Biomedical subjects

H Vuorela

Publications and source records attributed to H Vuorela.

At least 19 recordsLinked to original sources

PubMed2006

Preliminary antiproliferative effects of some species of Terminalia, Combretum and Pteleopsis collected in Tanzania on some human cancer cell lines.

Methanolic extracts (25 microug/ml) of species belonging to the genera of Combretum, Terminalia and Pteleopsis, collected during a field expedition in Tanzania in 1999, were screened for their antiproliferative and cytotoxic effects against three human cancer cell lines (HeLa, cervical carcinoma; T 24, bladder carcinoma; and MCF 7, breast carcinoma). A leaf extract of Combretum fragrans and a fruit extract of C. zeyheri gave the strongest antiproliferative and cytotoxic effects of all the twenty-four extracts screened in this investigation. In contrast to the highly powerful leaf extract of C. fragrans, the root extract of this species gave no cytotoxic effects against the investigated cancer cell lines at a concentration of 25 microg/ml. The other investigated species of Combretum and Terminalia differed greatly in their cytotoxic potential. Root extracts of Terminalia sambesiaca and T. sericea gave the strongest cytotoxic effects of the five species of Terminalia used in this study. Eight of the twenty-four investigated plant extracts showed pronounced cytotoxic effects (<30% proliferation compared to the control) against the T 24 bladder cancer cells, seven against the HeLa cells and four against the MCF 7 cells.

Antineoplastic Agents, Phytogenic↗

PubMed2006

Inhibitory effect of dietary phenolic compounds on Chlamydia pneumoniae in cell cultures.

Chlamydial infections are very common worldwide. All chlamydial species have a tendency to cause persistent infections, which have been associated to several chronic diseases including blinding trachoma, infertility and coronary heart disease (CHD). At present, no efficient treatment for the eradication of chronic chlamydial infections exists and, thus, new antichlamydial compounds are urgently needed. This study was designed to screen antichlamydial activity of natural flavonoids and other natural and structurally similar synthetic compounds against Chlamydia pneumoniae in human cell line (HL). HL cells were infected with C. pneumoniae and incubated 72 h with studied compounds. Reduction in the number of inclusions was determined with immunofluorescence staining. In vitro minimum inhibitory concentration was also determined for some of the most active compounds. Thirty seven percentage of the studied compounds (57 in total) were highly active against C. pneumoniae and all the studied compounds were non-toxic to the host cells at studied concentrations. Our study revealed direct antichlamydial effect for selected polyphenolic compounds against C. pneumoniae, in vitro. We also demonstrated the ability of some of the investigated compounds to accumulate inside cells or into cell membranes and cause inhibition, even when present only prior to infection.

Anti-Bacterial Agents↗

PubMed2004

Natural products in the process of finding new drug candidates.

Natural derived or originated compounds still play a major role as drugs, and as lead structures for the development of synthetic molecules. About 50% of the drugs introduced to the market during the last 20 years are derived directly or indirectly from small biogenic molecules. In the future, natural products will continue to play a major role as active substances, model molecules for the discovery and validation of drug targets. A multidisciplinary approach to drug discovery involving the generation of truly novel molecular diversity from natural product sources, combined with total and combinatorial synthetic methodologies provides the best solution to increase the productivity in drug discovery and development. Screening for new drugs in plants implies the screening of extracts for the presence of novel compounds and an investigation of their biological activities. It is currently estimated that approximately 420,000 plant species exist in nature. For the purpose of lead discovery, or for the scientific validation of a traditional medicinal plant or a phytopharmaceutical, active principals in complex matrices need to be identified. Therefore, the interfacing of biological and chemical assessment becomes the critical issue. Drug discovery from plants can be guided by epidemiologic studies facilitated with computer assisted HPLC microfractionation and microplate technology. Epidemiologic studies have shown that high dietary flavonoid intake may be associated with decreased risk for cardiovascular disease. Chlamydia pneumoniae is a common human pathogen and epidemiological and clinical studies have shown a connection between chronic C. pneumoniae infection, atherosclerosis and the risk of myocardial infarction. We will present here the detection of natural compounds active against C. pneumoniae as an example.

Animals↗

PubMed2002

Ethnobotanical and antimicrobial investigation on some species of Terminalia and Combretum (Combretaceae) growing in Tanzania.

