ABSTRACT
BACKGROUND: Recent evidence suggests that HIV infection, even with treatment, increases the risk of coronary heart disease (CHD) and that both chronic inflammation and traditional risk factors play key roles in HIV-associated CHD. SUBJECTS AND METHODS: Patients (N=152), attending Harare HIV clinic, 26% of them male and 82% of them on antiretroviral therapy (ART), were studied. Inflammatory markers comprising of cytokines such as pro-inflammatory tumor necrosis factor-α, (TNF-α), anti-inflammatory interleukin 10, (IL-10) and highly sensitive C reactive protein (hsCRP) together with lipids were assayed using enzyme linked immunosorbent assay (ELISA), immuno-turbidimetric and enzymatic assays, respectively. Correlation analysis of inflammatory markers versus lipid profiles was carried out using bivariate regression analysis. RESULTS: Anti-inflammatory cytokine IL-10 and inflammatory hsCRP levels were elevated when measured in all the HIV positive patients, while TNF-α and lipid levels were within normal ranges. Pro-inflammatory TNF-α was significantly higher in ART-naive patients than ART-experienced patients, whereas the reverse was observed for anti-inflammatory IL-10 and anti-atherogenic HDL-C. Correlation analysis indicated a significant positive linear association between IL-10 and total cholesterol (TC) levels but no other correlations were found. CONCLUSION: High cytokine ratio (TNF-α/IL-10) indicates higher CHD risk in ART-naive patients compared to the ART-exposed. The CHD risk could be further strengthened by interplay between inflammatory markers and high prevalence of low HDL-C. Lack of correlation between pro-inflammatory markers (hsCRP and TNF-α) with lipid fractions and correlation between anti-inflammatory IL-10 with artherogenic TC were unexpected findings, necessitating further studies in future.
ABSTRACT
BACKGROUND: Parinari curatellifolia and Combretum zeyheri are medicinal plants used in Zimbabwe and other Southern African countries for stomach ailments, fever, body aches, wound healing, cancer and tuberculosis. Glutathione transferases (GSTs) are mammalian enzymes that play a significant role in the detoxification and metabolism of many xenobiotic and endogenous compounds and as such can interact with many exogenous compounds including herbal medicines. The effects of Parinari curatellifolia and Combretum zeyheri leaf extracts on glutathione transferases of male Sprague-Dawley rats were investigated in vivo and in vitro after oral administration of either leaf ethanol or water extracts of each plant. METHODS: For Parinari curatellifolia, 18 male Sprague-Dawley rats were administered with 0, 500 and 1000 mg/kg body weight of the leaf extracts in corn oil or saline. Animals were sacrificed after 96 h and the kidney and liver samples were removed and used to prepare the cytosolic fractions. GST activity was determined using 1-chloro-2, 4-dinitrobezene. For Combretum zeyheri, twenty four male Sprague-Dawley rats were randomly divided into two groups. These two groups were further divided into three groups of four animals each. They were given either the aqueous or ethanol extract at doses of C. zeyheri at 0, 50 mg/kg body weight and 200 mg/kg body weight. The extracts were administered orally by oral gavage for four consecutive days and the rats were sacrificed by cervical dislocation on the fifth day. RESULTS: In animals administered with C. zeyheri, GST activity was significantly increased by the 200 mg/kg aqueous extract in the kidneys and livers in vivo whilst the ethanolic extract at 200 mg/kg decreased enzyme activity significantly both organs. Both the ethanol and aqueous extracts inhibited GST activity in vitro with the ethanol extract being more potent inhibitor than ethacrynic acid, a standard GST inhibitor. The increased GST activity in vivo and versus inhibition in vitro suggests that metabolites may be responsible for the effects observed in vivo. For P. curatellifolia, a dose-dependent decrease in GST activity was observed in vivo for the animals given the aqueous extract but no changes were observed with the ethanol extract. There was a concentration-dependent inhibition of cytosolic GSTs when P. curatellifolia leaf extracts in vitro. The ethanol extract of P. curatellifolia exhibited GST-inhibitory activity in the liver with an IC50 value of 12 µg/mL and for ethacrynic acid, the IC50 was found to be 10 µg/mL. This showed that this extract was a potent inhibitor of GSTs in vitro. CONCLUSIONS: C. zeyheri had an inductive effect on GST activity when administered in aqueous solution but inhibited GST in vitro whilst P. curatellifolia inhibited GST activity in vivo. Induction of GSTs would be cytoprotective against the toxic effects electrophilic chemicals. Since GSTs are responsible for the synthesis of prostaglandins, the inhibition of GST activity of by these two plants in vivo maybe one of the reasons that makes the plants important for use in the treatment pain and fever in ethnopharmacology.
