Influence of green tea extract with different concentrations of epigallocatechin gallate on calvaria bone repair of ovariectomized rats / Influencia del extracto de té verde con diferentes concentraciones de galato de epigalocatequina sobre la reparación ósea de calvaria de ratas ovariectomizadas

Impairing osteoporosis progression is a challenge, and recently the role of antioxidants has been associated to bone metabolism. Green tea extract is rich in catechins, especially epigallocatechin gallate (EGCG), which may help control osteoporosis damage in bone tissue. This investigation evaluated the efficacy of green tea ingestion containing different concentrations of EGCG in calvaria bone repair of ovariectomized rats. Wistar rats (n=15) were ovariectomized and divided into 3 groups: ovariectomized (OVX), ovariectomized + GTE 15 % EGCG (OVX/GTE15), and ovariectomized + GTE 94 % EGCG (OVX/GTE94). Green tea extract was administered by gavage in the concentration of 50 mg/kg and sham group (n=5) received water. Bone defects were performed in the calvaria 60 days after ovariectomy followed by 4 weeks until euthanasia. Bone samples were collected to perform qualitative and quantitative histological analysis of bone formation. Data obtained were submitted to normality and ANOVA statistical test for p<0.05. The mean values of neoformed bone for Sham, OVX, OVX/GTE15 and OVX/GTE94 were respectively: 21.11 ± 3.91; 19.92 ± 2.20; 33.05 ± 1.26 e 34.75 ± 0.54 (p<0.05). Results show that continuous ingestion of green tea extract immediately after ovariectomy shows positive effects in the prevention of bone loss in osteoporosis, even with low concentrations of EGCG.

La disminución en la progresión de la osteoporosis es un desafío, y recientemente el papel de los antioxidantes se ha asociado al metabolismo óseo. El extracto de té verde es rico en catequinas, especialmente el galato de epigalocatequina (EGCG), lo que puede ayudar a controlar el daño de la osteoporosis en el tejido óseo. Esta investigación evaluó la eficacia de la ingesta de té verde con diferentes concentraciones de EGCG en la reparación ósea de calvaria de ratas ovariectomizadas. Las ratas Wistar (n = 15) fueron ovariectomizadas y divididas en 3 grupos: ovariectomizadas (OVX), ovariectomizadas + GTE 15 % EGCG (OVX / GTE15), y ovariectomizadas + GTE 94 % EGCG (OVX / GTE94). El extracto de té verde se administró por sonda en una concentración de 50 mg/kg y el grupo simulado (n = 5) recibió agua. Los defectos óseos se realizaron en la calvaria 60 días después de la ovariectomía, seguido de 4 semanas hasta la eutanasia. Se obtuvieron muestras de hueso para realizar un análisis histológico cualitativo y cuantitativo de la formación ósea. Los datos obtenidos se sometieron a normalidad y prueba estadística ANOVA (p<0,05). Los valores medios de hueso neoformado para Sham, OVX, OVX / GTE15 y OVX / GTE94 fueron: 21,11 ± 3,91; 19,92 ± 2,20; 33,05 ± 1,26 y 34,75 ± 0,54 (p <0,05), respectivamente. Los resultados muestran que la ingesta continua de extracto de té verde, inmediatamente después de la ovariectomía, muestra efectos positivos en la prevención de la pérdida ósea ocurrida en la osteoporosis, incluso con concentraciones bajas de EGCG.

Caffeine in tea plants [Camellia sinensis (L) O. Kuntze]: in situ lowering by Bacillus licheniformis (Weigmann) Chester.

Tea plants (Camellia sinensis) contain 5-6% caffeine that is responsible for the stimulating effect of the beverage. As the tolerance to caffeine varies among individuals, low caffeine tea would be an ideal alternative. While assessing the potential of a few selected bacteria-Bacillus licheniformis, B. subtilis and B. firmus, to multiply on nutrient medium supplemented with glucose (5%) and tea leaf extract (2%), it was observed that only B. licheniformis could proliferate on this medium. Hence, B. licheniformis was used for further studies. Tea plants were sprayed with a suspension of B. licheniformis at a dilution of 5 x 10(8) CFU/ml containing 0.1% Tween 80 as surfactant. In situ lowering of caffeine from tea leaves was evident without affecting the quality of the other tea components. Further, there was no change in the morphological and physiological characteristics as well. It is suggested that spraying of B. licheniformis may be useful in yielding decaffeinated tea with good flavour and aroma.

Study of interaction between catechin and native and modified bovine serum albumin by physico-chemical methods.

The interaction of native and modified bovine serum albumin (BSA) with catechin, a flavanoid having vitamin P activity, has been studied using equilibrium dialysis, pH-metric, viscosity and spectrophotometric methods. The order of reactivity of catechin binding to proteins was found to be: esterified BSA greater than BSA greater than formylated BSA greater than acetylated BSA with log K values of 3.778, 3.879, 3.748 and 3.813 and free energy change equal to -5.11, -5.16, -5.07 and -5.15 kcal/mole, respectively.