Sheikh A. Tasduq

Terminalia chebula (fruit) prevents liver toxicity caused by sub-chronic administration of rifampicin, isoniazid and pyrazinamide in combination.

Terminalia chebula Gertn. (Combetraceae) is an important herbal drug in Ayurvedic pharmacopea. In the present study, a 95% ethanolic extract of T. chebula (fruit) (TC extract), which was chemically characterized on the basis of chebuloside II as a marker, was investigated for hepatoprotective activity against anti-tuberculosis (anti-TB) drug-induced toxicity. TC extract was found to prevent the hepatotoxicity caused by the administration of rifampicin (RIF), isoniazid (INH) and pyrazinamide (PZA) (in combination) in a sub-chronic mode (12 weeks). The hepatoprotective effect of TC extract could be attributed to its prominent anti-oxidative and membrane stabilizing activities. The changes in biochemical observations were supported by histological profile.

Effect of Emblica officinalis (fruit) against UVB-induced photo-aging in human skin fibroblasts.

ETHNOPHARMACOLOGICAL RELEVANCE Emblica officinalis fruit (EO), commonly known as Amla is a reputed traditional medicine and functional food used in Indian subcontinent. It has long been used in Indian folk medicine to treat liver diseases, stomach ulcers, inflammatory diseases, metabolic disorders, geriatric complaints, skin disorders and beauty care. AIM OF THE STUDY Recently, it has been shown to promote pro-collagen content and inhibit matrix metalloproteinase levels in skin fibroblast. The aim of the present study was to investigate the efficacy of EO to inhibit UVB-induced photo-aging in human skin fibroblasts. MATERIALS AND METHODS Mitochondrial activity of human skin fibroblasts was measured by MTT-assay. Quantifications of pro-collagen 1 and matrix metalloproteinase 1 (MMP-1) release were performed by immunoassay techniques. Hyaluronidase inhibition assay was studied in vitro using bovine testicular hyaluronidase and human umbilical cord hyaluronic acid. Cell cycle analysis was performed by flowcytometry using propidium iodide. RESULTS EO stimulated, the otherwise UVB inhibited cellular proliferation and protected pro-collagen 1 against UVB-induced depletion via inhibition of UVB-induced MMP-1 in skin fibroblasts (10-40 μg/mL, p>0.001). EO exhibited inhibitory activity of hyaluronidase (10-40 μg/mL, p>0.001). Treatment with EO also prevented UVB disturbed cell cycle to normal phase. CONCLUSION The results of the present study suggests that EO effectively inhibits UVB-induced photo-aging in human skin fibroblast via its strong ROS scavenging ability and its therapeutic and cosmetic applications remain to be explored.

Potentiation of isoniazid-induced liver toxicity by rifampicin in a combinational therapy of antitubercular drugs (rifampicin, isoniazid and pyrazinamide) in Wistar rats: A toxicity profile study

Aim:  Biochemical characterization of long‐term toxic manifestations of anti‐tubercular (anti‐TB) drugs – rifampicin (RIF), isoniazid (INH) and pyrazinamide (PZA) – individually and in two combinations: (i) RIF + INH, and (ii) RIF + INH + PZA in Wistar rats.

Oxidative stress mediated Ca2+ release manifests endoplasmic reticulum stress leading to unfolded protein response in UV-B irradiated human skin cells

BACKGROUND Exposure of skin to ultraviolet (UV) radiation, an environmental stressor induces number of adverse biological effects (photodamage), including cancer. The damage induced by UV-irradiation in skin cells is initiated by the photochemical generation of reactive oxygen species (ROS) and induction of endoplasmic reticulum (ER) stress and consequent activation of unfolded protein response (UPR). OBJECTIVE To decipher cellular and molecular events responsible for UV-B mediated ER stress and UPR activation in skin cells. METHODS The study was performed on human skin fibroblast (Hs68) and keratinocyte (HaCaT) cells exposed to UV-B radiations in lab conditions. Different parameters of UVB induced cellular and molecular changes were analyzed using Western-blotting, microscopic studies and flow cytometry. RESULTS Our results depicted that UV-B induces an immediate ROS generation that resulted in emptying of ER Ca(2+) stores inducing ER stress and activation of PERK-peIF2α-CHOP pathway. Quenching ROS generation by anti-oxidants prevented Ca(2+) release and subsequent induction of ER stress and UPR activation. UV-B irradiation induced PERK dependent G2/M phase cell cycle arrest in Hs68 and G1/S phase cell cycle arrest in HaCaT. Also our study reflects that UV-B exposure leads to loss of mitochondrial membrane potential, activation of apoptotic cascade as evident by AnnexinV/PI staining, decreased expression of Bcl-2 and increased cleavage of PARP-1 protein. CONCLUSION UV-B induced Ca(2+) deficit within ER lumen was mediated by immediate ROS generation. Insufficient Ca(2+) concentration within ER lumen developed ER stress leading to UPR activation. These changes were reversed by use of anti-oxidants which quench ROS.

