Cinnamic acid derivatives in cosmetics: current use and future prospects.

Cinnamic acid derivatives are widely used in cosmetics and possess various functions. This group of compounds includes both naturally occurring and synthetic substances. On the basis of the Cosmetic Ingredient Database (CosIng) and available literature, this review summarizes their functions in cosmetics, including their physicochemical and biological properties as well as reported adverse effects. A perfuming function is typical of many derivatives of cinnamaldehyde, cinnamyl alcohol, dihydrocinnamyl alcohol and cinnamic acid itself; these substances are commonly used in cosmetics all over the world. Some of them show allergic and photoallergic potential, resulting in restrictions in maximum concentrations and/or a requirement to indicate the presence of some substances in the list of ingredients when their concentrations exceed certain fixed values in a cosmetic product. Another important function of cinnamic acid derivatives in cosmetics is UV protection. Ester derivatives such as ethylhexyl methoxycinnamate (octinoxate), isoamyl p-methoxycinnamte (amiloxiate), octocrylene and cinoxate are used in cosmetics all over the world as UV filters. However, their maximum concentrations in cosmetic products are restricted due to their adverse effects, which include contact and a photocontact allergies, phototoxic contact dermatitis, contact dermatitis, estrogenic modulation and generation of reactive oxygen species. Other rarely utilized functions of cinnamic acid derivatives are as an antioxidant, in skin conditioning, hair conditioning, as a tonic and in antimicrobial activities. Moreover, some currently investigated natural and synthetic derivatives of cinnamic acid have shown skin lightening and anti-ageing properties. Some of them may become new cosmetic ingredients in the future. In particular, 4-hydroxycinnamic acid, which is currently indexed as a skin-conditioning cosmetics ingredient, has been widely tested in vitro and in vivo as a new drug candidate for the treatment of hyperpigmentation.

Design, synthesis and cardiovascular evaluation of some aminoisopropanoloxy derivatives of xanthone.

A series of aminoisopropanoloxy derivatives of xanthone has been synthesized and their pharmacological properties regarding the cardiovascular system has been evaluated. Radioligand binding and functional studies in isolated organs revealed that title compounds present high affinity and antagonistic potency for α1-(compound 2 and 8), ß-(compounds 1, 3, 4, 7), α1/ß-(compounds 5 and 6) adrenoceptors. Furthermore, compound 7, the structural analogue of verapamil, possesses calcium entry blocking activity. The title compounds showed hypotensive and antiarrhythmic properties due to their adrenoceptor blocking effect. Moreover, they did not affect QRS and QT intervals, and they did not have proarrhythmic potential at tested doses. In addition they exerted anti-aggregation effect. The results of this study suggest that new compounds with multidirectional activity in cardiovascular system might be found in the group of xanthone derivatives.

Design, physico-chemical properties and biological evaluation of some new N-[(phenoxy)alkyl]- and N-{2-[2-(phenoxy)ethoxy]ethyl}aminoalkanols as anticonvulsant agents.

A series of thirty N-(phenoxy)alkyl or N-{2-[2-(phenoxy)ethoxy]ethyl}aminoalkanols has been designed, synthesized and evaluated for anticonvulsant activity in MES, 6Hz test, and pilocarpine-induced status epilepticus. Among the title compounds, the most promising seems R-(-)-2N-{2-[2-(2,6-dimethylphenoxy)ethoxy]ethyl}aminopropan-1-ol hydrochloride (22a) with proved absolute configuration with X-ray analysis and enantiomeric purity. The compound is effective in MES test with ED50=12.92 mg/kg b.w. and its rotarod TD50=33.26 mg/kg b.w. The activity dose is also effective in a neurogenic pain model-the formalin test. Within high throughput profile assay, among eighty one targets, the strongest affinity of the compound is observed towards σ receptors and 5-HT transporter and the compound does not bind to hERG. It also does not exhibit mutagenic properties in the Vibrio harveyi test. Moreover, murine liver microsomal assay and pharmacokinetics profile (mice, iv, p.o., ip) indicate that the liver is the primary site of biotransformation of the compound, suggesting that both 22a and its metabolite(s) are active, compensating probably low bioavailability of the parent molecule.

Synthesis and evaluation of pharmacological properties of some new xanthone derivatives with piperazine moiety.

