Hordenine

Food Chem. 2013 Nov 1;141(1):174-81.

Hordenine, a single compound produced during barley germination, inhibits melanogenesis in human melanocytes.[Pubmed: 23768344]

Melanin plays an important role protecting skin against ultraviolet light injury. However, increased production and accumulation of melanin results in a large number of skin disorders.
METHODS AND RESULTS:
Here, we identified Hordenine as an active compound from germinated barley (Hordeum vulgare L.) and investigated the effects of Hordenine on melanogenesis and its mechanisms of action in human epidermal melanocytes. We measured melanin content, tyrosinase activity, expression of melanogenesis-related proteins, and cAMP production. Melanin content was significantly inhibited by Hordenine. The intracellular cAMP level was also reduced by Hordenine. In addition, expression of microphthalmia-associated transcription factor (MITF), an upstream transcription factor of tyrosinase as well as tyrosinase, tyrosinase related protein (TRP)-1, and TRP-2, was inhibited by Hordenine.
CONCLUSIONS:
Taken together, these results show that Hordenine inhibited melanogenesis by suppressing cAMP production, which is involved in the expression of melanogenesis-related proteins and suggest that Hordenine may be an effective inhibitor of hyperpigmentation.

Dtsch Tierarztl Wochenschr. 1995 Jun;102(6):228-32.

[Pharmacological effects of hordenine].[Pubmed: 8582256]

Hordenine is an ingredient of some plants which are used as feed for animals, i.e. in sprouting barley. After ingestion of such feed Hordenine may be detected in blood or urine of horses which in case of racing horses may be the facts of using prohibited compounds.
METHODS AND RESULTS:
Results of some experiments in pharmacological models show that Hordenine is an indirectly acting adrenergic drug. It liberates norepinephrine from stores. In isolated organs and those structures with reduced epinephrine contents the Hordenine-effect is only very poor. Experiments in intact animals (rats, dogs) show that Hordenine has a positive inotropic effect upon the heart, increases systolic and diastolic blood pressure, peripheral blood flow volume, inhibits gut movements but has no effect upon the psychomotorical behaviour of mice.
CONCLUSIONS:
All effects are short and only possible after high doses which are not to be expected after ingestion of Hordenine containing feed for horses. A measurable increase of the performance of racing horses is quite improbable.

J Pharm Pharmacol. 1989 Jun;41(6):421-3.

Deamination of hordenine by monoamine oxidase and its action on vasa deferentia of the rat.[Pubmed: 2570842]

The selectivity of the naturally occurring amine, N,N-dimethyltyramine (Hordenine) for monoamine oxidase (MAO) and its action upon isolated vasa deferentia of the rat was investigated.
METHODS AND RESULTS:
Hordenine was deaminated by rat liver MAO with a Michaelis constant of 479 microM and maximum velocity of 128 nmol (mg protein)-1 h-1 compared with 144 microM and 482 nmol (mg protein)-1 h-1 for tyramine. Studies, with selective irreversible inhibitors of MAO, showed that Hordenine was a highly selective substrate for MAO-B of liver and that it was not deaminated by the MAO-A of intestinal epithelium. In contrast to tyramine, Hordenine did not produce contractions of isolated vasa deferentia. However, 25 microM Hordenine potentiated contractile responses of vasa, from control animals, to submaximal doses of noradrenaline and inhibited responses to tyramine. It did not alter responses, to noradrenaline, of vasa denervated by chronic pretreatment of rats with guanethidine. Therefore, it appears that Hordenine acted as an inhibitor of noradrenaline uptake, in isolated vasa deferentia. These results indicate that dietary-Hordenine is unlikely to be deaminated by intestinal MAO as this is predominantly MAO-A.
CONCLUSIONS:
Consequently, it is likely to be absorbed and could affect the sympathetic nervous system, by virtue of its action as an inhibitor of noradrenaline uptake.

Biomed Chromatogr. 2014 Oct 30.

Selective extraction based on poly(MAA-VB-EGMDA) monolith followed by HPLC for determination of hordenine in plasma and urine samples.[Pubmed: 25355709]

Hordenine is an active compound found in several foods, herbs and beer.
METHODS AND RESULTS:
In this work, a novel sorbent was fabricated for selective solid-phase extraction (SPE) of Hordenine in biological samples. The organic polymer sorbent was synthesized in one step in the plastic barrel of a syringe by a pre-polymerization solution consisting of methacrylic acid (MAA), 4-vinylphenylboronic acid (VB) and ethylene glycol dimethacrylate (EGDMA). The conditions for preparation were optimized to generate a poly(MAA-VB-EGMDA) monolith with good permeability. The monolith exhibited good enrichment efficiency towards Hordenine. By using tyramine as the internal standard, a poly(MAA-VB-EGMDA)-based SPE-HPLC method was established for analysis of Hordenine. Conditions for SPE, including volume of eluting solvent, pH of sample solution, sampling rate and sample volume, were optimized. The proposed SPE-HPLC method presented good linearity (R2  = 0.9992) within 10-2000 ng/mL and the detection limits was 3 ng/mL, which is significantly more sensitive than reported methods.
CONCLUSIONS:
The method was also applied in plasma and urine samples; good capability of removing matrices was observed, while Hordenine in low content was well extracted and enriched. The recoveries were from 90.6 to 94.7% and from 89.3 to 91.5% for the spiked plasma and urine samples, respectively, with the relative standard deviations <4.7%.