Glucosides from the unripe fruit juice of Carica papaya Linn. (Caricaceae) cultivar 'Red Lady' with antioxidant activity

Natural antioxidants from Carica papaya ('Red Lady' cultivar) were investigated. Reversed phase chromatography of the fruit juice gave 12 fractions that were subjected to DPPH and hydroxyl radical scavenging assays. Purification of Cp7 afforded isopropyl 5-β-D-glucopyranosyloxy-2-hydroxybenzoate (1) while the methanol fractions Cp8-10 afforded methyl β-D-glucopyranoside (2). This is the first report on the isolation of these compounds from C.papaya. Compound (1) showed significant DPPH radical scavenging capacity. Compound (2) was an isolate giving 77% DPPH and 81% hydroxyl radical scavenging activities, which are close or equal to the values for the standard ascorbic acid (98% DPPH and 81% hydroxyl radical scavenging activities).