Filters
A new approach to obtain chitosan films – Characteristics of films prepared with tea and coffee kombucha as natural chitosan solvents
Biological Activity and Chemical Composition of Propolis from Various Regions of Poland
Propolis is one of the bee products, with multiple biological properties used in numerous applications. The research objective was to determine the chemical composition and biological properties (antibacterial, antifungal, antiviral, antioxidant, and cytoprotective activity) of propolis extracts collected from various regions of Poland. The results indicated that the total content of phenols (116.16–219.41 mg GAE/g EEP) and flavonoids (29.63–106.07 mg QE/g EEP) in propolis extracts depended on their geographic origin. The high content of epicatechin, catechin, pinobanksin, myricetin, and acids: vanillic and syringic in propolis samples was confirmed by chromatographic analysis. Moreover, the presence of caffeic acid phenethyl ester was confirmed in all samples. The origin of propolis also influenced the biological properties of its extracts. The propolis extracts were characterized by moderate DPPH free radical scavenging activity (29.22–35.14%), and relatively low ferrous iron chelating activity (9.33–32.32%). The results indicated also that the propolis extracts showed high activity in the protection of human red blood cells against free radicals generated from 2,2’-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The extracts exhibited diversified activity against the tested pathogenic bacteria and limited activity against fungal strains. The research of selected propolis extracts showed that only 2 of 5 examined samples showed moderate activity against HPV (human papillomaviruses) and the activity depended on its geographical distribution.
Aktywność biologiczna i profil fenolowy ekstraktu z łupiny orzecha włoskiego
Introduction. Walnut products are widely used. Green fruits, shells, leaves and bark have a high phenolic content and are used in the pharmaceutical and cosmetic industries. Seeds rich in unsaturated fatty acids are used in the food industry. Walnut wood is also valuable. Aim. The aim of the study was to determine the microbiological, antioxidant activity and concentration of phenolic acids of walnut shell extract. Material and methods. The methanol extract of walnut shells from trees growing in Greater Poland was used for the research. The antibacterial activity was determined by the point diffusion method against 7 strains of gram-positive bacteria and 6 strains of gram-negative bacteria. The method with the DPPH radical and the ability to chelate Fe2+ ions were used to determine the antioxidant activity. The content of phenolic compounds in the tested extract was also determined using the chromatographic method. Results. The tested walnut shell extract showed moderate antibacterial activity against gram-positive and gram-negative bacteria and high antioxidant activity in the radical cation test and lower chelating activity in the ferrozine test. Moreover, in the tested walnut shell extract, a higher concentration of phenolic acids, mainly caffeic acid, was determined as compared to the concentration of flavonoids. Conclusions. The tested walnut shell extract showed antiradical activity; therefore, it can be an alternative to synthetic antioxidants. The fact that shells shells are a by-product of the food industry is an added advantage when used in other industries as well.