Protective effect of gallic acid and Syzygium cumini extract against oxidative stress-induced cellular injury in human lymphocytes.

CONTEXT: Syzygium cumini (Myrtaceae) presents antioxidant, anti-inflammatory, hypoglycemic and antibacterial effects; however, the cellular and molecular mechanisms of action in the immune system are not yet completely elucidated. OBJECTIVE: This study evaluates the in vitro effect of gallic acid and aqueous S. cumini leaf extract (ASc) on adenosine deaminase (ADA) and dipeptidyl peptidase IV (DPP-IV) activities, cell viability and oxidative stress parameters in lymphocytes exposed to 2, 2'-azobis-2-amidinopropane dihydrochloride (AAPH). MATERIALS AND METHODS: Lymphocytes were incubated with ASc (100 and 500 µg/ml) and gallic acid (50 and 200 µM) at 37 °C for 30 min followed by incubation with AAPH (1 mM) at 37 °C for 2 h. After the incubation time, the lymphocytes were used for determinations of ADA, DPP-IV and lactate dehydrogenase (LDH) activities, lipid peroxidation, protein thiol (P-SH) group levels and cellular viability by colorimetric methods. RESULTS: (i) HPLC fingerprinting of ASc revealed the presence of catechin, epicatechin, rutin, quercitrin, isoquercitrin, quercetin, kaempferol and chlorogenic, caffeic, gallic and ellagic acids; (ii) for the first time, ASc reduced the AAPH-induced increase in ADA activity, but no effect was observed on DPP-IV activity; (iii) ASc increased P-SH groups and cellular viability and decreased LDH activity, but was not able to reduce the AAPH-induced lipid peroxidation; (iv) gallic acid showed less protective effects than ASc. DISCUSSION AND CONCLUSION: ASc affects the purinergic system and may modulate adenosine levels, indicating that the extract of this plant exhibits immunomodulatory properties. ASc also may potentially prevent the cellular injury induced by oxidative stress, highlighting its cytoprotective effects.

Adenosine deaminase, dipeptidyl peptidase-IV activities and lipid peroxidation are increased in the saliva of obese young adult.

BACKGROUND: Obesity is the hallmark of the metabolic syndrome representing a major global health problem. It is considered a state of chronic inflammation with minimal exploration of salivary biomarkers. Thus, the intent of the present study was to assess the activities of salivary dipeptidyl peptidase IV (DPP-IV), adenosine deaminase (ADA) and lipid peroxidation in obese young and overweight young subjects. METHODS: ADA, DPP-IV activities and lipid peroxidation were investigated in saliva, as well as insulin, glucose, HbA1c, HOMA and anthropometric measurements in 149 young adults, including 54 with normal weight, 27 overweight and 68 obese subjects. RESULTS: Salivary ADA and DPP-IV activities as well as lipid peroxidation were higher in patients with obesity compared to the normal weight group. Correlations between ADA/DPP-IV activities, lipid peroxidation/ADA activity, ADA activity/hip circumference and BMI/weight were observed. CONCLUSIONS: Our results indicate that the increase in the salivary ADA and DPP-IV activities as well as in the lipid peroxidation could be related of the regulation to various aspects of adipose tissue function and inflammatory obesity. It is suggested that these salivary biomarkers may be used as biochemical test in clinical abnormalities present in obesity, in the absence of oral inflammatory diseases.

Ischemia-modified albumin and inflammatory biomarkers in patients with prostate cancer.

BACKGROUND: Prostate cancer has become a public health problem in many countries and there is evidence which indicates that inflammation and oxidative stress play a key role in the pathogenesis of this disease. Thus, the aim of this study was to evaluate the concentrations of new biomarkers of oxidative stress, ischemia-modified albumin (IMA) and ferric reducing ability of plasma (FRAP), as well as the inflammatory markers in patients with prostate cancer. METHODS: CRP, IMA, FRAP, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid, creatinine, albumin, AST, ALT, ADA, total PSA (tPSA), free PSA, and proportion of free PSA (fPSA%) were measured in 25 patients with prostate cancer and in 30 healthy subjects. RESULTS: tPSA, CRP, and IMA were significantly higher in patients with prostate cancer. In contrast, fPSA% and FRAP were significantly lower in these patients. However, no significant differences were observed when IMA values were adjusted for serum albumin. Significant correlations were also observed for tPSA and CRP (r = 0.5104, p < 0.001) and for fPSA% and CRP (r = -0.5059, p < 0.001). CONCLUSIONS: We demonstrated that both inflammatory and oxidative processes are increased during prostate cancer and also that there is a reduction of antioxidant defenses in this pathology.