An ethnobotanical investigation on the medicinal uses of some species of Terminalia and Combretum (Combretaceae) was carried out in Mbeya, Tanzania during a 5-weeks field expedition. Of the sixteen species collected, Combretum fragrans F. Hoffm., Combretum molle G. Don., Combretum psidioides Welw., Combretum zeyheri Sond., Terminalia kaiserana F. Hoffm. and Terminalia sericea Burch ex. DC. have medical applications against various bacterial infections, such as gonorrhoea and syphilis, and against symptoms like diarrhoea, hypertension and even cancer. Antimicrobial screening of the crude extracts of the selected Combretum and Terminalia species was performed by the agar diffusion method. Among the most effective extracts were methanol extracts of the roots of Terminalia sambesiaca Engl. & Diels., T. kaiserana Guill. & Perrott., T. sericea Burch. ex DC., C. fragrans F. Hoffm. and Combretum padoides Engl. & Diels., all of which showed marked inhibition against Gram-positive bacteria, and were also good inhibitors of Enterobacter aerogenes. All four of the extracts of the roots of T. sericea tested, (methanol, ethanol, acetone and hot water) had good antimicrobial activity. A methanolic leaf extract of T. kaiserana was the only extract to have a bacteriocidic effect on Escherichia coli. Methanol root extracts of T. sambesiaca and methanol leaf extracts of T. sericea were the most effective against Candida albicans. The results of the antimicrobial screening support the ethnomedical uses of these plants.

Anti-Bacterial Agents↗

PubMed2001

Effects of simple aromatic compounds and flavonoids on Ca2+ fluxes in rat pituitary GH(4)C(1) cells.

The biological activity of phenolic compounds from plants is well documented in vitro, but little is known about the possible effect of simple aromatic compounds and flavonoids on voltage-operated Ca2+ channels (VOCCs). In pituitary cells, several intracellular pathways may regulate the activity of VOCCs. In this study, we investigated the effect of nine phenylpropanes and metanes, and 20 flavonoids on high K(+)-induced 45Ca2+ entry in clonal rat pituitary GH(4)C(1) cells. At the highest dose tested (20 microg/ml), flavone (a flavone) inhibited 45Ca2+ entry by 63.5%, naringenin (a flavanone) by 56.3% and genistein (an isoflavone) by 54.6%. The phenylmetane derivative octyl gallate was the most potent compound tested, with an IC(50) value of 15.0 microg/ml. The IC(50) value for the reference compound verapamil hydrochloride was 3.0 microg/ml. In sharp contrast to the above, the flavonols quercetin and morin potentiated 45Ca2+ entry. At 20 microg/ml, quercetin increased 45Ca2+ entry by 54.1% and morin by 48.0%. Quercetin increased the cellular cAMP content in a concentration-dependent manner. H 89, an inhibitor of protein kinase A, inhibited the effect of quercetin on 45Ca2+ entry. The results thus suggest that the effect of quercetin is the result of a protein kinase A-mediated activation of VOCCs. Quercetin induced a rapid and marked increase in both the transient (143.1+/-4.2%) and delayed (198.8+/-10.0%) Ca2+ currents, measured by the whole cell patch clamp technique. The onset of the inhibitory effect of octyl gallate was slow, but resulted in an almost complete inhibition of both Ca2+ currents.

Animals↗

PubMed2001

Effect of eluent on the ionization efficiency of flavonoids by ion spray, atmospheric pressure chemical ionization, and atmospheric pressure photoionization mass spectrometry.

The effect of nine different eluent compositions on the ionization efficiency of five flavonoids was studied using ion spray (IS), atmospheric pressure chemical ionization (APCI), and the novel atmospheric pressure photoionization (APPI), in positive and negative ion modes. The eluent composition had a great effect on the ionization efficiency, and the optimal ionization conditions were achieved in positive ion IS and APCI using 0.4% formic acid (pH 2.3) as a buffer, and in negative ion IS and APCI using ammonium acetate buffer adjusted to pH 4.0. For APPI work, the eluent of choice appeared to be a mixture of organic solvent and 5 mM aqueous ammonium acetate. The limits of detection (LODs) were determined in scan mode for the analytes by liquid chromatography/mass spectrometry using IS, APCI and APPI interfaces. The results show that negative ion IS with an eluent system consisting of acidic ammonium acetate buffer provides the best conditions for detection of flavonoids in mass spectrometry mode, their LODs being between 0.8 and 13 microM for an injection volume of 20 microl.

Journal Article↗

PubMed2001

Near infrared reflectance spectroscopy for the fast identification of PVC-based films.

