Dolan Das

Protective action of aqueous black tea (Camellia sinensis) extract (BTE) against ovariectomy-induced oxidative stress of mononuclear cells and its associated progression of bone loss.

The protective action of aqueous black tea extract (BTE) against ovariectomy‐induced oxidative stress of mononuclear cells and its associated progression of bone loss was demonstrated in this study. Eighteen female adult 6‐month‐old Wistar albino rats were divided into three groups: sham‐control (A), bilaterally ovariectomized (B) and bilaterally ovariectomized + BTE supplemented (C). Studies included the measurement of oxidative (nitric oxide, lipid peroxidation) and antioxidative (superoxide dismutase, catalase) markers, inflammatory cytokines (IL‐6, TNF‐α), osteoclast differentiation factor (RANKL) and bone resorption markers (tartrate‐resistant acid phosphatase and hydroxyproline). Also quantitative histomorphometry and histological studies were undertaken. The bone breaking force was measured. The results indicate that BTE was effective in preserving and restoring skeletal health by reducing the number of active osteoclasts. Such changes with BTE supplementation were steadily linked with the reduced oxidative stress of mononuclear cells, serum levels of bone resorbing cytokines, osteoclast differentiation factor and resorption markers. The results of the bone breaking force, histological and histomorphometric analyses further supported the hypothesis. This study suggests that BTE has both protective and restorative actions against ovariectomy‐induced mononuclear cell oxidative stress and associated bone loss. Copyright

Black tea prevents high fat diet-induced non-alcoholic steatohepatitis.

The chemoprotective actions of aqueous black tea extract (BTE) against high‐fat diet (HFD) (60%)‐induced non‐alcoholic steatohepatitis (NASH) were examined in Wistar rats of both sexes. The results indicated that the HFD rats had higher concentrations of serum glucose, cholesterol, triglycerides, low‐density lipoprotein, very low‐density lipoprotein, high‐density lipoprotein and bilirubin than the corresponding control rats. The enzymes serum aspartate aminotransferase and alanine aminotransferase, which are indicators of liver function, also exhibited higher levels of activity in HFD rats. BTE extract supplementation was found to correct such steatohepatitis‐linked biochemical changes. HFD‐induced steatohepatitis was associated with substantial pro‐oxidant conditions in rat liver, as evidenced by the higher content of malondialdehyde, nitric oxide production and glutathione depletion, with a concomitant decrease in liver antioxidant status caused by reducing superoxide dismutase and catalase activity. In addition, rats with steatohepatitis showed a significantly higher expression of inducible nitric oxide synthase, caspase‐3 activity and DNA fragmentation. BTE reversed the changes in the pro‐oxidant and antioxidant status of the liver, and protected against apoptotic, cytogenetic and hepatocellular damage. In summary, these data suggest that nutritional support with antioxidants may be useful in preventing oxidative damage and the progression of NASH. Copyright

Antiapoptotic efficacy of folic acid and vitamin B12 against arsenic-induced toxicity

Earlier, we proposed that the ability of folic acid and vitamin B12 to preserve systemic and mitochondrial function after short‐term exposure to arsenic may prevent further progression to more permanent injury and pathological changes leading to cell death. To elucidate its mechanism, the present study examined the antiapoptotic efficacy of folic acid and vitamin B12 against short‐term arsenic exposure‐induced hepatic mitochondria oxidative stress and dysfunction. Sixteen to eighteen weeks old male albino rats weighing 140–150 × g were divided into five groups: Control (A), Arsenic‐treated (B), Arsenic + folic acid (C), Arsenic +vitamin B12 (D), and Arsenic + folic acid + vitamin B12 (E). Data generated indicated that folic acid and vitamin B12 separately or in combination can give significant protection against alterations in oxidative stress and apoptotic marker parameters and downstream changes in mitochondria, namely pro‐oxidative (NO, TBARS, OH−) and antioxidative defense (SOD, CAT, GSH) markers, iNOS protein expression, mitochondrial swelling, cytochrome c oxidase and Ca2+‐ATPase activity, Ca2+ content, caspase‐3 activity. Additionally, results of hepatic cell DNA fragmentation, arsenic load of blood, hepatic tissue and urine, and histological observations, all strongly support that both these supplements have efficacy in preventing apoptotic changes and cellular damage. As the mechanisms of actions of both of these supplements are methylation related, a combined application was more effective. Results further reveal new molecular targets through which folic acid and vitamin B12 separately or in combination work to alleviate one critical component of arsenic‐induced liver injury: mitochondria dysfunction.

Black Tea May Be a Prospective Adjunct for Calcium Supplementation to Prevent Early Menopausal Bone Loss in a Rat Model of Osteoporosis

The present study was undertaken to find out the ability of black tea extract (BTE) as a suitable alternative of adjunct for calcium supplementation in treating an ovariectomized rat model of early osteoporosis. Female Wistar rats weighing 140–150 g were divided into four groups consisting of six animals in each group: (A) sham-operated control; (B) bilaterally ovariectomized; (C) bilaterally ovariectomized + BTE; (D) bilaterally ovariectomized + 17β-estradiol. Results suggest that BTE could promote intestinal absorption of calcium significantly (P < 0.01 for duodenum and ileum; and P < 0.05 for jejunum). This was found associated with enhanced activities of two relevant intestinal mucosal enzymes alkaline phosphatase (P < 0.01 for duodenum, jejunum, and ileum) and Ca2+ activated ATPase (P < 0.01 for duodenum, jejunum, and ileum). Such BTE-mediated promotion of calcium absorption was coupled with increase in serum estrogen titer (P < 0.01) and recovery of all urinary, bone, and serum osteoporotic marker parameters, including bone histological features. Serum parathyroid hormone level, however, was not altered in these animals (P > 0.05). A comparative study with 17β-estradiol, a well-known adjunct for calcium supplementation, indicated that efficacy of BTE in maintaining skeletal health is close to that of 17β-estradiol. This study suggests that simultaneous use of BTE is promising as a prospective candidate for adjunctive therapies for calcium supplementation in the early stage of menopausal bone changes.

Black Tea (Camellia sinensis) and Bone Loss Protection

The possible beneficial health effects of black tea consumption have been suggested by epidemiological studies and supported by laboratory findings. Animal studies in hypogonadal rats have indicated that black tea has phytoestrogenic potential and putative bone protection as well as restorative actions. These are evidenced by an increase in serum estrogen level, uterotrophic action, prevention of bone loss, increase in bone density (bone breaking strength) and preservation of microarchitecture of bone through modulation of several endogenous factors of bone metabolism. These actions of black tea have been attributed to its flavonoid and flavonol content, particularly theaflavins and thearubigins.