Secalonic Acid-D Represses HIF1α/VEGF-Mediated Angiogenesis by Regulating the Akt/mTOR/p70S6K Signaling Cascade

Tumor angiogenesis is a validated target for therapeutic intervention, but agents that are more disease selective are needed. Here, we report the isolation of secalonic acid-D (SAD), a mycotoxin from a novel source that exhibits potent antiangiogenic antitumor activity. SAD inhibited multiple HIF1α/VEGF-arbitrated angiogenesis dynamics as scored in human umbilical vascular endothelial cells and human MCF-7 breast tumor xenografts. Similarly, SAD suppressed VEGF-induced microvessel sprouting from rat aortic ring and blood vessel formation in the Matrigel plug assay in C57/BL6J mice. Under normoxic or hypoxic conditions, SAD inhibited cell survival through the Akt/mTOR/p70S6K pathway, with attendant effects on key proangiogenesis factors, including HIF1α, VEGFR, and MMP-2/MMP-9. These effects were reversed by cotreatment with the Akt inhibitors perifosine and GSK69069 or by the addition of neutralizing VEGF antibodies. The apoptotic properties of SAD were determined to be both extrinsic and intrinsic in nature, whereas the cell-cycle inhibitory effects were mediated by altering the level of key G1-S transition-phase proteins. In experimental mouse models of breast cancer, SAD dosing produced no apparent toxicities (either orally or intraperitoneal) at levels that yielded antitumor effects. Taken together, our findings offered a preclinical validation and mechanistic definition of the antiangiogenic activity of a novel mycotoxin, with potential application as a cancer-selective therapeutic agent.

Glycyrrhizic acid (GA), a triterpenoid saponin glycoside alleviates ultraviolet-B irradiation-induced photoaging in human dermal fibroblasts.

Glycyrrhizic acid (GA), a triterpenoid saponin glycoside from the roots and rhizomes of licorice is used in traditional and modern medicine for the treatment of numerous medical conditions including skin diseases and beauty care product. In the present study, we investigated the effect of GA against ultraviolet B (UVB) irradiation-induced photoaging in human dermal fibroblasts (HDFs) and its possible mechanism of action. HDFs were subjected to photoaging by sub-toxic dose of UVB (10 mj/cm(2)) irradiation. Cell viability, matrix metalloproteinase 1 (MMP1), pro-collagen 1, cellular and nuclear morphology, cell cycle, intracellular reactive oxygen species (ROS), caspase 3 and hyaluronidase inhibition assays were performed. Western blotting was used to evaluate the expression of NF-kappa B (NF-κB) and cytochrome-C proteins. GA treatment significantly inhibited photoaging. It achieved this by reducing ROS, NF-κB, cytochrome c, caspase 3 levels and inhibiting hyaluronidase enzyme. The main mechanism seems to be, most likely by blocking MMP1 activation by modulating NF-κB signaling. These findings may be useful for development of natural and safe photoprotective agents against UVB irradiation.

A Potent Inhibitor of Phosphoinositide 3-Kinase (PI3K) and Mitogen Activated Protein (MAP) Kinase Signalling, Quercetin (3, 3', 4', 5, 7-Pentahydroxyflavone) Promotes Cell Death in Ultraviolet (UV)-B-Irradiated B16F10 Melanoma Cells.

Ultraviolet (UV) radiation–induced skin damage contributes strongly to the formation of melanoma, a highly lethal form of skin cancer. Quercetin (Qu), the most widely consumed dietary bioflavonoid and well known inhibitor of phosphoinositide 3-kinase (PI3K) and mitogen activated protein (MAP) kinase signalling, has been reported to be chemopreventive in several forms of non-melanoma skin cancers. Here, we report that the treatment of ultraviolet (UV)-B-irradiated B16F10 melanoma cells with quercetin resulted in a dose dependent reduction in cell viability and increased apoptosis. The present study has brought out that the pro-apoptotic effects of quercetin in UVB-irradiated B16F10 cells are mediated through the elevation of intracellular reactive oxygen species (ROS) formation, calcium homeostasis imbalance, modulation of anti-oxidant defence response and depolarization of mitochondrial membrane potential (ΔΨM). Promotion of UVB-induced cell death by quercetin was further revealed by cleavage of chromosomal DNA, caspase activation, poly (ADP) ribose polymerase (PARP) cleavage, and an increase in sub-G1 cells. Quercetin markedly attenuated MEK-ERK signalling, influenced PI3K/Akt pathway, and potentially enhanced the UVB-induced NF-κB nuclear translocation. Furthermore, combined UVB and quercetin treatment decreased the ratio of Bcl-2 to that of Bax, and upregulated the expression of Bim and apoptosis inducing factor (AIF). Overall, these results suggest the possibility of using quercetin in combination with UVB as a possible treatment option for melanoma in future.

