Prevention of erosive/abrasive enamel wear due to orange juice modified with dietary supplements.

OBJECTIVE: The aim of this study was to evaluate the erosive/abrasive enamel wear after contact with orange juices modified with different dietary supplements. METHODS: A total of 96 bovine enamel samples were prepared and allocated to eight groups (1-8; n = 12). Samples were eroded (120 s) in 200 ml of the following eight solutions: 1: water (control), 2: orange juice, 3: water + calcium effervescent tablet, 4: orange juice + calcium effervescent tablet, 5: water + 0.75 g acid/base regulating powder (Probase), 6: water + 0.375 g Probase, 7: orange juice + 0.75 g Probase and 8: orange juice + 0.375 g Probase. After erosion, the samples were brushed with 40 brushing strokes (load 2.5 N). Enamel wear was measured using surface profilometry after 20 and 40 cycles of erosion/abrasion respectively. RESULTS: Highest mean enamel wear (± SD) after 20 and 40 cycles of erosion/abrasion was observed for the unmodified orange juice (group 2) (0.605 ± 0.240 µm; 1.375 ± 0.496 µm respectively). The enamel wear in all other groups (3-8) was significantly lower (P < 0.0001 respectively) with no significant difference within these groups and compared with water (control). CONCLUSION: Erosive/abrasive enamel wear induces by orange juice and tooth brushing could be reduced significantly by modification with free available dietary supplements.

Biofilm reduction and staining potential of a 0.05% chlorhexidine rinse containing essential oils.

OBJECTIVES: To assess the biofilm reduction and discolouration potential of a new 0.05% chlorhexidine (CHX) digluconate solution, containing additional essential oil and alcohol components, compared with that of standard control CHX solutions (0.05% and 0.2% CHX). METHODS: The potential to reduce total viable counts of growing mixed microbial populations was examined using the Zurich biofilm model. Biofilms were created on sterile pellicle-coated hydroxyapatite discs and exposed to test substances at different time points. After 64.5 h, mean colony-forming units and SDs were determined. Colour change measurements using light reflection analysis were carried out on saliva preconditioned bovine dentin and enamel samples, as well as on composite and glass ceramic restorative materials, after successive immersions in a standardized tea brew and the CHX solutions. RESULTS: The test solution was able to reduce biofilm formation by 3 log steps compared with a negative (water) control. This was significantly less effective than the standard control CHX solutions, which reduced viable counts by 6 log steps. Both the test and control solutions exhibited staining on all surfaces. Staining was most pronounced on dentin, followed by enamel and to a significantly lesser degree on the restorative materials. Furthermore, the staining caused by the test solution on these restorative materials was generally lower than that caused by the control solutions. CONCLUSIONS: The test solution exhibited an antimicrobial activity. The composition, however, seems to hamper its effectiveness. Accordingly, it produced statistically significant, although by trend less, staining on restorative materials.

Acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibition studies and antioxidant activities of 33 Scutellaria L. taxa from Turkey.

The members of Scutellaria L. (Lamiaceae) is known to be rich particularly in flavonoids and among them, S. baicalensis has been recorded to be used for memory-enhancing purpose. Therefore, we initiated a study to screen the methanol extracts prepared from the aerial parts of 33 Turkish Scutellaria species for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, which are the key enzymes taking place in pathogenesis of Alzheimer's disease. Besides, the methanol extracts were tested in vitro against another enzyme, tyrosinase, which is associated with melanin hyperpigmentation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenger effect, ferrous ion-chelating ability, and ferric-reducing antioxidant power (FRAP) of the ethyl acetate and methanol extracts were also determined. AChE, BChE, and tyrosinase inhibition of the extracts were performed on ELISA microplate reader by spectrophotometric method. The extracts showed weak inhibition against AChE and BChE, while the best tyrosinase inhibition was caused by the methanol extract of S. brevibracteata subsp. subvelutina. The extracts had a very high DDPH radical scavenging effect and moderate antioxidant activity in ferrous ion-chelating and FRAP tests.

Acetylcholinesterase inhibitory and antioxidant properties of Cyclotrichium niveum, Thymus praecox subsp. caucasicus var. caucasicus, Echinacea purpurea and E. pallida.

