Potential of Ocotea indecora Essential Oil for Controlling Drosophila suzukii: Molecular Predictions for Toxicity and Selectivity to Beneficial Arthropods.

The protection of soft-skinned fruits against Drosophila suzukii has relied primarily on the efficacy of a few synthetic molecules. Despite their short-term efficacy, these molecules can cause environmental pollution, unintendedly affect non-target organisms, and fail to provide sustainable control. The shortfalls of using synthetic pesticides warrant the search for alternatives, such as essential oils extracted from plants, with greater eco-friendlier properties. Here, we chemically characterized and evaluated the toxicity of the essential oil extracted from leaves of Ocotea indecora (Schott) Mez (Lauraceae) against D. suzukii via two exposure pathways (ingestion and contact). We also assessed the selectivity of the essential oil to two predatory natural enemies, Eriopis connexa and Chrysoperla externa and two pollinator bees, Apis mellifera and Partamona helleri. In addition, we conducted in silico predictions to investigate potential interactions between the major compound of the essential oil and the insects' transient receptor potential (TRP) channels. Our chromatographic analysis revealed sesquirosefuran (87%) as the major compound. Higher toxicity to adults of D. suzukii was observed in contact exposure (LC50 = 0.43 µL mL-1) compared to ingestion (LC50 = 0.72 µL mL-1). However, the essential oil did not cause mortality to the non-target organisms tested here, even when applied at 2.20 µL mL-1. Molecular predictions demonstrated that sesquirosefuran binds more stably to the TRP channels of D. suzukii than to those expressed in beneficial arthropods. Collectively, our findings provide the initial framework for the potential use of O. indecora essential oil as a sustainable alternative for managing D. suzukii infestations.

In vitro comparison between antimicrobial and antibiofilm effects of Green Propolis and Baccharis dracunculifolia against Staphylococcus pseudintermedius isolate.

Staphylococcus pseudintermedius is the leading cause of canine pyoderma. Honeybee products are common to treat this and other types of infections. High average annual population loss of bees has been observed. This study evaluated antibacterial and antibiofilm profile of Green Propolis and Baccharis dracunculifolia against S. pseudintermedius and the chemical similarities among both. Ethanolic extracts were produced and chemically characterized. The isolates were subjected to treatment with the extracts in both planktonic and sessile forms. Green propolis minimum inhibitory concentration (MIC) was 0.156 mg / mL, and minimum bactericidal concentration (MBC) was 0.312mg / mL. Baccharis dracunculifolia extract MIC and MBC was 0.312mg / mL and 2.5 mg / mL, respectivelly. Both extracts reduced SD55 formation of biofilm at minimum inhibitory concentration and at 1/8 minimum inhibitory concentration. The results observed in relation to ED99, were similar for both extracts. Besides that, similar chemical indicators between both extracts, including the presence of Artepellin C, suggest that the Baccharis dracunculifolia extract could be an alternative to the Green Propolis extract in the treatment of staph infections.

Thermoresponsive Hydrogel Containing Viscum album Extract for Topic and Transdermal Use: Development, Stability and Cytotoxicity Activity.

Viscum album L. (Santalaceae), also known as European mistletoe, is a semi-parasitic plant that grows on different host trees. Our group recently demonstrated the antitumoral activity of ethanolic V. album extracts in vitro, depending on the dose and the host tree, V. album ssp abietis from Abies alba being the most active extract. The goal of this work focused on the development of a new topical formulation containing V. album extracts, evaluation of in vitro toxicity and ex vivo skin permeation assays. The Poloxamer 407 hydrogel containing 5% of dry (VA_DEH) or aqueous (VA_AEH) extract presented dermal compatible pH and microbiological stability for 180 days. The hydrogels flow curve presented a non-linear relation, characteristic of non-Newtonian fluids, and the mean viscosity for the VA_DEH and VA_AEH was 372.5 ± 7.78 and 331.0 ± 2.83 Pa.s, respectively, being statistically different (Welch's t test; p < 0.01). Additionally, WST-1 in vitro assays revealed a dose-dependent toxicity for both formulations and VA_DEH presented a higher activity than the VA_AEH. The promising cytotoxic potential of VA_DEH lead to the ex vivo skin permeation assay with 2.73 ± 0.19 µg/cm2 of chlorogenic acid, which permeated at 8 h, showing a transdermal potential. These in vitro results support the idea that VA_DEH is a novel promising candidate for mistletoe therapy. Therefore, further in vivo and pre-clinical experiments should be performed to evaluate the safety and efficacy of this new dermic delivery system.

