Fermentation enhances the in vitro antioxidative effect of onion (Allium cepa) via an increase in quercetin content.

Yellow onion (Allium cepa) extract showed enhanced antioxidative effects in 2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant capacity (TEAC) and 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and acetyl ester (CM-H(2)DCFDA) assay after being treated with a crude enzyme extract from soybean paste fungi, Aspergillus kawachii. HPLC analysis showed two increased and two decreased peaks after enzyme treatment. The decreased peaks were identified as quercetin-3,4'-di-O-ß-d-glucoside (1) and quercetin-4'-O-ß-d-glucoside (2), and peaks that increased were quercetin-3-O-ß-d-glucoside (3) and quercetin (4), respectively. It was expected that 3 and 4 were originated from the glucosidic cleavage of their glucosides, 1 and 2. Among the increased compounds, only quercetin (4) showed strong antioxidative activity in the DPPH assay. In addition, the protective effect against glutamate-induced neurotoxicity in HT22 cells was increased when treated with 25 µg/ml of fermented onion. The enhanced neuroprotective effect was also originated from the increased quercetin content. As a consequence, fermentation raised the quercetin content in onion, and subsequently increased the antioxidative and neuroprotective activities.

Changes in aurantio-obtusin and glucoaurantio-obtusin content in Cassiae Semen via treatment with a crude enzyme extract from Aspergillus usamii.

Cassiae Semen (seeds of Cassia tora) showed a remarkably different HPLC chromatogram after being treated with a crude enzyme extract from Aspergillus usamii. Increased and decreased compounds were identified as aurantio-obtusin and glucoaurantio-obtusin, respectively. The aurantio-obtusin content reached its maximum level (133.58 +/- 0.39 microg/mg extract) after being incubated for 50 min at 37 degrees C, whereas the inactivated crude enzyme-treated control remained unchanged (54.13 +/- 1.33 microg/mg). On the other hand, the glucoaurantio-obtusin content decreased by less than one-third (51.09 +/- 1.63 microg/ mg) of the untreated control (143.19 +/- 2.12 microg/mg), suggesting that an increase in aurantio-obtusin content originated from the enzymatic cleavage of its glucoside glucoaurantio-obtusin.

Effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats.

The purpose of this study was to investigate the effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats. Male Sprague-Dawley rats weighing 100 +/- 10 g were randomly assigned to 1 normal group and 3 diabetic groups given a catechin-free diet (DM-0C group), 0.25% catechin diet (DM-0.25C group), or 0.5% catechin diet (DM-0.5C group), respectively. 5'-Lipoxygenase activity in the polymorphonuclear leukocytes significantly increased by 54% in the DM-0C group compared to the normal group, while the level in the DM-0.5C group remained the same as in the normal group. The leukotriene B4 content in the polymorphonuclear leukocytes increased 55% in the DM-0C group compared to the normal group, whereas the DM-0.25C and DM-0.5C groups exhibited the same level as the normal group. The superoxide radical content in the kidney microsomes increased 116% in the DM-0C group when compared to the normal group, yet decreased 29% in the DM-0.25C group and 50% in the DM-0.5C group compared to DM-0C group. The lipofuscin content was 197 and 136% higher in the DM-0C and DM-025C groups, respectively, than in the normal group, whereas the DM-0.5C group exhibited the same content as in the normal group. The carbonyl value increased 118% in the DM-0C group compared to the normal group, and the DM-0.25C and DM-0.5C groups were not significantly different from the DM-0C group. Accordingly, these results indicate that dietary catechin inhibited the generation of superoxide radicals, oxidized protein, and lipid peroxide in the kidney of streptozotocin-induced diabetic rats. Furthermore, green tea catechin supplementation in diabetic rats also appeared to inhibit the production of leukotriene B4 based on regulating the activity of 5'-lipoxygenase, thereby potentially reducing renal oxidative damage and inflammatory reactions.

Action of green tea catechin on bone metabolic disorder in chronic cadmium-poisoned rats.

The purpose of this study was to investigate the effects of green tea catechin on bone metabolic disorders and its mechanism in chronic cadmium-poisoned rats. Sprague-Dawley male rats weighing 100+/-10 g were randomly assigned to one control group and three cadmium-poisoned groups. The cadmium groups included a catechin free diet (Cd-0C) group, a 0.25% catechin diet (Cd-0.25C) group and a 0.5% catechin diet (Cd-0.5C) group according to their respective levels of catechin supplement. After 20 weeks, the deoxypyridinoline and crosslink values measured in urine were significantly increased in the Cd-0C group. Cadmium intoxication seemed to lead to an increase in bone resorption. In the catechin supplemented group (Cd-0.5C group), these urinary bone resorption marks, were decreased. The serum osteocalcin content in the cadmium-poisoned group was significantly increased as compared with the control group. In the catechin supplemented group serum osteocalcin content values were lower than the control group. The cadmium-intoxicated group (Cd-0C group), had lower bone mineral density than the control group (total body, vertebra, pelvis, tibia and femur). The catechin supplement increased bone mineral density to about the same as the control group. Bone mineral content showed a similar trend to total bone mineral density. Therefore, the bone mineral content of the Cd-0C group at the 20th week was significantly lower than the control group. The catechin supplemented group (Cd-0.5C group) was about the same as the control group. The cause of decreasing bone mineral density and bone mineral content by cadmium poisoning was due to the fast bone turnover rate, where bone resorption occurred at a higher rate than bone formation. The green tea catechin aided in normalizing bone metabolic disorders in bone mineral density, bone mineral content and bone calcium content caused by chronic cadmium intoxication.