Guava leaf extraction
Fresh guava leaves of 10.0 were gorund in 150 mL water (pH 7.0), diluted HCI (pH 4.8) or acetate buffer (pH 4.8) with a blending machine for 5 min. Then the suspension was filtered through filter paper no. 1 (Whatman) and the filtrate was kept at room temperature for further use. The extract was prepared daily.