Glycyrrhizic acid (GA) inhibits reactive oxygen Species mediated photodamage by blocking ER stress and MAPK pathway in UV-B irradiated human skin fibroblasts

BACKGROUND Previously we have reported that generation of reactive oxygen species is the prime event responsible for calcium mediated activation of PERK-eIF2α-CHOP pathway and apoptosis in UV-B irradiated human skin fibroblasts (Hs68). We have also reported that glycyrrhizic acid (GA) mediates potent photoprotective activity against UV-B - irradiation-induced photodamage in human skin fibroblast. OBJECTIVE In the present study, we aimed to investigate the role of GA in preventing oxidative stress mediated unfolded protein response (UPR) and mitogen activated protein kinases (MAPK) pathway. METHODS Human skin fibroblast (Hs68) cells were exposed to UV-B radiations in lab conditions. Different parameters of UVB induced cellular and molecular changes were analysed using western-blotting, microscopy and flow cytometry. RESULTS Our results show that GA has strong photoprotective action against UV-B induced cellular damage. It was observed that: (a) Oxidative disturbances and intracellular Ca(2+) imbalance induced by UV-B irradiation was significantly restored by GA treatment; (b) activation of PERK-eIF2α-CHOP and MAPK pathway induced by UV-B was significantly blocked by GA; (c) Loss of mitochondrial membrane potential and apoptosis induced by UV-B were reduced by GA treatment. CONCLUSION Based on the above findings we conclude GA has a highly significant ROS quenching activity, thereby blocking the cascade of events including release of calcium from ER and subsequent ER stress, MAPK pathway and cellular demise. GA offers highly potent anti photodamage effect and can be exploited for cosmetic or therapeutic purposes.

Simultaneous quantification of eight bioactive secondary metabolites from Codonopsis ovata by validated high performance thin layer chromatography and their antioxidant profile

Chemical investigation of Codonopsis ovata resulted in the isolation and identification of β-sitosterol-3-O-glycoside, luteolin, apigenin, gentiacaulein, swertiaperenine, β-sitosterol, taraxeryl-3-acetate, and 3β-acetoxyoleanane-12-one. A rapid, precise, sensitive and validated HPTLC method for simultaneous quantification of these natural products (NPs) was developed on silica-gel 60F254 plate using ternary solvent system, n-hexane:ethyl acetate:formic acid (10.5:3.5:0.43, v/v/v). Markers were quantified after post chromatographic derivatization with cerric ammonium sulfate reagent. The method was validated for accuracy, precision, LOD, LOQ and all calibration curves showed a good linear relationship (r>0.9924) within test range. Precision was evaluated by intra- and inter-day tests with RSDs <2.59%, accuracy validation recovery 92.43-99.50% with RSDs <1.00%. Apigenin was found major component (natural abundance: 1.103%) and β-sitosterol the least (0.0263%). The NPs displayed antioxidant activity with luteolin exhibiting maximum effect at 1μg/mL concentration (75.9% for DPPH and 43.7% for ABTS) and others at 10 and 25μg/mL, suggesting thereby their apparent potential use for the prevention of free radical induced diseases or as an additive element to food and pharmaceutical industry.

Effect of N-acetyl cysteine (NAC), an organosulfur compound from Allium plants, on experimentally induced hepatic prefibrogenic events in wistar rat

Aim of present study was to investigate the effect of NAC on experimental chronic hepatotoxicity models induced by carbon tetrachloride (CCl₄) and thioacetamide (TAA). CCl₄ toxicity was induced by administering 200 μl CCl₄ (diluted 2:3 in coconut oil)/100 g body weight, p.o., twice weekly for 8 weeks. TAA toxicity was induced by administering 150 mg/kg b. wt. of TAA i.p., twice weekly for 8 weeks. NAC treatment was started along with toxicants (CCl₄ and TAA) for 8 weeks and continued for further 4 weeks. Self reversal group was kept without any treatment for 4 weeks after completion of toxicant treatments. Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline phosphatase (ALP), Bilirubin were measured in serum. Hydroxyproline (HP), lipid peroxidation (LPO), catalase (CAT), Glutathione peroxidase (GPx) and Glutathione (GSH) were determined in liver samples by colorimetric methods. Cytochrome P450 2E1 (CYP 450 2E1), activity was determined as hydroxylation of aniline in liver microsomes. General examination and histological analysis were also performed. Serum markers of liver damage (AST, ALT, ALP and Bilirubin) were increased by CCl₄ and TAA intoxication (p<0.001), whereas co-treatment with NAC reversed such changes (p<0.001). HP was enhanced in toxicant groups (p<0.001 in CCl₄ and TAA), but inhibited by NAC (p<0.001). LPO was increased while as GSH, CAT and GPx decreased by the administration of CCl₄ and TAA (p<0.001); co-administration of NAC restored these liver markers to normal levels (p<0.001). Biochemical determinations were corroborated by general and histological findings. Keeping in view the biochemical and histopathological studies, it was concluded that CCl₄ and TAA are strong hepatotoxic agents that produce liver fibrosis with close proximity to human etiology (micronodular cirrhosis) and NAC has a significant protective activity against CCl₄ and TAA. NAC has also been validated as a model against oxidative burden in chronic liver pathology.