The dichloromethane, ethyl acetate, ethanol, and aqueous extracts of Cyclotrichium niveum (CN) and Thymus praecox subsp. caucasicus var. caucasicus (TP), Echinacea purpurea (EPU), and E. pallida (EPA) along with the essential oils of CN and TP were assessed for their anti-acetylcholinesterase (AChE) and antioxidant activities. AChE inhibition was estimated using spectrophotometric method of Ellman. Antioxidant activity was evaluated by 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferrous ion-chelating power tests. Ferric-reducing antioxidant power (FRAP) of CN and TP were also tested. CN essential oil was found to contain isomenthone (56.21%) and pulegone (19.76%). The ethyl acetate (83.11-87.98%) and dichloromethane (73.45-84.02%) extracts of CN showed the highest AChE inhibition. The ethyl acetate and ethanol extracts of TP exerted significant DPPH scavenger effect. The water extracts of CN and TP and the chloroform extract of the aerial parts of EPU displayed the highest ferrous ion-chelating effect. The leaf and flower essential oils of TP had the best FRAP.

In vitro antiprotozoal activity of the lipophilic extracts of different parts of Turkish Pistacia vera L.

Thirteen lipophilic extracts prepared with n-hexane from various parts of Pistacia vera L. tree (Anacardiaceae) growing in Turkey were screened for their in vitro activity against four parasitic protozoa, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. Melarsoprol, benznidazole, miltefosine, artemisinin and chloroquine were used as reference drugs. The cytotoxic potentials of the extracts on rat skeletal myoblast (L6) cells were also assessed and compared to that of podophyllotoxin. The screening method employed was medium-throughput, where the extracts were tested at two concentrations, at 0.8 and 4.8 microg/ml (T. brucei rhodesiense, L. donovani and Plasmodium falciparum), or at 1.6 and 9.7 microg/ml (T. cruzi and L6 cells). At 4.8 microg/ml concentration, the branch extract of Pistacia vera (PV-BR) significantly inhibited (77.3%) the growth of L. donovani, whereas the dry leaf extract (PV-DL) was active against Plasmodium falciparum (60.6% inhibition). The IC50 values of these extracts were determined as 2.3 microg/ml (PV-BR, L. donovani) and 3.65 microg/ml (PV-DL, Plasmodium falciparum). None of the extracts possessed cytotoxicity on mammalian cells.

Turkish freshwater and marine macrophyte extracts show in vitro antiprotozoal activity and inhibit FabI, a key enzyme of Plasmodium falciparum fatty acid biosynthesis.

The ethanolic extracts of a number of Turkish freshwater macrophytes (Potamogeton perfoliatus, Ranunculus tricophyllus and Cladophora glomerata) and marine macroalgae (Dictyota dichotoma, Halopteris scoparia, Posidonia oceanica, Scinaia furcellata, Sargassum natans and Ulva lactuca) were assayed for their in vitro antiprotozoal activity. Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum were used as test organisms. The cytotoxicity of the extracts was also assessed against primary rat skeletal myoblasts (L6 cells). Whereas none of the extracts were active against T. cruzi, all crude extracts displayed appreciable trypanocidal activity against T. brucei rhodesiense, with S. natans being the most active one (IC(50) 7.4microg/ml). Except for the marine alga H. scoparia, all extracts also possessed leishmanicidal potential. The best antileishmanial activity was exerted by U. lactuca and P. oceanica (IC(50)'s 5.9 and 8.0microg/ml, respectively). Five extracts that demonstrated inhibitory activity towards P. falciparum (IC(50)'s 18.1-48.8microg/ml) were simultaneously assayed against FabI, a crucial enzyme of the fatty acid system of P. falciparum, to find out whether FabI was their target. The extracts of C. glomerata and U. lactuca efficiently inhibited the FabI enzyme with IC(50) values of 1.0 and 4.0microg/ml, respectively. None of the extracts were cytotoxic towards mammalian L6 cells. This work reports for the first time antiprotozoal activity of some Turkish marine and freshwater algae, as well as a target-based antiplasmodial screening for the identification of P. falciparum FabI inhibitors from aquatic and marine macrophytes.

Determination of inorganic elements in poppy straw by scanning electron microscopy with energy dispersive spectrometry as a means of ascertaining origin.

Cultivation of poppy as a source of opium alkaloids for legitimate medical purposes has a long tradition in Turkey. The main products are poppy straw and concentrate of poppy straw, obtained from dried poppy capsules. The aims of the study reported in the present article were to establish inorganic element profiles for the poppy-growing provinces of Turkey by means of x-ray analysis by scanning electron microscopy with energy dispersive spectrometry (SEM/EDS) and to explore the potential of the technique for determination of origin. Ten elements (sodium, magnesium, silicon, phosphorus, sulphur, chlorine, potassium, calcium, copper and zinc) were analysed in poppy straw samples from 67 towns in nine provinces. As regards the determination of origin, the most significant finding was the presence of copper and zinc in the poppy straw samples from 8 of the 15 towns in Afyon Province. Since those elements are not normally found in soil, it is assumed that their presence is the result of environmental (industrial) contamination. Differences in the samples from the other eight provinces were less significant, possibly a result of their geographical proximity. Nevertheless, differences in the samples were apparent. Because the findings are relative rather than absolute in terms of presence or absence of individual inorganic elements, further research is required to convert them into operationally usable results. The inorganic element profiles generated in the study have been used to form the basis for the development of a comprehensive database on poppy straw samples, which may be used in comparing samples and determining their origin.

