Chemical derivatization of natural extracts obtained from Larrea divaricata Cav. increase in the antioxidant activity and protein precipitating capacity

Abstract

In the present work modified extracts of Larrea divaricata was obtained bychemical transformations in order to improve the antioxidant activity and theprotein precipitating capacity. Apigenine-7-methylether, quercetin, nordihydroguaiaretic acid, 3,4-dihydroxy-3,4-dimethoxy-6,7-cyclolignan and pcoumaricacid were identified in the methanolic extract by Electron Impact MassSpectrometry (EIMS). Chemically modified extracts were prepared through acidhydrolysis, sulfonylation, O-methylation, O-acylationand C-acylation reactions.Total phenolics and flavonoids contents were determined by spectrophotometricmethods. Antioxidant properties were evaluated by 2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2′-azinobis(3-ethylbenzthiazoline-6-acid) (ABTS) and ferric ionreducing power. In addition, the protein precipitating capacity was evaluated intwo protein system and significant changes were observed. Methanolic extractcontaining the highest amount of phenolic compounds and flavonoids exhibitedsignificative antioxidant activity. The hydrolyzed methanolic extract increasedtheir antioxidant properties. However, C-acylated and O-acylated methanolicextracts were the most active. In addition, these extracts revealed the highestprotein precipitating capacity in both protein system. In relation to obtainbioproducts, these results show that antioxidant activity and the proteinprecipitating capacity can be increased by chemical modifications of the naturalorganic extracts.