A series of new xanthone derivatives with piperazine moiety [1-7] was synthesized and evaluated for their pharmacological properties. They were subject to binding assays for α1 and ß1 adrenergic as well as 5-HT1A, 5-HT6 and 5-HT7b serotoninergic receptors. Five of the tested compounds were also evaluated for their anticonvulsant properties. The compound 3a 3-methoxy-5-{[4-(2-methoxyphenyl)piperazin-1-yl]methyl}-9H-xanthen-9-one hydrochloride exhibited significantly higher affinity for serotoninergic 5-HT1A receptors (Ki=24 nM) than other substances. In terms of anticonvulsant activity, 6-methoxy-2-{[4-(benzyl)piperazin-1-yl]methyl}-9H-xanthen-9-one (5) proved best properties. Its ED50 determined in maximal electroshock (MES) seizure assay was 105 mg/kg b.w. (rats, p.o.). Combining of xanthone with piperazine moiety resulted in obtaining of compounds with increased bioavailability after oral administration.

Ion channels as drug targets in central nervous system disorders.

Ion channel targeted drugs have always been related with either the central nervous system (CNS), the peripheral nervous system, or the cardiovascular system. Within the CNS, basic indications of drugs are: sleep disorders, anxiety, epilepsy, pain, etc. However, traditional channel blockers have multiple adverse events, mainly due to low specificity of mechanism of action. Lately, novel ion channel subtypes have been discovered, which gives premises to drug discovery process led towards specific channel subtypes. An example is Na(+) channels, whose subtypes 1.3 and 1.7-1.9 are responsible for pain, and 1.1 and 1.2 - for epilepsy. Moreover, new drug candidates have been recognized. This review is focusing on ion channels subtypes, which play a significant role in current drug discovery and development process. The knowledge on channel subtypes has developed rapidly, giving new nomenclatures of ion channels. For example, Ca(2+)s channels are not any more divided to T, L, N, P/Q, and R, but they are described as Ca(v)1.1-Ca(v)3.3, with even newer nomenclature α1A-α1I and α1S. Moreover, new channels such as P2X1-P2X7, as well as TRPA1-TRPV1 have been discovered, giving premises for new types of analgesic drugs.

Synthesis, alpha-adrenoceptors affinity and alpha 1-adrenoceptor antagonistic properties of some 1,4-substituted piperazine derivatives.

A series of different 1,4-substituted piperazine derivatives (1-11) was synthesized. It comprised 1-(substituted-phenoxyalkyl)-4-(2-methoxyphenyl)piperazine derivatives (1-5); 1,4-bis(substituted-phenoxyethyl)piperazine derivatives (6-8) and 1-(substituted-phenoxy)-3-(substituted-phenoxyalkylpiperazin-1-yl)propan-2-ol derivatives (9-11). All compounds were evaluated for affinity toward alpha 1- and alpha 2-receptors by radioligand binding assays on rat cerebral cortex using [3H]prazosin and [3H]clonidine as specific radioligand, respectively. Furthermore alpha 1-antagonistic properties were checked for most promising compounds (1-5 and 10) by means of inhibition of phenylephrine induced contraction in isolated rat aorta. Antagonistic potency stayed in agreement with radioligand binding results. The most active compounds (1-5) displaced [3H]prazosin from cortical binding sites in low nanomolar range (Ki = 2.1-13.1 nM). Compound 10 showed slightly lower affinity for alpha 1-adrenoceptor (Ki = 781 nM). Compounds 2-5 displayed the strongest antagonistic activity with pA2 values ranging from 8.441 to 8.807. Compound 1 gave a pA2 value of 7.868, while compound 10 showed the weakest antagonistic potency, giving a pA2 value of 6.374. 1-[3-(2-Chloro-6-methylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride (5) showed the best alpha 1- affinity properties with a Ki(alpha 1) value of 2.1 nM and it was 61.05 fold more selective toward alpha 1 than alpha 2-receptors. The best properties showed 1-[3-(2,6-dimethylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride (4) with a Ki(alpha 1) value of 2.4 nM, a 142.13 fold better selectivity to alpha 1 - over alpha 2-adrenoceptors and the best antagonistic potency (pA2 = 8.807). It is worth to emphasized that all most promising compounds possessed an 1-(o-methoxyphenyl)piperazine moiety which probably plays an important role in the affinity to alpha-adrenoceptors.

Evaluation of anticonvulsants for possible use in neuropathic pain.

Neuropathic pain is a kind of pain related with functional abnormality of neurons. Despite large progress in pharmacotherapy, neuropathic pain is still considered an unmet need. Nowadays, there are few drugs registered for this condition, such as pregabalin, gabapentin, duloxetine, carbamazepine, and lidocaine. Among them, pregabalin, gabapentin and carbamazepine are well known antiepileptic drugs. Among the group of new antiepileptic drugs, which are addressed to 1% of human world population suffering from seizures, it turned out that 30% of the seizures resistant to pharmacotherapy has not enough market to justify the costs of drug development. Therefore, it is already a phenomenon that researchers turn their projects toward a larger market, related with possible similar mechanism. Anticonvulsant mechanism of action is in the first place among primary indications for drugs revealing potential analgesic activity. Therefore, many drug candidates for epilepsy, still in preclinical stage, are being evaluated for activity in neuropathic pain. This review is focusing on antiepileptic drugs, which are evaluated for their analgesic activity in major tests related with neuropathic pain. Relation between structure, mechanism of action and result in tests such as the Chung model (spinal nerve ligation SNL), the Bennett model (chronic constriction injury of sciatic nerve CCI) and other tests are considered. The first examples are carbamazepine, gabapentin, and lacosamide as drugs well established in epilepsy market as well as drug candidates such as valnoctamide, and other valproic acid derivatives, novel biphenyl pyrazole derivatives, etc. Moreover, clinical efficacy related with listed animal models has been discussed.

