Antimicrobial activity of cyclodextrin entrapped allyl isothiocyanate in a model system and packaged fresh-cut onions

The aim of this work was to determine the antimicrobial effect of allyl isothiocyanate (AIT) entrapped in alpha and beta cyclodextrin inclusion complexes (ICs). In model experiments, AIT formulations were applied to filter paper discs fixed inside the lid of Petri dishes, where the agar surface was inoculated with the target organism (Penicillium expansum, Escherichia coli or Listeria monocytogenes). Solid phase microextraction coupled with gas chromatography was used to determine static headspace concentrations of AIT formulations. The antimicrobial effect of beta IC was determined during aerobic storage of packaged fresh-cut onions at 5 °C for 20 days. AIT entrapped in beta IC exhibited a significantly (p < 0.05) better antimicrobial effect compared to unentrapped AIT. AIT vapour concentrations in the static system were highest for unentrapped AIT followed by beta IC and alpha IC. Application of beta IC (200 μl/l) to packaged fresh-cut onions effectively decreased numbers of L. monocytogenes, which were also decreased at slower rates to undetectable levels on untreated cut onion. After 10 days, total aerobic counts were ca. 4 log CFU/g lower on onions treated with beta IC (100 and 200 μl/l) compared to untreated controls. This work demonstrates the utility of beta IC as an antimicrobial treatment with potential applications in packaged fresh-cut vegetable products.

Pharmacological and phytochemical study on a Sisymbrium officinale Scop. extract

ETHNOPHARMACOLOGICAL RELEVANCE

The aerial parts of Sisymbrium officinale Scop. are commonly used to treat airway ailments, moreover in antiquity the herbal drug was reputed to possess anticancer properties. The results obtained in present work support the traditional use and the properties ascribed to Sisymbrium officinale.

AIM OF THE STUDY

In order to give a scientific basis to the traditional uses of Sisymbrium officinale, this study was aimed to evaluate in vitro the myorelaxant activity, the antimicrobial properties and the antimutagenic effect of an aqueous dry extract of the aerial parts of the plant. A phytochemical characterization of the extract was also performed.

MATERIALS AND METHODS

The myorelaxant activity was studied against the contractions induced by carbachol, histamine and leukotriene C(4), in isolated guinea-pig trachea. The antimicrobial activity was tested against six bacteria and one yeast. The Ames test, performed by the preincubation method, was used to study the antimutagenic activity of the extract by its capability to inhibit the mutagenic effect of 2-nitrofluorene, sodium azide, methyl methanesulfonate and 2-aminoanthracene, in Salmonella typhimurium TA98, Salmonella typhimurium TA100 and Escherichia coli WP2uvrA strains. The chemical composition of the extract was analyzed by TLC and HPLC.

RESULTS

Sisymbrium officinale showed to reduce the chemically-induced contractions of isolated guinea-pig trachea with major potency against leukotriene C(4) and histamine. The extract did not show any antibacterial activity. The Ames test showed a strong antimutagenic activity against 2-aminoanthracene, in Escherichia coli WP2uvrA and in Salmonella typhimurium TA98 strains. The phytochemical study highlighted the presence of putranjivine, the glucosinolate marker of Sisymbrium officinale, and of proline.

CONCLUSIONS

The myorelaxant activity of Sisymbrium officinale offers a scientific basis to its use in traditional medicine. The strong antimutagenic effect suggests further studies to evaluate its possible chemopreventive activity.

Antimutagenic activity of a secoisopimarane diterpenoid from Salvia cinnabarina M. Martens et Galeotti in the bacterial reverse mutation assay

The effects of 3,4-secoisopimar-4(18),7,15-trien-3-oic acid, a diterpenoid isolated from Salvia cinnabarina, were evaluated in the Ames test on Salmonella typhimurium TA98 and TA100 and on Escherichia coli WP2uvrA, in presence and in absence of the metabolic activation system. The secoisopimarane diterpenoid not only showed to be devoid of mutagenic activity, but significantly inhibited the effect of some known mutagens, in all strains tested. The reduction of the number of chemically-induced revertant colonies reached the value of 92.2% against 2-aminoanthracene, 59.6% against 2-nitrofluorene, 50.9% against sodium azide and 39.9% against methyl methane sulfonate. It is hypothesized that the secoisopimarane diterpenoid acts by aspecific mechanisms, by alterating the cell permeability thus blocking the mutagen adsorption across the bacterial membrane, or by chemical or enzymatic inhibition of the mutagens.

