In vitro toxicity of latex, its terpenoidal fractions and isolated phorbol esters from Euphorbia umbellata (Pax) Bruyns on monocytic and melanoma cells

In Brazil, latex from Euphorbia umbellata (African milk tree) has been increasingly used in folk medicine to treat several types of cancer, including melanoma. The effect of lyophilized latex (LL), its hydroethanolic extract (E80), triterpene (F-TRI)- and diterpene (F-DIT)-enriched fractions, along with six isolated phorbol esters from LL and phorbol 12-myristate 13-acetate (PMA) on J774A.1, THP-1, SK-MEL-28, and B16-F10 cell line viability were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The compounds were identified by 2D-NMR and HRESIMS. The effect of the LL, extract and fractions on cell viability was also assessed through a resazurin reduction assay. At 100 μg/ml, LL, and its fractions moderately inhibited J774A.1 (37.5-59.5%) and THP-1 (12.6-43.6%) metabolism. LL (IC50 70 μg/ml) and F-TRI (IC50 68 μg/ml) were barely more effective against B16-F10 cells, and only F-TRI exerted an inhibitory effect on SK-MEL-28 cells (IC50 66-75 μg/ml). The samples did not effectively inhibit THP-1 growth (IC50 69-87 μg/ml, assessed by MTT). B16-F10 was susceptible to PMA (IC50 53 μM) and two 12-phenylacetate esters (IC50 56-60 μM), while SK-MEL-28 growth was inhibited (IC50 58 μM) by one of these kinds of esters with an additional 4β-deoxy structure. Synagrantol A (IC50 39 μM) was as effective as PMA (IC50 47 μM) in inhibiting J774A.1 growth in a dose-dependent manner. Furthermore, an in silico study with target receptors indicated a high interaction of the compounds with the PKC proteins. These results provide useful knowledge on the effect of tigliane-type diterpenes on tumor cell from the perspective of medicinal chemistry.

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.