Antimycobacterial screening of some Turkish plants.

Extracts of 44 plant species distributed among 17 families from Turkey were screened against Mycobacterium tuberculosis H(37)Ra using microplate Alamar blue assay test. Six plants inhibited growth of M. tuberculosis H(37)Ra at 50 microg/ml concentrations.

Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some Turkish medicinal plants.

The chloroform:medianol (1:1) extracts of a number of the plant species belonging to eight families, namely Corydalis solida (L.) Swartz subsp. solida and Glaucium corniculatum (L.) J. H. Rudolph (Papaveraceae), Rhododendron ponticum L. subsp. ponticum and Rhododendron luteum Sweet. (Ericaceae), Buxus sempervirens L. (Buxaceae), Vicia faba L. (Fabaceae), Robinia pseudoacacia L. (Caeselpiniaceae), Tribulus terrestris L. and Zygophyllum fabago L. (Zygophyllaceae), Lycopodium clavatum L. (Lycopodiaceae), Fumaria vaillantii Lois., Fumaria capreolata L., Fumaria kralikii Jordan, Fumaria asepala Boiss., Fumaria densiflora DC., Fumaria flabellata L., Fumaria petteri Reichb. subsp. thuretii (Boiss.) Pugsley, Fumaria macrocarpa Boiss. ex Hausskn., Fumaria cilicica Hauskkn., Fumaria parviflora Lam. and Fumaria judaica Boiss. (Fumariaceae) were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes by in vitro Ellman method at 10 microg/ml and 1 mg/ml concentrations. The extracts did not show any noticeable inhibitory activity against both of the enzymes at 10 microg/ml. The extracts of Rhododendron ponticum subsp. ponticum, Rhododendron luteum, Corydalis solida subsp. solida, Glaucium corniculatum, and Buxus sempervirens showed remarkable inhibitory activity above 50% inhibition rate on AChE at 1 mg/ml. Among them, Rhododendron ponticum subsp. ponticum, Corydalis solida subsp. solida and Buxus sempervirens were the most active extracts against BChE having 95.46 +/- 1.03%, 93.08 +/- 0.97%, and 93.45 +/- 0.88% inhibition rates, respectively. Among the extracts screened, all of the Fumaria extracts displayed highly potent inhibition against both of the enzymes at 1 mg/ml concentration compared to the standard.

Antimicrobial activity of the heartwood of Taxus baccata.

The ethanolic extract of Taxus baccata heartwood showed significant activity against selected gram-negative bacteria and against five out of nine tested fungi.

Anti-ulcerogenic effect of Momordica charantia L. fruits on various ulcer models in rats.

The mature fruits of Momordica charantia L. (Cucurbitaceae) are used externally for the rapid healing of wounds and internally for the treatment of peptic ulcers in Turkish folk medicine. For the evaluation of the latter activity, ethanol-induced ulcerogenesis model in rats was employed. The olive oil extract of the material as well as dried-powdered fruits in filtered honey showed significant and dose-dependent anti-ulcerogenic activity against this model. A potent and dose-dependent inhibitory activity was also observed by the administration of ethanol extract of the fruits. For the bioassay-guided fractionation, the material was first extracted with hexane and then by ethanol and both extracts were found active against the same ulcer model. Furthermore, ethanol extract of the fruits showed significant activity against HCl-EtOH induced ulcerogenesis in indomethacin-pretreated rats and diethyldithiocarbamate-induced ulcer models.

Triterpenoid saponins from Bongardia chrysogonum.

Two new triterpenoid saponins, 3-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-alph a-L-arabinopyranosyl]-hederagenin (1) and 3-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-alph a-L-arabinopyranosyl]-hederagenin 28-O-[beta-L-glucopyranosyl-(1-->6)-beta-L-glucopyranosyl] ester (2), together with five known saponins, were isolated from an ethanolic extract of the tubers of Bongardia chrysogonum. The structures of 1 and 2 were determined on the basis of spectroscopic studies.

Pyrrolizidine alkaloids from Senecio lorenthii.

The isolation and NMR spectra of otosenine (1) and seneciphylline (2) from Senecio lorenthii are reported.

