Barley (Hordeum vulgare L.) is the fourth most important cereal crop in the world and has the highest dietary fiber content; its malt for functional food is not only the world’s largest material for beer, but also often used as one of 300 species being used in Chinese herbal medicine. Regular consumption of whole grain barley and its hydroalcoholic extract reduces the risk of chronic diseases (diabetes, cancer, obesity, cardiovascular disease, etc.), based on phytochemicals including β-glucan, phenolic acids, flavonoids, lignans, tocols, phytosterols, and folate [1, 2]. Barley with preventive inflammatory and cardiovascular diseases has exhibited activities against all human platelet agonists inhibited both cyclooxygenase and lipoxygenase pathways of arachidonic acid metabolism, which elevated the SOD and GSH-Px activities .
Barley with cold and frost tolerance of growing at 4000 m is a key for ancient Tibetans climb to 3400 m ; Tibetan Plateau is an important origin and domestication base of cultivated barley . Human Flt3 ligand from barley is a glycoprotein including α(1,3)-fucose and α(1,2)-xylose, which showed expression of human growth factor in barley grains with active protein . The amino acid concentration in barley grass irradiated by artificial light (red 9 + blue 1) is greater than that by natural light, which can increase γ-tocopherol by 100% red light , but cyanogenic glucosides content is 4% less than that by sunlight . The accumulation of lutonarin (isoorientin-7-O-glucoside) and 3-feruloylquinic acid (C17H20O9) and xanthophyll-cycle pigments is greatly increased by high photosynthetically active radiation and ultraviolet exposure in barley leaves . Chronic disease of human beings is associated with the five evolutionary stages of the major dietary guidelines (i.e., the healthiest major dietary guidelines for modern humans): fruits or vegetables, grass or Cyperaceou, cereals (rice, wheat, millet, beans, barley, and corn), polished rice or wheat flour, and white rice or wheat flour + grass powder .
Barley grass (BG) has young green leaves and stem of vegetative growth stage from seedling at 10 days after sprouting (barley sprout) to elongation stage (barley green) for nutritional peak before the start of reproductive cycle of barley [11–13]; however, Vrs2 is associated with floral architecture by regulating hormonal homeostasis and gradients in barley . BG is not only consumed as a popular green-colored drink , but also used in preventive chronic diseases, especially circulatory disorders, anticancer, reducing obesity, antidiabetes, anti-arthritis, reducing cholesterol, antioxidant, and anti-inflammation . Light can promote cytokinin degradation and the formation of bioactive cytokinins in barley leaves, which has a positive correlation between cytokinin oxidase/dehydrogenase activity and senescence in most cases . The amino acid and vitamin C content in hydroponic BG are higher than those in organic soil . In spray-dried barley grass powder with good solubility and small size, its contents of the chlorophyll, flavonoids, and SOD enzyme activity are 56.7%, 68.1%, and 47.9% of vacuum freeze-dried powder with high nutrition and good color, respectively . Although BG has played an important role in human health, coevolution and functional ingredients as well as major mechanism in therapeutic role between preventive chronic diseases and young barley grass for functional foods of human beings are unclear.