Profile of non-volatiles in whisky with regard to superoxide dismutase activity.

SOD (Superoxide dismutase)-like activities of 23 kinds of single malt whisky (Scotch and Japanese) were evaluated. There was a positive correlation between SOD-like activity and the maturation age of whisky that exceeded the difference resulting from the manufacturing region. The SOD-like activity of Yamazaki 18, a typical single malt whisky in Japan, was approximately 1333 U/ml and that of non-volatile components in the whisky was 388U/mg, indicating that single malt whisky generally has a very strong SOD-like activity. To elucidate their contribution to SOD-like activity, the non-volatile components of whisky (Yamazaki 18) were ultrafiltered and separated with a Diaion HP20/water-EtOH system. Elution of the fraction less than 5000 molecular weight (<5000 MW fraction) with 60% (v/v) EtOH contributed most to SOD-like activity of the whisky. As this elution contained a considerable amount of polyphenolics, the content and SOD-like specific activity of ellagic acid, gallic acid, and lyoniresinol--the main whisky polyphenolics--were evaluated. The contribution of these compounds to the SOD-like activity of whisky was approximately 15%. Polyphenolics in whisky were relatively distributed to a higher MW fraction compared to carbohydrates in whisky, and specific activity (SOD-like activity per weight) of the >10,000 MW fraction was greater than that of the <5000 MW fraction, although the content of this fraction was low. These results indicate that various polyphenolics with higher molecular weights also contribute to the SOD-like activity of whisky together with main whisky polyphenolics.

Induction of heme oxygenase-1 by whisky congeners in human endothelial cells.

It is expected that the production of the cytoprotective heme oxygenase-1 (HO-1) protein in endothelial cells would reduce severity of vascular injuries, while phenolic compounds are known to induce HO-1 mRNA and protein in various cells. We investigated the activation of HO-1 by whisky, which contains various phenolic substances. The congeners of whisky stored from 4 to 18 y in oak barrels were shown to induce an increase of HO-1 protein in human umbilical vein endothelial cells, while those of freshly distilled whisky spirit exhibited no activity. To determine the compounds with potent HO-1-inducing activity among the whisky congeners, several chemicals that had been reported to exist in whisky or oak barrels were screened, and coniferyl aldehyde and sinapyl aldehyde showed the activity. Thus, compounds that emerged in whisky during barrel storage induced cytoprotective protein, HO-1, in human endothelial cells.

Inhibitory effects of whisky congeners on IgE-mediated degranulation in rat basophilic leukemia RBL-2H3 cells and passive cutaneous anaphylaxis reaction in mice.

Whisky is matured in oak casks. Many nonvolatile substances (whisky congeners, WC) seep from the oak cask during the maturing process. In this study, three antiallergic agents (syringaldehyde, SA; lyoniresinol, Lyo; and ellagic acid, EA) were isolated from WC. Treatment with SA, Lyo, and EA reduced the elevation of intracellular free Ca(2+) concentration ([Ca(2+)]i) and intracellular ROS production caused by FcepsilonRI activation. The inhibitions of the elevation of [Ca(2+)]i and intracellular ROS production by SA and Lyo were mainly due to the suppression of the NADPH oxidase activity and scavenging of the produced radical, respectively. On the other hand, EA inactivated spleen tyrosine kinase and led to the inhibition of the elevation of [Ca(2+)]i and intracellular ROS production. Furthermore, it was found that WC strongly inhibited IgE binding to the FcepsilonRIalpha chain, whereas SA, Lyo, and EA did not indicate this inhibitory effect. These results suggest that WC inhibits allergic reactions through multiple mechanisms. To disclose the in vivo effects of WC, SA, Lyo, and EA, these compounds were administered to type I allergic model mice, and the passive cutaneous anaphylaxis (PCA) reaction was measured. These compounds remarkably suppressed the PCA reaction. Taken together, these findings suggest that WC seemed to be beneficial to ameliorate allergic reactions.

Isolation and structure of whiskey polyphenols produced by oxidation of oak wood ellagitannins.

Three new phenolic compounds named whiskey tannins A and B and carboxyl ellagic acid were isolated from commercial Japanese whiskey, along with gallic acid, ellagic acid, brevifolin carboxylic acid, three galloyl glucoses, a galloyl ester of phenolic glucoside, 2,3-(S)-hexahydroxydiphenoylglucose, and castacrenin B. Whiskey tannins A and B were oxidation products of a major oak wood ellagitannin, castalagin, in which the pyrogallol ring at the glucose C-1 position of castalagin was oxidized to a cyclopentenone moiety. These tannins originated from ellagitannins contained in the oak wood used for barrel production; however, the original oak wood ellagitannins were not detected in the whiskey. To examine whether the whiskey tannins were produced during the charring process of barrel production, pyrolysis products of castalagin were investigated. Dehydrocastalagin and a new phenolcarboxylic acid trislactone having an isocoumarin structure were isolated, along with castacrenin F and ellagic acid. However, whiskey tannins were not detected in the products.

Inhibitory effects of whisky congeners on melanogenesis in mouse B16 melanoma cells.

We examined the effect of whisky congeners, substances other than ethanol in whisky, on melanogenesis in mouse B16 melanoma cells. Treatment with whisky congeners significantly blocked melanogenesis. Our results indicate that the inhibitory effects of whisky congeners on melanogenesis is due to direct inhibition of tyrosinase activity and to suppression of tyrosinase protein levels.