Chiang Mai Journal of Science

 Papain and bromelain, the protease enzymes from papaya (Carica papaya) latex and pineapple (Ananas comosus) fruits were extracted and purified by the simple precipitation method, with the percentage yields of 16.76 and 0.97%w/w and the molecular weight of 23 and 25 kDa as same as their standards, respectively. The standard papain exhibited higher free radical scavenging activity than the standard bromelain of 400 times. The extracted papain gave lower free radical scavenging activity than the standard papain of 560 times. Both the standard and extracted papain inhibited the lipid peroxidation similar to the standard vitamin C and E, while both the standard and extracted bromelain did not show this activity. All protease enzymes at 25 µg/ml did not only show any cytotoxicity by the sulforhodamine B assay, but exhibited an interesting relative MMP-2 stimulation by zymography on human skin fibroblasts. The extracted papain gave the highest MMP-2 stimulatory activity at 2.10±0.1 folds of the control which were higher than the standard papain, the standard and extracted bromelain of 1.04, 1.31 and 1.24 times, respectively. This study has suggested that the extracted papain from plant can be further developed for the treatment of keloids and hypertrophic scars.