Effects of Cimicifuga racemosa extract on liver morphology and hepatic function indices

Cimicifuga racemosa (black cohosh) is a herbaceous perennial plant, that has been traditionally used for a variety of ailments (dyspepsia, climacteric complaints, muscular rheumatisms, menstrual cramps). From laboratory and clinical studies, black cohosh seems to have a relatively good safety profile, even if a number of case reports of hepatotoxicity were a matter of recent concern.

AIM

A number of case reports indicated that C. racemosa could induce hepatotoxicity. We evaluated the effects of black cohosh extract on liver morphology, and on levels of various hepatic function indices in rats.

METHODS

Wistar rats received 300mg/kg/day of C. racemosa extract by gavage, for 30 days. Biochemical analysis of serum was conducted by an automated, random-access clinical chemistry analyzer. Liver samples were used for hystomorphological and immunohistochemical examination, for the detection of apoptosis (TUNEL assay), and for the determination of GSH level (spectrophotometrical analysis).

RESULTS

C. racemosa extract does not affect liver morphology and hepatic function indices, in rats.

CONCLUSIONS

On the basis of experimental data, the use of 300mg/kg/day of black cohosh appears quite safe in rats. Nevertheless, in humans the safety of C. racemosa should be further monitored, in terms of patient-related factors.

Modeling of a two-regime crystallization in a multicomponent lipid system under shear flow

The kinetics of phase transitions of milk fat triacylglycerols, as model multicomponent lipid systems, were studied under shear in a Couette cell at 17 degrees C, 17.5 degrees C and 20 degrees C under shear rates ranging from 0 to 2880s;-1 using synchrotron X-ray diffraction. Two-dimensional diffraction patterns were captured during the crystallization process. No effect of shear on onset time for phase alpha from the liquid was observed. Afterwards a two-regime crystallization process was observed. During the first regime, as observed in other systems, shear reduced the onset time of the phase transition from phase alpha to 2880s(-). The model previously developed for palm oil (ODE model) worked well to describe this regime, confirming the general value of the proposed ODE model. However, the ODE model did not satisfactorily describe the second regime. We found that, as the system gets closer to equilibrium, the growth regime becomes controlled by diffusion, manifested by the kinetics following a square roott dependence. This regime was found to be consistent with a mechanism combining step growth at a kink with progressive selection of the crystallizing moieties. This mechanism is in agreement with the displacement of the diffraction peak positions, which revealed how increased shear rate promotes the crystallization of the higher melting fraction affecting the composition of the crystallites.

Inhibitory activity of Melissa officinalis L. extract on Herpes simplex virus type 2 replication

Melissa officinalis L. (Lamiaceae) (lemon balm) is used in folk medicine for nervous complaints, lower abdominal disorders and, more recently, for treating Herpes simplex lesions. In this work the antiviral activity of a hydroalcoholic extract of lemon balm leaves against the Herpes simplex virus type 2 (HSV-2) was assessed by the cytopathic effect inhibition assay on Vero cells (ATCC CCL-81), in comparison with acyclovir. The cytotoxicity of the extract on Vero cells was previously tested by evaluating the cellular death and was confirmed by the Trypan blue test. Lemon balm showed to reduce the cytopathic effect of HSV-2 on Vero cells, in the range of non-toxic concentrations of 0.025-1 mg mL(-1) (with reference to the starting crude herbal material). The maximum inhibiting effect (60%) was obtained with 0.5 mg mL(-1). The viral binding assay showed that the extract does not prevent the entry of HSV-2 in the cells, thus suggesting a mechanism of action subsequent to the penetration of the virus in the cell. The extract was also chemically characterised by NMR and HPLC analysis; it showed to contain cinnamic acid-like compounds, mainly rosmarinic acid (4.1% w/w). Our experiments support the use of lemon balm for treating Herpes simplex lesions and encourage clinical trials on this medicinal plant.

