Optimization of Chitosan Microspheres Spray Drying via 32 Full Factorial Design.

BACKGROUND: Generally, the preparation of spray-dried microspheres is strongly affected by the process parameters. Particle size and production yield are mainly influenced by the spraying solution concentration and the pump rate of the spray dryer. AIM: The aim of this study was to assess optimum spray drying parameters - polymer concentration and pump rate required for the production of chitosan microspheres with high production yield and targeted for nasal administration particle size. MATERIALS AND METHODS: Full 32 factorial design was used to study the investigated parameters. Three different concentrations of the chitosan solution were selected: a low concentration of 1%, average concentration of 1.5% and high concentration of 2%. The rate of the peristaltic pump was also varied at three levels: low rate of 10%, medium rate of 14% and high rate of 18%. RESULTS: Nine models of chitosan microspheres were formulated and characterized in terms of shape, surface morphology, size, particle size distribution and production yield. The particles obtained from 2% chitosan solutions, sprayed at 10% pump rate were of the highest yield (64.33%) and appropriate for nasal administration median diameter (3,434 µm). CONCLUSION: The two investigated spray-drying parameters interact with each other and their influence on the production yield and the size of the chitosan microspheres should be evaluated together, instead of one at a time. The assessed process parameters allow the production of chitosan microparticles with high yield and desirable characteristics (size, size distribution and shape) for intranasal delivery.

Enzymatic Hydrolysis of Water Extractable Polysaccharides from Leaves of Plantago major L.

BACKGROUND: Plantago major L. leaves have been used for centuries by the traditional medicine in the treatment of infectious disorders of the respiratory, urinary and digestive tracts. Researchers have reported that hot water extracts of Plantago major possess a broad-spectrum of anticancer, antioxidant and antiviral activities, as well as activities which modulate cell-mediated immunity. Their beneficial properties may be due to the significant content of polysaccharides. The polysaccharides that have been isolated from the leaves of Plantago major L. have different structures - pectic substances, galactans, arabinogalactans, glucomannans. AIM: The aim of this paper was to study the correlation between the structure of the water extractable polysaccharides isolated from Plantago major L. leaves and their enzymatic hydrolysis with different carbohydrate hydrolases. MATERIALS AND METHODS: The hydrolysis reactions were performed with the enzymes hemicellulase and mannanase. Spectrophotometric total reducing sugars assay was used to examine the hydrolysis yield. The monosaccharide and oligosaccharide compositions were determined using HPLC analysis. RESULTS: The highest hydrolysis yield of the water extractable polysaccharides from Plantago major leaves was obtained by treatment with hemicellulase. The hydrolysis yield increased with the augmentation of the ratio of enzyme to polysaccharide. Galactose was the prevalent monosaccharide identified in the composition of the isolated polysaccharides. Oligosaccharides with different degree of polymerization were also detected. CONCLUSION: The enzymatic hydrolysis of water extractable polysaccharides from Plantago major leaves allows us to obtain different types of oligosaccharides with beneficial effects on both human health and industry.

Effect of Extracts of Bilberries (Vaccinium myrtillus L.) on Amyloglucosidase and α-Glucosidase Activity.

BACKGROUND: Vaccinium myrtillus L. is a species belonging to the genus Vaccinium of the family Ericaceae. Bilberries have drawn attention due to the multiple benefits for the human health, including antioxidant, anti-inflammatory, anticancer, anti-neurodegenerative, and cardioprotective effects. Recently, bilberries were shown to inhibit the activity of carbohydrate-hydrolysing enzymes that can help reduce the intensity of the metabolic syndrome and prevent type 2 diabetes. AIM: In this study, we investigated the α-glucosidase and amyloglucosidase inhibitory activities of polyphenol-rich extracts from fruit of Vaccinium myrtillus L. from different regions in Bulgaria. MATERIALS AND METHODS: The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu method. With HPLC analysis, phenolic acid composition of extracts was assessed. Enzymatic inhibitory activities were determined according to the methodology by Borooah et al. (1961), and Dewi et al. (2007). Amyloglucosidase assay and α-glucosidase assay were used to measure the inhibition potential of bilberries' extracts. RESULTS: Phenolic compound content ranged from 1299.60 mg to 510.88 mg GAE/100 g for organic extracts and from 453.63 mg to 290.83 mg GAE/100 g for aqueous extracts. Based on qualitative HPLC analyses, gallic acid and chlorogenic acid were found to be among the major phenolic acids present in bilberries. Methanol and aqueous extracts there were found to be effective inhibitors of α-glucosidase with an IC50 value of 20 µg GAE/ml and 55 µg GAE/ml, respectively. CONCLUSION: The inhibitory activity of bilberries' extracts towards α-glucosidase offers the patients with type 2 diabetes the opportunity to manage their own glycaemic levels with a diet.