Near infrared (NIR) reflectance spectroscopy was used to develop a non-destructive and rapid qualitative method for the analysis of plastic films used by the pharmaceutical industry for blistering. Three types of films were investigated: 250 microm PVC [poly(vinyl chloride)] films, 250 microm PVC films coated with 40 g m(-2) of PVDC [poly(vinylidene dichloride)] and 250 microm PVC films coated with 5 g m(-2) of TE (Thermoelast) and 90 g m(-2) of PVDC. Three analyses were carried out using different pre-treatment options and a PLS (partial least squares) algorithm. Each analysis was aimed at identifying one type of film and rejecting all types of false sample (different thickness, colour or layer). True and false samples from four plastics manufacturers were included in the calibration sets in order to obtain robust methods that were suitable regardless of the supplier. Specificity was demonstrated by testing validation sets against the methods. The tests showed 0% of type I (false negative identification) and 1% of type II errors (false positive identification) for the PVC method, 13 and 3%, respectively, for the PVC-PVDC method and no error for the PVC-TE-PVDC method. Type II errors, mostly due to the slight sensitivity of the methods to film thickness, are easily corrected by simple thickness measurements. This study demonstrates that NIR spectroscopy is an excellent tool for the identification of PVC-based films. The three methods can be used by the pharmaceutical industry or plastics manufacturers for the quality control of films used in blister packaging.

Drug Packaging↗

PubMed2001

The coumarin osthol attenuates the binding of thyrotropin-releasing hormone in rat pituitary GH4C1 cells.

The influence of two plant coumarins, osthol and xanthotoxin, on intracellular Ca2+ ([Ca2+]i) transients evoked by TRH were studied in clonal rat pituitary GH4C1 cells. Osthol, but not xanthotoxin, decreased the TRH-induced transient increase in [Ca2+]i in Fluo-3 loaded cells incubated in Ca(2+)-free buffer. Binding experiments with [3H]TRH showed that osthol decreased the binding of TRH to its receptor, whereas the affinity of the receptor for TRH increased. This resulted in a decreased TRH-evoked production of IP3 in cells treated with osthol, and a decreased mobilization of sequestered calcium. Osthol did not inhibit the release of calcium evoked by exogenous IP3 in permeabilized cells. Furthermore, osthol decreased the uptake of 45Ca2+ in response to high K+. Xanthotoxin had no effects in these experiments. The results show that osthol modulates TRH-evoked responses by interacting with the TRH receptor.

Animals↗

PubMed2000

Treatment of acute low back pain with the COX-2-selective anti-inflammatory drug nimesulide: results of a randomized, double-blind comparative trial versus ibuprofen.

STUDY DESIGN: A prospective, randomized double-blind comparative trial. OBJECTIVES: To evaluate the efficacy and tolerability of nimesulide, a cyclooxygenase (COX)-2-selective anti-inflammatory agent versus ibuprofen in patients with acute lumbosacral back pain. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been more effective than placebo in patients with uncomplicated acute low back pain in previous randomized controlled trials. The efficacy and tolerability of a new COX-2-selective anti-inflammatory drug have not yet been established. METHODS: One hundred four patients aged 18-65 years with acute low back pain were enrolled. The patients were randomly allocated either to oral nimesulide (100 mg twice daily for 10 days) or oral ibuprofen (600 mg three times daily for 10 days). Outcome measures on a visual analog scale were an average of the pain intensity and the pain relief, stiffness in the back, functional status, and the results of physical examinations. All side effects were recorded at each visit. RESULTS: With both study therapies, there was a clear improvement in all measured parameters of the pain and back function parameters measured from the third day of treatment onward. The patients' capacity for daily tasks, showed improvement in both groups (P < 0. 001), but a statistically significant difference was found between the two groups in favor of the nimesulide group (P < 0.05) after 10 days. Nimesulide was more effective than ibuprofen in improved lateral bending measurements (P = 0.026). Nimesulide and ibuprofen provided similar degrees of improvement in the modified Schober tests and in the pain intensity and back stiffness scores. More gastrointestinal side effects were reported with ibuprofen than nimesulide, and the comparison showed a trend (P = 0.067). Ten side effects occurred in the nimesulide group in 7 (13%) patients and 13 in the ibuprofen group in 11 (21%) patients. CONCLUSIONS: The results confirmed that the COX-2-selective inhibitor nimesulide is an effective and well-tolerated agent for use in general practices to treat acute low back pain. The incidence of gastrointestinal side effects seems to be lower with nimesulide than with ibuprofen.

Acute Disease↗

PubMed2000

Antimicrobial effects of Finnish plant extracts containing flavonoids and other phenolic compounds.

