Flavonoids, with various biological activities, are considered as key compounds in propolis. In this study, quantitative determinations of flavonoids in propolis were conducted by two complementary colorimetric methods, aluminum chloride method and 2,4-dinitrophenylhydrazine method. Results suggested that the sum of flavonoid contents determined by the above two individual methods may represent the real content of total flavonoids. In this work, six raw propolis samples were investigated and the total contents of flavonoids ranged from 10.38 ± 0.14% to 24.91 ± 0.53%. As for the 12 commercial propolis products examined, the levels of total flavonoids in tinctures were all below 7% and those in powdery products varied from 2.97 ± 0.05% to 22.73 ± 0.72%.
Proteins and trichloroacetic acid-soluble peptides were present in high concentrations in human intestinal contents and faeces. Free amino acids were also detected in millimolar...
Four org. dyes bearing the phenoxazine chromophore have been synthesized and applied in dye-sensitized solar cells (DSCs). The effect of different dye structures on the performa...
A high-capacity system was developed to monitor the expression of many genes in parallel. Microarrays prepared by high-speed robotic printing of complementary DNAs on glass were...
Ten conditions of trust were suggested by 84 interviews of managers, and two previous studies of managerial trust. Statements made in the interviews and the studies were used to...
To date, copper is the only heterogeneous catalyst that has shown a propensity to produce valuable hydrocarbons and alcohols, such as ethylene and ethanol, from electrochemical ...
Social media, news, blog, policy document mentions