Hyaluronic acid from bluefin tuna by-product: Structural analysis and pharmacological activities

The fishing and aquaculture industries generate a huge amount of waste during processing and preservation operations, especially those of tuna. Recovering these by-products is a major economic and environmental challenge for manufacturers seeking to produce new active biomolecules of interest. A new hyaluronic acid was extracted from bluefin tuna's vitreous humour to assess its antioxidant and pharmacological activities. The characterization by infrared spectroscopy (FT-IR), nuclear magnetic resonance ((1D1H) and 2D (1H COSY, 1H/13C HSQC)) and size exclusion chromatography (SEC/MALS/DRI/VD) revealed that the extracted polysaccharide was a hyaluronic acid with high uronic acid content (55.8 %) and a weight average molecular weight of 888 kDa. This polymer possesses significant anti-radical activity and ferrous chelating capacity. In addition, pharmacological evaluation of its anti-inflammatory and analgesic potential, using preclinical models, in comparison with reference drugs (Dexamethasone, diclofenac, and acetylsalicylate of lysine), revealed promising anti-inflammatory activity as well as interesting peripheral and central antinociceptive activity. Therefore, our new hyaluronic acid compound may therefore serve as a potential drug candidate for the treatment of pain sensation and inflammation of various pathological origins.

Characterization of compressed earth blocks using low frequency guided acoustic waves

The objective of this work was to analyze the influence of compaction pressure on the intrinsic acoustic parameters (porosity, tortuosity, air-flow resistivity, viscous, and thermal characteristic lengths) of compressed earth blocks through their identification by solving an inverse acoustic wave transmission problem. A low frequency acoustic pipe (60-6000 Hz of length 22 m, internal diameter 3.4 cm) was used for the experimental characterization of the samples. The parameters were identified by the minimization of the difference between the transmissions coefficients data obtained in the pipe with that from an analytical interaction model in which the compressed earth blocks were considered as having rigid frames. The viscous and thermal effects in the pores were accounted for by employing the Johnson-Champoux-Allard-Lafarge model. The results obtained by inversion for high-density compressed earth blocks showed some discordance between the model and experiment especially for the high frequency limit of the acoustic characteristics studied. This was as a consequence of applying high compaction pressure rendering them very highly resistive therefore degrading the signal-to-noise ratios of the transmitted waves. The results showed that the airflow resistivity was very sensitive to the degree of the applied compaction pressure used to form the blocks.

Design and synthesis of antimicrobial, anticoagulant, and anticholinesterase hybrid molecules from 4-methylumbelliferone

We designed and synthesized new series of diverse triazoles, isoxazoles, isoxazolines, and aziridines linked 4-methylumbelliferone 1 using intermolecular 1,3-dipolar cycloaddition reactions. Structures of these compounds were established on the basis of (1)H NMR, (13)C NMR, and ESI-HRMS. All prepared compounds were evaluated for their antimicrobial, anticoagulant, and anticholinesterase activities. Interestingly, among the tested molecules, some of the analogs displayed better activities than the parent 4-methylumbelliferone 1 such as 6a and 6d for their antifungal properties. Moreover, compounds 4, 5, 6, and 7 showed the importance of the added fragments to 4-methylumbelliferone 1 via the linker methylene to have good activity.

Triacylglycerols composition and volatile compounds of virgin olive oil from Chemlali cultivar: comparison among different planting densities

The present study focused on the comparison the chemical composition of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivar (Chemlali) grown in four planting densities (156, 100, 69, and 51 trees ha(-1)). Despite the variability in the triacylglycerols and volatile compounds composition, the quality indices (free fatty acids, peroxide value, and spectrophotometric indices K(232) and K(270)) all of the virgin olive oils samples studied met the commercial standards. Decanal was the major constituent, accounting for about 30% of the whole volatiles. Moreover, the chemical composition of the volatile fraction of the oil from fruits of trees grown at the planting density of 156, 100, and 51 trees ha(-1) was also characterised by the preeminence of 1-hexanol, while oils from fruits of trees grown at the planting density of 69 trees ha(-1) had higher content of (E)-2-hexenal (20.3%). Our results confirm that planting density is a crucial parameter that may influence the quality of olive oils.