Erythrocytic enzymes and antioxidant status in people with type 2 diabetes: beneficial effect of Syzygium cumini leaf extract in vitro.

The aim of the present study was to investigate the effects of Syzygium cumini leaf extract (ASc), on Adenosine deaminase (ADA) and Acetylcholinesterase (AChE) activities, and also on oxidative stress parameters in erythrocytes hemolysates (RBCs) and erythrocytes membranes (ghosts) from type 2 diabetics patients (Type 2 DM) under in vitro conditions. Non protein thiol groups (NP-SH), AChE, Catalase (CAT) and Superoxide Dismutase (SOD) activities were measure in RBCs. Further, ADA activity, Thiobarbituric Acid-Reactive Substances (TBARS) levels and protein thiol groups (P-SH) were estimated in ghosts. Also, P-SH and Vitamin C (VIT C) were measure in plasma sample. The results demonstrated that ADA and AChE activities, besides TBARS levels were higher in erythrocytes of Type 2 DM, while SOD activity and NP-SH levels were decreased when compared to control group. ASc, in vitro, reduced ADA and AChE activities and some parameters of oxidative stress. Furthermore, we observed correlations between VIT C and P-SH levels, ADA activity and P-SH levels, as well as NP-SH and TBARS levels in diabetics. The results suggest that ASc in vitro is able to promote the reduction of inflammation and oxidative stress parameters, and act against biochemical changes occurring in Diabetes mellitus (DM).

Expression of CD26 and its association with dipeptidyl peptidase IV activity in lymphocytes of type 2 diabetes patients.

Immune response and inflammation were suggested to play certain roles in the development and complications of type 2 diabetes mellitus. The main objective of this study was to investigate the CD26 expression and its relationship with adenosine deaminase (ADA), dipeptidyl peptidase IV (DPP-IV), γ-glutamyltransferase (GGT), and N-acetyl-ß-glucosaminidase (NAG) activities in lymphocytes of type 2 diabetics (T2DM) patients. These parameters were assessed in 25 T2DM patients and 20 control subjects. We observed a decrease in CD26 expression and a significant increase in the ADA activity in T2DM patients when compared with control subjects. There were no differences between activities of DPP-IV, NAG, and GGT in lymphocytes of T2DM patients and control subjects. Meanwhile, a significant negative correlation was observed between CD26 expression and DPP-IV activity in lymphocytes of T2DM patients. Moreover, a positive correlation was found between DPPIV and ADA activities. The results suggest that the reduction of CD26 expression may be associated in the regulation of DPP-IV in T2DM patients.

Comparative evaluation of adenosine deaminase activity in cerebral cortex and hippocampus of young and adult rats: effect of garlic extract (Allium sativum L.) on their susceptibility to heavy metal exposure.

Adenosine plays an important neuromodulatory role in the central nervous system, and adenosine deaminase is an important enzyme in the degradation of adenine nucleotides. Methylmercury is the most prevalent form of mercury found in the environment. Methylmercury neurotoxicity has been correlated to the production of reactive oxygen species. In this study, its potential pathogenic effects were investigated in vitro in cerebral cortex and hippocampus of rats. We first observed that adenosine deaminase activity was higher in young rat brains when compared to the 60-day-old rats and was higher in hippocampus when compared to the cortex. Methylmercury (0.1, 1.0, 20 microM) inhibited adenosine deaminase activity in 7- and 60-day-old rats in a concentration-dependent manner. We have demonstrated that methylmercury-induced inhibition was antagonized by garlic alcoholic extract, but sodium selenate did not alter enzyme activity. In addition, glutathione and dithiothreitol restored the methylmercury-induced decrease of adenosine deaminase activity. These results demonstrated that there are age-related changes in adenosine deaminase activity and that thiol agents may contribute to the maintenance of adenosine deaminase activity and may be important in the neuromodulation of adenosine. Garlic alcoholic extract may be effective in reducing the effect of methylmercury-induced adenosine deaminase, which may be due to its sulphur-containing compounds.