Mitochondrial affectation, DNA damage and AChE inhibition induced by Salvia officinalis essential oil on Aedes aegypti larvae.

The aim of this research study was to understand the mechanism of action of Salvia officinalis (Lamiaceae) essential oil (EO) on Aedes aegypti larvae. We evaluated the effect on DNA damage, acetylcholinesterase (AChE) inhibition and mitochondrial enzymatic alterations. The major components were analyzed in silico using OSIRIS and Molispiration free software. Aedes aegypti DNA was extracted from mosquito larvae between third (L3) and fourth (L4) instars to determine the DNA fragmentation or degradation at S. officinalis EO lethal concentrations (LC10, LC20, LC50, and LC90). DNA integrity was assessed in both LCs in larvae treated for 24 h and in larvae homogenized with EO; we also assessed purified DNA larvae by a densitometric analysis. The AChE inhibition was quantified in protein larvae L3-L4 following Ellman's method and the enzymatic activities related to the mitochondrial respiratory chain of mitochondrial proteins was estimated by spectrophotometry. In silico analysis of 1,8-cineol and of α-thujone, major EO components, showed that they were highly permeable in biological membranes without mutagenic risks. Alterations in the integrity of DNA were observed in larvae exposed and homogenized with S. officinalis EO. The EO induced an AChE inhibition of 37 ±â€¯2.6% to IC50. On the other hand, mitochondrial bioenergetics suggest that EO inhibits electrons entry to the respiratory chain, via Complex II. AChE activity alteration causes mortality of individuals, by blocking the insect cholinergic functions. These results indicate that EO affects the integrity of DNA, the mitochondrial respiration chain and the AChE activity.

Effects of new tetrahydroquinoline-isoxazole hybrids on bioenergetics of hepatocarcinoma Hep-G2 cells and rat liver mitochondria.

New molecular hybrids were synthesized by combining tetrahydroquinoline (THQ) and isoxazole (ISX) scaffolds, in search for chemical structures with improved pharmacological properties. Our tetrahydroquinoline (THQ) and isoxazole (ISX) hybrids differ in the X and Y substituents: FM53 (X = H; Y= H), FM49 (X = CH3; Y= OCH3), FM50 (X = Cl; Y= H) and FM48 (X = Cl; Y= OCH3). Aiming at exploring their bioactivity in liver cancer cells, in this paper we report the effect of four THQ-ISX hybrids on viability, respiration and oxidative stress in Hep-G2 human hepatoma cells. In addition, we measured the alterations induced by these compounds on oxygen uptake and respiratory chain enzymes in isolated mitochondria. Cell viability assay indicated that these THQ-ISX hybrids displayed antiproliferative activity on Hep-G2 cells. Among these, FM50 (IC50 = 5.2 ±â€¯1.9 µM) and FM53 (IC50 = 6.8 ±â€¯0.7 µM) had the highest cytotoxicity. These four hybrids also inhibited the Hep-G2 cells respiration in the uncoupled state, with FM50 decreasing all respiratory states (basal, leak, uncoupled). While only FM49 and FM53 altered the Hep-G2 cells redox function. In terms of mitochondrial bioenergetics, THQ-ISX hybrids decreased the oxygen consumption in state 3 (via complex I and II), and also inhibited NADH oxidase and NADH cytochrome c reductase enzyme activities. In these experiments, the structural homologues FM50 and FM53 had a remarkable inhibitory effect (~50%) with respect to FM49 and FM48. These results show that THQ-ISX hybrids are promising compounds for hepatoma cancer treatment and that the phenyl substituent (Y= H) in the ISX scaffold intensifies both, the cytotoxicity in Hep-G2 cells and, inhibition of electron transport through complex I of the mitochondrial respiratory chain.