Active compounds and derivatives of camellia sinensis responding to erosive attacks on dentin

Abstract This research explored the potential of Camellia sinensis-derived teas and active compounds to be used as treatments to prevent dentin wear. Human root dentin slabs were randomly assigned to 5 groups (n = 10) as follows: distilled water (DW, control), epigallocatechin-3-gallate (EGCG), theaflavin gallate derivatives (TF), commercial green tea (GT), and commercial black tea (BT). The samples were submitted to a pellicle formation and an erosive cycling model (5x/day, demineralization using 0.01 M hydrochloric acid/60 s) followed by remineralization (human stimulated saliva/60 min) for three days. The samples were treated for 5 min using the test group solutions between the erosive cycles. Dentin changes were assessed with profilometry analysis and FT-Raman spectroscopy. The data regarding wear were analyzed by ANOVA followed by Tukey's test (p < 0.05). EGCG, TF derivatives, and both regular teas significantly suppressed erosive dentin loss (38-47%, p < 0.05). No obvious changes in the Raman spectra were detected in the specimens; however, the DW group had a minor relationship of 2880/2940 cm−1. The phenolic contents in both green and black tea and the important catechins appear to have protective effects on dentin loss.

Effect of Gallic acid on dementia type of Alzheimer disease in rats: electrophysiological and histological studies

Introduction: To study the effect of gallic acid [GA] on hippocampal long-term potentiation [LTP] and histological changes in animal model of Alzheimer disease [AD] induced by beta-amyloid [Abeta]

Methods: Sixty-four adult male Wistar rats [300 +/- 20 g] were divided into 8 groups: 1] Control [Cont]; 2] AD; 3] Sham; 4-7] AD+GA [50, 100, and 200 mg/kg for 10 days, orally] or vehicle, 8] Cont+GA100, Abeta [1microg/microL in each site] was infused into hippocampus bilaterally. Changes of amplitude and slope of LTP induced in hippocampal dentate gyrus [DG] were evaluated by high frequency stimulation [HFS] of perforant path [PP]

Results: Data showed that LTP amplitude and area under curve significantly impaired in AD rats [P<0.001], while significantly improved in AD rats treated with GA [P<0.05, P<0.01]

Conclusion: Current findings suggest that GA reduces neural damage and brain amyloid neuropathology and improves cognitive function via free radicals scavenging and inhibiting oligomerization of Abeta but with no effect on healthy rats

Effect of gallic acid on alkaline phosphatase and peptidase activities in rat intestine.

Gallic acid is a normal constituent of many edible foods, thus directly interacts with epithelial tissue in intestine. In the present study, the effect of gallic acid on intestinal alkaline phosphatase (IAP) and peptidase activities in rat intestine was evaluated. Gallic acid (0.27-0.5 mM) inhibited activities of leucine aminopeptidase (LAP) and -glutamyl transpeptidase (-GTP) by over 90%, compared to controls in rat intestine. In contrast, 0.1-0.6 mM gallic acid either had no effect or stimulated the activity of IAP in rat intestine. The observed inhibition of peptidases by gallic acid was reversible in nature. Kinetic analysis revealed no change in Vmax of LAP (0.42-0.44 units/mg protein) and -GTP (0.22-0.24 units/mg protein), while the values of apparent Km were increased 6-7 fold, exhibiting competitive-type of enzyme inhibition by gallic acid. The values of Ki for LAP and -GTP were 0.037 mM and 0.017 mM, respectively. These observations indicate that gallic acid is a potent inhibitor of brush border peptidases, and thus may interfere in the digestion and absorption of proteins in the intestine.

Growth of in vitro Fusarium oxysporum f. sp. niveum in chemically defined media amended with gallic acid

Gallic acid was artificially added to the media to grow Fusarium oxysporum f.sp.niveum to investigate its effect on the pathogenic fungus. Results indicate that gallic acid inhibited the growth of F. oxysporum f.sp.niveum. The colony diameter, the conidia germinating rate and the conidia yield were reduced by 5.7-22.9 percent percent, 35.8-55.6 percent and 38.9-62.2 percent respectively. However, the virulence factors by the fungus were stimulated. The activity of pectinase, proteinase and cellulase increased by 12.3-627.8 percent, 11.8-41.2 percent and 0.5-325.0 percent respectively, while the activity of amylase increased slightly. The results suggest that gallic acid repressed growth but facilitated the relative pathogenicity of invading pathogens.

Anti-HSV-1 and anti-HIV-1 activity of gallic acid and pentyl gallate

The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gallates, are widely employed as antioxidants by food and pharmaceutical industries. The inhibitory effects of GA and 15 gallates on Herpes Simplex Virus type 1 (HSV-1) and Human Immunodeficiency Virus (HIV-1) replication were investigated here. After a preliminary screening of these compounds, GA and pentyl gallate (PG) seemed to be the most active compounds against HSV-1 replication and their mode of action was characterized through a set of assays, which attempted to localize the step of the viral multiplication cycle where impairment occurred. The detected anti-HSV-1 activity was mediated by the inhibition of virus attachment to and penetration into cells, and by virucidal properties. Furthermore, an anti-HIV-1 activity was also found, to different degrees. In summary, our results suggest that both compounds could be regarded as promising candidates for the development of topical anti-HSV-1 agents, and further studies concerning the anti-HIV-1 activity of this group of molecules are merited.

Anti-endotoxic effects of syringic acid of Radix Isatidis / 华中科技大学学报（医学）（英德文版）

The anti-endotoxic effect of syringic acid (SA) isolated from Radix Isatidis (Banlangen, BLG) was studied. SA was extracted and isolated from BLG and diluted into 1% solution. The content of SA-pretreated endotoxin (ET) was quantitatively determined using Limulus test. The ability of fever induction of ET pretreated with SA was measured using endotoxin-induced fever test in rabbits. The LPS-induced death in mice pretreated with and without SA was compared. Results showed that after pretreatment with SA, 83.16% of ET was destroyed, the ET-induced fever in rabbits relieved markedly and the LPS-induced death rate in mice dropped from 68% to 20%. It was concluded that SA isolated from BLG had anti-endotoxic effects.

Effect of bismuth subgallate (local hemostatic agent) on wound in rats: histological and histometric findings

O objetivo do presente trabalho foi avaliar o efeito do subgalato de bismuto (SGB) no processo de reparação de feridas. Em 40 ratos Wistar, duas feridas padronizadas foram feitas no dorso dos animais utilizando-se um bisturi circular para biópsia (punch) de 3,5 mm X 2,0 mm. As feridas teste foram preenchidas com SGB e as controle, com salina 0,9 por cento e avaliadas com 1, 4, 7, 11 e 18 dias. A evolução qualitativa do tecido de granulação foi avaliada histologicamente e imagens digitalizadas foram medidas histometricamente. A avaliação histológica não demonstrou diferenças significativas entre teste e controle e histometricamente, houve diferenças significativas (ANOVA- dias 1 e 4; teste student, p<0,05 - dias 7, 11 e 18) em relação aos parâmetros analisados, ou seja, no dia 1: área de ulceração; dia 2: distância entre bordas epiteliais; dia 7, 11 e 18: área de tecido de granulação. Pode-se concluir que o SGB apresenta-se biocompatível aos tecidos em reparação e não interferiu significativamente com o desenvolvimento do processo de reparação.