Pinobanksin 5-methyl ether

Simultaneous quantification of eight major bioactive phenolic compounds in Chinese propolis by high-performance liquid chromatography.[Pubmed:19634328]

Nat Prod Commun. 2009 Jun;4(6):813-8.

A simple, sensitive and specific high-performance liquid chromatography-UV (HPLC-UV) method has been developed to simultaneously quantify the eight major bioactive phenolic compounds in Chinese propolis, namely caffeic acid, isoferulic acid, 3,4-dimethoxycinnamic acid, Pinobanksin 5-methyl ether, pinocembrin, benzyl caffeate, chrysin and galangin. This HPLC assay was performed on an Agilent Zorbax Extend-C18 (250 x 4.6 mm, 5 microm) column with a gradient of methanol and 0.2% aqueous acetic acid (v/v) in 50 min, at a flow rate of 1.0 mL/min, and detected at 290 nm. All calibration curves showed good linearity (r2 > 0.999) within the test ranges. The intra- and inter-day assay precision (RSD) of eight phenolic compounds were in the range of 0.07-4.92%. The recoveries were between 98.3% and 104.8%. This assay was applied to the evaluation of nineteen samples from different origins in China. The results indicated that the developed assay could be readily utilized for the quality control of propolis.

Honey constituents up-regulate detoxification and immunity genes in the western honey bee Apis mellifera.[Pubmed:23630255]

Proc Natl Acad Sci U S A. 2013 May 28;110(22):8842-6.

As a managed pollinator, the honey bee Apis mellifera is critical to the American agricultural enterprise. Recent colony losses have thus raised concerns; possible explanations for bee decline include nutritional deficiencies and exposures to pesticides and pathogens. We determined that constituents found in honey, including p-coumaric acid, pinocembrin, and Pinobanksin 5-methyl ether, specifically induce detoxification genes. These inducers are primarily found not in nectar but in pollen in the case of p-coumaric acid (a monomer of sporopollenin, the principal constituent of pollen cell walls) and propolis, a resinous material gathered and processed by bees to line wax cells. RNA-seq analysis (massively parallel RNA sequencing) revealed that p-coumaric acid specifically up-regulates all classes of detoxification genes as well as select antimicrobial peptide genes. This up-regulation has functional significance in that that adding p-coumaric acid to a diet of sucrose increases midgut metabolism of coumaphos, a widely used in-hive acaricide, by approximately 60%. As a major component of pollen grains, p-coumaric acid is ubiquitous in the natural diet of honey bees and may function as a nutraceutical regulating immune and detoxification processes. The widespread apicultural use of honey substitutes, including high-fructose corn syrup, may thus compromise the ability of honey bees to cope with pesticides and pathogens and contribute to colony losses.