In vitro antifungal and anti-elastase activity of some aliphatic aldehydes from Olea europaea L. fruit

Olea europaea preparations are traditionally employed in a variety of troubles, including skin infections. Olive extracts and some of their pure compounds have shown antimicrobial activity in vitro. The present study deals with the antifungal activity of some aliphatic aldehydes from olive fruit [hexanal, nonanal, (E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal] against Tricophyton mentagrophytes (6 strains), Microsporum canis (1 strains) and Candida spp. (7 strains). The capability of these substances to inhibit elastase, a virulence factor essential for the dermatophytes colonization, and their cytotoxicity on cultures of reconstructed human epidermis, are also described. Aldehydes tested, inhibited the growth of T. mentagrophytes and M. canis in the range of concentration between <1.9 and 125 microg/ml; the unsaturated aldehydes showed the most broad spectrum of activity in that inhibited all strains tested. None of the aldehydes exhibited activity against Candida spp. strains. (E)-2-octenal and (E)-2-nonenal inhibited the elastase activity in a concentration-dependent manner; the anti-elastase activity suggests an additional target of the antimicrobial activity of these compounds. Aldehydes were devoid of cytotoxicity on cultures of human reconstructed epidermis. The antifungal activity of the aldehydes from olive fruit here reported, substantiates the use of olive and olive oil in skin diseases and suggests that these natural compounds could be useful agents in the topical treatment of fungal cutaneous infections.

Antifungal activity of Lavandula angustifolia essential oil against Candida albicans yeast and mycelial form

The antifungal activity of the essential oil of Lavandula angustifolia Mill. (lavender oil) and its main components, linalool and linalyl acetate, was investigated against 50 clinical isolates of Candida albicans (28 oropharyngeal strains, 22 vaginal strains) and C. albicans ATCC 3153. Growth inhibition, killing time and inhibition of germ tube formation were evaluated. The chemical composition of the essential oil was determined by gas chromatography and mass spectrometry. Lavender oil inhibited C. albicans growth: mean minimum inhibitory concentration (MIC) of 0.69% (vol./vol.) (vaginal strains) and 1.04% (oropharyngeal strains); mean MFC of 1.1% (vaginal strains) and 1.8% (oropharyngeal strains). Linalool was more effective than essential oil: mean MIC of 0.09% (vaginal strains) and 0.29% (oropharyngeal strains); mean MFC of 0.1% (vaginal strains) and 0.3% (oropharyngeal strains). Linalyl acetate was almost ineffective. Lavender oil (2%) killed 100% of the C. albicans ATCC 3153 cells within 15 min; linalool (0.5%) killed 100% of the cells within 30 s. The essential oil inhibited germ tube formation (mean MIC of 0.09%), as did the main components (MIC of 0.11% for linalool and 0.08% for linalyl acetate). Both the essential oil and its main components inhibited hyphal elongation of C. albicans ATCC 3153 (about 50% inhibition at 0.016% with each substance). Lavender oil shows both fungistatic and fungicidal activity against C. albicans strains. At lower concentrations, it inhibits germ tube formation and hyphal elongation, indicating that it is effective against C. albicans dimorphism and may thus reduce fungal progression and the spread of infection in host tissues.

Evaluation of an ELISA to detect antibodies to maedi-visna virus in individual and pooled samples of milk from sheep

An elisa was used to detect antibodies to maedi-visna virus in samples of serum and milk from individual sheep; the results obtained indicated that the elisa can be used to detect antibodies in milk. The assay was also applied to samples of bulk-tank milk; a standard curve was created and used to calculate the seroprevalence of maedi-visna in 11 flocks of sheep and the results were compared with the results obtained by applying the elisa to individual serum samples. There was good agreement between the seroprevalences calculated from the standard curve for bulk-tank milk and from the individual serum samples.

The antimutagenic activity of Lavandula angustifolia (lavender) essential oil in the bacterial reverse mutation assay

Essential oils from Melaleuca alternifolia (tea-tree oil) and Lavandula angustifolia (lavender oil) are commonly used to treat minor health problems. Tea-tree oil possesses broad-spectrum antimicrobial activity, and is increasingly used for skin problems. Lavender oil, traditionally used as an antiseptic agent, is now predominantly used as a relaxant, carminative, and sedative in aromatherapy. Despite their growing use no data are available on their mutagenic potential. In this study, after determining the chemical composition of tea-tree oil and lavender oil, by gas-chromatography and mass spectrometry, we investigated their mutagenic and antimutagenic activities by the bacterial reverse mutation assay in Salmonella typhimurium TA98 and TA100 strains and in Escherichia coli WP2 uvrA strain, with and without an extrinsic metabolic activation system. Neither essential oil had mutagenic activity on the two tested Salmonella strains or on E. coli, with or without the metabolic activation system. Conversely, lavender oil exerted strong antimutagenic activity, reducing mutant colonies in the TA98 strain exposed to the direct mutagen 2-nitrofluorene. Antimutagenicity was concentration-dependent: the maximal concentration (0.80 mg/plate) reduced the number of histidine-independent revertant colonies by 66.4%. Lavender oil (0.80 mg/plate) also showed moderate antimutagenicity against the TA98 strain exposed to the direct mutagen 1-nitropyrene. Its antimutagenic property makes lavender oil a promising candidate for new applications in human healthcare.

