Materials and Methods
Preparation of pineapple shell extracts (PSE)
The shells of pineapple at ripening stage 4 were obtained from Dole Thailand Ltd. It was
blended in liquid N2, then extracted with distilled water at 1:2 (w/w) by using magnetic stirrer for 20
min and filtered the extract with Whatman paper filter No.4. The supernatant was pineapple shell
extract (PSE) used for further study.