Essential oils (EOs) of the leaves of three Eugenia punicifolia specimens from two different Reservation Parks, namely Parque Nacional das Nascentes do Rio Parnaíba (EpNRP-I and EpNRP-II) and Parque Nacional da Chapada das Mesas (EpCM), in the state of Maranhão, Brazil, were extracted by hydrodistillation and investigated by gas chromatography coupled to mass spectrometry. Principal component and hierarchical cluster analyses indicated differences between the samples. Antiproliferative EOs activity was determined for U-251 (glioblastoma), MCF-7 (breast adenocarcinoma), NCI/ADR-RES (multidrug-resistant ovarian adenocarcinoma), OVCAR-3 (ovarian adenocarcinoma), HT-29 (colorectal adenocarcinoma), and HaCaT (non‑tumor keratinocyte) cell lines applying the colorimetric method using 3-(4,5-dimethyl- 2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to determine the GI50 (50% growth inhibition) concentration. The extraction yields of the analyzed EOs were 0.58, 1.42 and 0.84%. The main constituents identified in two samples were α-pinene (49.75%), 1,8-cineole (13.77%) and α-terpineol (7.32%), and in the third sample, germacrene B (16.25%), (E)-caryophyllene (13.21%) and β-pinene (12.81%). The main GI50 results for sample EpNRP-I were noted for the U-251 (2.13 μg mL−1) and MCF-7 (6.72 μg mL−1) tumor lines. For the non-tumoral line HaCaT, the calculated GI50 was higher than the positive control comprising doxorubicin hydrochloride (13.35 μg mL−1). In addition, a flow cytometry analysis revealed that this same sample arrests the cell cycle of the MCF-7 line in the second interphase stage.

The tick Rhipicephalus microplus affects cattle health, with production loss in tropical and subtropical regions. Moreover, the use of commercial acaricides has been reduced due to the resistance of this parasite. Although alternatives such as plant bioactive molecules have been sought, essential oils present variations in their chemical constituents due to environmental factors, which can interfere with their acaricidal activity. The objective of the present study was to evaluate the seasonal influence of the essential oil of Ocimum gratissimum and its major constituents on acaricidal activity against R. microplus larvae. A high-yield essential oil of O. gratissimum and its major constituents were used, and a plant with a thymol-type oil was selected for seasonal analysis and acaricidal activity against R. microplus. Gas chromatography (GC) and GC-mass spectrometry (MS) were employed to identify 31 oil constituents (average yield of 6.26%). The main compounds were found to be thymol (33.4 to 47.9%), γ-terpinene (26.2 to 36.8%), and p-cymene (4.3 to 17.0%). Concerning acaricidal activity, the December (LC 0.84 mg/mL) and September (LC 1.58 mg/mL) oils obtained in the dry season were the most active, and assays performed with commercial standards revealed LC values of p-cymene, thymol, and γ-terpinene of 1.41, 1.81, and 3.08 mg/mL, respectively. Overall, lower acaricidal activities were found for oils produced from plants harvested in the rainy season. The results showed that seasonal variation in the chemical composition of the O. gratissimum essential oil influences its acaricidal activity. The seasonal variations in the thymol-type essential oil of O. gratissimum can represent an important strategy for the control of R. microplus.

The fall armyworm, Spodoptera frugiperda, causes damage at several stages of the maize crop cycle. Due to its resistance to synthetic insecticides and the high costs of pest control, there is an ever-increasing amount of research on alternative or complementary products that have a minor environmental and financial impact on agriculture. Therefore, the aim of this study was to evaluate the chemical composition and insecticidal potential of Ocimum gratissimum (african basil) leaves essential oil and the effect of its major component, thymol, on S. frugiperda control. Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified p-cymene, γ-terpinene, and thymol compounds as the main constituents of the oil, which presented a yield of 4.75%. Among the 30 identified compounds, thymol (33.2%) was the major constituent, representing 97.8% of the total oil. The efficacy of both the oil and thymol standard (Sigma-Aldrich) was evaluated against S. frugiperda using topical acute toxicity and contact surface tests at different concentrations. The oil was more active than thymol standard, with topical acute toxicity of LD50 at 0.020 μl/insect and LC50 at 0.171 μl/cm2 for contact surface toxicity. The oil proved to be superior to the thymol standard, offering an effective and promising alternative for the control of S. frugiperda, which is most likely due to the contribution of other oil components that acted synergistically. Consequently, this result provides an opportunity for further study and the development of an effective fall armyworm control system.

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Plectranthus amboinicus (Lour.) Spreng., da família Lamiaceae, tem propriedades terapêuticas e nutricionais atribuídas aos seus compostos fitoquímicos naturais, que são altamente valorizados na indústria farmacêutica. O objetivo do estudo foi avaliar as condições nutricionais ofertadas por dois tipos de adubações orgânicas no cultivo dessa espécie e verificar o aproveitamento desses nutrientes pelas folhas do vegetal. A pesquisa foi realizada com adubação de estercos avícola e bovino associados (Tratamento A) e adubação apenas com esterco bovino (Tratamento B). Foram mensuradas as propriedades do solo em relação ao: pH, soma das bases (SB), complexo sortivo, teor disponível de fósforo, enxofre e de micronutrientes, saturação do complexo sortivo por bases e capacidade de troca de cátions (CTC). Na diagnose foliar foi realizada a determinação dos teores de macronutrientes e de micronutrientes. O Tratamento B aumentou os teores de Ca e Mg, SB e CTC no solo. O Tratamento A elevou os teores de P, Fe, Mn e Cu no solo e de N (30,8 g/kg), P (4,9 g/kg), B (59 mg/dm3), Cu (19,1 mg/dm3), Fe (615 mg/dm3) e Zn (57 mg/dm3) nas folhas de Plectranthus amboinicus. Houve melhora do teor nutricional das folhas da espécie em estudo pela utilização de esterco avícola associado ao esterco bovino na adubação do solo.