Essential oil and fenchone extracted from Tetradenia riparia (Hochstetter.) Codd (Lamiaceae) induce oxidative stress in Culex quinquefasciatus larvae (Diptera: Culicidae) without causing lethal effects on non-target animals.

We investigated the larvicidal activity of the essential oil (EO) from Tetradenia riparia and its majority compound fenchone for controlling Culex quinquefasciatus larvae, focusing on reactive oxygen and nitrogen species (RONS), catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE) activities, and total thiol content as oxidative stress indicators. Moreover, the lethal effect of EO and fenchone was evaluated against Anisops bouvieri, Diplonychus indicus, Danio rerio, and Paracheirodon axelrodi. The EO and fenchone (5 to 25 µg/mL) showed larvicidal activity (LC50 from 16.05 to 18.94 µg/mL), followed by an overproduction of RONS, and changes in the activity of CAT, GST, AChE, and total thiol content. The Kaplan-Meier followed by Log-rank (Mantel-Cox) analyses showed a 100% survival rate for A. bouvieri, D. indicus, D. rerio, and P. axelrodi when exposed to EO and fenchone (262.6 and 302.60 µg/mL), while α-cypermethrin (0.25 µg/mL) was extremely toxic to these non-target animals, causing 100% of death. These findings emphasize that the EO from T. riparia and fenchone serve as suitable larvicides for controlling C. quinquefasciatus larvae, without imposing lethal effects on the non-target animals investigated.

Pineapple (Ananás comosus) leaves ash as a solid base catalyst for biodiesel synthesis.

Homogeneous catalysts used for biodiesel synthesis have several limitations, including non-recoverability/reusability, saponification, emulsification, equipment corrosion, and environmental pollution. To overcome these limitations, we synthesized a novel catalyst via calcination of pineapple leaves waste. This catalyst was characterized by X-ray powder diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and soluble alkalinity measurements. The catalyst's activity with regards to soybean oil transesterification was analyzed, and multiple process parameters (temperature, catalyst amount, reaction time, and methanol:oil molar ratio) were examined. A high catalytic activity, probably related to the 85 wt% content of alkali/alkali metals (K, Ca and Mg), was observed after a 30 min reaction time, 60 °C, 4 wt% of catalyst, oil to methanol molar ratio of 1:40, reaching an oil to biodiesel conversion above 98%. We conclude that the novel catalyst presented here is efficient, cost-effective, and sustainable, while simultaneously abundant waste is reduced.