Protective effects of a chemically characterized extract from solanum torvum leaves on acetaminophen-induced liver injury.

Distinct parts of Solanum torvum Swartz. (Solanaceae) are popularly used for a variety of therapeutic purposes. This study determined the phytochemical composition of a phenolic fraction of S. torvum leaf aqueous extract and investigated its antioxidant and liver-protective properties. A phenolic compound-enriched fraction, or phenolic fraction (STLAE-PF) of an infusion (STLAE) of S. torvum leaves, was tested in vitro (antagonism of H2O2 in cytotoxicity and DCF assays with HepG2/C3A cells), and in vivo for antioxidant activity and protective effects against acetaminophen (APAP)-induced liver injury in mice. Thirty-eight compounds (flavonoids, esters of hydroxycinnamic acid, and chlorogenic acid isomers) were tentatively identified (high-performance liquid chromatography coupled to high-resolution electrospray mass spectrometry) in the STLAE-PF fraction. In vitro assays in HepG2/C3A cells showed that STLAE-PF and some flavonoids contained in this phenolic fraction, at noncytotoxic levels, antagonized in a concentration-dependent manner the effects of a powerful oxidant agent (H2O2). In C57BL/6 mice, oral administration of STLAE (600 and 1,200 mg/kg bw) or STLAE-PF (300 mg/kg bw) prevented the rise in serum transaminases (ALT and AST), depletion of reduced glutathione (GSH) and elevation of thiobarbituric acid reactive species (TBARs) levels in the liver caused by APAP (600 mg/kg bw, i.p.). The hepatoprotective effects of STLAE-PF (300 mg/kg bw) against APAP-caused liver injury were comparable to those of N-acetyl-cysteine (NAC 300 or 600 mg/kg bw i.p.). These findings indicate that a phenolic fraction of S. torvum leaf extract (STLAE-PF) is a new phytotherapeutic agent potentially useful for preventing/treating liver injury caused by APAP overdosing.

Chemical profile, liver protective effects and analgesic properties of a Solanum paniculatum leaf extract.

BACKGROUND/AIM: Solanum paniculatum L. (Solanaceae) is a plant native to South America where it is used in traditional medicine for different therapeutic indications. This study evaluated the chemical composition and the hepatoprotective and analgesic activities of S. paniculatum leaf extracts. MATERIAL AND METHODS: The chemical profile of an ethyl acetate partition (SPOE) of a S. paniculatum leaf infusion (SPAE) was analysed by high performance liquid chromatography coupled to high-resolution electrospray mass spectrometry (HPLC-ESIMS). Liver protective effects of SPAE (600 and 1200 mg/kg bw, po), or SPOE (300 mg/kg bw, po) were evaluated in a C57BL/6 mouse model of acetaminophen (AP, 600 mg/kg bw, ip) hepatotoxicity by measuring alanine (ALT) and aspartate (AST) aminotransferase activity in the serum, and reduced glutathione (GSH), and thiobarbituric acid reactive species (TBARs) levels in the hepatic tissue. RESULTS: HPLC-ESIMS analysis of the SPOE fraction tentatively identified 35 flavonoids, esters of hydroxycinnamic acid and isomers of chlorogenic acid. SPAE (600 and 1200 mg/kg bw) and SPOE (300 mg/kg bw) antagonized the rise in ALT and AST, and the depletion of GSH, and elevation of TBARs levels in the liver caused by AP. The liver protective effects of SPOE (300 mg/kg bw) against AP-induced liver toxicity mimicked those of N-acetyl-cysteine (NAC 300 or 600 mg/kg bw ip). The mouse writhing assay showed that SPOE (300 mg/kg bw po) has anti-nociceptive effects comparable to those of AP (180 mg/kg bw po). CONCLUSION: This study suggests that an extract of S. paniculatum leaves (SPOE), rich in phenolic compounds, is a promising herbal drug to prevent and treat AP poisoning and presents analgesic properties as well.

Traditional use and safety of herbal medicines

In the European Union, traditional herbal medicines that are regarded as "acceptably safe, albeit not having a recognized level of efficacy" fit into a special category of drugs ("traditional herbal medicine products") for which requirements of non-clinical and clinical studies are less rigorous. A regulation proposal published by the Brazilian National Health Surveillance (Anvisa) defines a similar drug category ("traditional phytotherapeutic products") for registration purposes. Regarding herbal medicines, both agencies seem to be lenient regarding proof of efficacy, and consider long-standing folk use as evidence of safety and a waiver of a thorough toxicological evaluation. Nonetheless, several herbal products and constituents with a long history of folk usage are suspected carcinogenic and/or hepatotoxic. Herbal products have also been shown to inhibit and/or induce drug-metabolizing enzymes. Since herbal medicines are often used in conjunction with conventional drugs, kinetic and clinical interactions are a cause for concern. A demonstration of the safety of herbal medicines for registration purposes should include at least in vitro and in vivo genotoxicity assays, long-term rodent carcinogenicity tests (for drugs intended to be continuously used for > 3 months or intermittently for > 6 months), reproductive and developmental toxicity studies (for drugs used by women of childbearing age), and investigation of the effects on drug-metabolizing enzymes.