Insulin resistance has a critical role in type 2 diabetes. The aim of this study was to investigate the effect of pinobanksin, galangin, chrysin, and pinocembrin from propolis on insulin resistance. Our study shows that galangin and pinocembrin can ameliorate insulin resistance; on the contrary, pinobanksin and chrysin are ineffective. Galangin and pinocembrin treatments substantially increase glucose consumption and glycogen content by enhancing the activities of hexokinase and pyruvate kinase. Galangin treatment with 80 μM increased hexokinase and pyruvate kinase activities by 21.94% and 29.12%, respectively. Moreover, we hypothesize that galangin and pinocembrin may have a synergistic effect on the improvement of insulin resistance via Akt/mTOR signaling pathway, through distinctly upregulating the phosphorylation of IR, Akt, and GSK3β and remarkably downregulating the phosphorylation of IRS. Most notably, this is the first study to our knowledge to investigate pinocembrin about the alleviation of insulin resistance. Our results provide compelling evidence for the depth development of propolis products to ameliorate insulin resistance.

The synergistic interactions between the ectoparasitic mite Varroa destructor and Deformed wing virus (DWV) lead to the reduction in lifespan of the European honey bee Apis mellifera and often have been implicated in colony losses worldwide. However, to date, the underlying processes and mechanisms that form the multipartite interaction between the bee, mite, and virus have not been fully explained. To gain a better understanding of honey bees’ defense response to Varroa mite infestation and DWV infection, the DWV titers and transcription profiles of genes originating from RNAi, immunity, wound response, and homeostatic signaling pathways were monitored over a period of eight days. With respect to DWV, we observed low viral titers at early timepoints that coincided with high levels of Toll pathway transcription factor Dorsal, and its downstream immune effector molecules Hymenoptaecin, Apidaecin, Abaecin, and Defensin 1. However, we observed a striking increase in viral titers beginning after two days that coincided with a decrease in Dorsal levels and its corresponding immune effector molecules, and the small ubiquitin-like modifier (SUMO) ligase repressor of Dorsal, PIAS3. We observed a similar expression pattern for genes expressing transcripts for the RNA interference (Dicer/Argonaute), wound/homeostatic (Janus Kinase), and tissue growth (Map kinase/Wnt) pathways. Our results demonstrate that on a whole, honey bees are able to mount an immediate, albeit, temporally limited, immune and homeostatic response to Varroa and DWV infections, after which downregulation of these pathways leaves the bee vulnerable to expansive viral replication. The critical insights into the defense response upon Varroa and DWV challenges generated in this study may serve as a solid base for future research on the development of effective and efficient disease management strategies in honey bees.

A liquid chromatography–tandem mass spectrometric method was established for the simultaneous determination of residues of metronidazole, chloramphenicol and 10 sulfonamides (sulfadiazine, sulfathiazol, sulfapyridin, sulfamerazin, sulfameter, sulfamethazine, sulfamethoxypyridazine, sulfachloropyridazine, sulfamethoxazole and sulfadimethoxin) in honey samples. Samples were first dissolved in water. Sonication was carried out in an ultrasonic bath to extract the target analytes with acetonitrile and the extract was concentrated by rotary evaporation. Chromatographic separation was carried out on an MGIII-C₁₈ column (2.1 mm × 150 mm, 5 μm) using a mobile phase made up of methanol and 50 mmol L⁻¹ ammonium acetate aqueous solution (include 0.3% formic acid) and gradient elution. Metronidazole, chloramphenicol and the sulfonamides were monitored in negative ion or positive ion selected reaction monitoring modes and quantified by the external standard method. The limit of detection was 0.1 μg kg⁻¹ for chloramphenicol and 1.0 μg kg⁻¹ for metronidazole and each sulfonamide, respectively. The linear range for chloramphenicol was 0.1–25.0 μg kg⁻¹, and for both metronidazole and the sulfonamides were 1.0–100.0 μg kg⁻¹, and all the correlation coefficients were greater than 0.99. The average spike recoveries of the method ranged from 81.6% to 99.7% with relative standard deviations of 3.61–8.97%. Therefore this method is convenient, rapid, sensitive and reliable, and can be successfully applied for the simultaneous detection of metronidazole, chloramphenicol and 10 sulfonamide residues in commercial products.

To understand the material basis of antitumor activity of Chinese propolis water extract (CPWE), we developed a simple and efficient method using macroporous absorptive resin coupled with preparative high performance liquid chromatography and separated and purified eleven chemical components (caffeic acid, ferulic acid, isoferulic acid, 3,4‐dimethoxycinnamic acid, pinobanksin, caffeic acid benzyl ester, caffeic acid phenethyl ester, apigenin, pinocembrin, chrysin, and galangin) from CPWE; then we tested the antitumor activities of these eleven components using different human tumor cell lines (MCF‐7, MDA‐MB‐231, HeLa, and A549). Furthermore, cell migration, procaspase 3 level, and reactive oxygen species (ROS) of effective components from CPWE were investigated. Our data showed that antitumor activities of the eleven components from CPWE were different from each other. CPWE and its effective components induced apoptosis by inhibiting tumor cell migration, activating caspase 3, and promoting ROS production. It can be deduced that the antitumor effects of propolis did not depend on a single component, and there must exist “bioactive components,” which also provides a new idea for Chinese propolis quality control.