Green tea and thermogenesis: interactions between catechin-polyphenols, caffeine and sympathetic activity.

The thermogenic effect of tea is generally attributed to its caffeine content. We report here that a green tea extract stimulates brown adipose tissue thermogenesis to an extent which is much greater than can be attributed to its caffeine content per se, and that its thermogenic properties could reside primarily in an interaction between its high content in catechin-polyphenols and caffeine with sympathetically released noradrenaline (NA). Since catechin-polyphenols are known to be capable of inhibiting catechol-O-methyl-transferase (the enzyme that degrades NA), and caffeine to inhibit trancellular phosphodiesterases (enzymes that break down NA-induced cAMP), it is proposed that the green tea extract, via its catechin-polyphenols and caffeine, is effective in stimulating thermogenesis by relieving inhibition at different control points along the NA-cAMP axis. Such a synergistic interaction between catechin-polyphenols and caffeine to augment and prolong sympathetic stimulation of thermogenesis could be of value in assisting the management of obesity. International Journal of Obesity (2000) 24, 252-258

Efficacy and tolerance of Harpagophytum procumbens versus diacerhein in treatment of osteoarthritis.

In a double-blind, randomized, multicentre clinical study, the efficacy and tolerance of a herbal medicine product, Harpadol (6 capsules/day, each containing 435 mg of powdered cryoground powder Harpagophytum procumbens), was compared with diacerhein 100 mg/day in the treatment, for 4 months, of 122 patients suffering from osteoarthritis of the knee and hip. Assessments of pain and functional disability were made on a 10 cm horizontal visual analogue scale; severity of osteoarthritis was evaluated by Lequesne's index. Spontaneous pain showed a significant improvement during the course of the study and there was no difference in the efficacy of the two treatments. Similarly, there was a progressive and significant reduction in the Lequesne functional index and no statistical difference was found between Harpadol and diacerhein. At completion of the study, patients taking Harpadol were using significantly less NSAIDs and antalgic drugs. The frequency of adverse events was significantly lower in the Harpadol group. The most frequent event reported was diarrhea, occurring in 8.1% and 26.7% of Harpadol and diacerhein patients respectively. The global tolerance assessment by patients at the end of treatment favoured Harpadol. The results of this study demonstrate that Harpadol is comparable in efficacy and superior in safety to diacerhein.

Green tea extract (AR25) inhibits lipolysis of triglycerides in gastric and duodenal medium in vitro.

In this study, we aimed to evaluate in vitro the inhibitory activity of a green tea extract (AR25 standardized at 25% catechins) on gastric and pancreatic lipase activities. We first used tributyrin as a substrate to evaluate the capability of AR25 to induce digestive lipase inhibition. Gastric lipase was totally inhibited by 40 mg AR25/g tributyrin whereas pancreatic lipase inhibition was maximum (78.8 +/- 0.7%) with 80 mg AR25/g tributyrin. We then used triolein, a long-chain triglyceride, to check whether AR25 could alter lipase activities on a physiologic substrate. AR25 60 mg/g triolein induced a dramatic inhibition of gastric lipase (96.8 +/- 0.4%) whereas pancreatic lipase activity was partially reduced (66.50 +/- 0.92%). Finally, the concerted action of gastric and pancreatic lipases was studied with an excess of enzymes to mimic the physiologic conditions observed in vivo. Incubation of AR25 with an excess of digestive lipases resulted in a drastic decrease in gastric lipolysis but the inhibitory effect on pancreatic lipase was less marked. On the whole, as compared to the control, lipolysis of triolein under the successive action of the two digestive lipases was reduced by 37 +/- 0.6% in the presence of AR25. Because a lipid/water interface is necessary for lipolysis to occur, lipid emulsification and emulsion droplet size were measured in gastric and duodenal media in the presence of AR25. In gastric and duodenal conditions, AR25 inhibited the lipid emulsification process. From these data we conclude that (1) in vitro, fat digestion is significantly inhibited by 60 mg AR25/g triolein, and (2) gastric as well as pancreatic lipase inhibition could be related to altered lipid emulsification in gastric or duodenal media. The green tea extract AR25 exhibiting marked inhibition of digestive lipases in vitro is likely to reduce fat digestion in humans.

Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans.

BACKGROUND: Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system. OBJECTIVE: We investigated whether a green tea extract, by virtue of its high content of caffeine and catechin polyphenols, could increase 24-h energy expenditure (EE) and fat oxidation in humans. DESIGN: Twenty-four-hour EE, the respiratory quotient (RQ), and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men. On 3 separate occasions, subjects were randomly assigned among 3 treatments: green tea extract (50 mg caffeine and 90 mg epigallocatechin gallate), caffeine (50 mg), and placebo, which they ingested at breakfast, lunch, and dinner. RESULTS: Relative to placebo, treatment with the green tea extract resulted in a significant increase in 24-h EE (4%; P < 0.01) and a significant decrease in 24-h RQ (from 0.88 to 0.85; P < 0.001) without any change in urinary nitrogen. Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo (40%, P < 0.05). Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines. CONCLUSIONS: Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.

Influence of human obesity on the metabolic fate of dietary long- and medium-chain triacylglycerols.

