Megumi Hamano Nagaoka

Dietary unripe apple polyphenol inhibits the development of food allergies in murine models

The incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. We first showed that apple condensed tannin (ACT) intake would inhibit the development of the oral sensitization and that the inhibition could correlate with the rise in the population of TCRγδ‐T cells in the intestinal intraepithelial lymphocytes (IEL) using W/WV mice and B10A mice which were ovalbumin (OVA)‐orally sensitized. Serum OVA‐specific immunoglobulin E and immunoglobulin G1 titers in the OVA‐orally sensitized W/WV and B10A mice ad libitium fed ACT were extremely inhibited compared to those of the control. The ACT intakes of OVA‐sensitized W/WV and B10A mice inhibited the immediate reduction of the body temperature or the rise in serum histamine induced by active systemic anaphylaxis. The proportions of the TCRγδ‐T cells in the IEL of the OVA‐orally sensitized W/WV and B10A mice ad libitium fed ACT were significantly greater than that in the controls. Furthermore, ACT feeding by itself could induce the rise in the percentage of the TCRγδ‐T cells among the IEL of the W/WV and B10A mice. This suggests that the ACT intake may prevent the development of food allergies and this effect could be correlated with the rise in the percentage of TCRγδ‐T cells among the IEL.

Determination of genotoxic phenylhydrazine agaritine in mushrooms using liquid chromatography–electrospray ionization tandem mass spectrometry

A new method with good sensitivity and specificity for detecting and quantifying genotoxic hydrazines, agaritine and 4-(hydroxymethyl)phenylhydrazine (HMPH), was developed using liquid chromatography–electrospray tandem mass spectrometry (MS). Synthetic agaritine and HMPH were structurally assigned by 1H-, 13C- and two-dimensional nuclear magnetic resonance (NMR) analysis (HMBC and HMQC), high-resolution fast-atom bombardment (HR-FAB) MS and time of flight (TOF) MS. The polar molecule agaritine was separated on an ODS column using 0.01% AcOH–MeOH (99:1, v/v) as an eluent with a simple solid-phase extraction cleanup. There were no interference peaks for any of the mushrooms. Agaricus spp. contained 1247 and 2017 µg g−1 agaritine. Other species of mushroom had no agaritine. Recoveries of agaritine from spiked mushroom samples were 60.3–114%. Intra-day precision values were 5.5 and 4.2%, and the inter-day precision values were acceptable (15.0 and 23.0%), as agaritine is unstable. The limit of quantification was 0.003 µg g−1. Even a trace amount of agaritine in mushrooms can, therefore, be determined using this method. We also directly analysed HMPH, an active free hydrazine form of genotoxic agaritine, and obtained direct evidence of its absence from mushrooms. A precursor ion scan confirmed that agaritine derivatives, which could exert similar toxicity, were absent. The results indicate that this specific and sensitive analytical method for detecting and quantifying agaritine and its derivatives could help evaluate the risk of mushroom hydrazines to humans.