Application of near-infrared reflectance spectroscopy to the simultaneous prediction of alkaloids and phenolic substances in green tea leaves.

A near-infrared reflectance spectroscopic (NIRS) method for the prediction of polyphenol and alkaloid compounds in the leaves of green tea [Camellia sinensis (L.) O. Kuntze] was developed. Reference measurements of the individual catechins, gallic acid, caffeine, and theobromine were performed by reversed-phase HPLC. The total polyphenols were determined according to the colorimetric Folin-Ciocalteu assay. Using the partial least-squares algorithm, very good calibration statistics were obtained for the prediction of gallic acid, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, caffeine, and theobromine (R(2) > 0.85) with standard deviation/standard error of cross-validation (SD/SECV) ratio ranging from 2.00 to 6.27. Simultaneously, the dry matter content of the tea leaves can be analyzed very precisely (R(2) = 0.94; SD/SECV = 4.12). Furthermore, it is possible to discriminate tea leaves of different age by principal component analysis on the basis of the received NIR spectra. Prediction of the total polyphenol content is performed with a lower accuracy, which might be due to the lack of specificity in the colorimetric reference method. The study demonstrates that NIRS technology can be successfully applied as a rapid method not only for breeding and cultivation purposes but also to estimate the quality and taste of green tea and to control industrial processes, for example, decaffeination.

Protective effects of Gingko biloba extract EGb 761 on myocardium of experimentally diabetic rats. I: ultrastructural and biochemical investigation on cardiomyocytes.

Chronic diabetes in man and animal models develops cardiomyopathic alterations which cannot be absolutely avoided by insuline therapy. Since diabetic damage is partly attributed to oxidative stress antioxidative treatment could be able to reduce the alterations. Aim of this study was to investigate the cardioprotective effects of EGb 761, known as a radical scavenger, against diabetic alterations in rats. The diabetes was induced by i.p. injection of 60 mg/kg body weight streptozotocin. Duration of diabetes was 4 months, the protected group received 100 mg/kg body weight EGb 761 with the drinking water over 3 months. Electron and light microscopic morphometry of left-ventricular samples revealed typical diabetic alterations consisting in decrease of volume fraction of myofibrils, SR and t-tubules and diminishing of cardiomyocyte diameter, increase of interstitial volume, mitochondrial size and volume fraction, and of vacuoles and of lipid drops. EGb treatment could gradually prevent the loss of myofibrils and reduction of myocyte diameter but has only little influence on interstitial and mitochondria volume. The diabetic-induced increase of lipid and vacuoles and the decrease of SR and t-tubules were not influenced. Biochemical parameters of oxidative stress: malondialdehyde (MDA) was only insignificantly altered by diabetes and EGb. The superoxide dismutase (SOD) activity was increased by diabetes and more increased by EGb treatment. Creatine kinase (CK) activity was diminished by diabetes but slightly increased by EGb. The polymerase chain reaction (PCR) of i-NOS was not different between the diabetic and protected diabetic groups.

Influence of different properties of a reaction time task on the pre-movement gating of input from Ia afferents to motoneurons.

The monosynaptic reflex (H reflex) is facilitated before movement onset in human subjects who are performing a conditioned plantar flexion of the ankle in a reaction time task. The aim of this study was to investigate how tightly this gating of Ia spindle input is coupled with the conditioned muscle contraction. Test H reflexes were elicited at various times during the reaction time (RT) in order to test the efficacy of Ia volleys on the soleus motoneurons. Tactile, auditory and visual go stimuli were used. The RT to a tactile stimulus was about the same as the RT to an auditory stimulus although distance and therefore conduction time from the site of stimulation to the cerebral cortex was much larger for the tactile than for the auditory modality. The RT to visual stimulation was about 20 ms longer than to the other two modalities. Although central latencies depended clearly on the stimulus modality the duration of the H reflex facilitation, i.e. the interval between the onset of the facilitation and the onset of the voluntary muscle contraction, was always the same. Similarly, the reflex facilitation was insensitive to the succeeding contrast of a visual go stimulus. The subjects were also examined in visual RT tasks in which different advance information about the laterality and the execution of the contraction was given. By combination the following four RT situations were realized: (1) simple, go, (2) choice, go, (3) simple, go-no go and (4) choice, go-no go.(ABSTRACT TRUNCATED AT 250 WORDS)

[Anti-angina effect of gallopamil in comparison with another calcium antagonist and a placebo]. / Die antianginöse Wirkung von Gallopamil im Vergleich mit einem anderen Calciumantagonisten und Placebo.

UNLABELLED: In 12 male patients with angiographically confirmed coronary heart disease and stable angina the antianginal effects of 50 mg Gallopamil have been studied in comparison with 10 mg Nifedipine and placebo. The study has been carried out using a double-blind cross-over protocol with standardized exercise stress tests. Patients underwent 5 exercise step tests, without any medication and 120 minutes after randomized drug administration (placebo, placebo, Gallopamil, Nifedipine). Both Gallopamil and Nifedipine had good antianginal effects. Following 50 mg Gallopamil, ischemic ST-depression was reduced by 45% compared to placebo and by 50% compared to ergometry without any medication. The reduction of ST-depression after 10 mg Nifedipine was 26% compared to placebo and 31% compared to a drug-free exercise test. Due to the negative chronotropic effects, Gallopamil led to a slight but significant reduction of heart rate at rest and during exercise of about 5%. In contrast, after Nifedipine administration, a reflex-mediated increase in heart rate could be seen. In normotensive patients both channel-blocking agents showed a slight reduction of arterial blood pressure. CONCLUSIONS: The results indicate a considerable antianginal effect of a single oral dose of 50 mg Gallopamil. In comparison to 10 mg Nifedipine this effect is more pronounced.