2.1. Materials

Sappan heartwood powder was purchased from Lan Laung Co., Ltd. (Bangkok, Thailand). Commercial bovine gelatin (type B, 150 Bloom) was obtained from Nutrition SC Co., Ltd. (Nakhonpathom, Thailand). Glycerol was purchased from Merck (Darmstadt, Germany). 2,4,6-tripyridyl-s-triazine (TPTZ) was purchased from Acros Organics (Geel, Belgium). 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) were purchased from Aldrich (Steinheim, Germany). Mueller-Hinton broth, agar powder, Escherichia coli TISTR 527, and Staphylococcus aureus TISTR 746 were received from Mae Fah Luang University’s Biological Laboratory (Chiang Rai, Thailand).