Antioxidant activity of Moringa oleifera tissue extracts.

Moringa oleifera is an important source of antioxidants, tools in nutritional biochemistry that could be beneficial for human health; the leaves and flowers are used by the population with great nutritional importance. This work investigates the antioxidant activity of M. oleifera ethanolic (E1) and saline (E2) extracts from flowers (a), inflorescence rachis (b), seeds (c), leaf tissue (d), leaf rachis (e) and fundamental tissues of stem (f). The radical scavenging capacity (RSC) of extracts was determined using dot-blots on thin layer chromatography stained with a 0.4 mM 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) solution; spectrophotometric assays were recorded (515 nm). Antioxidant components were detected in all E1 and E2 from a, b and d. The best RSC was obtained with E1d; the antioxidants present in E2 reacted very slowly with DPPH. The chromatogram revealed by diphenylborinate-2-ethylamine methanolic solution showed that the ethanolic extract from the flowers, inflorescence rachis, fundamental tissue of stem and leaf tissue contained at least three flavonoids; the saline extract from the flowers and leaf tissue revealed at least two flavonoids. In conclusion, M. oleifera ethanolic and saline extracts contain antioxidants that support the use of the plant tissues as food sources.

Determining the genotoxicity of an aqueous infusion of Bauhinia monandra leaves / Determinação da genotoxicidade do infuso aquoso das folhas da Bauhinia monandra

Bauhinia monandra, commonly known as "cow's-foot", is native from Asia and widely used all over the world to treat a variety of illnesses, in particular diabetes. The high usage of the plant in Brazil and to fulfill the need of medicinal plant regulation by the Ministry of Public Health, we aimed at determining the genotoxicity, cytotoxicity and mutagenicity of an aqueous infusion from B. monandra leaves. The results were correlated to the chemical compounds found after phytochemical selection. Tests were performed in an in vitro system with plasmid DNA, in the presence and absence of exonuclease III, and in vivo system employing prokaryotic (transformation into competent DH10B bacteria) and eukaryotic (Allium cepa) assays. The infusion concentrations were 0.8 µg/µL, 4 µg/µL, 20 µg/µL and 100 µg/µL. The infusion concentrations did not cause mutagenicity or cytotoxicity, however the highest concentrations were able to induce breaks in DNA phosphodiester bonds and form abasic sites, an effect suggested by the presence of phenolic hydroxyls. The results revealed risks and benefits of plant extracts for therapeutic use and their effect on genetic integrity, especially when commonly employed as a hypoglycemic.

Bauhinia monandra, popularmente conhecida como "pata-de-vaca", é nativa da Ásia e amplamente utilizada em todo o mundo para o tratamento de várias doenças, em especial diabetes. Diante da grande utilização dessa planta no Brasil, e de forma a satisfazer a necessidade de regulamentação das plantas medicinais pelo Ministério Público de Saúde, objetivamos determinar a genotoxicidade, citotoxicidade e mutagenicidade do infuso aquoso das folhas da B. monandra. Os resultados foram correlacionados com os compostos químicos encontrados após realização de uma triagem fitoquímica. Os testes foram realizados em sistema in vitro como o DNA plasmidial, na presença e ausência de exonuclease III, e in vivo empregando sistema procarioto (transformação com bactérias competente DH10B) e eucarioto (teste Allium cepa). As concentrações do infuso foram 0,8 µg/µL, 4 µg/µL, 20 µg/µL e 100 µg/µL. Nessas concentrações o infuso não causou mutagenicidade ou citotoxicidade, porém as concentrações mais elevadas foram capazes de induzir quebra nas ligações fosfodiéster do DNA e formar sítios abásicos, efeito sugerido pela presença de hidroxilas fenólicas. Os resultados revelaram riscos e benefícios desse extrato vegetal para uso terapêutico e seus efeitos sobre integridade do material genético, especialmente quando empregados como hipoglicêmico.