RESUMO

Arthropod-borne viral diseases are important public health threats in tropical countries. In the Americas, diseases such as Dengue, Zika, Chikungunya, Mayaro, and Yellow fever, which are mainly transmitted by Aedes aegypti L. are responsible for high rates of morbidity and mortality in the populations. The incidence of those viruses has increased in the last few years, due to the decrease of vector control programs, as well as, the resistance of this vector in front of many products that have been used in this proposal. Plant-based products such as essential oils are a promising alternative for Ae. aegypti control. In this context, the present work aims to investigate the seasonality effect on the larvicidal potential and safety of essential oils from 4 endemic plants of the Brazilian Amazon, as well as to verify their larvicidal activity and safety. The species were collected in the rainy and dry periods (Eugenia uniflora L., Lantana camara L., Ocimum basilicum L., Plectranthus neochilus Schlrt.). The essential oils were extracted by hydrodistillation and chemical composition was determined by gas chromatography coupled to mass spectrometry. The larvicidal activity was performed according to the methodology recommended by the World Health Organization. The safety of the oil use was evaluated against two non-target organisms: Artemia salina Leach and Danio rerio Hamilton Buchanan. Essential oils of E. uniflora, L. camara, O. basilicum, P. neochilus, presented as major compounds, in both collection periods, the substances Curzerene, Germacrene D, Methyl chavicol and, Caryophyllene, respectively. However, showed a qualitative and quantitative variation of this composition. All oils showed promising results against Ae. aegypti larvae with LC50 between 41.7 and 275.8 µg/mL. They were efficient against Ae. aegypti but showed high toxicity to non-target organisms, requiring additional safety studies. Despite these results showing that those essential oils are not ideal larvicides because they presented toxicity to non-target organisms, bioprospection is a promising tool to help reduce the dissemination of arboviruses, and they can use in artificial breeders of Ae. aegypti larvae, where water will not be reused for human consumption or have other cohabiting organisms.

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RESUMO

Essential oil from the leaves of Artemisia vulgaris L. (Compositae) cultivated in Brazil was investigated for its chemical composition and biological activities including antibacterial, antifungal, and anthelmintic. The constituents of essential oils isolated by hydro-distillation were examined by GC-MS and a total of 18 components were identified. The essential oil was dominated by oxygenated sesquiterpenes (44.4%), sesquiterpene hydrocarbons (33.3%), and oxygenated monoterpenes (16.6%). Caryophyllene (37.45%), germacrene D (16.17%), and humulene (13.66%) were the major components. The essential oils from A. vulgaris showed bactericidal and fungicidal properties against Staphylococcus aureus and Candida albicans, respectively. Anthelmintic activity against Haemonchus contortus was absent in this essential oil. Altogether above results indicate that essential oils from A. vulgaris can be used for various medicinal purposes.

RESUMO

Exudates released from plants, consist of complex mixtures of organic and inorganic molecules that have been used in traditional medicine from several years. They may vary among genera, species or within a genus and mainly include latex, sap, gums, resins, seed or root exudates. Plant exudates are known to possess several biological activities including, antimicrobial, anti-inflammatory, antioxidant, wound healing and anti-nociceptive. Exudates oozed out from plants have also been used as ingredients in medicines, food, perfumes and cosmetics. The present review provides brief overview about the exudates released from plants, their biological properties and beneficial effects for human beings. Due to the presence of various compounds, different methodologies and procedures have been employed for their collection and analyses. Literature studies suggest that plant exudates have extensive therapeutic potential for curing diseases with minimal toxic effects. This aspect could be taken into account in prospective studies regarding the search of new products derived from plant exudates with pharmaceutical value.

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RESUMO

Mentha piperita L. (peppermint) possesses antimicrobial properties, but little is known of its ability to modulate macrophages. Macrophages are essential in bacterial infection control due to their antimicrobial functions and ability to link the innate and adaptive immune responses. We evaluated the effects of the peppermint leaf hydroalcoholic extract (LHAE) on cultured murine peritoneal macrophages stimulated or not with lipopolysaccharide (LPS) in vitro. Vehicle-treated cells were used as controls. The constituents of the extract were also identified. Epicatechin was the major compound detected in the LHAE. LPS-induced macrophage death was reversed by incubation with LHAE (1-30 µg/ml). Higher concentrations of the extract (≥100 µg/ml) decreased macrophage viability (49-57%) in the absence of LPS. LHAE (1-300 µg/ml) attenuated H2O2 (34.6-53.4%) but not nitric oxide production by these cells. At similar concentrations, the extract increased the activity of superoxide dismutase (15.3-63.5-fold) and glutathione peroxidase (34.4-73.6-fold) in LPS-treated macrophages. Only LPS-unstimulated macrophages presented enhanced phagocytosis (3.6-6.6-fold increase) when incubated with LHAE (3-30 µg/ml). Overall, the LHAE obtained from peppermint modulates macrophage-mediated inflammatory responses, by stimulating the antioxidant pathway in these cells. These effects may be beneficial when the excessive activation of macrophages contributes to tissue damage during infectious disease.

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