Atractylis gummifera L. poisoning: an ethnopharmacological review

Atractylis gummifera L. (Asteraceae) is a thistle located in the Mediterranean regions. Despite the plant's well-known toxicity, its ingestion continues to be a common cause of poisoning. The toxicity of Atractylis gummifera resides in atractyloside and carboxyatractyloside, two diterpenoid glucosides capable of inhibiting mitochondrial oxidative phosphorylation. Both constituents interact with a mitochondrial protein, the adenine nucleotide translocator, responsible for the ATP/ADP antiport and involved in mitochondrial membrane permeabilization. Poisoned patients manifest characteristic symptoms such as nausea, vomiting, epigastric and abdominal pain, diarrhoea, anxiety, headache and convulsions, often followed by coma. No specific pharmacological treatment for Atractylis gummifera intoxication is yet available and all the current therapeutic approaches are only symptomatic. In vitro experiments showed that some compounds such as verapamil, or dithiothreitol could protect against the toxic effects of atractyloside, but only if administered before atractyloside exposure. New therapeutic approaches could come from immunotherapy research: some studies have already tried to produce polyclonal Fab fragments against the toxic components of Atractylis gummifera.

Study on the mechanisms of the antibacterial action of some plant alpha,beta-unsaturated aldehydes

AIMS

In this paper the mechanisms involved in the antibacterial effect of six 2E-alkenals [(E)-2-hexenal, (E)-2-eptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal and (E,E)-2,4-decadienal] were investigated.

METHODS AND RESULTS

We measured the release of carboxyfluorescein (CF) trapped in liposomes of phosphatidylcholine (PC) following exposure to the aldehydes mentioned above, in comparison with that elicited by hexanal and nonanal; the modifications of the thermotropic behaviour of liposomes of dimyristoylphosphatidylcholine (DMPC) induced by (E,E)-2,4-decadienal (the aldehyde endowed with the highest microbicidal activity) were evaluated by means of differential scanning calorimetry. With the exception of hexanal, all aldehydes tested caused rapid CF leakage from PC liposomes. The effectiveness order correlates well with the chain length and the presence of the alpha,beta-double bond. Furthermore (E,E)-2,4-decadienal is able to interact with and cross DMPC bilayers.

CONCLUSIONS

The present findings suggest that the 2E-alkenals tested elicit, very likely, a gross perturbation of the lipidic fraction of plasmatic membranes and are able to penetrate into bacterial cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

These data represent an interesting background for a rational employment of the plant 2E-alkenals tested as antimicrobial agents.

In vitro activity of tea tree oil against Candida albicans mycelial conversion and other pathogenic fungi

The antifungal activity of Melaleuca alternifolia Maiden (Myrtaceae) essential oil against yeasts (Candida spp., Schizosaccharomyces pombe, Debaryomyces hansenii) and dermatophytes (Microsporum spp. and Tricophyton spp.) is reported. We focused on the ability of tea tree oil to inhibit Candida albicans conversion from the yeast to the pathogenic mycelial form. Moreover we carried out broth microdilution test and contact tests to evaluate the killing time. M. alternifolia essential oil inhibited the conversion of C. albicans from yeast to the mycelial form at a concentration of 0.16% (v/v). The minimum inhibitory concentrations (MICs) ranged from 0.12% to 0.50% (v/v) for yeasts and 0.12% to 1% (v/v) for dermatophytes; the cytocidal activity was generally expressed at the same concentration. These results, if considered along with the lipophilic nature of the oil which enables it to penetrate the skin, suggest it may be suitable for topical therapeutic use in the treatment of fungal mucosal and cutaneous infections.

