Identification of cinobufagin metabolites in the bile of rats.

Cinobufagin (1) is a major bufadienolide in ChanSu (a traditional Chinese medicine) with a wide range of pharmacological activities. In this paper, the in vivo metabolites of 1 in rats were studied. Nine metabolites were isolated from the bile of rats, and their structures were identified as: desacetylcinobufagin (2), 3-ketodesacetylcinobufagin (3), 3-epi-desacetylcinobufagin (4); 5beta-hydroxy-3-epi-desacetylcinobufagin (5), 1alpha-hydroxy-3-epi-desacetylcinobufagin (6), 12beta-hydroxy-3-epi-desacetylcinobufagin (7), 1beta-hydroxy-3-epi-desacetylcinobufagin (8), 1alpha,5alpha-dihydroxy-3-epi-desacetylcino-bufagin (9), and 2alpha, 5beta-dihydroxy-3-epi-desacetylcinobufagin (10), respectively, on the basis of widely spectroscopic studies including two-dimensional-nuclear magnetic resonance (NMR). Among them, metabolites 6-10 are new compounds. The results show that hydroxylation is the main reaction involved in metabolism of 1, and the preferred hydroxylation sites were C-1 and C-5.

Stabilizing oils from smoked pink salmon (Oncorhynchus gorbuscha).

Smoking of meats and fish is one of the earliest preservation technologies developed by humans. In this study, the smoking process was evaluated as a method for reducing oxidation of pink salmon (Oncorhynchus gorbuscha) oils and also maintaining the quality of oil in aged fish prior to oil extraction. Salmon heads that were subjected to high temperatures (95 degrees C) during smoking unexpectedly produced oils with fewer products of oxidation than their unprocessed counterparts, as measured by peroxide value (PV), thiobarbituric acid reactive substances (TBARS), and fatty acids (FA). Higher temperatures and longer smoking times resulted in correspondingly lower quantities of oxidative products in the oils. Fatty acid methyl ester (FAME) analysis of smoke-processed oils confirmed that polyunsaturated fatty acids (PUFA) were not being destroyed. Smoke-processing also imparted antioxidant potential to the extracted oils. Even when antioxidants, such as ethoxyquin or butylated hydroxytoluene, were added to raw oils, the smoke-processed oils still maintained lower levels of oxidation after 14 d of storage. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 degrees C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. Results suggest that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their usefulness when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.

Antioxidant supplementation may improve renal transplant function: a preliminary report.

Dysfunction of the renal graft may not only be due to rejection but also other causes such as ischemia and reperfusion injury and calcineurin inhibitor nephrotoxicity. Antioxidant free radical scavengers may decrease oxidative stress and lipid peroxidation. Previous animal studies suggest that vitamins C (ascorbic acid) and E (alpha-tocopherol) are both strong antioxidants, that decrease oxidative stress caused by ischemia-reperfusion injury and calcineurin inhibitor nephrotoxicity. But there have been only limited reports about clinical efficacy. We report five cases supplemented with vitamin C (500 mg per day), vitamin E (500 mg per day), or both. After a 1- to 3-month prescription, the serum creatinine level decreased more than 20% from the original value. Interestingly, one patient had this experience: he ceased vitamin E for 1 month due to noncompliance. The serum creatinine level increased more than 50%. When he took vitamin E again, his serum creatinine level declined and returned to the previous level. From our limited experience, antioxidant supplementation with vitamin C or E may improve renal transplant function, especially in grafts donated from marginal donors.