Modification of the Antioxidant Capacity of Plant Extracts by Acid and Enzimatic Hydrolysis

BASSANI, G; MICHELONI, O; LOPEZ, SN; FURLAN, RLE

Ouro Preto

Congreso; VII Meeting of the Latin American Society of Phytochemistry - 3rd Brazilian Conference on Natural Products; 2011

Universidad de Mina Gerais, etc

The study of plant extracts as sources of compounds with palliative or curative effects on diseases goes back to the earliest moments of history. One active area research is the search for new antioxidant natural products. It is known that the excess of reactive oxygen species can lead to the oxidation of lipids, DNA, proteins, carbohydrates and other biological molecules that can cause DNA mutation and/or damage to cells or tissues and, consequently, senescence and cell death. Such oxidative damage is considered to be associated with several degenerative diseases. A complementary approach to the traditional methodology of investigation of natural products is the directed chemical modification of natural extracts to affect their biological properties.3 Since the cleavage of glycosidic linkages has shown to affect the antioxidant properties of natural products; we decided to study such reaction to produce chemically engineered extracts and to evaluate the changes introduced in antioxidant properties. In this work, we initially carried out the acid and the enzymatic hydrolysis of crude extracts of several edible or medicinal herbaceous plants. In parallel, each crude extract was partitioned with solvents of increasing polarity to produce a series of sub-extracts that were also subjected to hydrolysis with HCl-ethanol and almond b-glucosidase. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of natural and hydrolyzed mixtures were compared. The two hydrolysis protocols used affected the antioxidant properties of different natural mixtures. This was particularly noticeable when the butanol and aqueous sub-extracts of Dipsacus fullonum, Lamiun ampleuxicaule, Nicotiana longiflora and Rapistrum rugosum species were studied. This strategy is a promising alternative for obtaining active antioxidants in plant extracts.