Chemoprevention assessment, genotoxicity and cytotoxicity of flavonoids from Inga laurina leaves (FABACEAE).

This study aimed to identify and evaluate the cytotoxicity, genotoxicity, antigenotoxicity and chemoprevention assessment of flavonoids myricetin-3-O-(2″-O-galloyl)-α-rhamnopyranoside and myricetin-3-rhamnoside from Inga laurina leaves extract. The Quinone reductase induction as a biomarker for cancer chemoprevention was evaluated in murine hepatocellular carcinoma, the cytotoxicity was evaluated by sulforhonamide B assay and genotoxicity was evaluated by comet assay using HepG2 cell line. The results demonstrated that the flavonoids didn´t show cytotoxicity in HepG2 cells. In the chemoprevention evaluations were not able to promote the induction of Quinone Reductase and also no genotoxic effect was observed by evaluation of the comet assay in none of the concentrations tested. In the antigenotoxicity test, all compounds had a protective effect against damage induced by hydrogen peroxide and were repaired against damage. Although none of the flavonoids were capable of inducing the enzyme Quinone Reductase at the concentrations tested, the antigenotoxicity results showed a powerful chemoprotective action.

Anticholinesterasic, nematostatic and anthelmintic activities of pyridinic and pyrazinic compounds.

In the search for acetylcholinesterase inhibitors as a potential target for the discovery of anthelmintic drugs, a series of 27 pyridinic and pyrazinic compounds have been designed on the basis of molecular hybridization of two known AChE inhibitors, namely, tacrine and (-)-3-O-acetylspectaline, and on the concept of isosterism. The synthesized compounds generally presented moderate anticholinesterasic activities when compared with the positive control physostigmine, but one compound (ethyl 2-[(6-chloropyrazin-2-yl)sulfanyl] acetate) exhibited an in vitro ability to immobilize the root-knot nematode Meloidogyne incognita that was highly comparable to that of the positive control Temik. Moreover, in anthelmintic assays against the gastrointestinal parasitic nematode Nippostrongylus brasiliensis (L4), some of the compounds, such as (6-chloropyrazin-2-yl)sulfanyl ethanol (32, EC50 = 33 nM), presented activities that were considerably stronger than that of the positive control albendazole (EC50 = 340 nM). In the light of the positive results obtained in the anthelmintic evaluations, the acute oral toxicity of the representative compound diethyl 2,2'-[(3-nitropyridine-2,6-diyl) bissulfanediyl] diacetate was determined in rats, and the drug was shown to be non-toxic at a dose of 2000 mg/kg. These results, allied with the relatively simple structures of the active compounds and their facile synthesis, highlight their potential use as anthelmintic or nematicidic agents.