Local anaesthetic activity of monoterpenes and phenylpropanes of essential oils

The local anaesthetic activity of a number of compounds with different structures, contained in essential oils, was studied. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve-hemidiaphragm technique. Among the substances tested terpineol and trans-anethole (10(-3) - 1 microg/ml) were able to drastically reduce the electrically evoked contractions of rat phrenic nerve-hemidiaphragm in a concentration-dependent manner, but not eugenol, (-)- and (+)-citronellal, (-)- and (+)-carvone, trans cinnamaldehyde and alpha-terpinene. In the rabbit conjunctival reflex test, the treatment with a solution of terpineol and trans-anethole (10 - 100 microg/ml) effected a concentration-dependent increase in the number of stimuli required to evoke the reflex, thus confirming in vivo the local anaesthetic activity observed in vitro. Eugenol, (-)- and (+)-citronellal, trans-cinnamaldehyde, (-)- and (+)-carvone and alpha-terpinene were as ineffective in the in vivo test as they were in the in vitro results.

Diagnostic accuracy of the anti-citrulline antibody assay for rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is the most common autoimmune rheumatic disease, but specific and practicable tests for its diagnosis are lacking. We evaluated the diagnostic accuracy of a new commercial ELISA in detecting anti-cyclic citrullinated peptide (CCP) antibodies for the diagnosis of RA.

METHODS

Anti-CCP antibodies were determined in 330 serum samples: 98 from RA patients and 232 from controls, including patients with connective tissue diseases, other rheumatic diseases, viral infections, Lyme disease, autoimmune thyroiditis, cancer, and monoclonal gammopathy, and sex- and age-matched healthy subjects. Intra- and interassay CVs were 5-13% and 9-17%, respectively. Rheumatoid factor (RF) was also assayed in every sample, and results were compared to anti-CCP for sensitivity and specificity.

RESULTS

At a cutoff value of 50 units, sensitivity was 41% (confidence interval, 31-50%) and specificity was 97.8% (95-100%). Anti-CCP-positive RA patients had a mean antibody concentration of 1100 units (range, 57-3419 units), and anti-CCP-negative RA patients and controls had mean values of 7.6 and 6.8 units, respectively (range, 1-39 units). The area under the ROC curve was 0.71 (95% confidence interval, 0.63-0.78). RF had a higher sensitivity (62%) and a lower specificity (84%) than anti-CCP. When the two antibodies were used together, specificity was 99.6%.

CONCLUSION

Anti-CCP antibody testing may be useful if performed concomitantly with RF assay to diagnose patients with suspected early RA.

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.

Isolation of praeruptorins A and B from Peucedanum praeruptorum Dunn. and their general pharmacological evaluation in comparison with extracts of the drug

The root of Peucedanum praeruptorum Dunn. was extracted with solvents at different polarity obtaining three chemical fractions: aqueous (H2O), n-butanol (BuOH) and ethyl acetate (AcOEt). From AcOEt praeruptorins A and B were isolated by column chromatography on silica gel, using toluene/ethyl acetate as eluent, and identified by 1H and 13C NMR analysis. The extracts and the praeruptorins were tested for gross behavioural effects and acute toxicity in mice; the cytotoxicity on Artemia salina Leach and the antimicrobial activity were also evaluated. None of the tested substances evoked behavioural effects or acute toxicity after oral administration in mice; delayed mortality was observed with AcOEt and praeruptorin A only after intraperitoneal administration of high doses (1 g/kg). In Artemia salina test AcOEt, and praeruptorins A and B had LC50 values of 40.2, 121.2 and 34.5 microg/ml, respectively. AcOEt and praeruptorin A showed antimicrobial activity on Streptococcus agalactiae; their MIC values were 250 and 100 microg/ml, respectively.

Local anaesthetic activity of beta-caryophyllene

In this work we studied the local anaesthetic activity of beta-caryophyllene, one of the main components of clove oil obtained from the dried flower-buds of Syzygium aromaticum (Myrtaceae family). We compared its activity to a chemically related compound, caryophyllene oxide. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve-hemidiaphragm preparation. Beta-caryophyllene (10(-4) - 1 microg/ml), but not caryophyllene oxide, was able to reduce drastically, in a dose-dependent manner, the electrically evoked contractions of the rat phrenic hemidiaphragm. In the rabbit, conjunctival reflex test treatment with a solution of beta-caryophyllene (10-1000 microg/ml) allowed a dose-dependent increase in the number of stimuli necessary to provoke the reflex. As in the in vitro results, caryophyllene oxide was ineffective also in the in vivo test. In conclusion, these data evidence the local anaesthetic activity of beta-caryophyllene, which appears to be strictly dependent on its chemical structure.

