A novel efficient method to identify beta-glucuronidase activity in rat small intestine

Protective effect of kombucha on rats fed a hypercholesterolemic diet is mediated by its antioxidant activity

CONTEXT

Kombucha (KT) is claimed to have various beneficial effects on human health, but there is very little scientific evidence available in the literature.

OBJECTIVE

The present study investigates the effects of Camellia sinensis (GT) Linn. (Theaceae) and KT, two natural drinks, on cholesterol and antioxidant status using a hypercholesterolemia rat model.

MATERIALS AND METHODS

The present study compared the free-radical scavenging abilities and polyphenol levels of GT and KT. Wistar rats fed cholesterol-rich diets were given KT or GT (5 mL/kg body weight per day, po) for 16 weeks, then fasted overnight and sacrificed. The plasma lipid levels, thiobarbituric acid reactive substances (TBARS) and aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyl transpeptidase (GGT) serum levels, antioxidant activities of superoxide dismutase (SOD) and catalase (CAT), and creatinine and urea rats were examined.

RESULTS

KT had a phenolic compound of 955 ± 0.75 mg GAE/g) followed, by GT (788.92 ± 0.02 mg GAE/g). The free radical scavenging activity of KT was higher than GT. Compared with GT, KT induced lowered serum levels of TC, TG, VLDL-C, and LDL-C by 26, 27, 28, and 36%, respectively, and increased the serum level of high-density lipoprotein cholesterol (HDL-C). KT induced a 55% decrease of TBARS level in liver and 44% in kidney, compared with those of rats fed a cholesterol-rich diet alone. Moreover, CAT and SOD activities were reduced by 29 and 33%, respectively, in liver and 31 and 35%, respectively, in kidney, after oral administration of KT, compared with those of HCD-fed rats.

CONCLUSION

The findings revealed that KT administration induced attractive curative effects on hypercholesterolemic, particularly in terms of liver-kidney functions in rats. Its effect on humans needs to be studied further.

Effect of Kombucha, a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats

Diabetic complications associated with increased oxidative stress can be suppressed by antioxidants. In the present study we investigated the antidiabetic and antioxidant effects of Kombucha (KT), a fermented black tea, in comparison to that of unfermented black tea (BT), in ALX-induced diabetic rats. ALX exposure lowered the body weight and plasma insulin by about 28.12% and 61.34% respectively and elevated blood glucose level and glycated Hb by about 3.79 and 3.73 folds respectively. The oxidative stress related parameters like lipid peroxidation end products (increased by 3.38, 1.7, 1.65, 1.94 folds respectively), protein carbonyl content (increased by 2.5, 2.35, 1.8, 3.26 folds respectively), glutathione content (decreased by 59.8%, 47.27%, 53.69%, 74.03% respectively), antioxidant enzyme activities were also altered in the pancreatic, hepatic, renal and cardiac tissues of diabetic animals. Results showed significant antidiabetic potential of the fermented beverage (150 mg lyophilized extract/kg bw for 14 days) as it effectively restored ALX-induced pathophysiological changes. Moreover, it could ameliorate DNA fragmentation and caspase-3 activation in the pancreatic tissue of diabetic rats. Although unfermented black tea is effective in the above pathophysiology, KT was found to be more efficient. This might be due to the formation of some antioxidant molecules during fermentation period.

Hypoglycemic and antilipidemic properties of kombucha tea in alloxan-induced diabetic rats

Background

Diabetes has become a serious health problem and a major risk factor associated with troublesome health complications, such as metabolism disorders and liver-kidney dysfunctions. The inadequacies associated with conventional medicines have led to a determined search for alternative natural therapeutic agents. The present study aimed to investigate and compare the hypoglycemic and antilipidemic effects of kombucha and black tea, two natural drinks commonly consumed around the world, in surviving diabetic rats.

