No abstract

Pesquisas em Plantas Alimentícias Não Convencionais (PANC) quanto à presença de compostos bioativos e antimicrobianos são escassas e a ampliação do conhecimento a respeito de suas propriedades torna-se necessária. Neste estudo, quatro tipos diferentes de extratos (aquosos e hidroalcoólicos obtidos por refluxo e sonicação) de ora-pro-nóbis (Pereskia grandifolia Haw) foram investigados quanto à presença de compostos fenólicos, antioxidantes e antibacterianos. Os extratos de Pereksia grandifolia Haw obtidos por refluxo foram mais eficientes do que a sonicação, pois extraíram uma quantidade maior de compostos fenólicos, antioxidantes, flavonas e flavonóis. Em relação ao solvente, detectou-se que o hidroalcoólico permitiu uma maior quantificação de flavonóides totais (flavonas e flavonóis, flavanonas e di-hidroflavonóis) e antioxidantes (medidos pelos métodos de DPPH, molibdato e poder quelante). Quando a água foi usada como solvente extrator, maiores quantidades de compostos fenólicos totais e antioxidantes (medidos pelo DPPH e poder quelante) foram observados. Todos os extratos apresentaram atividade inibitória contra Staphylococcus aureus e Pseudomonas aeruginosa, sendo os extratos aquosos obtidos por refluxo e sonicação os que apresentaram maiores halos de inibição. Porém, quando a concentração minima bactericida foi determinada, apenas o extrato hidroalcoólico obtido por refluxo apresentou resultado efetivo nas concentrações testadas. A caracterização e quantificação dos compostos fenólicos, antioxidantes e antibacterianos de Pereskia grandifolia Haw fornecem informações importantes para aumentar o uso dessa planta, como fonte alternativa de compostos benéficos à saúde, e com potencial antimicrobiano.

The phenolic compound content, the antioxidant and α-amylase inhibition potentials of different extracts of the Plectranthus amboinicus, P. barbatus and P. ornatus were evaluated. We also evaluated the influence of plant growth and harvest time on the chemical composition of the essential oil (EO) of P. amboinicus, its antioxidant and anti-Candida activities and the α-amylase and lipoxygenase inhibitions. The turbo-extract of P. barbatus showed the greatest phenolic compound content and antioxidant activity. No α-amylase inhibition activity was observed in the analyzed extracts, but the turbo-extraction and refluxing extracts possessed high antioxidant activities. Protected cultivation and morning harvest conditions gave the best antioxidant activities, which was associated to the highest carvacrol content. P. amboinicus EO antioxidant activity could contribute to the reduction of oxidative stress in diabetes. Causal Candida strains of diabetic foot ulcers showed sensitivity to P. amboinicus EO. C. albicans and C. dubliniensis were the most sensitive of the selected Candida strains. Turbo-extracts or refluxing of the three species extracts and the EO of P. amboinicus should be considered as a potential candidate for the management the complications of type 2 diabetes.

An increase in crop productivity should be linked to the effective control of production costs. Thus, the chemical and selective control of weeds is an appropriate method because it saves labor and energy, requires little manpower, and allows control throughout the crop cycle. The present study aimed to evaluate the sensitivity of avocado seedlings to the phytotoxic effects of postemergence herbicide application. The experiment was carried out on avocado seeds of the cultivar Margarida in a greenhouse in the fruit sector of the Department of Agriculture, Federal University of Lavras. The experimental design was randomized block design, with four replicates and eight treatments, and each experimental plot consisted of three seedlings. The herbicides paraquat, oxyfluorfen, fomesafem, carfentrazone-ethyl, and glyphosate caused damage to avocado seedlings and should not be recommended based on the commercial dosage used. Paraquat caused the plants to die within 30 days after application. Fluazifop-p-butyl and imazethapyr proved to be the most promising for use in avocado orchards because they caused less damage to the crop.

The purpose of the present work was to evaluate the vegetative growth of Mentha piperita L. cultivated under different water availability, as well its influence in content, chemical composition and in vitro antioxidant activity of its essential oil. Plants were propagated by mother plants microcutting and scions were transplanted to 5 L pots with soil and cattle manure. Afterward, were kept at field capacity for 30 days and under treatment for 40 days. It was treated with different levels of water deficit treatments: (T1): 100 of field capacity (FC); (T2): 80 of FC; (T3): 60 of FC; (T4) 40 of FC with 5 blocks. Vegetative growth was evaluated by dry matter contents of all part of plants and by root/aerial rate. The essential oil of the leaves was extracted by hydrodistillation, analyzed by GC-FID and GC-MS and in vitro antioxidant potential was evaluated. A significant decrease in the dry matter of leaves and stems accompanied with a decrease in the roots dry matter was observed with an increase in the water stress. Quantitative chemical differences were observed in the chemical composition of the essential oil, according water availability. Total antioxidant activity showed a gradual increase as water stress progressed.