Activity of Oyster Mushrooms, Genus Pleurotus (Agaricomycetes), on Lucilia cuprina (Diptera).

Lucilia cuprina is a vector of important diseases in humans and animals that causes myiasis in sheep, leading to enormous damage to the sheep sector. Chemical products are used to control these flies; however, there are reports of resistance in addition to these products causing toxicity to the environment, humans, and animals, so alternative controls have been studied to reduce these impacts. Pleurotus spp. are basidiomycete fungi and present bioactive compounds with medicinal properties. Due to the potential use of fungi to control Diptera, this study aimed to verify the activity of Pleurotus florida, P. ostreatus, and P. djamor in the control of larvae and adults of L. cuprina, as well as the effects of aqueous extracts of the fungi P. ostreatus, P. djamor, and P. florida on larvae and adults of L. cuprina. The aqueous extract from P. florida was the only one that showed larvicidal activity against L. cuprina, with a half-maximal effective concentration of 11.42 mg/mL. In the test with adult stages, 30 insects were used for each solution concentration, sprinkled with 1 mL of the solution. All aqueous extracts showed adulticidal activity at all concentrations, P. ostreatus showing the best results, with adult mortality ranging from 75.86 to 100%. Our results demonstrated an important larvicidal effect of P. florida and an adulticidal effect of all AE, with emphasis on P. ostreatus.

Eucalyptus oil nanoemulsions against eggs and larvae of Haemonchus contortus.

Haemonchus contortus is a highly pathogenic and prevalent helminth that causes many deaths in sheep herds. Anthelmintics are usually employed to overcome this issue; however, they do not guarantee immediate and lasting efficacy because of the occurrence of drug-resistant parasites. Among substances that are used in scientific studies for parasitic control, essential oils are known to have different pharmacological properties. However, they demonstrate instability owing to several factors, and therefore, nanoemulsification is considered an alternative to control the instability and degradability of these compounds. The objective of this study was to evaluate the cytotoxicity of nanoemulsions containing essential oil of Eucalyptus globulus against the blood of healthy sheep and to verify their activity against the parasite H. contortus in sheep. The results presented adequate nanotechnological characteristics (diameter 72 nm, PDI 0.2, zeta -11 mV, and acidic pH) and adequate morphology. Further, the corona effect and cytotoxic profiles of the free oil and nanoemulsion against blood cells from healthy sheep were evaluated. The tests results did not present a toxicity profile. For evaluating efficacy, we observed an important anthelmintic action of the nanoemulsion containing oil in comparison to the free oil; the results demonstrate a potential role of the nanoemulsion in the inhibition of egg hatchability and the development of larvae L1 to L3 (infective stage). Based on these results, we developed an important and potential anthelmintic alternative for the control of the parasite H. contortus.

Adulticidal Activity of Melaleuca alternifolia (Myrtales: Myrtaceae) Essential Oil With High 1,8-Cineole Content Against Stable Flies (Diptera: Muscidae).

The stable fly, Stomoxys calcitrans (Linnaeus 1758), is a hematophagous fly responsible for causing loss of performance in horses, causing losses in cattle productivity, and impacting the animals' health through the spread of pathogenic microorganisms. The objective of this work was to investigate the insecticidal activity of essential oil obtained from Melaleuca alternifolia (Cheel), presenting high 1,8-cineole content, against S. calcitrans adults. Insecticidal activity was determined using surface application methods and exposure to oil impregnated paper. It was observed that treatments at 25 and 50 µg/cm2 (P < 0.05) present fumigant activity through exposure to the impregnated paper, and in the first 15 min of exposure, the mortality rates obtained for these treatments were, respectively (96.6 ± 3.3% and 100%), equivalent to the positive control. Using the superficial application method, the only treatment concentration presenting adulticidal action was 5% (w/v) (P < 0.05). Respective toxicities LC50 (%, w/v) and LC80 for the impregnated paper method were 1.06 ± 0.02 and 1.47 ± 0.17; for the superficial application method, they were 3.82 ± 0.65 and 5.53 ± 0.74. As demonstrated, M. alternifolia essential oil presents adulticidal potential against S. calcitrans.

Nematocidal Effect of Oyster Culinary-Medicinal Mushroom Pleurotus ostreatus (Agaricomycetes) against Haemonchus contortus.

The nematocidal effect of Pleurotus ostreatus (white variety of oyster mushroom) aqueous extract (AE) was evaluated against Haemonchus contortus eggs and infective larvae (L3) in vitro and in artificially infected gerbils (Meriones unguiculatus). The chemical analyses indicated that constituents of AE are tridecanoic, tetradecanoic, linolelaidic, 9,15-octadecadienoic, and oxalic acids. P. ostreatus extract inhibited larval hatching by 100% at the concentration of 2.24 mg/mL and (50% effective concentration) EC50 of 0.73 mg/mL. In the larval development test, AE induced a larvicidal effect at the concentration of 50 mg/mL and EC50 of 17.24 mg/mL. The larval migration test revealed a reduction of 94.7% at a concentration of as low as 4 mg/mL and EC50 of 1.25 mg/mL. No significant effects of treatment with P. ostreatus AE were seen on H. contortus in the gerbil model. Thus, our results demonstrate an important nematocidal in vitro effect of P. ostreatus AE against the parasite H. contortus. However, further investigations are necessary to confirm the anthelmintic potential of P. ostreatus extract in small ruminants.