Antioxidant Constituents of the Fruits of Euterpe oleracea (Açaí)

Abstract

Euterpe oleracea Mart. (Arecaceae), of which the fruits are commonly known as “açaí”, grows in the northern regions of South America. The fruits of E. oleracea are used to make a juice, ice cream, and desserts in Brazil, and are currently exported to other countries in North America, western Europe, and east Asia [1]. Açaí products are new being sold in the United States, and were ranked as a “Hot Supplement” and top-selling botanical dietary supplement in 2005 [2]. Previous phytochemical investigations have shown that anthocyanidins and flavonoids are constituents of the fruits of E. oleracea [3]. Antioxidant activities, a vasodilatory effect, iNOS mediation, and apoptosis induction by açai fruits or its individual constituents have been revealed so far [3–6]. Of these biological activities, antioxidant effects have been reported most commonly, but the individual constituents responsible have not been fully investigated. As part of ongoing investigations of potential cancer chemopreventive agents from botanical dietary supplements, an initial screening procedure using a hydroxy radical-scavenging assay was conducted. A chloroform-soluble extract of the fruits of E. oleracea (açaí) was chosen for phytochemical work-up and biological testing due to its observed antioxidant activity. In the present work, activity-guided fractionation of the fruits of E. oleracea led to the isolation of twenty known compounds including nine lignans not reported previously as constituents of açaí. These lignans were found to be active in the radical-scavenging assay and hence were evaluated for their cytoprotective activity in cultured MCF-7 cells stressed by H2 O2. Acknowledgement: This investigation was supported by start-up funding from The Ohio State University Comprehensive Cancer Center to A.D. Kinghorn (Molecular Carcinogenesis and Cancer Chemoprevention Program).