Slow pyrolysis of Terminalia catappa L. municipal solid waste and the use of the aqueous fraction produced for bovine mastitis control.

The Terminalia catappa L. tree is an ornamental and shade tree producter of a large amount of biological waste sent to landfills. Therefore, this plant constitutes so-called municipal solid wood waste (MSWW), which causes undesirable impacts on the environment, such as the generation of methane through the action of microorganisms. Sustainable solutions for the proper use and disposal of MSWW are a topic that has assumed great relevance at present due to the high quantities of MSWW generated worldwide. Pyrolysis constitutes an attractive alternative for the sustainable use of MSWW to produce higher value-added products. This study investigated the slow pyrolysis of Terminalia catappa L. fruit and the use of the aqueous fraction produced for bovine mastitis control. We obtained four fractions from the pyrolysis process, with average yields of the aqueous phase (36.22 ± 2.0 %), bio-oil (5.52 ± 0.4 %), biochar (37.55 ± 2.8 %) and gas (20.71 ± 2.0 %). The aqueous fraction was extracted with organic solvents and analyzed by gas chromatography coupled to mass spectrometry (GC‒MS). The extracts were composed mainly of phenols (50 %), furan derivatives, cyclic ketones, and others with lower contents, such as alcohols and esters. The aqueous fraction had bactericidal activity against Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, which are responsible for bovine mastitis. In addition, the fraction showed low cytotoxicity against a murine melanoma cell line from a C57BL/6J mouse, B16F10 cells and mouse peritoneal cells.

Biotechnological Potential of Eugenol and Thymol Derivatives Against Staphylococcus aureus from Bovine Mastitis.

Bovine mastitis is an infectious disease that affects the mammary gland of dairy cattle with considerable economic losses. Staphylococcus aureus is the main microorganism involved in this highly contagious process, and the treatment is only using antibiotics. Currently, the search for new treatment and/or compounds is still in need due to microbial resistance. In this work, we evaluated the potential of eugenol and thymol derivatives against S. aureus strains from bovine mastitis. On that purpose, nine derivatives were synthesized from eugenol and thymol (1-9), and tested against 15 strains of S. aureus from subclinical bovine mastitis. Initially, the strains were evaluated for the biofilm production profile, and those with strong adherence were selected to the antimicrobial sensitivity determination in the Minimum Inhibitory Concentration (MIC) assays. Herein the compounds toxicity was also evaluated by in silico analysis using Osiris DataWarrior® software. The results showed that 60% of the strains were considered strongly adherent and three strains (S. aureus 4271, 4745 and 4746) were selected for the MIC tests. Among the nine eugenol and thymol derivatives tested, four were active against the evaluated strains (MIC = 32 µg mL-1) within CLSI standard values. In silico analysis showed that all derivatives had cLopP < 5, cLogS > - 4 and TPSA < 140 Å2, and similar theoretical toxicity parameters to some antibiotics currently on the market. These molecules also showed negative drug-likeness values, pointing to the originality of these structures and theoretical feasibility on escaping of resistance mechanism and act against resistant strains. Thus, these eugenol derivatives may be considered as promising for the development of new treatments against bovine mastitis and future exploring on this purpose.

Evaluation of essential oils as an ecological alternative in the search for control Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus microplus is a significant problem for livestock, causing losses of billions of dollars per year. This work aimed to determine the chemical composition of essential oils obtained from Laurus nobilis and Copaifera officinalis and evaluate activity against engorged R. microplus females. Chemical composition analyzed by GC-MS revealed the presence of 39 components accounting for 95.38% of the oil in L. nobilis, the most abundant being 1,8-cineol (25.7%), trans-sabinene-hydrate (20.8%), and α-terpinil acetate (15.0%). Chemical analysis of C. officinalis oil identified 25 components corresponding to 80.5% of the total constituents, where the major compounds were ß-caryophyllene (21.1%), caryophyllene oxide (10.7%), and α-trans-bergamotene (9.3%). Adult immersion test (AIT) showed that L. nobilis essential oil at 5% or 10% caused 80.5% mortality of engorged females after 24 h and reached 96.9% and 100% mortality on the third day after treatment, respectively. While the essential oil from C. officinalis caused 84.7% mortality after six days at 10% and at 5%, achieved approximately 100% mortality rate at the end of the experiment (day 15). Both essential oils and the combination significantly inhibited egg-laying; however, the combination treatment showed higher effectiveness than the isolated oils at 2.5%. A possible synergic action of L. nobilis and C. officinalis against the cattle tick R. microplus is therefore suggested. The present work introduces a potential alternative for the development of a formulation environment-friendly (green pesticide) used to control cattle tick infestations.

