AHyaluronic acid (HA) is part of the extracellular matrix of connective, epithelial and neural tissues, as well as the synovial fluid, skin, and cartilage. It is composed of repeating disaccharide units of D-glucuronic acid and N-acetyl glucosamine. Hyaluronic acid is used in abdominal surgery, ophthalmology, dermatology, rhinology; it is usable for the osteoarthritis treatment. The membranes of eggshell are a natural source of hyaluronic acid, collagen, glycosaminoglycan and collagenous proteins. In paper, we tested the possibility of extraction hyaluronic acid from the eggshell membranes by enzymatic hydrolysis. We identified optimal conditions of hydrolysis with trypsin at reaction temperature of 37 °C and pH 8; with pepsin at 40 °C and pH 3, as well as with papain at 60 °C and pH 7.5. The content of hyaluronic acid in samples was determined spectrophotometrically using the carbazole method. The experimental results showed a yield of ~ 4 -4.5 % hyaluronic acid per 1 g of dry eggshell membranes.
Martin Hrašna, Eva Ürgeová and Alžbeta Krutošíková
Synthesis, Complex Compounds and Antimicrobial Activity of Some Derivatives of Furo[3,2-C]Pyridine and Their Starting Compounds
Some [3,2-c]pyridine derivatives were synthesized. 3-(Furan-2-yl)propenoic acid (1a) was prepared from furan-2-carbaldehyde under the Perkin's conditions. Obtained acid was converted to the corresponding azide 3, which in turn was cyclized to give furo[3,2-c]pyridin-4(5H)-one (4a). The reaction of pyridone 4a with phosphorus oxychloride rendered the chloroderivative 7a, which was treated in the condition of Suzuki coupling reaction with boronic acid to give 4-phenylfuro[3,2-c]pyridine (8e) and an unexpected product 10. Some title compounds have shown moderate to good antimicrobial activity against tested bacteria Xanthomonas sp., Erwinia amylovora, and filamentous fungi Pyrenophora avenae, Fusarium graminearum.