Quercetin and curcumin are well-known natural antioxidant molecules used to prevent the malignant effect caused by free radicals on biological systems. This work addressed the creation of eutectic mixtures from quercetin and curcumin molecules through mechanochemical treatment, that is, 75%, 50%, 20%, and 10% mixtures of curcumin and quercetin were obtained by mechanochemical synthesis. Moreover, the grinding time and solvent-assisted variables were tested to obtain the best conditions for creating eutectic mixtures. The obtained products were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible (UV-vis) and infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopy. The antioxidant capacities of quercetin, curcumin, and eutectic mixtures were evaluated using the 1,1-diphenyl-2-pycril-hydrazil (DPPH) radical inhibition method (RFS 50). A superior antioxidant capacity was observed of the mixtures (3.143 mg L⁻¹) compared with the pure components (quercetin = 3.444 mg L⁻¹ and curcumin = 9.141 mg L⁻¹). These results indicate that eutectic mixtures are an excellent option to increase and enhance the biological activity of natural antioxidant products or medicines.

Leaf-cutter ants are agricultural and urban pests that defy chemical control methods. Laboratory and field studies have revealed repellent and insecticidal activity by the extracts of Tithonia diversifolia (Asteraceae), known as Mexican sunflower, as a promising alternative for the control of the leaf-cutter ant Atta cephalotes. This study evaluated the effects of different extracts (non-polar and polar) of T. diversifolia dry leaves on worker ants from laboratory colonies of A. cephalotes through ingestion and contact. In addition, the biological activity of the extracts as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was evaluated. A dichloromethane extract at 1000 ppm presented the highest insecticidal activity through ingestion, causing 70% and 90% worker ant mortality after five and seven days of treatment, respectively. The acetylcholinesterase inhibition values showed that the dichloromethane presented the best AChE concentration of inhibition (IC₅₀) at 73.9 ± 11.06 μg/mL, compared to its fractions, which demonstrates that its activity is potentiated when the crude extract is used. Our results can be attributed to the existence of terpenes and sesquiterpene lactones, which are likely inhibitors of AChE, in T. diversifolia.

Oleaginous yeasts have emerged as promising microbial cell factories for lipid production, offering sustainable alternatives to traditional sources of biodiesel and nutraceuticals. In this study, the lipid accumulation potential of yeast strains isolated from two freshwater aquatic ecosystems in Cali, Colombia, was evaluated to identify novel candidates for biotechnological applications. A total of 56 strains were tested for their oleaginous nature using a gravimetric lipid assay with glucose as a carbon source. Of the assessed strains, 46.15% exceeded 20% lipid yields relative to the dry biomass. Seven strains were selected using glycerol as a carbon source, but only five yeasts were further characterized for their lipid profiles. Molecular identification revealed diverse species, including Aureobasidium sp., Papiliotrema rajashtanensis, Rhodotorula spp., and Clavispora lusitaniae. The selected strains demonstrated unique lipid profiles, with high proportions of monounsaturated and polyunsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2). In particular, Aureobasidium sp. accumulated uncommon fatty acids such as petroselinic acid under conditions induced by glycerol. This fatty acid, which has a double bond in position 6,7 and a melting point of 33 °C, highlights its potential as an alternative to margarine production, as well as a precursor to sophorolipids, estolide esters, soaps, and plastics. Rhodotorula sp. exhibited very long-chain fatty acids such as docosadienoic and docosatrienoic acids in its lipid profile. These findings underscore the biotechnological value of yeasts from lentic aquatic systems as sustainable lipid producers, paving the way for innovations in biofuels, nutraceuticals, and oleochemicals.