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.

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.

In vitro antibacterial activity of some aliphatic aldehydes from Olea europaea L

In the present paper we report the 'in vitro' activity of eight aliphatic long-chain aldehydes from olive flavor (hexanal, nonanal, (E)-2-hexenal, (E)-2-eptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal and (E,E)-2,4-decadienal) against a number of standard and freshly isolated bacterial strains that may be causal agents of human intestinal and respiratory tract infections. The saturated aldehydes characterized in the present study do not exhibit significant antibacterial activity, while the alpha,beta-unsaturated aldehydes have a broad antimicrobial spectrum and show similar activity against Gram-positive and Gram-negative microorganisms. The effectiveness of the aldehydes under investigation seems to depend not only on the presence of the alpha,beta-double bond, but also on the chain length from the enal group and on the microorganism tested.

Local anaesthetic activity of (+)- and (-)-menthol

In this work we studied the local anaesthetic activity of (+)- and (-)-menthol, a substance used after topical application to induce a feeling of coolness. We compared its activity to two chemically related compounds thymol and (-)-menthone. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve hemidiaphragm preparation. Both enatiomers of menthol (10(-4)-1 micrograms/ml), but not thymol and (-)-menthone, were able to drastically reduce, in a dose-dependent manner, the electrically evoked contractions of rat phrenic hemidiaphragm. In the rabbit conjunctival reflex test, treatment with a solution of (+)- and (-)-menthol (30-100 micrograms/ml) allowed a dose-dependent increase in the number of stimuli necessary to provoke the reflex, thus confirming in vivo the local anaesthetic activity observed in vitro. Similar to the in vitro results, thymol and (-)-menthone were ineffective also in the in vivo test. In conclusion, these data evidence the local anaesthetic activity of menthol, which appears to be strictly dependent on its chemical structure.

Conformational studies by dynamic NMR. 79. Dimesityl sulfine revisited: detection of the helical antipodes and determination of their enantiomerization pathways

By means of low-temperature NMR spectra, it is demonstrated that dimesityl sulfine (Mes2C=SO) adopts in solution the same chiral propeller conformation (C1 symmetry) determined by X-ray diffraction in the crystalline state. With the help of MM calculations, it has been also shown that a correlated rotation (cog wheel effect) of the two mesityl rings reverses the molecular helicity according to an enantiomerization process entailing a one-ring flip pathway with delta G++ = 5.9 kcal mol-1 and a two-ring flip pathway with delta G++ = 13.8 kcal mol-1. On the contrary the Z- and E-isomers of mesityl phenyl sulfine (MesPhC=SO) adopt essentially achiral conformations (Cs symmetry), having the Ph-CSO rotation barriers equal to 5.2 and 5.8 kcal mol-1, respectively, and the mesityl-CSO rotation barriers equal to 21.3 and 15.1 kcal mol-1, respectively.

Antimicrobial triterpenoids from Licania heteromorpha

Six triterpenoids having a lupane and oleane skeleton were isolated from the leaves and young branches of Licania heteromorpha Bentham var. heteromorpha and were identified as: betulinic acid 1, alphitolic acid 2, 3 beta-O-trans-p-coumaroyl alphitolic acid 3, 3 beta-O-cis-p-coumaroyl alphitolic acid 4, 3 beta-O-trans-p-coumaroyl maslinic acid 5, 3 beta-O-cis-p-coumaroyl maslinic acid 6. The antimicrobial activity of these compounds was evaluated in vitro on clinically isolated microorganisms employing a microdilution method. Compounds 2, 3, 5, and 6 showed antimicrobial activity on Gram-positive bacteria and yeasts, whereas none of the six triterpenoids were active against Gram-negative organisms.

Antimicrobial investigation of semipurified fractions of Ginkgo biloba leaves

A total methanolic extract of Ginkgo biloba leaves was fractionated by solvent partition using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). The antimicrobial activity of the three fractions was evaluated using a number of Gram-positive and -negative bacteria and yeasts. The apolar fraction A appeared to be the most interesting because of its activity against several microorganisms; this fraction was further separated by high performance liquid chromatography, and shown to contain substances with strong inhibitory activity against Enterococcus faecalis 31, different from the major known chemical components of G. biloba leaves.

