A família Lauraceae destaca-se pela predominância na composição florística de grande parte dos ecossistemas florestais do país e pelo seu potencial aromático, madeireiro e medicinal. Estudos mostram que estas espécies são compostas quimicamente por alcalóides, neolignanas, sesquiterpernos, fenilpropanóides, flavonóides e taninos, classes de metabólicos especiais que têm mostrado muita atividade biológica, tais como vermífugas, antibacterianas, inseticidas e antioxidantes. A procura de substâncias naturais, biologicamente ativas, tem encorajado a utilização de substâncias como agentes antioxidantes em alimentos e em medicamento à base de plantas. Espécies reativas de oxigênio (EROs) são formadas e degradadas por organismos aeróbicos, sendo sua formação conduzida a concentrações fisiológicas, requeridas para a função celular normal, ou quantidades excessivas que levam ao aumento do estresse oxidativo , o que tem levado a fisiopatologia de várias doenças crônicas, tais como arteriosclerose, câncer, e doenças degenerativas. Dessa forma, a descoberta de novas substâncias com capacidade antioxidante pode ser de grande relevância na prevenção e terapêutica de doenças relacionadas com o aumento do estresse oxidativo. O objetivo deste trabalho é avaliar a atividade antioxidante dos extratos etanólicos de espécies pouco conhecidas da família Lauraceae através dos ensaios espectrofotométrico com o radical 2,2 difenil-1-picril-hidrazil (DPPH ), o radical 2,2 -azinobis-(3-etilbenzotiazolina-6-ácido sulfônico) (ABTS +), com os fenóis totais e com superóxido, determinando assim a capacidade e o potencial de novas espécies vegetais na captura de radicais livres.

The essential oil composition of the Ocotea bicolor, native plant of Brazil, was studied for the first time. The essential oil of the leaf was obtained by hydrodistillation and analyzed by GC/MS. The analytical procedure revealed a predominance of sesquiterpenes, δ-cadinene (7.39%), β-sesquiphellandrene (6.67%), β-elemene (5.41%) and α-cadinol (5,23%). The essential oil was submitted to brine shrimp toxicity evaluation, antioxidant and antibacterial tests. The antioxidant activity by the formation of phosphomolybdenum complex method presented positive results. The minimum inhibitory concentration (MIC) values were higher than 1000 μg/mL for the microorganisms tested. Toxicity activity revealed LC50 results of 40.10 (μg/mL), being toxic to the organisms in this study.

The article has aimed to characterize the essential oil extracted from Ocotea diospyrifolia (Meisn.) Mez. leaves, in terms of its chemical composition and antioxidant, hemolytic, and phytotoxic potentials, as well as its toxicity against Artemia salina. The major constituents identified by CG-MS were δ-elemene, spathulenol, and β-atlantol. When screened for potential biological activities, the essential oil presented low toxicity against Artemia salina, and a capacity of lysing red blood cells. Also, the evaluation of its in vitro antioxidant activity, using the phosphomolybdenum method, showed better results when compared to butylhydroxytoluene (BHT) and rutin. In conclusion, the results obtained showed certain in vitro toxicity, leading to an interesting target for cytotoxicity evaluations of carcinoma cells.

Essential oils from four Ocotea species collected in southern Brazil were evaluated for chemical composition using gas chromatography coupled with mass spectrometry. The primary compound identified in O. acutifolia essential oil was an unsaturated tetracyclic diterpene, phyllocladene (67.7%), followed by a sesquiterpene hydrocarbon, β-selinene (18.0%). The sesquiterpene fraction was predominant in oils from two collections of O. puberula; β-caryophyllene (25.2%) and globulol (22.6%) were the major compounds identified in collections 1 and 2, respectively. O. silvestris essential oil contained predominantly germacrene D and bicyclogermacrene. These compounds were also predominant in essential oil from O. indecora leaves collected from shady habitats. By contrast, essential oil extracted from O. indecora grown under direct sunlight contained mainly oxygenated sesquiterpenes, such as guaiol (30.2%), α-eudesmol (27.6%), and β-eudesmol (12.7%). Chemotaxis assays showed that Ocotea essential oils had no significant inhibitory activity on leukocyte migration compared with a chemotactic stimulant (lipopolysaccharide from Escherichia coli). However, the oils exhibited antifungal activity against Candida parapsilosis, with a minimum inhibitory concentration of 500 µg/mL. To our knowledge, this is the first study to investigate the in vitro antifungal and antichemotactic activities of essential oils from Ocotea species native to southern Brazil.

Hybridization and introgression are complex evolutionary mechanisms that can increase species diversity and lead to speciation, but may also lead to species extinction. In this study, we tested the presence and genetic consequences of hybridization between the rare and Ecuadorian endemic O. loxensis van der Werff and the widespread O. infrafoveolata van der Werff (Lauraceae). Phenotypically, some trees are difficult to identify, and we expect that some might in fact be cryptic hybrids. Thus, we developed nuclear microsatellites to assess the existence of hybrids, as well as the patterns of genetic diversity and population structure in allopatric and sympatric populations. The results revealed high levels of genetic diversity, even in the rare O. loxensis, being usually significantly higher in sympatric than in allopatric populations. The Bayesian assignment of individuals into different genetic classes revealed a complex scenario with different hybrid generations occurring in all sympatric populations, but also in allopatric ones. The absence of some backcrossed hybrids suggests the existence of asymmetric gene flow, and that some hybrids might be more fitted than others might. The existence of current and past interspecific gene flow also explains the blurring of species boundaries in these species and could be linked to the high rates of species found in Ocotea.

The major components of Laurus nobilis and L. novocanariensis leaf oils were identifi ed and their acaricidal activity against Psoroptes cuniculi evaluated. Monoterpenes were predominant in L. nobilis oil (91.8%), while ses quiterpenes were only 1.4%. The main components of this oil were 1,8-cineole (39.2%), α-terpinyl acetate (11.3%), sabinene (10.6%) and linalool (7.4%). The acaricidal activity of L. nobilis oil, at a concentration of 10%, led to a mortality rate of 73%; at 5% the average activity was signifi cantly reduced to 51%, while dilutions of 2.5%, 1.25% and 0.625% were ineffective. Laurus novocanariensis oil, compared to L. nobilis, was richer in sesquiterpenes; the main constituents were α-pinene (10.4%), 1,8-cineole (9.6%) and β-selinene (7.2%). After 24 h of contact, the oil of L. novocanariensis killed all the mites when used at 10% and 5% concentrations. At lower concentrations the mortality signifi cantly decreased; a dilution of 0.625% was ineffective.

Methanolic leaf extracts of four Lauraceae species endemic to Laurisilva forest (Apollonias barbujana, Laurus novocanariensis, Ocotea foetens and Persea indica) were investigated for the first time for their potential to inhibit key enzymes linked to type-2 diabetes (α-amylase, α-glucosidase, aldose reductase) and obesity (pancreatic lipase), and protein glycation. Lauraceae extracts revealed significant inhibitory activities in all assays, altough with different ability between species. In general, P. indica showed the most promissing results. In the protein glycation assay, all analysed extracts displayed a stronger effect than a reference compound: aminoguanidine (AMG). The in vitro anti diabetic, anti-obesity and anti-glycation activities of analysed extracts showed correlation with their flavonols and flavan-3-ols (in particular, proanthocyanins) contents. These Lauraceae species have the capacity to assist in adjuvant therapy of type-2 diabetes and associated complications, through modulation of the activity of key metabolic enzymes and prevention of advanced glycation end-products (AGEs) formation.