Roasted barley extract or mugi-cha is a popular caffeine-free traditional drink in Japan.
This slightly bitter beverage is consumed by Japanese children, infants and adults.
The roasting process of barley extract produces a cyclic peptide 2,5-Diketopyperazine.
A clinical trial was recently designed and completed by a research group out of Japan to determine if barley extract can improve blood flow to the skin.
In traditional Chinese medicine cold sensation (hiesho) is know as blood stasis (oketsu).
Cold sensation is caused by an imbalance of the autonomic nerve system, which causes vasoconstriction and lowers cutaneous blood flow.
Blood flow plays a role in controlling the body temperature.
Thus, decreased skin temperature leads to a decline in cutaneous blood flow.
It is believed to decrease the quality of life and can be related to various vascular disease including high blod pressure and atherosclerosis.
The results were published in the journal of Food and Agricultural Chemistry.
Here are the details of the study
– Fifteen participants were enrolled in the study.
– The human subjects consumed roasted barley extract on the day of the study as a single dose.
– RBE was prepared as follows: roasted barley (100 grams) was added to boiling water (1000 grams), steeped for 30 min, and diluted with 4000 grams of water.
– RBE was divided into aliquots of 250 g.
– The RBE drink contained 250 μg of cyclo(d-Phe-l-Pro)/250 mL bottle.
– To induce cold sensation in the test subjects the rooms were set to a cold temperature and subjects were were not allowed to wear heavy clothing. Skin temperature and blood flow was then measured.
Here are the main results
– Roasted barley extract containing cyclo (d-Phe-l-Pro) prevents lowering of cutaneous blood flow and skin temperature under air conditioning.
– The change in cutaneous blood flow in the roasted barley extract −0.79 ± 0.38 ml/min/100 grams and in the placebo group was −2.03 ± 0.35 ml/min/100 grams. *
– The change in the skin temperature in the roasted barley extract was −1.85 ± 0.35 and the placebo group was −3.02 ± 0.30 °C. *
*Difference between barley extract and placebo was statistically significant.
Here are the comments by the authors of the study
Thus, RBE containing cyclo(d-Phe-l-Pro) prevents the decrease in the cutaneous blood flow and skin temperature under air conditioning.
Take away message
In traditional Chinese medicine rapid changes in air temperature such as walking in from the heat to a cold air-conditioned building is a risk factor for disease. This study was able to show that a single dose of roasted barley extract was able to prevent changes in blood flow to the skin and skin temperature changes caused by air conditioning.
One of the active ingredients in roasted barley extract is believed to be cyclic peptide 2,5-Diketopyperazine.
Reference:
Ashigai et al. Roasted Barley Extract (Mugi-cha) Containing Cyclo(d-Phe-l-Pro) Prevents Lowering of the Cutaneous Blood Flow and Skin Temperature under Air Conditioning: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study. Journal of Agricultural and Food Chemistry. 2018, Volume 66 (Issue 23), pages 5901 to 5906
His research on plant medicine has led to more than 45 publications and abstracts.This research has been presented at international meetings in the USA, France, Turkey, Peru, Israel, Austria, and Italy.
Categories: Clinical Trials, Plant Medicine, Skin