Evaluation of mutagenic and antimutagenic properties of some bioactive xanthone derivatives using Vibrio harveyi test.

AIMS: Drug safety evaluation plays an important role in the early phase of drug development, especially in the preclinical identification of compounds' biological activity. The Vibrio harveyi assay was used to assess mutagenic and antimutagenic activity of some aminoalkanolic derivatives of xanthone (1-5), which were synthesized and evaluated for their anticonvulsant and hemodynamic activities. METHODS AND RESULTS: A novel V. harveyi assay was used to assess mutagenic and antimutagenic activity of derivatives of xanthone 1-5. Two V. harveyi strains were used: BB7 (natural isolate) and BB7M (BB7 derivative containing mucA and mucB genes on a plasmid pAB91273, products of these genes enhance error-prone DNA repair). According to the results obtained, the most beneficial mutagenic and antimutagenic profiles were observed for compounds 2 and 3. A modification of the chemical structure of compound 2 by the replacement of the hydroxy group by a chloride improved considerably the antimutagenic activity of the compound. Thus, antimutagenic potency reached a maximum with the presence of tertiary amine and chloride atom in the side chain. CONCLUSIONS: Among the newly synthesized aminoalkanolic derivatives of xanthone with potential anticonvulsant properties, there are some compounds exhibiting in vitro antimutagenic activity. In addition, it appears that the V. harveyi assay can be applied for primary mutagenicity and antimutagenicity assessment of compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained preliminary mutagenicity and antimutagenicity results encourage further search in the group of amino derivatives of xanthone as the potential antiepileptic drugs also presenting some antimutagenic potential. Furthermore, V. harveyi test may be a useful tool for compounds safety evaluation.

Antiarrhythmic properties of some aroxyethylamine derivatives with adrenolytic activity.

A series of aroxyethylamines (1-10) have been previously evaluated for antihypertensive and adrenolytic properties. Of the derivatives tested, four (compounds 4, 7, 8 and 10) displayed significant antihypertensive activity and binding affinities for alpha- and beta-adrenergic receptors. As a continuation of our study, we present here the in vivo and in vitro antiarrhythmic activity of compounds 1-10, as well as their electrocardiographic properties. Only compounds 4, 7, 8 and 10 demonstrated strong antiarrhythmic activity in adrenaline induced arrhythmia after intravenous and oral administration. In addition, compounds 4 and 7 significantly decreased heart rhythm disturbances in arrhythmia induced by coronary artery occlusion and reperfusion. The pharmacological results and receptor binding studies suggest that the antiarrhythmic activity of the compounds tested may be related to their adrenolytic properties. Moreover, the presence of a methoxyphenylpiperazine moiety seems to be required for their pharmacological activity.

Synthesis and anticonvulsant activity of some piperazine derivatives.

Various 1,4-substituted derivatives of piperazine (I-XII) were synthesized and evaluated for their anticonvulsant activity in the maximal electroshock (MES) and subcutaneous pentylenetetrazole (ScMet)--induced seizures and for neurotoxicity (TOX) in the rotorod test in mice and rats. The most promising compounds seem to be 1-[(2,4,6-trimethyl)-phenoxyethyl]-4-(2-hydroxyethyl)-piperazine dihydrochloride (II) and 1,4-bis-[(4-chloro-3-methyl)-phenoxyethyl]-piperazine dihydrochloride (X) which displayed anti-MES activity with their protective index (PI) higher than that for valproate II (rats), X(mice)).

Central activity of new xanthone derivatives with chiral center in some pharmacological tests in mice.

The study was designed to investigate some central effects of chiral xanthone derivatives [(R,S)-2-N-(6-chloro-2-xanthonemethyl)-amino-1-propanol - MH-31, R enantiomer - MH-32 and S enantiomer - MH-33] in mice. The effects of these chiral compounds were examined in picrotoxin-induced seizures, spontaneous locomotor activity and chimney tests. The tested compounds demonstrated variable influence on the central nervous system in mice. The compound MH-32 exhibits anticonvulsant activity in picrotoxin-induced seizures, whereas MH-31 and its R enantiomer--compound MH-32 demonstrated antidepressant-like activity in the forced swimming test. Moreover, all tested xanthones reduced the locomotor activity in mice. The obtained results indicate the importance to examine pharmacologically enantiomers rather than only racemic mixtures of newly synthesized compounds.