Chemical composition and acaricidal activity of Ocotea notata (Lauraceae), an endemic species from Brazil, against the cattle tick Rhipicephalus microplus / Composición química y actividad acaricida de Ocotea notata (Lauraceae), una especie endémica de Brasil, contra la garrapata del ganado Rhipicephalus microplus

Rhipicephalus microplus, is one parasites that cause severe productivity losses in the cattle industry of Brazil and shows increasing resistance to conventional pesticides. This research aims to study the chemical composition, and acaricidal activity of the essential oil from Ocotea notata leaves, a brazilian endemic species, against R. microplus. The effect on R. microplus engorged adult females was evaluated using the immersion test. The oil reduced the survival by 90% after incubation for 15 days and there was 100% reduction for posture inhibition and reproductive capacity. These results suggest that the O. notata essential oil has activity on the R. microplus.

Rhipicephalus microplus, es un parásito que causa graves pérdidas de productividad en la industria ganadera de Brasil y muestra una creciente resistencia a los pesticidas convencionales. Esta investigación tiene como objetivo estudiar la composición química y la actividad acaricida del aceite esencial de las hojas de Ocotea notata, una especie endémica brasileña, contra R. microplus. El efecto sobre las hembras adultas engordadas de R. microplus se evaluó mediante la prueba de inmersión. El aceite redujo la supervivencia en 90% después de la incubación durante 15 días y hubo una reducción del 100% para la inhibición de la postura y la capacidad reproductiva. Estos resultados sugieren que el aceite esencial de O. notata tiene actividad contra R. microplus.

In Vitro Evaluation of Essential Oils Derived from Piper nigrum (Piperaceae) and Citrus limonum (Rutaceae) against the Tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

The present research aimed to study the chemical composition and acaricidal activity of Citrus limonum and Piper nigrum essential oils against the cattle tick Rhipicephalus microplus. GC-MS analysis of C. limonum essential oil showed limonene (50.3%), ß-pinene (14.4%), and γ-terpinene (11.7%) as the major components; P. nigrum oil was mainly composed of ß-caryophyllene (26.2%), σ-ocymene (5.8%), and α-pinene (5.5%). Acaricide activity was evaluated at concentrations of 2.5, 5.0, and 10.0% (v/v) of each plant oil, as well as 1 : 1 combination of both oils (5% : 5%, 2.5% : 2.5%, and 1.25% : 1.25% each), by immersing engorged R. microplus females for one minute. The LC90 of oils from C. limonum, P. nigrum, and the combination were 4.9%, 14.8%, and 5.1%, respectively. C. limonum essential oil caused 100% mortality of engorged females at the highest concentration (10%). P. nigrum essential oil inhibited egg-laying by up to 96% in a concentration-dependent manner, suggesting it reduces tick fecundity. When combined, the oils presented toxicity as to C. limonum oil alone, but with stronger inhibition of oviposition (5% : 5%), indicating a possible additive effect against R. microplus. The present data provide support for further investigation of novel natural products to control bovine tick infestations.

Acaricidal properties of the essential oil from Zanthoxylum caribaeum against Rhipicephalus microplus.

Zanthoxylum caribaeum Lamarck (Rutaceae) is plant species with a variety of medical applications, including insecticidal activity. This study determined the bioacaricidal activity of the essential oil from Z. caribaeum leaves against engorged Rhipicephalus (Boophilus) microplus (Canestrini, 1887) females using the adult immersion test. For this purpose, three serial concentrations (5.0, 2.5, and 1.25%, vol:vol, in 1% dimetilsulfoxide) of the essential oil were used. Essential oil 5% caused 65% mortality on the first day after treatment, 85% on the second day, and 100% mortality by the fifth day. To our knowledge, this is the first demonstration of the acaricidal activity of the essential oil from Z. caribaeum leaves against cattle ticks.