Anticoagulant activity of a sulfated polysaccharide from the green alga Arthrospira platensis

BACKGROUND

The polysaccharide of culture medium from Arthrospira platensis was extracted by ultrafiltration, partially characterized and assayed for anticoagulant activity.

METHODS

The crude polysaccharidic fraction was fractionated by anion exchange chromatography on DEAE-cellulose, subjected to acetate cellulose electrophoresis and characterized by physicochemical procedures. The anticoagulant effect of the ultrafiltrated polysaccharide was checked by several coagulation tests.

RESULTS

Anion exchange chromatography revealed in the whole ultrafiltrated polysaccharidic fraction the occurrence of a sulfated spirulan-like component designated PUF2. The average molecular weight of PUF2 was determined by size exclusion chromatography combined with multi-angle light scattering (SEC-MALS) and viscosimetry and was 199 kDa and the sulfate content was 20% weight/dry weight. The physicochemical characterization indicated the occurrence of rhamnose (49.7%), galacturonic and glucuronic acid (32% of total sugar). The anticoagulant effect of this sulfated polysaccharide was mainly due to the potentiation of thrombin inhibition by heparin cofactor II and was 4-times higher than that of the porcine dermatan sulfate whereas it had no effect on anti-Xa activity.

CONCLUSIONS

An ultrafiltrated sulfated polysaccharide, likely a calcium spirulan was obtained from the culture medium of A. platensis and showed an anticoagulant activity mediated by heparin cofactor II.

GENERAL SIGNIFICANCE

Old culture medium of A. platensis may represent an important source for the spirulan-like PUF2 which was endowed with potentially useful anticoagulant properties whereas its obtention by ultrafiltration may represent an extraction procedure of interest.

Characterization of a novel dermatan sulfate with high antithrombin activity from ray skin (Raja radula)

INTRODUCTION

A novel dermatan sulfate (DS) from the skin of the ray Raja radula with high anticoagulant activity was identified and its monosaccharide composition and anticoagulant mode of action and potency were determined.

MATERIALS AND METHODS

The DS isolated from the ray skin was identified by chondroitinase treatment and characterized by FT-IR and (1)H NMR spectroscopy. Its anticoagulant activity was checked by activated partial thromboplastin time (aPTT), thrombin time (TT), thrombin generation (TG), heparin cofactor II (HCII) and antithrombin (AT)-mediated inhibition of thrombin. The effects on platelet activation and aggregation were investigated using flow cytometry and aggregometry, respectively.

RESULTS

Chemical backbone structures of DS from Raja radula were close to that of DS from porcine intestinal mucosa. However, (1)H NMR indicated that iduronic acid was the major hexuronic acid moiety in the ray skin DS and also suggested that the amount of 2-O-sulfonated iduronic acid was higher in comparison with mammalian DS along with the occurrence of 4-O-sulfonated N-acetylgalactosamine residues. The anticoagulant effect of the ray skin DS was mainly due to the potentiation of thrombin inhibition by HCII but also, although to a lesser extent, by AT and was higher than that of the DS standard. Moreover, it had no effect on platelet activation and aggregation induced by various agonists.

CONCLUSION

Altogether, these results indicated that DS from raja radula skin is an anticoagulant drug of interest potentially useful in anticoagulant therapy.

Decompression sickness in caisson workers

El Ghawabi, S. H., Mansour, M. B., Youssef, F. L., El Ghawabi, M. H., and Abd El Latif, M. M. (1971).Brit. J. industr. Med.,28, 323-329. Decompression sickness in caisson workers. An investigation of 55 bridge construction workers is reported. The overall bends rate was 0·97%. (The term `bends' as used in this study is defined in the paper.) Chokes were encountered in 67·27% of workers. A clinical, haematological, and radiological study was performed.

Definite bony changes were found in 43·6% of all workers; 91·6% of these had lesions around the elbow. The presence of dense areas in the neck of the scapula is reported in two cases for the first time. The relatively high haematocrit value is thought to play a part in the pathogenesis of bone infarction through its relation with blood viscosity.