Evaluation of some aroxyethylamine derivatives for hypotensive properties and their affinities for adrenergic receptors.

A series of aroxyethylamines (1-10) was synthesized and evaluated for hypotensive activity in rats after intravenous and oral administration. The 4 compounds (4, 7, 8 and 10) containing a (2-methoxy)phenylpiperazine moiety displayed hypotensive activity and their affinities for alpha1-, alpha2- and beta1-adrenoreceptors were determined by radioligand binding assays. Compounds 4, 7, 8 and 10 were also tested for their effect on the pressor responses to epinephrine, norepinephrine, methoxamine, tyramine and DMPP. The results suggest that the hypotensive effect of these compounds is related to their alpha- and beta-adrenolytic properties.

Princípios éticos na experimentação animal / Ethical principles in the animal experimentation

O uso adequado de animais utilizados em modelos experimentais exige a formação de profissionais qualificados para atender as necessidades e exigências para a realização destes procedimentos associados à experimentação para fins didáticos-científicos, desenvolvimento e inovações tecnológicas e ensaios laboratoriais. A implementação de normas objetivou a obtenção de resultados confiáveis para as pesquisas científicas e atividades didáticas e impedir procedimentos questionáveis ou inaceitáveis aos princípios da ética, que pudessem causar danos ao bem-estar dos animais.

Refining the intestinal motility test in mice to reduce animal stress

Um novo protocolo que preconiza a utilização de jejum com tempo reduzido para 3-h em animais foi utilizado para o ensaio da motilidade intestinal em camundongos. O desenvolvimento deste teste teve como objetivo a concordância ao Princípio dos 3Rs, a fim de reduzir o estresse dos animais. Nossos resultados vêm ao encontro da conscientização para o desenvolvimento de novas recomendações que possam estar incluídas nos protocolos de experimentação animal.

Pharmacological properties of some aminoalkanolic derivatives of xanthone.

A series of appropriate aminoisopropanoloxy derivatives of 2-, 3- or 6-xanthone was synthesized and evaluated for anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole seizure threshold (ScMet) assays and for neurotoxicity (TOX). The most interesting result was the anticonvulsant activity of (+/-)-3-(2-propylamino)-1- [(2-methyl)-6-xanthonoxy]-2-propanol hydrochloride (10), which displayed anti-MES activity with a protective index (TD50/ED50) of 0.80. Some of the obtained compounds were also tested for their effect on the circulatory system (influence on the non-working heart perfusion, protection against adrenaline induced-arrhythmia) and acute toxicity.

Spectrophotometric determination of sparfloxacin in pharmaceutical formulations using bromothymol blue.

A visible light spectrophotometric method is described for the determination of sparfloxacin in tablets. The procedure is based on the complexation of bromothymol blue 0.5% and sparfloxacin to form a compound of yellow colour with maximum absorption at 385 nm. The Lambert-Beer law was obeyed in the concentration range of 2-12 mg/l. The present study describes a sensitive and accurate method for the determination of the concentration of sparfloxacin in tablets. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay.

Development and validation of a nonaqueous titration with perchloric acid to determine sparfloxacin in tablets.

A simple, rapid and inexpensive method for the determination of sparfloxacin in tablets is described. The procedure is based on the use of volumetric dosage in a nonaqueous medium in glacial acetic acid with 0.1 M perchloric acid. The method validation yielded good results and included precision and accuracy. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay.

Pharmacological properties of some xanthone derivatives.

A series of aminoalkanolic derivatives of xanthone were examined in some experimental models of epilepsia, i.e., pilocarpine, aminophylline and pentetrazole-induced seizures. A final objective of this research was to examine the action of these compounds on the central nervous system, namely on spontaneous locomotor activity, amphetamine-induced hyperactivity and narcotic sleep induced by hexobarbital, as well as their influence on the gamma-aminobutyric acid (GABA) level and glutamic acid decarboxylase (GAD) activity in mice brain. The most interesting were the pharmacological results of (R)-2-N-methylamino-1-butanol derivative of 7-chloro-2-methylxanthone [Id], which displayed protective activity against the seizures induced by maximum electroshock and pentetrazole induced seizures; moreover, this compound had a relatively low toxicity and did not exhibit a neurotoxic effect. The influence on the locomotor activity as well as on the amphetamine-induced locomotor hyperactivity in mice was also seen for Id. Compound Id did not decrease the GABA level in mice brain.