Local anaesthetic activity of the essential oil of Lavandula angustifolia

In this work we studied the local anaesthetic activity of the essential oil obtained from Lavandula angustifolia Mill., a medicinal plant traditionally used as an antispasmodic. We compared its activity to the essential oils obtained from two citrus fruits, Citrus reticulata Blanco and Citrus limon (L.) Burm. f., which have no medical uses. Biological tests were also performed on the major pure components of L. angustifolia Mill. essential oil: linalol and linalyl acetate as determined by GC and confirmed by GC-MS. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test, and in vitro in a rat phrenic nerve-hemidiaphragm preparation. The essential oil of L. angustifolia, linalyl acetate and linanol (0.01-10 micrograms/ml) but not the oils of Citrus reticulata and Citrus limon were able to drastically reduce, in a dose-dependent manner, the electrically evoked contractions of rat phrenic-hemidiaphragm. In the rabbit conjunctival reflex test treatment with a solution of essential oil of L. angustifolia, as well as linalyl acetate and linalol (30-2500 micrograms/ml administered in the conjunctival sac) allow a dose-dependent increase in the number of stimuli necessary to provoke the reflex, thus confirming in vivo the local anaesthetic activity observed in vitro.

Paradoxical effect of neuroleptic drugs on prolactin secretion by rat pituitary cell cultures

Several antipsychotic drugs reverse the dopamine-induced inhibition of prolactin release by rat pituitary cell cultures. Paradoxically, at high doses and without dopamine, antipsychotic drugs can also inhibit prolactin secretion. The mechanism underlying this phenomenon is unclear. Some evidence suggests that these drugs have an agonistic action. We sought to verify whether clozapine and fluphenazine, at doses higher than those reversing dopamine-induced inhibition of prolactin secretion in vitro, show this paradoxical effect and eventually a partial agonistic action. Both antipsychotics inhibited prolactin secretion, clozapine at doses starting from 10(-6) M and fluphenazine from 10(-7) M. Haloperidol reversed clozapine-induced prolactin inhibition but left fluphenazine-induced inhibition unchanged. These in vitro findings suggest that clozapine has a partial agonistic action on dopaminergic receptors but fluphenazine does not.

Inhibition of Candida rugosa lipase by berberine and structurally related alkaloids, evaluated by high-performance liquid chromatography

It is known that certain microorganisms produce extracellular lipase to better colonize the skin and mucosal surfaces. Since different extracts from medicinal plants have anti-lipase activity (Shimura et al., Biosci. Biotechnol. Biochem., 56: 1478-1479, 1992), we examined the effects of selected natural substances on Candida rugosa lipase. In the presence of the compounds under examination, the enzyme was incubated with beta-naphthyl laurate, and beta-naphthol, produced by the enzymatic reaction, was extracted with ethyl acetate and analyzed by reversed phase HPLC, using a C-18 column. Thus, the inhibitory activity was calculated by a proper formula based on the variations of the area under the chromatographic peak of beta-naphthol. The method was validated by analyzing substances with known anti-lipase activity such as saturated fatty acids (C10-16) and tetracycline. Berberine and a number of structurally related alkaloids such as chelidonine, chelerythrine, and sanguinarine appeared active. This property of berberine and sanguinarine is of interest because they are used in pathological conditions in which microbial lipases could play a pathogenic role.

Determination of silymarine in the extract from the dried silybum marianum fruits by high performance liquid chromatography and capillary electrophoresis

Silybine (SBN), isosilybine (ISBN), silycristine (SCN), silydianine (SDN), and taxifoline (TXF) are the main active flavanoids, generally found in the dried fruits of silybum marianum. The concentrations of these compounds, excepted TXF, are all together usually expressed as silymarine content. In this paper the determination of the silymarine titre was made by high performance liquid chromatography (HPLC), and high performance capillary electrophoresis (HPCE). Two reversed stationary phases, RP-18 and RP-8, were observed comparing the resolutions of all considered flavanoids with each stationary phases. The HPCE was carried out considering the possible improvement in the resolution of SBN, CN, SDN and TXF using, 8-cyclodextrines or organic modifier. The qualitative and quantitative data obtained by HPLC and HPCE were compared.

