Fedele Manna

Comparative chemical evaluation of two commercially available derivatives of hyaluronic acid (Hylaform@ from rooster combs and Restylane* from streptococcus) used for soft tissue augmentation

Hyaluronic acid (HA) derivatives have been developed to try to enhance Theological properties of this molecule to make it suitable for various medical applications. The main dermatological application of HA derivatives is the augmentation of soft tissues, via injection into the dermis. HA derivatives are indicated for the correction of cutaneous contour deficiencies of the skin, particularly in cases of ageing or degenerative lesions or to increase lips. Two HA derivatives have been evaluated: Hylaform® Viscoelastic Gel (Hylan B), derived from rooster combs and subjected to cross‐linking, and Restylane®, produced through bacterial fermentation (streptococci) and stabilized, as declared by the producer. In both cases the purpose is to improve HA rheological characteristics and slow down its degradation once it is in contact with biological structures. Distribution of particle dimensions, pH, protein concentration and rheological properties have been investigated in order to evaluate their reliability as fillers for soft tissue augmentation. The results of the analyses showed that there are differences between Restylane® and Hylaform®. Especially as far as rheological characteristics are concerned, the results outline different structures of the products: Hylaform® behaves as a strong hydrogel, Restylane® as a weak hydrogel; theologically Hylaform® is clearly superior to Restylane®. Hylaform® contains a definitely minor quantity (about a quarter) of cross‐linked hyaluronic acid than Restylane®. Furthermore, although not declared by the manufacturer, Restylane® contains protein, resulting from bacterial fermentation or added to enable cross‐linking reaction; the quantity of proteins contained by Restylane® can be as much as four times the quantity contained by Hylaform®, for the same volume (1 ml). It is evident that Hylaform® offers higher safety margin than Restylane®. Furthermore, wide literature and 20 years of clinical experience on hyaluronan derived from rooster combs confirm the reliability of this derivative while we did not find evidence regarding about the safety of HA obtained from streptococcus.

Inhibition of Amine Oxidases Activity by 1-Acetyl-3,5-diphenyl- 4,5-dihydro-(1H)-pyrazole Derivatives

A novel series of 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives have been synthesised and investigated for the ability to inhibit selectively monoamine oxidases, swine kidney oxidase, and bovine serum amine oxidase. The newly synthesised compounds 1-6 proved to be reversible and non-competitive inhibitors of all types of the assayed amine oxidases. Compounds inhibit monoamine oxidases potently, displaying low I(50) values of particular interest. In particular 1-acetyl-3-(2,4-dihydroxyphenyl)-5-(3-methylphenyl)-4,5-dihydro-(1H)-pyrazole 6 showed to be a potent monoamine oxidase inhibitor with a K(i) of about 10(-8)M. Further insights in the theoretical evaluation of the possible interactions between the compounds and monoamine oxidase B have been developed through a computational approach.

Anti-inflammatory, analgesic and antipyretic 4,6-disubstituted 3-cyano-2-aminopyridines

Abstract 4,6-diaryl and 4,6-aryl-indolyl substituted 3-cyano-2-aminopyridines were synthesized and submitted to evaluation for their anti-inflammatory, analgesic and antipyretic activity. The electronegativity of the substituents and their displacement on the 4- or 6-aryl ring of the 4,6-diaryl-3-cyano-2-aminopyridine nucleus ( 3a – q ) influenced the anti-inflammatory activity which was higher in the presence of electron-realising groups. The introduction of the indol-3-yl substituent in the 4-position of the 3-cyano-2-aminopyridine nucleus ( 6a – x ) increased the anti-inflammatory and analgesic power, but there was no evidence of the relationship among the electronic characteristic of the substituents, their displacement on the 6-phenyl ring and the activity. Conversely, the displacement of the 2-hydroxyphenyl group in the 4-position ( 4a – e ) and of the indol-3-yl group in the 6-position ( 8h – w ) decreased the anti-inflammatory activity. All derivatives did not show any significative antipyretic activity.

Synthesis and biological evaluation of N-substituted-3,5-diphenyl-2-pyrazoline derivatives as cyclooxygenase (COX-2) inhibitors

Eighteen new 1-N-substituted-3,5-diphenyl-2-pyrazoline derivatives have been synthesized and cyclooxygenase (COX-1 and COX-2) inhibitory activities have been evaluated. The results of these biological assays showed that all of new derivatives are not endowed with improved anti-inflammatory activity against COX-1, but some of them showed a good activity against COX-2. To evaluate the binding mode of the most significative compounds (2d, 2f, 2g and 2k) docking studies were carried out. These studies confirmed biological data, in fact these compounds were able to fit into the active site of COX-2.