Antiviral activities in extracts of Turkish medicinal plants.

A total of 16 ethanol extracts of Turkish medicinal plants were evaluated for antiviral activities against herpes simplex virus (HSV) and Sindbis virus (SINV). Extracts of Galanthus elwesii and Rheum ribes showed the most potent anti-HSV activities, while six other extracts had weaker activities. Galanthus elwesii and Leucojum aestivum were the most potent anti-SINV extracts with four others showing weaker activities. In total, five extracts were active against both viruses, three were selective for HSV and one was selective for SINV. Evidence for an antiviral photosensitizer was obtained in two anti-HSV extracts, in which activity was either completely dependent on light, or was con-siderably enhanced by light. Thus, several Turkish medicinal plants appear to be promising sources of antiviral activities.

Structure-activity relationships of imperialine derivatives and their anticholinergic activity.

In order to check the structure-activity relationship and prepare more potent derivatives of imperialine with anticholinergic activity, imperialinol (2), 3 beta-acetoxyimperialine (3), 3 beta-propionoxyimperialine (4), and 3 beta-butyroxyimperialine (5) were prepared. Compounds 4 and 5 displayed better anticholinergic activity against muscarinic receptors of the heart and brain than imperialine (1). The decrease in activity in 2 showed the importance of the 6-keto functionality in imparting the anticholinergic activity.

New steroidal alkaloids from Buxus longifolia.

Four new steroidal alkaloids, (+)-cyclovirobuxeine F (1), N-benzoyl-O-acetylbuxalongifoline (2), buxasamarine (3), and (+)-cyclobuxamidine (4), along with two known steroidal bases, 16 alpha-acetoxybuxabenzamidienine (5) and trans-cyclosuffrobuxinine (6), were isolated from the leaves of Buxus longifolia. The alkaloids 1-4 showed significant antibacterial activity.

Antinociceptive effect of some amaryllidaceae plants in mice.

The antinociceptive effects of ethanolic extracts of Pancratium maritimum L., Narcissus tazetta subspecies tazetta and Leucojum aestivum L. bulbs have been investigated in mice using the p-benzoquinone-induced abdominal constriction and hot-plate tests. In the p-benzoquinone-induced abdominal constriction test the ethanolic extracts of P. maritimum (300, 600 or 1200 mg kg-1, s.c.) and N. tazetta subsp. tazetta (5, 50, 100 or 200 mg kg-1, s.c.) caused dose-dependent inhibition of abdominal constrictions whereas a fluctuating response was obtained from ethanolic extracts of L aestivum (2.5-500 mg kg-1, s.c.). In the hot-plate test P. maritimum and L. aestivum caused a significant increase of latency only at the highest concentrations used (1200 mg kg-1 and 500 mg kg-1, i.p., respectively). However, at these concentrations they also caused significant toxic effects. In contrast with P. maritimum and L. aestivum, N. tazetta subsp. tazetta (5-500 mg kg-1, i.p.) extracts had no antinociceptive effect in this test. These findings indicate that the antinociceptive effect of Amaryllidaceae plants differs depending on the model of nociception investigated.

A bidesmosidic hederagenin hexasaccharide from the roots of Symphytum officinale.

A new bidesmosidic triterpenoidal saponin 3-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-alpha-L - arabinopyranosyl]-hederagenin-28-O-[alpha-L-rhamnopyranosyl- (1-->4)-beta-D- glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, was isolated from the roots of Symphytum officinale. The structure was assigned by chemical methods and spectral analysis (1H, 13C, DEPT, NMR, EI-MS and FAB-MS) including 1H-1H COSY, 1H-13C COSY and HOHAHA. The prosapogenin of this saponin is also a new compound.

Hypoglycaemic effect of Momordica charantia extracts in normoglycaemic or cyproheptadine-induced hyperglycaemic mice.

The hypoglycaemic effect of orally administered extracts of Momordica charantia L. fruits was examined in normoglycaemic or cyproheptadine-induced hyperglycaemic mice. The aqueous extract reduced the fasting glucose levels of hyperglycaemic or normoglycaemic mice. However, the ethanol extract did not affect the fasting or nonfasting glucose levels significantly in both groups of mice. There was no significant difference between the glucose-loaded and glucose-loaded plus aqueous extract given group. On the other hand, oral glucose-loading of the cyproheptadine-induced hyperglycaemic animals reduced the fasting glucose levels significantly. These results showed that aqueous extract of M. charantia fruits has a hypoglycaemic activity without improving the tolerance to glucose in cyproheptadine-induced diabetic mice.