Inhibition of protein denaturation by fatty acids, bile salts and other natural substances: a new hypothesis for the mechanism of action of fish oil in rheumatic diseases

Natural hydrophobic substances like bile salts (cholate, deoxycholate, chenodeoxycholate, lithocholate and their conjugates with glycine and taurine), fatty acids (caprylic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acid) were much more active (EC50 approximately 10(-4)-10(-5) M) than selected amino acids (EC50 > 10(-2) M) and inorganic salts (EC50 approximately 10(-1) M) in inhibiting heat-induced denaturation of human serum albumin in vitro. Fish oil, rich in n-3-polyunsaturated acids such as eicosapentaenoic acid and docosahexaenoic acid, administered p.o. (1 ml/kg) in the rat, protected ex vivo (after 2 hr) serum against heat-induced denaturation more than bendazac, a known antidenaturant drug. Thus, we speculated that the antidenaturant activity of fish oil may be partly (in addition to the known effect on endogenous eicosanoid composition) responsible for its beneficial effects in rheumatoid arthritis and other rheumatic conditions. In this connection, it is of note that the in vitro antidenaturant activity of fish oil fatty acids was higher than that of known antidenaturant drugs such as bendazac and bindarit and nonsteroidal anti-inflammatory drugs like phenylbutazone and indomethacin which could exert beneficial effects in chronic inflammatory conditions by stabilizing endogenous proteins.

Modelling of the 3-D structure of IFN-alpha-k and characterization of its surface molecular properties

The 3-D structure of IFN-alpha-k (one of the alpha-interferon family) was constructed and optimized by molecular modelling starting from the X-ray structure of IFN-beta. The molecular surface of the optimized 3-D structure of IFN-alpha-k was then evaluated and characterized for its hydrophobicity/hydrophilicity. The structure of IFN-alpha-k was completed with its first segment (23 amino acid residues) called signal peptide. The 3-D structure of this segment was predicted to be in helical form bonded to the core by one loop. It was found that the complete structure of IFN-alpha-k can exist in at least two main conformations as far as the orientation of the signal peptide is concerned, i.e. in the open form (in which the signal peptide is directed outward of the 'body' of the molecule) and the closed form (where the signal peptide is aligned with the body). The relative stability of these forms strongly depends on the stabilization by the environment (e.g. by solvation) due to the prevailing hydrophilicity of the body and hydrophobic character of the signal peptide.

Effect of clozapine on dopamine-induced inhibition of prolactin release from cultured rat pituitary cells

Although the atypical antipsychotic agent clozapine has little propensity to induce hyperprolactinemia in humans it increases serum prolactin levels in the rat. In this study, the effects of clozapine and of some typical antipsychotic drugs on basal and dopamine-mediated prolactin secretion from cultured rat pituitary cells were compared. Despite being less potent than the other antipsychotic agents tested, clozapine reverted the effect of dopamine on prolactin secretion in vitro. This finding suggests that clozapine interferes with dopamine receptors in the pituitary gland.

Probabilistic investigation of the life behavior of power capacitors operating under distorted supply voltage

A probabilistic approach to the problem of life evaluation of power capacitors subjected to non-sinusoidal voltage is presented. In order to account for the stochastic nature of harmonic distortion, a probability density function representing the random occurrency of non-sinusoidal voltages is employed, while the stress-failure time relationship is provided by a multi-stress life model appropriate for life evaluation of a polymeric insulation. In such a way, the knowledge of harmonic amplitude distributions provides that of stresses affecting insulation life, i.e. electric field and temperature. Thus, life evaluation under distorted supply voltage is allowed, and comparison can be made with respect to performance in sinusoidal conditions.

Is HLA B27 a true marker of axial involvement in psoriatic arthropathy?

Sixty-six patients with psoriatic arthropathy were subdivided into nine groups on the basis of the presence of peripheral arthritis, axial disease whether or not fulfilling the New York criteria for ankylosing spondylitis both associated and not associated with peripheral arthropathy and bilateral or monolateral lateral sacro-iliitis. Only the group with axial disease sacroiliitis+spondylitis) without peripheral arthritis and not fulfilling the NY criteria showed a truly increased B27 prevalence. However, in this atypical group, only 2 patients had a true ankylosing pattern-like spondylitis. On the other hand, in the group with axial disease fulfilling the NY criteria, only one of 9 patients was B27+. We conclude that B27 is not a true marker of axial involvement in psoriatic arthropathy.