Beatrice Tita

Extracts of various species of Epilobium inhibit proliferation of human prostate cells

This study examined whether various species of Epilobium, a phytotherapeutic agent used in folk medicine as a treatment for benign prostatic hyperplasia, may have an antiproliferative effect in PZ‐HPV‐7 human prostatic epithelial cells in‐vitro. The MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl‐tetrazolium bromide) test, [methyl‐3H]thymidine incorporation into DNA and flow cytometry analysis were used to evaluate cell proliferation. Ethanolic extracts of E. spicatum, E. rosmarinifolium and E. tetragonum inhibited DNA synthesis in PZ‐HPV‐7 cells. While at high concentrations all extracts were cytotoxic, DNA synthesis was also decreased at levels that caused no or little cytotoxicity. Treatment of cells with Epilobium extracts did not result in a formation of DNA fragments (evaluated by the TUNEL assay) or chromatin condensation (assessed by Hoechst staining). Flow cytometry analysis indicated that Epilobium extracts inhibit the progression of the cell cycle from the G0/G1 phase. These results suggest that extracts of Epilobium inhibit proliferation of human PZ‐HPV‐7 cells in‐vitro by affecting progression of the cell cycle. This study provides some initial biological plausibility for the use of Epilobium extracts in benign prostatic hyperplasia.

Antimicrobial activity of Epilobium spp. extracts

The antimicrobial activity of the Epilobium angustifolium, E. hirsutum, E. palustre, E. tetragonum and E. rosmarinifolium ethanolic extracts was studied in vitro on Gram-positive and Gram-negative bacteria, yeasts and fungi. The cytotoxicity of the extracts was also evaluated using the Artemia salina test. All the extracts showed antimicrobial activity in a range of concentrations between 10 and 650 microgml of dry extract. E. angustifolium and E. rosmarinifolium had the most broad spectrum of action inhibiting bacteria, yeasts and fungi. The extracts were devoid of toxicity on Artemia salina within the range of antimicrobial concentrations, suggesting that the action is selective on microorganisms.

Characterization of the effect of Epilobium extracts on human cell proliferation.

We have previously shown that extracts of different Epilobium species, a phytotherapeutic agent used in folk medicine as a treatment for benign prostatic hyperplasia, inhibit proliferation of human prostate cells. The selectivity of this effect was evaluated in four different human cell lines (PZ-HPV-7, normal prostate cells; LNCaP, transformed prostate cells; HMEC, mammary cells, and 1321N1, astrocytoma cells). Different extracts of Epilobium species (E. rosmarinifolium, E. spicatum, and E. tetragonum) had similar growth-inhibitory effects in all cell lines tested, indicating a lack of specificity for prostate cells. Inhibition of DNA synthesis was mostly due to the nonpolar fraction of the extracts which is expected to contain flavonoids and sterols. Polar fractions were devoid of activity with the exception of that from E. rosmarinifolium. This species is the most potent in the antiproliferative effect and contains the highest concentration of oenothein B, a hydrolyzable ellagitannin. Oenothein B inhibited DNA synthesis in all four cell lines tested. Extracts of E. angustifolium (the Linné denomination of E. spicatum) and of E. spicatum from different sources were compared for their ability to inhibit DNA synthesis and for their oenothein B content. The E. angustifolium extract contained an amount of oenothein B 40-fold higher than the other extract of the same species and was ten times more potent in inhibiting DNA synthesis in a human prostate cell line. These results indicate that Epilobium extracts inhibit proliferation of prostate cells in a nonspecific manner. Oenothein B may play a role in this effect, but other active compounds are also present. The difference observed between extracts from the same species underscores the importance of determination and standardization of active ingredients in phytotherapeutic agents.

Analgesic properties of Epilobium angustifolium, evaluated by the hot plate test and the writhing test

The analgesic properties of Epilobium angustifolium (Ea), a plant containing flavonoids with anti-inflammatory activity, have not been sufficiently studied so far. Thus, we decided to evaluate, by the classical hot plate test and the writhing test, the analgesic effect of a dry extract of Ea obtained by evaporating a commercially available mother tincture. In the former assay, the effect of Ea (380 mg/kg) was slightly lower than that of morphine (10 mg/kg s.c.). In the writhing test, which is more sensitive for non-steroidal analgesics, the effect of Ea was already significant (P < 0.05) at 95 mg/kg while at doses > or = 190 mg/kg, its activity was similar to that of lysine acetylsalicylate (300 mg/kg). The LD50 of this dry extract of Ea was 1.4+/-0.1 g/kg. Further studies are necessary for the identification of the active principles and the elucidation of their mechanism of action.

