Hydro-ethanolic extract of Khaya grandifoliola attenuates heavy metals-induced hepato-renal injury in rats by reducing oxidative stress and metals-bioaccumulation.

People living in developing countries are exposed to hepato-renal injuries induced by heavy metals like lead (Pb), cadmium (Cd), and mercury (Hg) since drinking water supplied is often polluted with a high concentration of those metals. Accordingly, it is necessary to search for antidotes against heavy metals poisoning. Hence, medicinal plants bearing anti-hepatotoxic properties represent a credible option; and such plant is Khaya grandifoliola. However, there is a paucity of knowledge regarding its protective effect on heavy metals-induced hepato-renal toxicity. Thus, this study was designed to assess the protective effect of the hydro-ethanolic stem bark extract of K. grandifoliola (HKG) against hepato-renal injuries induced by chronic consumption of drinking water containing high contents of Pb, Cd, and Hg; in addition to the investigation of the chemical antioxidant properties of HKG. For the antioxidant assays, HKG was tested as a potential inhibitor of lipid peroxidation, reducer of ferric and phosphomolybdenum, and scavenger of hydroxyl and 2,2-Diphenyl-Picryl-Hydrazyl radicals. Its protective effects were evaluated by daily co-treating rats with heavy metals solution (10 mL/kg b.w) containing 0.9, 0.58, and 1.13 ppm respectively for Pb, Cd and Hg and HKG (25 or 100 mg/kg b.w) for five consecutive months; and biochemical parameters associated to liver and kidneys functions, oxidative stress and metals bioaccumulation were assessed. HKG displayed a strong antioxidant capacity (IC50/EC50 range 3.95-17.17 µg/mL) correlated to its polyphenols content and comparable to that of Ascorbic acid. Serum levels of alkaline phosphatase, alanine/aspartate aminotransferase, and creatinine; renal and hepatic content of Cd and Pb, malondialdehyde and glutathione, activities of superoxide dismutase and catalase showed the protective effect of HKG, further evidenced by histopathological analysis. Taking together, these results demonstrated that HKG alleviates heavy metals-induced hepato-renal injuries in rats by reducing oxidative stress and metals-bioaccumulation.

Inhibition of CYP2E1 and activation of Nrf2 signaling pathways by a fraction from Entada africana alleviate carbon tetrachloride-induced hepatotoxicity.

Entada africana is used in non-conventional medicine for the management of liver ailments. A fraction, designated EaF10 (methylene chloride/methanol 90:10, v/v) with promising hepatoprotective activity has been isolated. Since the mechanisms underlying EaF10 hepatoprotective action remain unknown, this study was undertaken to investigate the anti-hepatotoxic mechanism of the fraction against carbon tetrachloride (CCl4)-induced hepatotoxicity and its antioxidant properties. Antioxidant activities of EaF10 were assessed through four chemical antioxidant assays and its anti-hepatotoxic effect evaluated in vivo and in vitro by post-treatment (25 or 100 mg/Kg) or co-treatment (6.25-100 µg/mL) in CCl4-intoxicated mice and normal human liver cells line L-02 hepatocytes respectively; and biochemical and molecular parameters assessed respectively by spectrophotometry, and by quantitative real-time polymerase chain reaction and western blot analysis. EaF10 exhibited strong antioxidant activities correlated with its polyphenol content. Serum levels of alanine/aspartate aminotransferase (AST/ALT) and nitrite oxide, liver contents of glutathione (GSH) protein carbonylation and malondialdehyde (MDA), liver activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) and cell viability showed the anti-hepatotoxic effect of EaF10, supported by histopathological observations. The fraction decreased the protein level of Cytochrome P450 2E1 (CYP2E1) and Kelch-like ECH-associated protein-1 (Keap-1), induced nuclear translocation of Nuclear factor-erythroid 2-related factor-2 (Nrf2) coupled to an increase of the mRNA levels of CAT, SOD1 and GST in CCl4-intoxicated L-02 hepatocytes. These findings evidenced that the studied plant fraction possesses a strong antioxidant capacity and prevents CCl4-induced hepatotoxicity, likely through inhibition of CYP2E1 and activation of the Nrf2 signaling pathway.

Khaya grandifoliola C.DC: a potential source of active ingredients against hepatitis C virus in vitro.

