Fresh leaves of A. marmelos were picked from the tree,
thoroughly washed thrice with deionized water, dried in a hot
air oven at 40–45 8C for 48 h to 6% final moisture content
(analyzed by Sartorious MA-150 moisture analyzer), and then
crushed into powder using a grinder. An intense brown color LE
was obtained by mixing 1 g of leaf powder in 20 mL ultrapure
water (i.e. 5%, w/v) and then heated at 100 8C for 10 min in a hot
water bath. The residue was separated by filtration through
Whatman 42 filter paper and subsequently centrifuged at
20,000 rpm (Sigma, Model No. 3-30K, Germany) to remove very
fine suspended particles