Anti-inflammatory, analgesic and antipyretic N-acetyl-Δ2-pyrazolines and dihydrothienocoumarines

Abstract 1-Acetyl-3-(2-hydroxyphenyl)-5-(R,R′-aryl)-4,5-dihydro-(1H)pyrazoles (2a–o) were synthesized and showed anti-inflammatory and analgesic activity. The substituents on the 5-aryl group were necessary for biological activity. R-R′-aryl-2-dihydro-1,2(4H)thieno(2,3-c)benzo(e)pyranone-4 derivatives (3a–f) also showed analgesic and anti-inflammatory activity. The position and the number of the substituents caused a modulation of analgesic or anti-inflammatory activity of the N-acetyl-Δ2-pyrazoline2 and dihydrothienocoumarines 3. All compounds showed low antipyretic activity.

Synthesis, Biological Evaluation and 3D-QSAR of 1,3,5-Trisubstituted-4,5- Dihydro-(1H)-Pyrazole Derivatives as Potent and Highly Selective Monoamine Oxidase A Inhibitors

The present report provides a extended study of the chemistry, the inhibitory activity against monoamino oxidases (MAO), and molecular modeling including the 3D-QSAR hypothesis of 1,3,5-trisubstituted-4,5-dihydro-(1H)-pyrazole derivatives. Four series of about eighty novel pyrazoline derivatives were prepared and investigated for their ability to inhibit the activity of the A and B isoforms of MAO selectively. Most of the new synthesized compounds proved more reversible, potent, and selective inhibitors of MAO-A than of MAO-B, and could be taken into account to develop the search further in this field, knowing that reversible and selective MAO-A inhibitors are used as antidepressant and antianxiety drug. The 30 most active compounds show inhibitory activity on MAO-A in the 8.6 x 10(-8) - 9.0 x 10(-9)M range. Moreover, it should be pointed out that for most of them a high IC(50) > or = 10(-9)M value is associated with a high A-selectivity (Selectivity Index MAO-B/MAO-A in the 10,000-16,250 range). Furthermore, due to the presence of a chiral centre at the C5 position of the pyrazole moiety, we performed the semi-preparative chromatographic enantioseparation of the most potent, selective, and chiral compounds. The separated enantiomers were then submitted to in vitro biological evaluation, and from the results of these experiments it has been possible to point out a difference in inhibiting the two isoforms selectively between the racemic mixture and the single enantiomers. The molecular modeling work was carried out combining the Glide docking approach with CoMFA with the aim to rationalize the structure-activity relationships of each pyrazoline inhibitor toward MAO-A and MAO-B isoforms and to derive a suitable selectivity model.

Anti-inflammatory, analgesic and antipyretic 4,6-disubstituted 3-cyanopyridine-2-ones and 3-cyano-2-aminopyridines

Abstract 3-Cyano-4-(R,R′-aryl)-6(2-hydroxyphenyl)-2-(1H)pyridones 2a–o and 3-cyano-4-(R-R′-aryl)-6-(2-hydroxyphenyl)-2-aminopyridines were synthesized which showed anti-inflammatory and analgesic activity. Electron withdrawing substituents in 2′ or 4′ position on 4-aryl group of compounds 2 increased the anti-inflammatory activity, while their displacement in the 3′ position produced an increase of analgesic activity and the appearance of an edematous reaction. All compounds showed low antipyretic and antimicrobial activity. The compounds 2b, 2d, 2i, 2m and 2o did not show any interesting activity in the β-adrenolytic, antihypertensive and heart frequency tests.

Synthesis, molecular modeling studies and selective inhibitory activity against MAO of N1-propanoyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives

A series of N1-propanoyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives were synthesized and assayed as inhibitors of MAO-A and MAO-B isoforms. Most of the tested compounds showed inhibitory activity with micromolar values and MAO-A selectivity. In addition a computational work was carried out on the most selective compound 3b to highlight the most relevant interactions in the mechanism of recognition within both the MAO-A and the MAO-B enzyme active sites.

Synthesis of a carbocyclic sialic acid analogue for the inhibition of influenza virus neuraminidase.

The influenza virus neuraminidase (NA) is essential for viral infection and offers a potential target for antiviral drug development. We prepared a carbocyclic sialic acid analogue, potentially able to inhibit NA. Its structure is an analogue of the transition-state of the reaction catalysed by NA. As starting material, quinic acid was selected owing to its ready availability and its stereochemical feature suitable for the target structure. The quinic acid was first converted in the shikimic acid; then two of the three hydroxyl functions of this product were selectively functionalised to obtain the target molecule (3R,4S,5R)-4-acetamido-3-guanidino-5-hydroxycyclohex-1-ene-1-carboxylic acid.

Synthesis and antimicrobial activity of coumarin 7-substituted cephalosporins and sulfones

Some coumarin 7-substituted cephalosporins and related sulfones were prepared and an antimicrobial assay was performed. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) carried out on cephalosporins showed a potential activity of some of the synthesized compounds against Gram-positive microorganisms. The tests performed on the corresponding sulfones showed no significant activity, neither as antimicrobial agents nor as inhibitors of beta-lactamase. An association of sulfone 6a with ampicillin was observed to inhibit Gram-positive microorganisms with a lower MIC than for ampicillin alone.