RESUMO
Bauhinia monandra Kurz. is used in Brazil for the treatment of diabetes. Since this activity may be correlated with the presence of antioxidant compounds, leaf extracts of B. monandra were evaluated for their radical scavenging capacity (RSC). An ethanolic extract was taken up in aqueous methanol and partitioned with hexane, chloroform, ethyl acetate to yield three organic extracts together with remaining aqueous extract. The RSC was determined spectrophotometrically using 1,1-diphenylpicrylhydrazyl free radical (DPPH). The chloroform and ethyl acetate extracts were the most appropriate as sources of antioxidant compounds as shown by their inhibition concentration (IC50) and inhibition percentage (IP) values. The antioxidant activity of such extracts was attributed to the presence of three compounds of different polarities (flavonoids and steroids). The chloroform and ethyl acetate extracts exhibited an IC50 of approximately 2 mg/g DPPH and IP values in the range of 60-65%. The results indicate that the extracts of B. monandra have a very potent antioxidant activity, compared with the pure catechins used as positive controls and with other plant extracts.
Assuntos
Antioxidantes/metabolismo , Bauhinia/química , Compostos de Bifenilo/metabolismo , Sequestradores de Radicais Livres/metabolismo , Hidrazinas/metabolismo , Folhas de Planta/química , Acetatos , Clorofórmio , Cromatografia em Camada Fina , Hexanos , Concentração Inibidora 50 , Cinética , Picratos , Extratos Vegetais/metabolismo , EspectrofotometriaRESUMO
Transgenic roots of Solanum spp. containing extra copies of an hmgr gene derived from Artemisia annua have been obtained via transformation with Agrobacterium rhizogenes. Hairy root clones of Solanum aviculare which were transgenic for hmgr typically grew faster than those which did not contain extra copies of this gene and also accumulated up to 4.2 times more solasodine when grown under dark, but not light, conditions. The implications of these findings with respect to the regulation of solasodine production in Solanum spp. are considered.
Assuntos
Raízes de Plantas/metabolismo , Rhizobium/genética , Solanaceae/metabolismo , Alcaloides de Solanáceas/biossíntese , Cromatografia Líquida de Alta Pressão , Técnicas de Cultura , Escuridão , Hidroximetilglutaril-CoA Redutases/genética , Hidroximetilglutaril-CoA Redutases/metabolismo , Luz , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Rhizobium/enzimologia , Solanaceae/genética , Alcaloides de Solanáceas/metabolismo , Simbiose , Transformação GenéticaRESUMO
Two novel approaches, the use of Agrobacterium-transformed plant roots and mycelia cultures of fungi, are considered as research tools in the study of the remediation of soil, groundwater, and biowastes. Transformed roots are excellent model systems for screening higher plants that are tolerant of various inorganic and organic pollutants, and for determining the role of the root matrix in the uptake and further metabolism of contaminants. Edible and/or medicinal fungi may also be natural environmental remediators. Liquid cultures of fungal mycelia are appropriate model systems with which to commence screening and biochemical studies in this under-researched area of biotransformation.
