Xanthine

Noncommercial salacca vinegars made from Pondoh, Gula Pasir, Madura, Madu, and Swaru salacca fruits were prepared according to the method of [12 ]. Chemical composition of salacca vinegar made from selected local salacca types can be seen in Table 1.
White female Wistar rats Rattus norvegicus (age 2.5–3.0 months; body weight 150–200 g) were obtained from laboratory of Pharmacology, Faculty of Health and Biomedicine, Brawijaya University, Malang. Comfeed PARS feed (PT. JapfaComfeed Indonesia Tbk.), miliQ water, Streptozotocin (STZ) (Nacalai Tesque, Kyoto, Japan), ether, Buffer Neutral Formalin (BNF) 10%, HCL 1 N, TCA, Na-Thiobarbiturate, PBS, xanthine, xanthine oxidase, NBT, hematoxylin eosin (HE), and paraffin were all obtained from Laboratory of Pharmacology and Laboratory of Pathology Anatomy, Faculty of Health and Biomedicine, Brawijaya University, Malang.

xanthine oxidase (XO) (Wako, final 5 mU/ml) dissolved in Krebs-HEPES buffer was pre-incubated with DMSO/bortezomib at a volume of 80 μ l in a 96-well white plate on ice for 10 min. Immediately after the addition of 10 μ l of L-012 (final concentration of 100 μ M) and 10 μ l of xanthine (final concentration of 0.2 mM, Nacalai Tesque, Japan), chemiluminescence was measured at 37^°C for 30 min.