Indazole carboxylic acids in male contraception

Two new chemical entities, 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide and 1-(2,4-dichlorobenzyl)-indazole-3-acrylic acid, were synthesized based on the core structure of lonidamine (1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid). These compounds apparently exert their effects in the testis by perturbing the Sertoli-germ cell adherens junctions causing germ cell loss from the seminiferous epithelium. Recently completed studies in the rat have demonstrated the efficacy, reversibility, and potential use of these two compounds as oral contraceptives for men. Neither compound affected the hypothalamus-pituitary-testicular axis, and both compounds were neither hepatotoxic nor nephrotoxic. These results suggest that these two compounds are safe for further development.

Anti-proliferative effect on a prostatic epithelial cell line (PZ-HPV-7) by Epilobium angustifolium L

Symptomatic benign prostatic hyperplasia (BPH) is a common condition in elderly men and has a significant impact on their daily lives. The drugs prescribed for treatment include alpha1-blockers, 5-alpha-reductase inhibitors and plant preparations. Epilobium angustifolium L. is deemed to be helpful in BPH therapy, although there is less information regarding the mechanism of its biological activity. The present study evaluated the effect of E. angustifolium extract on human prostatic epithelial cells (PZ-HPV-7). The exposure to E. angustifolium extract induced a marked inhibition of cell growth in all tested conditions. The anti-proliferative effect observed in in vitro systems clearly indicates a biologically relevant effect of compounds present in the extract. Considering these results, the use in traditional medicine of E. angustifolium extract against BPH seems to be justified. However, further experimental studies are needed to determine the biochemical mechanism of the action and the clinical value of the E. angustifolium extract.

Intracellular signal transduction pathways as targets for neurotoxicants.

The multiple cascades of signal transduction pathways that lead from receptors on the cell membrane to the nucleus, thus translating extracellular signals into changes in gene expression, may represent important targets for neurotoxic compounds. Among the biochemical steps and pathways that have been investigated are the metabolism of cyclic nucleotides, the formation of nitric oxide, the metabolism of membrane phospholipids, the activation of a multitude of protein kinases and the induction of transcription factors. This brief review will focus on the interactions of three known neurotoxicants, lead, ethanol and polychlorinated biphenyls, with signal transduction pathways, particularly the family of protein kinase C isozymes, and discusses how such effects may be involved in their neurotoxicity.

Modulation of DNA synthesis by muscarinic cholinergic receptors

Abstract Acetylcholine muscarinic receptors are a family of five G-protein—coupled receptors widely distributed in the central nervous system and in peripheral organs. Activation of certain subtypes of muscarinic receptors (M1, M3, M5) has been found to modulate DNA synthesis in a number of cell types. In several cell types acetylcholine, by activating endogenous or transfected muscarinic receptors, can indeed elicit cell proliferation. In other cell types, however, or under different experimental conditions, activation of muscarinic receptors has no effect, or inhibits DNA synthesis. A large number of intracellular pathways are being investigated to define the mechanisms involved in these effects of muscarinic receptors; these include among others, phospholipase D, protein kinases C and mitogen-activated-protein kinases. The ability of acetylcholine to modulate DNA synthesis through muscarinic receptors may be relevant in the context of brain development and neoplastic growth.

Ocular absorption and distribution of bendazac after topical administration to rabbits with different vehicles

Ocular and systemic absorption of bendazac was investigated after topical administration to rabbits of 0.5% solutions of bendazac lysine in different polysaccharide vehicles. The results show that the drug is absorbed into the retina-choroid via an extracorneal, or sclero-conjunctival route; the iris and the ciliary body are presumably supplied via both the transcorneal and the extracorneal pathways. The extent of absorption via the extracorneal route is not related to vehicle viscosity but rather to the chemical features of vehicle. The transcorneal penetration appears to be hindered by the binding of the drug to corneal tissues.

Physical Carboxymethylscleroglucan/Calcium Ion Hydrogels as Modified Drug Delivery Systems in Topical Formulations

A carboxymethyl derivative of scleroglucan (Scl-CM) with a 65±5% carboxylic group degree of derivatization (DD) was recently synthesized and characterized. Aqueous solutions of the polymer underwent to a sharp transition toward a gel like behaviour in the presence of divalent ions such as Ca+2. Physical hydrogels with different Scl-CM/Ca+2 ratios were prepared and characterized for their rheological behaviour. Their potential as drug delivery systems was also evaluated. To this end three non steroidal anti-inflammatory drugs (NSAIDs) were loaded into the hydrogels obtained with 2% w/v solution of Scl-CM and 0.05 and 0.1 M CaCl2. The release rate of the drugs was critically related to the salt concentration. By an appropriate combination of the hydrogels prepared using different amounts of salt, it was possible to obtain a system able to release diclofenac with zero-order kinetics. Primary skin irritation tests showed a good biocompatibility of the new polymer, as well as of its hydrogels. These results suggest a potential of the new hydrogels for the development of modified delivery systems in topical formulations.