Hepatoprotective activity of picroliv, curcumin and ellagic acid compared to silymarin on paracetamol induced liver toxicity in mice

Recent advances in herbal medicine for treatment of liver diseases

CONTEXT

Liver disease is a serious ailment and the scenario is worsened by the lack of precise therapeutic regimens. Currently available therapies for liver ailments are not apposite and systemic toxicity inhibits their long term use. Medicinal plants have been traditionally used for treating liver diseases since centuries as the toxicity factor appears to be on the lower side.

OBJECTIVE

Several phytochemials have been identified which have significant hepatoprotective activity with minimal systemic adverse effects which could limit their long term use. The scenario calls for extensive investigations which can lead to development of lead molecules for hepatoprotective molecules of future. This review deals with the biological activity, mode of action and toxicity and forthcoming application of some of these leads.

METHODS

These generally have strong antioxidative potential and cause induction of antioxidant enzymes like superoxide dismutase, reduced glutathione and catalase. Additional mechanisms of hepatoprotection include stimulation of heme oxygenase-1 activity, inhibition of nitric oxide production, hepatocyte apoptosis and nuclear factor-κB activation.

RESULTS AND CONCLUSION

Out of the several leads obtained from plant sources as potential hepatoprotective agents, silymarin, andrographolide, neoandrographolide, curcumin, picroside, kutkoside, phyllanthin, hypophyllanthin, and glycyrrhizin have been established as potent hepatoprotective agents. The hepatoprotective potential of several herbal medicines has been clinically evaluated. Significant efficacy has been seen with silymarin, glycyrrhizin and Liv-52 in treatment of hepatitis, alcoholic liver disease and liver cirrhosis.

Pharmacodynamics of ellagic acid on cardiac troponin-T, lyosomal enzymes and membrane bound ATPases: mechanistic clues from biochemical, cytokine and in vitro studies

The anti lipid peroxidative and antioxidant effects of ellagic acid against isoproterenol-induced myocardial infarcted rats were reported previously. This study was designed to evaluate the protective effects of ellagic acid on the levels of cardiac troponin-T, lysosomal enzymes, and membrane bound ATPases along with the role of pro inflammatory cytokine. Male albino Wistar rats were pretreated with ellagic acid (7.5 and 15 mg/kg body weight) daily for a period of 10 days. After the pretreatment period isoproterenol (100mg/kg) was subcutaneously injected to rats twice at an interval of 24h. The protective effects of pretreatment with ellagic acid were measured by biochemical analysis and reverse transcriptase polymerase chain reaction. Evidence of myocardial infarction in isoproterenol induced rats included significant increase in the serum level of cardiac troponin-T and decreased levels of creatine kinase and lactate dehydrogenase in heart tissue homogenate .The pretreatment with ellagic acid restored the levels of cardiac markers in the serum and heart tissue homogenates. The activities of lysosomal enzymes (β-d-glucuronidase, β-N-acetyl glucosaminidase, β-galactosidase, cathepsin-d and acid phosphatase) were increased significantly in the serum and heart tissue of isoproterenol-induced rats. The activity of Na(+)/K(+)ATPase declined while the activities of Ca(2+)ATPase and Mg(2+)ATPase were increased significantly in the heart of isoproterenol-induced rats. Pretreatment with ellagic acid restored the activities of lysosomal enzymes and membrane bound ATPases. The higher expressions of pro-inflammatory cytokines such as interleukin-1β, interleukin-6 and tumour necrosis factor-α in the isoproterenol-induced rats were controlled by the pretreatment with ellagic acid. Our results imply that oral pretreatment with ellagic acid protects the heart lysosomal membrane against isoproterenol-induced cardiac damage. The observed effects might be due to the free radical scavenging, membrane stabilizing and anti-inflammatory properties of ellagic acid.

Abrogation of nimesulide induced oxidative stress and mitochondria mediated apoptosis by Fumaria parviflora Lam. extract

ETHNOPHARMACOLOGICAL RELEVANCE

[corrected] Fumaria parviflora Lam. is used for treating aches and pains, diarrhea, fever, influenza and other complications. The herb mixed with honey is taken to prevent vomiting as per Ayurvedic text.

AIM OF THE STUDY

In vivo studies were conducted to explore the hepatoprotective potential of Fumaria parviflora Lam. Fp extract against nimesulide induced oxidative stress and regulation of critical events in mitochondria mediated apoptosis.

