Abstract

In this study, three types of solvent extracts from two cultivars of papaya fruit (Hongkong and Eksotika) were used to examine the effects of extraction solvent on total phenolics content (TPC), total flavonoids content (TFC) and antioxidant activity by ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picryl hydrazyl radical scavenging (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) were determined spectrophotometrically. Results showed that extraction solvent had significant effects on TPC, TFC, and antioxidant activity of methanol and acetone extract. The highest content of TPC, TFC and antioxidant activity (FRAP, DPPH and ABTS) were found in 50% methanol and 50% acetone extracts. The TPC varied for both cultivars (Hongkong and Eksotika) from 16.35 to 46.65, 67.50 to 23.38 mg gallic acid/100 g fresh weight, and TFC were between 19.40 and 36.17, 39.81 and 21.04 mg quercetin/100 g fresh weight and antioxidant activity (FRAP from 124.84 to 90.23, 190.59 to 159.98 mg Trolox equivalents/100 g fresh weight), DPPH were between 47.82 and 28.72%, 74.56 and 38.57%) and (ABTS from 57.34 to 31.49% and 69.06 to 34.84%), respectively. The largest amount of TPC and TFC which leads to more effective radical scavenging effect was shown by 50% methanol extract. Moreover, amount of phenolic compounds and antioxidant activities increased in methanol and acetone extract. Therefore, a positive correlation occurred between antioxidant activity and phenolics compound. Methanol 50% and acetone 50% solvent showed the greatest capability in extracting antioxidants and inhibiting the free radicals produced. It was concluded that extraction solvent play important roles on the phenolics compounds and their antioxidant activity of papaya fruit extract.

Key words: Papaya, extraction solvent, antioxidant activity, phenolic compound.