Study of the effects of Lemna minor extracts on human immune cell populations.

OBJECTIVE: Lemna minor is a plant with a huge repertoire of secondary metabolites. The literature indicates that extracts of Lemna minor have antioxidant, antiradical, immunomodulatory and anti-inflammatory properties. The objective of the present study was to find a suitable technique to extract active compounds from this plant and verify whether these extracts have immunomodulatory activity. MATERIALS AND METHODS: We grew L. minor on a standard medium with Gamborg B5 and vitamins. We extracted compounds from the plant by maceration and decoction. The phytochemical profile of the extracts was characterized by chromatography, spectrophotometry, and spectroscopy. The extracts were tested on cultures of mononuclear cells from four human subjects. These cells were pulsed with carboxyfluorescein succinimidyl ester, grown in triplicate in standard culture medium without (control) and with increasing concentrations of Lemna extracts. Flow cytometry was used to evaluate cell death and proliferation of the total mononuclear cell population and of CD4+, CD8+, B cell and monocyte populations. RESULTS: The Lemna extracts were not cytotoxic and did not cause cell necrosis or apoptosis in immune cells. At low concentrations, they induced very limited proliferation of CD4+ cells within 48 hours. At high concentrations, they induced proliferation of CD8+ cells and B lymphocytes within 48 hours. CONCLUSIONS: Unfortunately, we failed to confirm any immunomodulatory activity of Lemna extracts. Growth and death rates of human immune cells were not significantly affected by adding Lemna extracts to the culture medium.

Impedance spectroscopy of conductive commercial hydrogels for electromyography and electroencephalography.

In biomedical applications such as the electroencephalogram, electrocardiogram and electromyogram, usually conductive hydrogels are applied to the skin providing a skin-electrode layer, with the aim of lowering contact impedance and improving the signal/noise ratio. It is important to know the electrical behavior of these materials, obtaining reliable values of their conductivity. It can be extracted by the whole cell impedance, which is affected not only by the bulk but also by the surface properties. The aim of the present work is to characterize the impedance of some currently available conductive hydrogels in the frequency range 5 Hz-1 MHz. For this purpose we have designed a novel cell, with silver electrodes, optical detection of the gap and guard ring. In this paper the results are compared with those obtained by means of a commercial cell with stainless steel electrodes, without a guard ring. In order to extract the different contributions of the bulk and the interface, we fitted the experimental data with a very simple model: the bulk properties are described by a single RC-parallel, whereas the interface is represented by a constant phase element.

Distribution of hyoscyamine and scopolamine in Datura stramonium.

The production of hyoscyamine and scopolamine in Datura stramonium has been investigated in the different plant parts, at different stages of their life cycle. Maximum contents were found in the stems and leaves of young plants, hyoscyamine being always the predominant component.

Quality control of aromatic drugs reported in European Pharmacopoeia 3rd edition.

The apparent current explosion of interest and commercial activity in the area of herbal products should be followed by accurate quality control. In this work, the authors carried out the specific quality assays of all the aromatic drugs reported in European Pharmacopoeia. For each drug, several samples of different brands were bought in pharmacies, herbalist's shops, or supermarkets. The worst results were obtained in the assay for the essential oil content and this is very negative as the medicinal activities of these drugs are ascribed to their essential oil content. The samples of different brands yielded very different results from a qualitative point of view. In most cases, the analyzed samples were very far from the acceptable qualitative standards that they definitely lacked any health benefits.

Botanical drugs and preparations in the traditional medicine of West Azerbaijan (Iran).

We present the results of an investigation of the traditional ethnobotany and ethnomedicine of West Azerbaijan (Iran). In this region medicinal plants are often the only easily accessible health care alternative for most of the population in rural areas and in fact folk herbal medicine is the most used remedy to cure common diseases. In this paper we present the most frequently used native species and the most common preparations made from them, in order to preserve the plant popular knowledge, which has traditionally been only an oral one.

Luminous-flux measurements by an absolute integrating sphere.

We present an original implementation of the absolute-sphere method recently proposed by Ohno. The luminous-flux unit, the lumen, is realized by means of an integrating sphere with an opening calibrated by a luminous-intensity standard placed outside. The adapted experimental setup permits one to measure luminous-flux values between 5 and 2500 lm with a significant improvement with respect to the simulated performances reported in the literature. Traditionally, the luminous-flux unit, the lumen, is realized by goniophotometric techniques in which the luminous-intensity distribution is measured and integrated over the whole solid angle. Thus sphere results are compared with those obtained with the Istituto Elettrotecnico Nazionale goniophotometer. In particular, a set of standards, characterized by luminous-flux values of ~2000 lm, has been calibrated with both techniques. We highlight some of the problems encountered. Experimental results show that the agreement between the two methods is within the estimated uncertainty and suggest promising areas for future research.

Direct measurement of the two principal refractive indexes of a nematic liquid crystal slab.

A new technique to measure the principal refractive indexes of a nematic liquid crystal is presented. The method is based on an indirect measurement of the refraction angle by determining the direction of a magnetic field which minimizes the light scattering. With this technique one can perform different light scattering experiments, which require a knowledge of the refractive indexes, on the same crystal slab. The accuracy is better than +/-0.15%. A discussion about the systematic error due to the distortion of the director profile near the holder edges and the relative correction is given.