Methods

Alloxan diabetic rats were orally supplied with kombucha and black tea at a dose of 5 mL/kg body weight per day for 30 days, fasted overnight, and sacrificed on the 31st day of the experiment. Their bloods were collected and submitted to various biochemical measurements, including blood glucose, cholesterol, triglcerides, urea, creatinine, transaminases, transpeptidase, lipase, and amylase activities. Their pancreases were isolated and processed to measure lipase and α-amylase activities and to perform histological analysis.

Results

The findings revealed that, compared to black tea, kombucha tea was a better inhibitor of α-amylase and lipase activities in the plasma and pancreas and a better suppressor of increased blood glucose levels. Interestingly, kombucha was noted to induce a marked delay in the absorption of LDL-cholesterol and triglycerides and a significant increase in HDL-cholesterol. Histological analyses also showed that it exerted an ameliorative action on the pancreases and efficiently protected the liver-kidney functions of diabetic rats, evidenced by significant decreases in aspartate transaminase, alanine transaminase, and gamma-glytamyl transpeptidase activities in the plasma, as well as in the creatinine and urea contents.

Conclusions

The findings revealed that kombucha tea administration induced attractive curative effects on diabetic rats, particularly in terms of liver-kidney functions. Kombucha tea can, therefore, be considered as a potential strong candidate for future application as a functional supplement for the treatment and prevention of diabetes.

Effects of Kombucha on oxidative stress induced nephrotoxicity in rats

BACKGROUND

Trichloroethylene (TCE) may induce oxidative stress which generates free radicals and alters antioxidants or oxygen-free radical scavenging enzymes.

METHODS

Twenty male albino rats were divided into four groups: (1) the control group treated with vehicle, (2) Kombucha (KT)-treated group, (3) TCE-treated group and (4) KT/TCE-treated group. Kidney lipid peroxidation, glutathione content, nitric oxide (NO) and total blood free radical concentrations were evaluated. Serum urea, creatinine level, gamma-glutamyl transferase (GGT) and lactate dehydrogenase (LDH) activities were also measured.

RESULTS

TCE administration increased the malondiahyde (MDA) and NO contents in kidney, urea and creatinine concentrations in serum, total free radical level in blood and GGT and LDH activities in serum, whereas it decreased the glutathione (GSH) level in kidney homogenate. KT administration significantly improved lipid peroxidation and oxidative stress induced by TCE.

CONCLUSION

The present study indicates that Kombucha may repair damage caused by environmental pollutants such as TCE and may be beneficial to patient suffering from renal impairment.

Isoflavones from tofu are absorbed and metabolized in the isolated rat small intestine

Studies suggest a variety of biological effects of soybean isoflavones, but there is little information regarding small intestinal absorption and metabolism. The aim of this study was to investigate intestinal handling of luminally administered soybean-based tofu in an isolated preparation of the luminally and vascularly perfused rat small intestine (male Sprague-Dawley, approximately 45 d old). A synthetic emulsion free from blood components was used as vascular medium, with a perfluorocarbon as oxygen carrier. Luminal media consisted of tofu, predigested with pepsin and pancreatin and emulsified with bile acids, containing 39. 5 micromol/L genistein compounds and 19.1 micromol/L daidzein compounds. Viability of the organ preparation was maintained during the entire perfusion, confirmed by lack of significant differences between tofu and control perfusion experiments for arterial pressure, glucose consumption, oxygen uptake, lactate-pyruvate ratio and acid-base homeostasis. Daidzein (8.9%) and genistein (8.0%) compounds from tofu exhibited almost the same (P: > 0.05) absorption rate during small intestinal passage. The majority of the absorbed genistin appeared vascularly as genistein (4.4%), in addition to minor amounts of unchanged genistin (2.1%) and genistein glucuronide (1.5%). In the luminal effluent, a considerable increase of genistein (338%) as well as daidzein (190%) as cleavage products of the glucosides and malonyl-glucosides was observed. The distribution of daidzein compounds in the small intestine was not different from that of genistein compounds (P: > 0.05), except for the blood vessels, which had extremely low total amounts. Sulfate derivatives of genistein and daidzein compounds were not detectable. An effect of tofu ingredients was observed on absorption rate of genistin, on glucuronidation and on distribution of genistein glucuronide in the intestine.