The metabolic fate of an oral long-chain-triacylglycerol (LCT) load and of a mixed oral LCT and medium-chain-triacylglycerol (MCT) load was followed for 6 h in eight control and eight obese subjects with normal postabsorptive triacylglycerol concentrations. Labeled triacylglycerol and indirect calorimetry were used. Results showed that LCTs were less oxidized in obese than in control subjects (3.2+/-0.5 compared with 6.0+/-0.4 g, P < 0.01). Moreover, the amount of LCT oxidized was negatively correlated with fat mass (r = -0.77, P < 0.01). Appearance in plasma of dietary triacyglycerol-derived long-chain fatty acids was blunted in obese subjects and it was negatively related to fat mass (r = -0.84, P < 0.01) and positively to LCT oxidation (r = 0.70, P < 0.01). On the contrary, MCT oxidation was not altered in obese subjects compared with control subjects. Furthermore, the proportion of MCTs oxidized was higher in both groups compared with LCTs (x+/-SEM: 57.5+/-2.6% compared with 15.2+/-1.6%, P < 0.01, n = 16). Our conclusion is that obesity is associated with a defect in the oxidation of dietary LCTs probably related to an excessive uptake by the adipose tissue of meal-derived long-chain fatty acids. MCTs, the oxidation of which is not altered in obesity, could therefore be of interest in the dietary treatment of obesity.

Efficacy and safety of Buxus sempervirens L. preparations (SPV(30)) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial.

The objective of the present study was to compare the efficacy and safety of two doses of SPV(30) in HIV asymptomatic patients. The study was designed as a randomized double-blind multicentre trial of two doses of SPV(30) (990 mg/d and 1980 mg/d) versus placebo. 145 previously untreated subjects with asymptomatic HIV infection (CDC group IV) and CD4 cell counts between 250 and 500 × 10(6)/1 were recruited. There was a statistically significant difference in therapeutic failures between groups in favor of SPV(30) 990 mg including decreases of CD4 cell count < 200 × 10(6)/1 and/or number of clinical aggravations (progression to AIDS or AIDS related complex). The treatment groups differed statistically in the rate of disease progression also in favor of SPV(30) 990 mg/d. Fewer patients receiving SPV(30) 990 mg/d had at the end an increase of viral load greater than 0.5 log (P = 0.029). No severe side-effects were reported in the 3 groups. From these results we conclude that SPV(30) 990 mg/d has beneficial effects in HIV asymptomatic patients and appears to delay the progression of HIV disease.

[In vitro bacteriocidal activity of 5 oral antiseptics against the principal microorganisms implicated in oral disease]. / Activité bactéricide in vitro de 5 antiseptiques buccaux vis-à-vis des principaux germes impliqués dans les affections bucco-dentaires.

Bactericidal activities of five mouthrinses containing cetylpyridinium chloride, hexetidine or chlorhexidine have been tested in vitro, against the main microorganisms involved in buccal affections. Mouthrinses containing hexetidine or chlorhexidine are effective, but chlorhexidine activity appears more extensive and homogeneous.

[Effect of chlorhexidine on bacterial fibrinolytic and collagenolytic activity]. / Effet de la chlorhexidine sur des activités fibronectinolytiques et collagenolytiques bactériennes.

Destructive periodontal diseases are characterized by tissue breakdown partly mediated by various enzymes originating from bacteria and/or tissue. Collagen and fibronectin are two of the main substrates available for enzyme activity. Since chlorhexidine is largely used during and after periodontal therapy, we have investigated the effects of chlorhexidine upon some bacterial proteases. Our data indicate that chlorhexidine inhibits, on a dose-dependent manner, both fibronectin and collagen hydrolysis mediated by either bacteroides (porphyromonas) gingivalis or bacteroides intermedius. Thus, it might be hypothesized that a side from its bactericidal activity, chlorhexidine helps to prevent periodontal tissue destruction directly by enzyme inhibition.

Ciclopirox nail lacquer 8%: in vivo penetration into and through nails and in vitro effect on pig skin.

This report presents original methods to assess the bioavailability of an antifungal drug from a varnish preparation in finger nails. For the studies with human volunteers a ciclopirox 8% nail lacquer was used to determine its efficacy in the treatment of onychomycoses. In vivo studies were performed on the fingernails of healthy volunteers by determining the total amount of ciclopirox penetrated per milligram of nail and the partition of the drug in the plate of the nails (technically divided into four layers). Ciclopirox concentrations were evaluated by measuring the inhibition of Candida pseudotropicalis growth in vitro. The ciclopirox concentration after 30 days treatment was determined as 3.35 +/- 0.82 micrograms/mg nail material. This is a sufficient amount to kill the fungal pathogens. In addition, in vitro penetration experiments were carried out with excised pig skin. Lacquer formulations from 0.5 to 8% were used to inhibit the growth of Trichophyton mentagrophytes. Formulations from 2 to 8% led to a strong to total inhibition of the dermatophyte after 30 min treatment time.

Ciclopiroxolamine cream 1%: in vitro and in vivo penetration into the stratum corneum.

Studies were conducted to assess the penetration of 1% ciclopiroxolamine cream, establishing the concentrations of the antimycotic compound in different layers of the stratum corneum with two skin models. Results of in vitro studies using skin from domestic pigs indicate that ciclopiroxolamine has the ability to penetrate fast into the epidermis, by inhibiting and killing inoculated Trichophyton mentagrophytes. In vivo investigation of the stratum corneum has been performed in healthy human volunteers by 20 strippings collected in four layers. Fungicidal concentrations of ciclopiroxolamine were determined after extraction from the strippings. These studies demonstrate that the concentrations reached levels which are sufficient to inhibit and kill pathogenic fungi.