In this study, we examined the antiviral properties of Khaya grandifoliola C.DC (Meliaceae) on the hepatitis C virus (HCV) life cycle in vitro and identified some of the chemical constituents contained in the fraction with the most antiviral activity. Dried bark powder was extracted by maceration in a methylene chloride/methanol (MCM) system (50:50; v/v) and separated on silica gel by flash chromatography. Infection and replication rates in Huh-7 cells were investigated by luciferase reporter assay and indirect immunofluorescence assay using subgenomic replicons, HCV pseudotyped particles, and cell-culture-derived HCV (HCVcc), respectively. Cell viability was assessed by MTT assay, and cellular gene expression was analysed by qRT-PCR. The chemical composition of the fraction with the most antiviral activity was analysed by coupled gas chromatography and mass spectrometry (GC-MS). Five fractions of different polarities (F0-F100) were obtained from the MCM extract. One fraction (KgF25) showed the strongest antiviral effect on LucUbiNeoET replicons at nontoxic concentrations. Tested at 100 µg/mL, KgF25 had a high inhibitory effect on HCV replication, comparable to that of 0.01 µM daclatasvir or 1 µM telaprevir. This fraction also inhibited HCVcc infection by mostly targeting the entry step. KgF25 inhibited HCV entry in a pan-genotypic manner by directly inactivating free viral particles. Its antiviral effects were mediated by the transcriptional upregulation of the haem oxygenase-1 gene and interferon antiviral response. Three constituents, namely, benzene, 1,1'-(oxydiethylidene)bis (1), carbamic acid, (4-methylphenyl)-, 1-phenyl (2), and 6-phenyl, 4-(1'-oxyethylphenyl) hexene (3), were identified from the active fraction KgF25 by GC-MS. Khaya grandifoliola contains ingredients capable of acting on different steps of the HCV life cycle.

Antioxidant fractions of Khaya grandifoliola C.DC. and Entada africana Guill. et Perr. induce nuclear translocation of Nrf2 in HC-04 cells.

The in vitro antioxidant properties, cytoprotective activity, and ability to induce nuclear translocation of nuclear factor E2-related factor-2 (Nrf-2) of five solvent fractions of the methylene chloride/methanol (1:1 v/v) extract of Khaya grandifoliola (Meliaceae) and Entada africana (Fabaceae) were evaluated. Five antioxidant endpoints were used in the antioxidant activity investigation. The total phenolic content of the fractions was assessed as to the Folin-Ciocalteu method and the profile of interesting fractions analyzed by high-performance liquid chromatography (HPLC). The cytoprotective activity of fractions was determined by H2O2-induced oxidative stress in HC-04 cells by measuring lactate dehydrogenase (LDH) leakage into culture medium. HC-04 cells were used to investigate the ability to induce nuclear translocation of Nrf2. For both plants, the methylene chloride/methanol (90/10; v/v) fraction (F10), methylene chloride/methanol (75/25; v/v) (F25), and the methanolic fraction (F100) were found to have the highest total polyphenol content and exhibited high antioxidant activity strongly correlated with total polyphenol content. The cytoprotective activity of fraction F25 from both plants was comparable to that of quercetin (3.40 ± 0.05 µg/mL), inhibiting LDH leakage with a low half inhibition concentration (IC50) of 4.05 ± 0.03 and 3.8 ± 0.02 µg/mL for K. grandifoliola and E. africana, respectively. Lastly, fraction F25 of K. grandifoliola significantly (P < 0.05) induced nuclear Nrf2 translocation by sixfold, whereas that from E. africana and quercetin was only twofold. The results indicate for the first time that fraction F25 of the studied plants is more antioxidant and cytoprotective and induces nuclear translocation of Nrf2 in a human hepatocyte cell line.

Rubescins A, B and C: new havanensin type limonoids from root bark of Trichilia rubescens (Meliaceae).

Three new limonoids, rubescins A-C (1-3), and three known compounds including, havanensin type limonoid TS3 (4), ß-sitosterol, and stigmasterol were isolated from the root bark of Trichilia rubescens. Their structures were elucidated by means of extensive spectroscopic analyses, particularly one dimensional (1D)- and 2D-NMR techniques in conjunction with mass spectrometry. Rubescins A-C (1-3) and limonoid TS3 (4) were evaluated for their protective effects against oxidative stress induced in HC-04 cells by H2O2. Compound (1) showed strong inhibitory effects on lactase dehydrogenase (LDH) leakage, being as active (IC50 value of 0.0026 µM) as the positive control quercetin (IC50 value of 0.0030 µM).