Jurkat) and acute promyelocytic leukemia (HL60). This compound was found to be acutely toxic to these cell lines with IC50 values of 35.0 and 26.5 µg/ml respectively

Anti-proliferative effect of Ficus pumila Linn. on human leukemic cell lines

Background: Cancer is one of the many diseases of global concern due to its high mortality rate with drug resistance becoming a major challenge to chemotherapy and this have propelled many cancer patients to seek alternative and complementary methods of treatment. The objective for this study was, therefore, to determine the antiproliferative activity as well as phytochemical, total phenolic content (TPC), and antioxidant activity of the stem and leaf extracts (FPS and FPL) of Ficus pumila (L.) using standard methods.Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate anti-proliferative effect and spectrophotometric-based assays for antioxidant and TPC. Phytochemical constituents were accessed by standard methods.Results: The hydroethanolic extracts of the leaves and stems were rich in tannins, general glycosides, saponins, terpenoids, alkaloids, flavonoids (leaves only), and sterols (stem only). Strong total antioxidant activities were observed with FPL and FPS with EC50 values of 0.07 mg/ml and 0.089 mg/ml, respectively. All the crude extracts showed anti-proliferative effect towards the three human leukemic cell lines used (Jurkat, CEM, and HL-60). However, FPL gave the strongest inhibition concentration at 50% values of 130.97 µg/ml (Jurkat) and 56.31 µg/ml (HL-60).Conclusion: These findings suggest that crude extracts of FPS and FPL have anti-proliferative effect on the leukemia cells. The antioxidant properties of the plant including phenolics may be partly responsible for the anti-proliferative activity. Further studies are required to isolate chemical components of the plant and establish their anti-proliferative activities and mechanism of action

ANTIOXIDANT AND ANTI-PROLIFERATIVE EFFECTS OF AN ETHYL ACETATE FRACTION OF THE HYDRO-ETHANOLIC EXTRACT OF SYNEDRELLA NODIFLORA (L) GAERTN

Objective: Synedrella nodiflora is traditionally used in the treatment of several ailments. Pharmacologically, this plant has anticonvulsant, sedative, anti-nociceptive and anti-proliferative effects. This study further investigated S. nodiflora for its antioxidant and in vitro inhibition of cancerous cell lines. Methods: Phytochemical assays, and the DPPH radical scavenging method were employed in preliminary screening for antioxidant activities of the crude hydro-ethanolic extract (SNE) and resulting fractions. The potent ethyl acetate fraction (EAF), was further investigated for total phenol and flavonoid contents, reducing power, lipid peroxidation potential, and cytotoxic effects on human breast cancer (MCF-7), leukemic (Jurkat), and normal liver (Chang’s liver) cell lines. Results: The extract contained phenols, flavonoids, tannins, glycosides, sterols, terpenoids, and alkaloids. It scavenged for DPPH with an IC50 of 114 µg/ml, whereas that of EAF was 8.9 µg/ml. EAF prevented peroxidation of egg lecithin at an IC50 of 24.01±0.08 µg/ml. These IC50s are four and three times lower than the reference standards. EAF produced anti-proliferative effects against MCF-7, and Jurkat cell lines with IC50s of 205.2 and 170.9 µg/ml, respectively. EAF had a high IC50 of 252.2 µg/ml against Chang’s liver cells. At 0.1 mg/ml EAF had similar total flavonoid content to SNE, but a significantly higher total phenol content. Conclusion: The ethyl acetate fraction of S. nodiflora, exhibited the most potent antioxidant activity. It inhibited the proliferation of breast and leukemic cancer cell lines, whiles having weak cytotoxic effect on normal liver cells. These can be explored for further drug development

Assessment of Heavy Metal Contamination and Distribution in Surface Soils and Plants along the West Coast of Ghana

Onshore oil drilling activity is ongoing at Jubilee oil fields, Ghana. This activity could lead to heavy metal exposure with consequential adverse effects on public health in nearby coastal communities. Therefore, we assessed heavy metal levels and spatial distribution in soils and plants from the west coast of Ghana to obtain baseline values for monitoring heavy metal exposure. Surface soils were collected from six coastal communities, and analyzed for arsenic, cadmium, copper, mercury, lead, selenium and zinc using atomic absorption spectrophotometer. Mean heavy metal concentrations in soil samples were 2.06, 6.55, 0.016, 21.59, 0.18 and 39.49mg/kg for arsenic, copper, mercury, lead, selenium and zinc, respectively. Mean heavy metal concentrations in plants were 2.70, 17.47, 3.17, 91.74, 1.51 and 9.88mg/kg for arsenic, cadmium, copper, lead, selenium and zinc, respectively. Concentrations of arsenic, cadmium and lead in plants exceeded WHO/FAO permissible limits. Enrichment factor for arsenic was significant and extremely high for selenium, while geoaccumulation index showed moderate pollution for selenium. Soil contamination factors for arsenic, lead, and selenium indicated considerable contamination. In view of these findings remediation methods must be adopted to safeguard the communities. The data will be useful for future monitoring of heavy metal exposure in the communities and to assess the impact of the ongoing crude oil drilling activity on the environment