Papers by R. Appiah-opong
Background: Cancer is still a major public health burden in many countries and despite the resear... more Background: Cancer is still a major public health burden in many countries and despite the research strides made in respect of therapeutic interventions, challenges still abound in cancer treatment. Ageratum conyzoides has increasingly been used in folklore for the treatment of a wide range of diseases including cancer. Aim: This study was aimed at investigating the antioxidant and anticancer potentials as well as the phytochemical constituents of 50% hydroethanolic crude extracts and fractions of leaf extracts of Ageratum conyzoides. Methodology: Antioxidant activities were evaluated by the DPPH, Folin-Ciocalteau and glutathione assays. The in vitro 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used for the determination of anticancer activities of the plant samples against four selected human cell lines: leukemic (Jurkat), prostate (LNCap), breast (MCF-7), and normal human prostate (PNT2) cell lines. The selectivity indices were also estimated. Mea...
Journal of Food Biochemistry, 2015
Ghana medical journal, 2011
Aqueous extracts of Tridax procumbens (TP) (Compositae) and Phyllanthus amarus (PA) (Euphorbiacea... more Aqueous extracts of Tridax procumbens (TP) (Compositae) and Phyllanthus amarus (PA) (Euphorbiaceae) are used in traditional medicine in Ghana to treat malaria. Previous studies have demonstrated the anti-trypanosoma, anti-bacterial and anti-HIV effects of TP and PA. To assess the antiplasmodial activity of extracts of TP and PA. Aqueous extracts of TP and PA were prepared. A portion of each was freeze-dried and the remaining extracted sequentially with ethyl acetate and chloroform. Ethanolic extracts were also prepared. The antiplasmodial activity of the extracts was assessed with the 3H-hypoxanthine assay using chloroquine-resistant (Dd2) Plasmodium falciparum parasites. Chloroquine was used as the reference drug. The modified tetrazolium-based colorimetric assay was also used to evaluate the red blood cell (RBC)-protective/antiplasmodial activities and cytotoxicities of the extracts. Results showed that TP and PA have antiplasmodial activities. The aqueous and ethanolic extracts o...
Xenobiotica; the fate of foreign compounds in biological systems, 2009
Glutathione S-transferases (GSTs) are important phase II drug-metabolizing enzymes that play a ma... more Glutathione S-transferases (GSTs) are important phase II drug-metabolizing enzymes that play a major role in protecting cells from the toxic insults of electrophilic compounds. Curcumin, a promising chemotherapeutic agent, inhibits human GSTA1-1, GSTM1-1, and GSTP1-1 isoenzymes. In the present study, the effect of three series of curcumin analogues, 2,6-dibenzylidenecyclohexanone (A series), 2,5-dibenzylidenecyclopentanone (B series), and 1,4-pentadiene-3-one (C series) substituted analogues (n = 34), on these three human GST isoenzymes, and on human and rat liver cytosolic GSTs, was investigated using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. Most of the 34 curcumin analogues showed less potent inhibitory activities towards GSTA1-1, GSTM1-1, and GSTP1-1 than the parent curcumin. Compounds B14 and C10 were the most potent inhibitors of GSTA1-1 and human liver cytosolic GSTs, with IC(50) values of 0.2-0.6 microM. The most potent inhibitors of GSTM1-1 were C1, C3 and C10, wit...
East African medical journal, 1998
A study to investigate the association between blood glutathione (GSH) levels and biliary excreto... more A study to investigate the association between blood glutathione (GSH) levels and biliary excretory status was conducted in apparently healthy Ghanaian subjects without frank biliary disease and anaemia. The results showed that, in adults (mean age: 38.5 years) and children (mean age: 13.0 years), plasma conjugated bilirubin is inversely correlated with blood GS (respective site r = -0.524, p < 0.011 and -0.395, p < 0.005). Persons with elevated plasma conjugated bilirubin compared to controls (mean: 6.0 versus 2.5 umol/L, p < 0.001) also exhibited low blood GSH values (3.5 versus 4.2 umol/gHb, p < 0.029). Malaria parasites with counts up to 2,453 parasites/ul blood had no effect on the obtained data. The results suggest that low blood GSH levels may be relevant to delays in biliary excretion of conjugated toxins from the liver, as exemplified by the rise in conjugated bilirubin levels in the plasma, and predispose liver cells to increased oxidant state and damage.
Toxicology Letters, 1999
Methylglyoxal, a metabolic by-product of glycolysis is also formed during food processing and has... more Methylglyoxal, a metabolic by-product of glycolysis is also formed during food processing and has serious toxicological effects when in excess. In this study, ddY mice were exposed to low levels of methylglyoxal (1% v/v) via drinking water while in utero continuing until 2 months of age when investigations on blood GSH status and selected GSH dependent functions in the blood, and glucose tolerance were carried out. The results showed that GSH content was significantly decreased in the blood of methylglyoxal exposed mice when compared with controls (mean, 0.756 mmol/l vs. 1.090 mmol/l, p &lt; 0.001). The data showed significant (p &lt; 0.001) decreases in blood GSH-S-transferase activity and red blood cell (rbc) capacity to refract oxidative stress. Impaired glucose tolerance was 5.3 times more prevalent in the methylglyoxal exposed mice when compared with the controls. The results indicate that chronic intake of methylglyoxal, at levels that could be attained in food, is toxic by depletion of blood GSH and could have adverse effect on some GSH dependent functions in vivo.
Chemico-Biological Interactions, 2003
In the present study, the inhibition of human glutathione S-transferase P1-1 (GSTP1-1) by the fla... more In the present study, the inhibition of human glutathione S-transferase P1-1 (GSTP1-1) by the flavonoid quercetin has been investigated. The results show a time-and concentration-dependent inhibition of GSTP1-1 by quercetin. GSTP1-1 activity is completely inhibited ...
British Journal of Pharmaceutical Research, 2015
Aim: Isoflavones in soybean have been linked to reduced risk of some cardiovascular diseases as w... more Aim: Isoflavones in soybean have been linked to reduced risk of some cardiovascular diseases as well as some type of cancers. Extensive epidemiological, in-vitro and animal data suggests lower incidence of cardiovascular disease, hormone-dependent cancers of the breast and prostate, for consumers of soy and soy products. In this study, isoflavones were isolated from Soybean (SB) and soymilk powder (SMP) and the anti-proliferative effects of these isoflavones on Burkitt's lymphoma (DG-75) and Leukemia (CEM) cell lines were investigated. Methodology: Isoflavanoids were isolated and HPLC done to confirm the isolate. Isoflavanoids were isolated form SB and SMP and the anti-proliferative effect of isoflavanoid isolated from SB, SMP, pure genistein and daidzein on lymphoma and leukaemia cells were compared using tetrazolium-based colorimetric (MTT) assay.
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Papers by R. Appiah-opong