This study evaluated the allelopathic effect of the Hesperozygis ringens essential oil using dicotyledonous and monocotyledonous seeds which are classified as weeds [Bidens pilosa and Lolium multiflorum], bioindicators [Lactuca sativa and Avena strigosa] and crops [Glycine max and Oryza sativa]. The essential oil from the leaves was extracted and analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. The extractive was diluted in ethanol, Tween 20 and water, and then tested at concentrations of 0.25, 0.50, 1.00, 2.50, and 5.00% (v/v). Water and the highest concentration of the solvents were used as control groups. The analyzed variables were germination, emergence velocity index, roots and shoot lengths and total seedlings length. Pulegone was the major essential oil compound representing 82.02% of the composition. Considering dicot seeds, the highest concentration of the extractive completely inhibited the germination of Bidens pilosa without affecting the germination of Lactuca sativa and Glycine max. On monocots, the highest essential oil concentration affected the germination of Lolium multiflorum and Avena strigosa without affecting the Oryza sativa one. The results indicate that the extractive has the potential to control weeds because they were more affected than the crops.

This study analyzed the performance, antioxidant status, hepatopancreatic lipoperoxidation, and proximate composition of Macrobrachium rosenbergii juveniles fed diets supplemented with clove basil (Ocimum gratissimum) essential oil (EO-OG). A total of 360 M. rosenbergii (initial weight 0.028 g ± 0.004) were randomly divided into four experimental groups with six replications each (n = 6). The prawns were fed diets with different EO-OG inclusion levels: 0.0, 1.0, 2.0, and 3.0 g kg⁻¹ EO-OG. After a 42-day feeding trial, dietary EO-OG showed no significant effect on prawn performance or carcass proximate composition, except on final antenna length. Prawns fed 3.0 g kg⁻¹ EO-OG displayed a 1.2- to 1.3-fold longer final antenna length than prawns from all other experimental groups. Likewise, prawns fed 3.0 g kg⁻¹ EO-OG presented a 2.6- to 3.2-fold higher catalase activity than prawns from all other experimental groups. Prawns fed EO-OG, regardless of the inclusion level, showed a 1.6- to 1.7-fold decreased hepatopancreatic lipoperoxidation compared to the control group. Therefore, EO-OG has been demonstrated to be a potential management tool as a non-nutritional dietary immunostimulant and animal welfare promoter for freshwater prawn farming, without affecting animal performance. This study recommends the dietary inclusion level of 3.0 g kg⁻¹ EO-OG for M. rosenbergii juveniles.

This study evaluated the effectiveness of the essential oil of Hesperozygisringens (EOHR) for anesthesia of Colossomamacropomum by documenting hematological and blood biochemical responses after biometric handling. In Experiment 1, juveniles (14.12 ± 3.53 g) were exposed to different concentrations of EOHR: 0 (control), 75, 150, 300 and 450 µL L-1 (n=10 fish for each concentration), to determine times for induction and recovery from anesthesia, as well as its effects on ventilatory frequency (VF). Based on these results, Experiment 2 evaluated the effects of 0 (control), 75 (with induction and recovery times outside that recommended for fish anesthesia) and 150 µL L-1 EOHR (within recommended times) on hematological and biochemical variables of juveniles (20.52 ± 3.47 g) after anesthesia and after 24 h of recovery (n = 6 fish for each concentration and collection time). Survival was 100%. Induction time showed a quadratic effect of EOHR concentration. Recovery time did not differ among EOHR concentrations. Concentrations between 150 and 450 µL L-1 EOHR caused rapid induction (< 3 min) and recovery (< 5 min). EOHR concentration affected VF. The concentration of 150 µL L-1 EOHR had little influence on hematological and biochemical parameters of C. macropomum of 20 g.

Ergosterol is responsible for important functions in the fungal plasma membrane. The influence of fungitoxic agents on membrane ergosterol content is one of the most important mechanisms of antifungal action and its knowledge allows the generation of products that associate active compounds of different mechanisms, consequently improving the effectiveness of wood preservatives. Therefore, this study optimized a method for quantifying ergosterol in wood-decay fungi. The white-rot species selected were Ganoderma applanatum and Trametes versicolor, while the brown-rot were Gloeophyllum trabeum and Lentinus lepideus. Mycelial discs of each species were transferred to Petri dishes containing a cellophane-covered potato-dextrose-agar medium. Mycelia of each fungus were collected, weighed, and transferred to test tubes with 5 mL of 25% alcoholic potassium hydroxide. The tubes were vortexed for 5 min, subjected to ultrasound for 5 min, incubated at 85 °C for 4 h, followed by the addition of 2 mL of sterile distilled water and 5 mL of n-heptane and subsequent ultrasound shaking for 2 min. The n-heptane layer was analyzed by UV spectrophotometry between 230 and 300 ηm. The blank sample only contained n-heptane. The mycelia wet weight of the fungi ranged from 0.061 to 0.296 g. Ergosterol content was 0.007% for Lentinus lepideus and 0.004% for the other species. The absorbance was higher than the ones observed in the blank for all samples. The adapted method was efficient for ergosterol extraction.