MATERIALS AND METHODS

Group of Wistar rats were fed with nimesulide for 5 days (80 mg/kg/day, po), another group was pre-treated with Fp extract/silymarin (200mg/kg/day, po) for 5 days followed by nimesulide exposure. Liver serum biomarkers and histopathology were done to assess hepatotoxicity caused by nimesulide. Antioxidant enzymes (SOD, LPO, GPx, GR) were assessed using biochemical assays as well as gene expression by RT-PCR. GSH content and ROS generation was also evaluated using flow cytometry. Key apoptotic markers like phosphatidyl serine externalization, Bax, Bcl-2 translocation, mitochondrial membrane potential, cytochrome c release, caspases (9/3) activation and DNA damage were also observed in all the groups to confirm involvement of mitochondrial pathway.

RESULTS

Pre-treatment with Fp extract for 5 days significantly reduced the impact of nimesulide induced toxicity as evident from the serum biomarkers of liver damage and histopathology. It also modulated antioxidant enzymes mRNA expression as well as activity (SOD, glutathione peroxidase, glutathione reductase) and reduced lipid peroxidation during nimesulide toxicity. Nimesulide exposure decreased GSH content (92.9%) and increased reactive oxygen species (9.29 fold) which was attenuated in Fp treated rats. Fp pre-treatment significantly altered key apoptotic events like Bcl2 and Bax translocation, inhibited mitochondrial depolarization, prevented cytochrome c release, caspase-9/caspase-3 activation and DNA damage.

CONCLUSION

Our in vivo findings regarding protection accorded by Fp extract against nimesulide toxicity suggest that Fp not only reduced hepatotoxicity but attenuated critical control points of apoptotic cell death.

Silymarin modulates doxorubicin-induced oxidative stress, Bcl-xL and p53 expression while preventing apoptotic and necrotic cell death in the liver

The emergence of silymarin (SMN) as a natural remedy for liver diseases, coupled with its entry into NIH clinical trial, signifies its hepatoprotective potential. SMN is noted for its ability to interfere with apoptotic signaling while acting as an antioxidant. This in vivo study was designed to explore the hepatotoxic potential of Doxorubicin (Dox), the well-known cardiotoxin, and in particular whether pre-exposures to SMN can prevent hepatotoxicity by reducing Dox-induced free radical mediated oxidative stress, by modulating expression of apoptotic signaling proteins like Bcl-xL, and by minimizing liver cell death occurring by apoptosis or necrosis. Groups of male ICR mice included Control, Dox alone, SMN alone, and Dox with SMN pre/co-treatment. Control and Dox groups received saline i.p. for 14 days. SMN was administered p.o. for 14 days at 16 mg/kg/day. An approximate LD(50) dose of Dox, 60 mg/kg, was administered i.p. on day 12 to animals receiving saline or SMN. Animals were euthanized 48 h later. Dox alone induced frank liver injury (>50-fold increase in serum ALT) and oxidative stress (>20-fold increase in malondialdehyde [MDA]), as well as direct damage to DNA (>15-fold increase in DNA fragmentation). Coincident genomic damage and oxidative stress influenced genomic stability, reflected in increased PARP activity and p53 expression. Decreases in Bcl-xL protein coupled with enhanced accumulation of cytochrome c in the cytosol accompanied elevated indexes of apoptotic and necrotic cell death. Significantly, SMN exposure reduced Dox hepatotoxicity and associated apoptotic and necrotic cell death. The effects of SMN on Dox were broad, including the ability to modulate changes in both Bcl-xL and p53 expression. In animals treated with SMN, tissue Bcl-xL expression exceeded control values after Dox treatment. Taken together, these results demonstrated that SMN (i) reduced, delayed onset, or prevented toxic effects of Dox which are typically associated with hydroxyl radical production, (ii) performed as an antioxidant limiting oxidative stress, (iii) protected the integrity of the genome, and (iv) antagonized apoptotic and necrotic cell death while increasing antiapoptotic Bcl-xL protein levels and minimizing the leakage of proapoptotic cytochrome c from liver mitochondria. These observations demonstrate the protective actions of SMN in liver, and raise the possibility that such protection may extend to other organs during Dox treatment including the heart.