Plant phenolics, especially dietary flavonoids, are currently of growing interest owing to their supposed functional properties in promoting human health. Antimicrobial screening of 13 phenolic substances and 29 extracts prepared from Finnish plant materials against selected microbes was conducted in this study. The tests were carried out using diffusion methods with four to nine microbial species (Aspergillus niger, Bacillus subtilis, Candida albicans, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Staphylococcus aureus and Staphylococcus epidermidis). Flavone, quercetin and naringenin were effective in inhibiting the growth of the organisms. The most active plant extracts were purple loosestrife (Lythrum salicaria L.) against Candida albicans, meadowsweet (Filipendula ulmaria (L.) Maxim.), willow herb (Epilobium angustifolium L.), cloudberry (Rubus chamaemorus L.) and raspberry (Rubus idaeus L.) against bacteria, and white birch (Betula pubescens Ehrh.), pine (Pinus sylvestris L.) and potato (Solanum tuberosum. L.) against gram-positive Staphylococcus aureus.

Anti-Bacterial Agents↗

PubMed2000

Antimicrobial activity of some coumarin containing herbal plants growing in Finland.

Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia solani. The growth of Heterobasidium annosum was inhibited, whereas that of Phytophtora (cactorum) was promoted by all the extracts. The antibacterial and antifungal activities of six natural coumarin compounds were weak, except for the inhibitory effect against Fusarium culmorum.

Anti-Bacterial Agents↗

PubMed2000

Aging in Pinus sylvestris L. seeds: changes in viability and lipids.

Aging of Scots pine seeds (Pinus sylvestris L.) leads to changes in seed quality, such as loss of germinability, delayed growth and abnormality in developing seedlings. The knowledge of biochemical changes responsible for these aging processes is plentiful in some seeds, which are of world-wide interest, but for pine seeds these studies are rare. The aim of the present study, was to analyse pine seeds of varying ages in order to identify biochemical changes occurring in aged pine seeds, and to see if a correlation existed between these results and traditionally used seed-quality parameters, such as germinability and electrolyte leakage.

Cycadopsida↗

PubMed1999

A bioassay using Artemia salina for detecting phototoxicity of plant coumarins.

Artemia salina (brine shrimp) has been successfully used for toxicity testing, and a screening test for phototoxicity has been developed based on this method. The ability of the method to test the phototoxic potential of seven known compounds was investigated. Athamantin (an angular furanocoumarin) and umbelliferone (a simple coumarin) showed no phototoxicity, while linear furanocoumarins exhibited phototoxic activity in the following order: psoralen > bergapten > peucedanin > xanthotoxin. The applicability of this method was also tested in screening the phototoxicity of plant material. Six plants from Apiaceae [Aegopodium podagraria L., Anethum graveolens L., Angelica archangelica L., Levisticum officinalis Koch, Petroselinum crispum (P. Mill) A. W. Hill., and Peucedanum palustre (L.) Moench] and one from Rutaceae (Ruta graveolens L.) were selected, all of them known to contain furanocoumarins. Extracts from leaves collected at different times during the growth period were used in the screening. Our results were in accordance with the furanocoumarin content of these plants and with the results of other phototoxicity tests. The Artemia salina method proved to be rapid, simple and inexpensive, and is therefore ideal in the initial biological screening of large numbers of samples for simultaneous detection of both toxicity and phototoxicity.

Animals↗

PubMed1998

High-performance liquid chromatography methods for the separation and quantitation of spironolactone and its degradation products in aqueous formulations and of its metabolites in rat serum.

HPLC assays have been developed for the determination of spironolactone and its degradation products 7 alpha-thiospirolactone and canrenone in aqueous solutions of beta-cyclodextrins and for the determination of spironolactone and its metabolites 7 alpha-thiospirolactone, 7 alpha-thiomethylspirolactone, 6 beta-hydroxy-7 alpha-thiomethylspirolactone and canrenone in rat serum samples. Both methods were well suited for their respective applications, i.e., studying the stability of spironolactone in liquid formulations of beta-cyclodextrins and the oral absorption of spironolactone in rats. The HPLC method developed for spironolactone and its metabolites in rat serum requires very small volumes of serum making it possible to take several blood samples over a period of time.

Animals↗

PubMed1998

Optimization of selectivity in high-performance liquid chromatography using desirability functions and mixture designs according to PRISMA.

