The protective effects of green tea extract against L-arginine toxicity to cultured human mesangial cells

Periodontal Ligament Fibroblast Cell Viability Following Treatment with Different Concentrations of Green Tea, Aloe Vera and a Mixture of their Extracts

Objectives: Various studies have identified green tea and Aloe vera as a suitable medium for avulsed teeth. The aim of this study was to evaluate and compare the viability of periodontal ligament (PDL) fibroblasts following treatment with the extracts of these two plants and their mixture. Materials and Methods: Human PDL fibroblasts were purchased and treated with different concentrations of Aloe vera, green tea, and a combination of these two extracts. Hank's balanced salt solution and culture medium were employed as positive and negative controls, respectively. Viability was assessed using the MTT assay. Two-way ANOVA and post-hoc tests were used for statistical analysis (P<0.05). Results: There was a significant difference in PDL fibroblast viability between different concentrations of the extracts. Higher concentrations of green tea and the combination of the two extracts significantly increased cell viability. Higher concentrations of Aloe vera had the least positive effect on maintaining the viability of these cells. Conclusion: If confirmed by further studies, the combination of Aloe vera and green tea extracts might be considered as a suitable media for different purposes like storing avulsed teeth.

Comparative evaluation of four transport media for maintaining cell viability in transportation of an avulsed tooth - An in vitro study

OBJECTIVES

The study was performed to compare and evaluate the efficacy of four experimental storage media (Hank's balanced salt solution, Ringer's lactate solution, tender coconut water, and green tea extract) for maintaining cell viability of human periodontal cells at different time intervals of 15 min 30 min, 60 min, and 90 min.

MATERIALS AND METHODS

Human periodontal cells were cultured and stored in the four media. After 15 min 30 min, 60 min, and 90 min, the different media were examined under optical microscope and viabilities analyzed using an optical calorimeter. Mean and standard deviation were estimated from the results that were statistically analyzed using one-way analysis of variance (ANOVA) to identify the significant groups.

RESULTS

The results indicated that there was no difference in cell viability between the four media up to a period of 60 min, whereas green tea extract showed a lower cell viability after 90 min.

CONCLUSION

Within the limitations of the present study, it appears that due to superior osmolality, cost effectiveness, and easier availability, Ringer's lactate, tender coconut water, and green tea extract can be used as alternate storage media for avulsed tooth.

Protective effects of epigallocatechin gallate (EGCG) on streptozotocin-induced diabetic nephropathy in mice

There is increasing evidence suggesting that antioxidants in green tea extracts may protect kidneys on the progression of end-stage renal disease. We investigated the protective impacts of (-)-epigallocatechin 3-O-gallate (EGCG) against streptozotocin (STZ)-induced diabetic nephropathy in mice. The mice were divided into 5 groups (n=10 per group): control (saline, i.p.), STZ (200mg/kg, i.p.), EGCG50 (50mg/kg, S.Q.), EGCG100 (100mg/kg, S.Q.), and EGCG200 (200mg/kg, S.Q.). Animals were sacrificed at scheduled times after EGCG administration and then quantitative and qualitative analysis were performed. Compared with the control group, the STZ group showed an increase in levels of blood glucose, blood urea nitrogen, creatinine and urine protein amounts with a decrease in body weight. All the above parameters were significantly reversed with EGCG treatment, especially in the EGCG100 group. After STZ injection, there was a mesangial proliferation with increased renal osteopontin accumulation and its protein expression in the glomeruli and the proximal tubules. Mice kidneys after EGCG-treatment showed a reduced expression of above parameters and relatively improved histopathological findings. These results indicated that EGCG 100mg/kg might provide an effective protection against STZ-induced diabetic nephropathy in mice by osteopontin suppression.

Unexpected combined effects of NADH dehydrogenase subunit-2 237 Leu/Met polymorphism and green tea consumption on renal function in male Japanese health check-up examinees: a cross-sectional study

Background

NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is associated with longevity in Japanese. A previous study has shown that ND2-237 Leu/Met polymorphism modulates the effects of green tea consumption on risk of hypertension. For men with ND2-237Leu, habitual green tea consumption may reduce the risk of hypertension. Moreover, there is a combined effect of ND2-237 Leu/Met polymorphism and alcohol consumption on risk of mildly decreased estimated glomerular filtration rate (eGFR) (<90 ml/min/1.73 m²). Several beneficial effects of green tea on the kidney have been reported. The objective of this study was to investigate whether ND2-237 Leu/Met polymorphism modifies the effects of green tea consumption on risk of mildly decreased eGFR in male Japanese health check-up examinees.

Results

For ND2-237Leu genotypic men, after adjustment for confounding factors, green tea consumption may increase the risk of mildly decreased eGFR (P for trend = 0.016). The adjusted odds ratio (OR) for mildly decreased eGFR was significantly higher in subjects with ND2-237Leu who consume ≥6 cups of green tea per day than those who consume ≤1 cup of green tea per day (adjusted OR = 5.647, 95% confidence interval: 1.528-20.88, P = 0.009). On the other hand, for ND2-237Met genotypic men, green tea consumption does not appear to determine the risk of mildly decreased eGFR.

Conclusion

The present results suggest that ND2-237 Leu/Met polymorphism unexpectedly modifies the effects of green tea consumption on eGFR and the risk of mildly decreased eGFR in male Japanese subjects.

Cytotoxic and immunomodulatory effects of polyhydroxyoctane isolated from Lentinus polychrous mycelia

A polyhydroxyoctane, 6-methylheptane-1,2,3,4,5-pentaol (MHP), was first isolated from mycelia of the Thai edible mushroom Lentinus polychrous. MHP was evaluated for its cytotoxic and immunomodulatory effects in vitro. MHP was slightly cytotoxic to murine splenocytes but not to RAW264.7 cells or peripheral blood mononuclear cells. MHP decreased nitric oxide and intracellular O2 (-) production from lipopolysaccharide- and phorbol-12-myristate-13-acetate-activated RAW264.7 cells at levels of 78.98 ± 4.72 and 78.48 ± 2.41 % of controls, respectively. The mRNA expression of pro-inflammatory mediators, including iNOS, TNF-α, IL-1β, IL-6, COX-1 and COX-2, were significantly suppressed by MHP. In addition, MHP significantly increased the proliferation of phytohemagglutinin and pokeweed mitogen-induced splenocytes. These results indicate that MHP is able to modulate inflammatory responses and the proliferation of both T- and B-lymphocyte cells, suggesting that MHP may be a good natural immunomodulator.

Green tea extracts attenuate doxorubicin-induced spermatogenic disorders in conjunction with higher telomerase activity in mice

PURPOSE

The aim of this study was to investigate the protective effect of green tea extracts against doxorubicin-induced damage in the mouse testes correlating with telomerase activity.

METHODS

Green tea extracts were administered orally. Doxorubicin was coadministered intraperitoneally. These testes were evaluated histologically and the telomerase activity was analyzed. Additional immunostaining was carried out.

RESULTS

Both the sperm density and sperm motility were significantly increased in green tea extracts coadministration groups as compared to the doxorubicin-treated groups. By histological analysis, germ cell damage was greatly attenuated by green tea extracts coadministration. Telomerase activity significantly increased in association with the coadministration of green tea extracts as compared to that of doxorubicin-only groups. In all groups, human telomerase reverse transcriptase signals were mainly observed in the spermatocytes and spermatids.

CONCLUSIONS

These findings suggest that green tea extracts exert protective effects against doxorubicin-induced spermatogenic disorders in conjunction with higher telomerase activity levels.