The Effects of Adlay Tea Intake on Immune Homeostasis and Vascular Endothelial Function in Healthy Adults: A Randomized, Double-Blind, Parallel-Group Comparative Study.

Excessive immune response and inflammation are associated with an increased risk of various diseases. In particular, excessive myeloperoxidase (MPO) activity in neutrophils causes inflammatory reactions and lifestyle-related diseases. Adlay has a long history of being used as a traditional Chinese medicine. Polyphenols present in adlay seeds are expected to have the effect of suppressing excessive immune and inflammatory responses. Here, we conducted a randomized, double-blind, parallel group, placebo-controlled study was conducted to evaluate the suppressing effects of adlay seeds extract on excessive immune responses. One hundred and twenty adults participated in the study and they were equally divided into an adlay tea intake group and a placebo group. MPO activity was significantly elevated in the placebo group after 8-wk ingestion, while no significant change was observed in the adlay group. Vascular endothelial functions improved in the adlay group, especially in subjects over 40 y old. These results indicate that adlay tea intake may suppress an excessive immune and inflammatory responses, and improve arterial stiffness. Since caffeic acid, p-coumaric acid, and ferulic acid detected in adlay tea are known to inhibit MPO activity, these polyphenols may be the major functional molecules. Collectively, adlay tea is considered to have a preventative effect against lifestyle-related diseases through improving vascular endothelial function by effects to maintain immune homeostasis of the contained polyphenols. This trial was registered at University Hospital Medical Information Network Clinical Trials Registry (UMIN000032263).

Competitive immunochromatographic assay for leptosperin as a plausible authentication marker of manuka honey.

Manuka honey is known as one of the premium honeys because of its unique property: a potent antibacterial activity. Leptosperin, methyl syringate 4-O-ß-d-gentiobioside, has been specifically identified in manuka honey. Because leptosperin is relatively stable under warmer conditions, measuring leptosperin levels may be applied to authenticate manuka honey. In this study, an immunochromatographic separation and quantification of leptosperin techniques have been developed. The concentration of leptosperin measured by immunochromatography was significantly correlated with the concentration measured by high-performance liquid chromatography (HPLC) or enzyme-linked immunosorbent assay (ELISA). Because the immunochromatographic method is rapid and reliable, it could be applied to on-site quality control or inspection of honey samples by a beekeeper, a manufacturer, an inspector, a retailer, or a consumer.

Immunochemical authentication of manuka honey using a monoclonal antibody specific to a glycoside of methyl syringate.

Leptosperin, a novel glycoside of methyl syringate, is exclusively present in manuka honey derived from the Leptospermum species Leptospermum scoparium. Quantification of leptosperin might thus be applicable for authentication of honey. The concentration of leptosperin has high linearity with antibacterial activity. We established a monoclonal antibody to leptosperin and characterized the antibody in detail by a competitive enzyme-linked immunosorbent assay (ELISA), comparing the results with those of the high-performance liquid chromatography (HPLC) method for validation. The antigen in manuka honey was confirmed as leptosperin by HPLC fractionation with quantitation by an ELISA. Leptosperin contents of 50 honey samples were analyzed by an established ELISA, which can handle 20 samples (duplicate) on one 96-well plate. Significant coincidence with the chemical quantitation was observed. Immunochemical quantitation of leptosperin would be an economical and facile method for the possible authentication of manuka honey, allowing many honey samples to be processed and analyzed by an ELISA simultaneously.

Plausible authentication of manuka honey and related products by measuring leptosperin with methyl syringate.

Manuka honey, obtained from Leptospermum scoparium flowers in New Zealand, has strong antibacterial properties. In this study, plausible authentication of the manuka honey was inspected by measuring leptosperin, methyl syringate 4-O-ß-D-gentiobiose, along with methyl syringate. Despite a gradual decrease in methyl syringate content over 30 days at 50 °C, even at moderate 37 °C, leptosperin remained stable. A considerable correlation between nonperoxide antibacterial activity and leptosperin content was observed in 20 certified manuka honey samples. Leptosperin and methyl syringate in manuka honey and related products were analyzed using HPLC connected with mass spectrometry. One noncertified brand displayed significant variations in the leptosperin and methyl syringate contents between two samples obtained from different regions. Therefore, certification is clearly required to protect consumers from disguised and/or low-quality honey. Because leptosperin is stable during storage and specific to manuka honey, its measurement may be applicable for manuka honey authentication.

Low-cost and easy-to-use "on-chip ELISA" for developing health-promoting foods.

We have determined that a biological molecule can be physically immobilized on a polymer containing an azobenzene (azopolymer) using irradiating light. We immobilized antibodies and antigens on the surface of an azopolymer coated glass slide (antibody array) to establish "on-chip ELISAs". The assays used the flat-surface of a glass slide and could be applied to both sandwich and competitive ELISAs. The sensitivity and accuracy of the on-chip ELISA were similar to a conventional ELISA using a polystyrene plate. Using the assay system, we proved that representative oxidative-biomarkers could be simultaneously measured from uL of urine. That should realize low-cost study on animal or human, and accelerate development of health-promoting foods. So, this new concept antibody array has promising applications in proteomic studies, and could be used to examine biomarkers to investigate health-promoting food.