ISOLATION, IDENTIFICATION, AND ANTIOXIDANT ACTIVITY OF CHEMICAL COMPOUND IN ETHANOL EXTRACT OF PAPAYA LEAVES (CARICA PAPAYA L.)

Objective: The purpose of this research was to isolate and identify the active antioxidant compound in ethanol extract of papaya leaves (Carica papaya L.).Methods: The methods used were fractionation using vacuum liquid chromatography (VLC), and the active fraction was purified using column chromatography (CC). The pure isolate was obtained with preparative thin-layer chromatographic (TLC) identified by spectroscopy. Its antioxidant activity was evaluated using 2,2-diphenyl-picryl-hydrazyl. The presence of phenols was analyzed using ultraviolet (UV)-visible, Fourier-transform infrared (FTIR), and gas chromatography (GC)–mass spectrometry (MS).Results: The results showed that ethanol extract of papaya leaf has a strong antioxidant activity with IC50 value of 100.0±0.07 ppm. The result of VLC fractionation using mobile phase of chloroform-methanol indicated that the active fraction was EtOH.3 that has antioxidant activity with IC50 of 121.6±0.66 ppm. The purification using CC produced active fraction EtOH.3.3 with IC50 value of 176.4±0.76 ppm. After identified, the active isolate compound EtOH.3.3.1 from preparative TLC, the results of UV-visible spectrophotometry, FTIR spectrophotometry, and GC–MS show the presence of the phenol compounds.Conclusion: The ethanol extract has antioxidant activity and the extract was suspected to contain 2-methoxy-4-vinylphenol compound.

High Pressure Liquid Chromatographic Determination of Aflatoxins in Soy Sauce and Fermented Soybean Paste

A procedure for the quantitative determination of aflatoxins B1, B2, G1, and G2 in soy sauce and fermented soybean paste is proposed using high pressure liquid chromatography with ultraviolet detection after CB extraction and SEP-FAK and preparative thin layer chromatographic cleanups. Recoveries of 71.3 to 89.3% were obtained for soy sauce spiked with 1, 5, 20, and 100 ppb aflatoxins. Similar recoveries (77.0 to 90.8%) were obtained with concentrated soy sauce and fermented soybean paste spiked at 20 and 100 ppb. In comparison with other procedures, the proposed procedure is relatively fast and precise and gives good recoveries. Aflatoxins were not stable in soy sauce. During storage, half of aflatoxins B1, and G1, were deteriorated at 60 and 120 days, respectively.