Repellency effect of Pilocarpus spicatus A. St.-Hil essential oil and nanoemulsion against Rhipicephalus microplus larvae.

Rhipicephalus microplus, the cattle tick, is a major cause of economic losses in bovine production. Due to the widespread acaricidal resistance to commercially available products, as well as their toxicity and environmental impact, alternative control methods are required. Nanoformulations produced from plant extracts as bioactive substances are very promising as innovative acaricidal agents. Thus, the aim of this study was to evaluate the in vitro repellent activity of Pilocarpus spicatus essential oil and its nanoemulsion against R. microplus, using larval repellent test (RT). The essential oil was extracted by hydrodistillation, using a Clevenger-type apparatus. The nanoemulsion was prepared with 5% essential oil, 5% tween 80, and 90% water, using the phase inversion method (50 mg/mL). Limonene was the major component (46.8%) of the essential oil, as determined by gas chromatography-mass spectrometry (GC/MS) and confirmed by flame ionization detection (GC/FID). According to the RT results, the essential oil had a repellent activity greater than 69%, from concentrations of 3.12 mg/mL (69.81 ± 10%) to 50 mg/mL (98.10 ± 0.6%), whereas the nanoemulsion at 50 mg/mL presented repellent activities of 97.14 ± 1.37% and 97.89 ± 0.52% 6 and 10 h after treatment, respectively. These values regarding to total repellency were very close to those calculated for mortality corrected by Abbott's formula. The phase inversion method preserved the chemical and physical characteristics of the essential oil since both reached an equal repellent effect at the same concentration. Therefore, P. spicatus essential oil and nanoemulsion had excellent repellent activities against R. microplus larvae, demonstrating its potential for future use as an alternative for tick control.

Anti-inflammatory and analgesic activities of Hypericum brasiliense (Willd) standardized extract / Atividades anti-inflamatória e analgésica de extratos padronizados de Hypericum brasiliense (Willd)

As atividades antiinflamatória e antinociceptiva do extrato padronizado de Hypericum brasiliense (HBSE) (Guttiferae) foi avaliada em modelos animais. Ratos Wistar machos foram tratados com extrato de H. brasiliense (50, 250 e 500 mg/kg, v.o.) em solução 3 por cento Tween 80 0,9 por cento NaCl. O tratamento com HBSE (500 mg/kg) mostrou inibição significativa sobre o edema induzido por carragenina comparado ao grupo controle. Nessa dose, o edema foi reduzido em 31,25 por cento na terceira hora (pico do edema) após o tratamento, mas na dose de 50 mg/kg, o edema apresentou redução de 53,13 por cento (p < 0,05). Ainda com a dose de 50 mg/kg, a diminuição do edema induzido por dextrana foi similar ao controle positivo, ciproeptadina. Houve diminuição na formação do tecido granulomatoso (6,6 por cento) comparável ao grupo controle. O HBSE também inibiu o número de contorções abdominais em 46,4 por cento, estatisticamente igual ao controle positivo, tratado com indometacina (42,9 por cento). Na dose de 250 mg/kg, houve inibição do número de contorções em 70,7 por cento quando comparado ao grupo controle (p < 0,001). No teste da placa-quente, foi verificado aumento no tempo de latência com a dose de 50 mg/kg. Os resultados demonstram que o HBSE possui atividade antiinflamatória sobre processos agudos, principalmente quando sua gênese está relacionada à síntese dos derivados do ácido araquidônico, e seu efeito analgésico provavelmente envolve ação sobre o Sistema Nervoso Central.