A computer program for the mobile phase optimization of high-performance liquid chromatography (HPLC) is described. The desirability function technique combined to the prisma mixture design was employed to enhance the quality of HPLC separations. The use of statistical models to predict the behaviour of retention times (tR) and band broadening at the different eluent compositions obtained by prisma was examined for dansyl amides and coumarins. The study showed that the dependence between the eluent composition and tR values of dansyl amides and coumarins can be expressed using quadratic regression models with a high degree of accuracy. Band broadening given by means of the band width at half-height (wh) was described by a linear regression model. Both models were used in calculating and predicting the resolution (Rs) in various solvent combinations. The desirability function converted the calculated (Rs) value into the desirability value (D), and the overall optimum was then defined by means of the overall desirability. The optimal eluent mixtures for the separation of compounds were easily read from the contour plot inside the horizontal plane of the prisma model. A good separation was achieved using the optimized solvent combination. Depending on the aims of the optimal separation, the program allows either optimization of critical pairs or achieving the overall optimum giving a reasonable separation for as many compounds as possible.

Chromatography, High Pressure Liquid↗

PubMed1997

Behaviour of resolution by changing solvent strength and selectivity in the 'PRISMA' model using reversed-phase HPLC for biogenic amines.

The retention behaviour of 17 dansylated biogenic amines in 6 linear gradients at 13 solvent combinations, expressed by the selectivity points (Ps) according to the 'PRISMA' model, was investigated. The dependence between the retention times (tr) and different gradients was examined. Three dimensional resolution (Rs) maps for each peak-pair in the different gradients at the 13 selectivity points were constructed, and the affect of the gradients on separation were investigated. The study showed that the dependence between the gradients and tr values of dansyl amides can be expressed using quadratic functions with a high degree of accuracy. These functions are well suited for estimating the resolution in different gradients and Ps. The three dimensional Rs maps clearly demonstrated the changes between the different gradients and Ps. This was of considerable benefit when searching the optimum mobile phase by changing both the solvent strength (ST) and selectivity.

Biogenic Amines↗

PubMed1997

Isolation and immunomodulatory effect of flavonol glycosides from Epimedium hunanense.

The ethyl acetate and n-butanol fractions from aerial parts of E. hunanense were initially screened to find active fractions with immunomodulatory activity. Nine compounds, tricin (1), luteolin (2), thalictoside (3), icariin I (4), baohuoside I (5), quercitrin (6), icariin (7), epimedin C (8), and B (9) were isolated from this species for the first time, and 3 was isolated for the first time from flavonoid extracts of the genus. Their structures were established by chemical and spectroscopic methods. The immunomodulatory effects of the n-butanol fraction and epimedin C isolated from the fraction were investigated. Hydrocortisone acetate (HCA) was used as an immunosuppressant to inhibit the immune response of mice. The n-butanol fraction and epimedin C significantly enhanced the response of spleen antibody-forming cells (SAFC) to near normal in the mice treated with HCA. They also significantly enhanced lymphocyte proliferation and caused a significant recovery of interleukin-2 (IL-2) production in the mice inhibited with HCA. In conclusion, they are active principles with immunoenhancing effects.

Adjuvants, Immunologic↗

PubMed1997

Anti-inflammatory activity of extracts from leaves of Phyllanthus emblica.

Leaves and fruits of Phyllanthus emblica L. have been used for the anti-inflammatory and antipyretic treatment of rural populations in its growing areas in subtropical and tropical parts of China, India, Indonesia, and the Malay Peninsula. In the present study, leaves of Ph. emblica were extracted with ten different solvents (n-hexane, diethyl ether, methanol, tetrahydrofuran, acetic acid, dichloromethane, 1,4-dioxane, toluene, chloroform, and water). The inhibitory activity of the extracts against human polymorphonuclear leukocyte (PMN) and platelet functions was studied. Methanol, tetrahydrofuran, and 1,4-dioxane extracts (50 micrograms/ml) inhibited leukotriene B4-induced migration of human PMNs by 90% and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced degranulation by 25-35%. The inhibitory activity on receptor-mediated migration and degranulation of human PMNs was associated with a high proportion of polar compounds in the extracts as assessed by normal phase thin layer chromatography. Diethyl ether extract (50 micrograms/ml) inhibited calcium ionophore A23187-induced leukotriene B4 release from human PMNs by 40%, thromboxane B2 production in platelets during blood clotting by 40% and adrenaline-induced platelet aggregation by 36%. Ellagic acid, gallic acid and rutin, all compounds isolated earlier from Ph. emblica, could not explain these inhibitory activities on PMNs or platelets by Ph. emblica extracts. These results show that the leaves of Ph. emblica have inhibitory activity on PMNs and platelets, which confirm the anti-inflammatory and antipyretic properties of this plant as suggested by its use in traditional medicine. The data suggest that the plant leaves contain as yet unidentified polar compound(s) with potent inhibitory activity on PMNs and chemically different apolar molecule(s) which inhibit both prostanoid and leukotriene synthesis.

Anti-Inflammatory Agents, Non-Steroidal↗