Gastrointestinal nematode infections significantly impact small ruminant production, causing substantial economic losses worldwide. The rising resistance to anthelmintics has led to the search for alternative treatments, including phytotherapeutic approaches. This study investigates the chemical composition and anthelmintic activity of crude extracts and fractions from Simarouba berteroana, an endemic plant from Hispaniola, against a multidrug-resistant isolate of Haemonchus contortus. Chemical analyses revealed high contents of phenolic compounds, tannins, and flavonoids and confirmed the presence of 22 quassinoids, 5 phytosterol lipids, 3 terpenoid quinones, 3 alkaloids, and 1 naphthoquinone. The hydroalcoholic and iso-butanol fractions showed the strongest egg hatching inhibition (IC₅₀ = 0.93 and 1.21 mg/mL, respectively), while hexane fractions were less effective (p < 0.05). Fluorescence microscopy showed that the extracts and fractions adhered to eggshells, causing evisceration and cuticle detachment in hatched larvae. All extracts, except for hexane fractions, inhibited larval exsheathment at 0.3 mg/mL, with phenolic compounds being responsible for this effect. These results provide the first evidence of the ovicidal and larval exsheathment inhibition activities of S. berteroana extracts and fractions against H. contortus, highlighting their potential in managing gastrointestinal nematodes in small ruminants. Further in vivo studies are needed to confirm these findings.

Polar extracts of Tapirira guianensis Aubl. were prepared for evaluation of biological activities. Identification and quantification of phenolic compounds, antioxidant activity, inhibition of acetylcholinesterase enzyme and antifungal potential were performed in all extracts. High contents of total phenols were detected in the ethanolic and aqueous extracts of the leaves (237.10±5.39 mg EAG/g and 346.46±5.67 mg EAG) respectively. The same extracts had a free radical scavenging potential by both DPPH and ABTS+ methods. Ethanolic extract of the leaves with IC₅₀= 15.06±0.02 µg/mL and 16.49±0.01µg/mL) and aqueous extracts (11.54±0.01 µg/mL and 15.14±0.02 µg/mL respectively. In the study by high-performance liquid chromatography the phenolic substances were recorded: gallic acid, rutin, ellagic acid, quercetin and apigenin in the leaves and gallic acid and quercetin in the stem bark. Ethanolic and aqueous extracts of the leaves and stem bark showed high potency of inhibiting the enzyme acetylcholinesterase, with IC₅₀ values = 13.94±0.02 µg/mL, 13.69±0.08 µg/mL and 14.79±0.20 µg/mL respectively. The aqueous extract of the leaves showed anti-Candida action against all four strains of the microorganism. The in silico studies evidenced that all the ligands analyzed presented interaction with the SAP5 protein highlighting the ellagic acid, the rutin and the quercetin. With these results, the activities previously reported for the species T. guianensis are confirmed, highlighting the polar extracts, mainly aqueous as a source of antioxidant, acetylcholinesterase inhibitor and antifungal substances.

Caseous lymphadenitis (CLA) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis, resulting in significant economic losses in sheep and goat farming. Considering limited treatment options, the use of natural compounds has emerged as a promising alternative. This study aimed to evaluate the antibacterial potential of essential oils from Lippia origanoides (EOLO) and Ocimum micranthum (EOOM) against C. pseudotuberculosisstrains isolated from small ruminants with clinical CLA. Thirty isolates were genotypically characterized using quadruplex polymerase chain reaction (PCR) (16S rRNA, rpoB, pld, narG genes). The essential oils were extracted by hydrodistillation, and their chemical compositions were analyzed by gas chromatography-mass spectrometry (GC-MS). Antibacterial activity was determined by disk diffusion and broth microdilution assays. Minimum inhibitory concentration resulting in complete growth inhibition (MIC₁₀₀) and minimum bactericidal concentrations leading to complete bacterial eradication (MBC₁₀₀) were determined. Susceptibility to penicillin and tetracycline was assessed by disk diffusion. All strains were confirmed as biovar ovis (16S rRNA⁺, rpoB⁺, pld⁺, narG⁻). EOLO presented thymol (66.23%) as the major compound, while eugenol (38.62%) was the principal constituent in EOOM. EOLO exhibited large inhibition zone diameters (IZD), ranging from 40.67 mm to 98.33 mm, indicating strong activity. EOOM also demonstrated strong inhibition, with IZD values between 18.67 mm and 31.67 mm. All isolates were classified as “I” for penicillin (susceptible, increased exposure) and as susceptible (“S”) to tetracycline. EOLO showed MIC₁₀₀ values ranging from 15 to 250 µg/mL, while EOOM ranged from 62.5 to 125 µg/mL. MBC₁₀₀ values ranged from 125 to 1,000 µg/mL. This study seems to be the first report of the in vitro antibacterial activity of EOLO and EOOM against C. pseudotuberculosis, highlighting their potential as effective, natural alternatives for the treatment and control of CLA in small ruminants.