The anti-inflammatory and antinociceptive activities of the standardized leaves extract (HBSE) of Hypericum brasiliense (Guttiferae) were evaluated in animal models. Male Wistar rats were treated with H. brasiliense extract (50, 250 and 500 mg/kg, p.o.) in 3 percent Tween 80 0.9 percent saline solution. The treatment of the edema induced by carrageenin with HBSE (500 mg/kg) showed significant inhibition when compared to the control group. At this dose, the edema decreased by 31.25 percent in the third hour after treatment (edema peak), but the dose of 50 mg/kg has inhibited the edema by 53.13 percent (p < 0.05). At the dose of 50 mg/kg, the decrease of the edema induced by dextran was similar to that caused by cyproheptadine. The decrease of the formation of granulomatous tissue (6.6 percent) was comparable to the control group. The HBSE inhibited the abdominal constrictions induced by acetic acid. At a dose of 50 mg/kg, the inhibition of the abdominal constrictions (46.4 percent) was comparable to that produced by indomethacin (42.9 percent). A dose of 250 mg/kg inhibited these constrictions by 70.66 percent when compared to control (p < 0.001). In the hot-plate test, an increase in the latency time was observed at a 50 mg/kg dose. These data suggest that HBSE has anti-inflammatory activity on acute process, developed principally by arachdonic acid derivates and analgesic effect due to its probable involvement in the Central Nervous System.

Effects of the essential oil obtained from Pilocarpus spicatus Saint-Hilaire (Rutaceae) on the development of Rhodnius prolixus nymphae

Bioassays against fifth-instar nymphae of Rhodnius prolixus were conducted with essential oil of Pilocarpus spicatus extracted by hydrodistillation. The main results may be summarized as follows: (i) high levels of toxicity and paralysis together with discrete moulting inhibition were caused by topical application of either 0.5 µL or 1.0 µL per insect of the crude essential oil; (ii) partial fagoinhibition, high moulting inhibition, prolonged intermoulting period and high number of paralyzed insects, but no toxicity were observed after oral treatment using either 5 µL or 10 µL of Pilocarpus spilcatus essential oil per mL of ingested blood meal. The importance of these results in relation to the relevant biological events in R. prolixus is herein discussed.

Bioensaios contra ninfas de 5º estádio de Rhodnius prolixus foram conduzidos utilizando-se óleo essencial de Pilocarpus spicatus extraído por hidrodestilação. Os principais resultados podem ser resumidos como se segue: (i) altos níveis de toxicidade e paralisia associados à discreta inibição da muda foram induzidos pela aplicação tópica de 0,5 µL ou 1,0 µL do óleo essencial por inseto; (ii) fagoinibição parcial, altos níveis de inibição da muda, período intermuda prolongado e alto número de insetos paralisados mas ausência de toxicidade foram observados após tratamento oral com 5,0 µL ou 10 µL de óleo essencial de P. spicatus por mL de sangue ingerido. A importância destes resultados em relação a eventos biológicos relevantes em R. prolixus é aqui discutida.

The official use of medicinal plants in public health

Medicinal plants are widely employed in both rural and urban Brazil, many in accordance with traditional practices that were developed by the native population or were brought to the country by immigrant peoples from Europe, Africa and Asia. Their use in official public health care requires however more than traditional knowledge. Recently published laws which will come into force by the end of the century, require that scientific evidence be brought to support the popular use, that possible toxicity, especially when chronic use is contemplated, be known to the medical profession and that the raw plant material and final formulation have a chemical composition that lies within limits that can be specific and checked by analysis. Clinical evidence of efficacy should be provided and wherever possible some indication of the mechanism of action and what components of the original plant contribute to this action, are desirable. At the same time, once a plant of given chemical compositon is approved for use, then its widespread production must be organized in such a way that suppy of a product of established quality meets the demand.