Hull-Less Barley ( <i>Hordeum vulgare</i> L. var. <i>nudum</i> Hook. f.): A Review of Its Phytochemistry, Bioactivities, Pharmacology and Applications

Hull-less Barley (HB) is a staple crop cultivated on the Tibetan Plateau with a history of over 3500 years. It contains abundant nutrients and active components, including dietary fiber, proteins, starch, polyphenols, and γ-aminobutyric acid, exhibiting diverse physiological activities including immunomodulatory, antioxidant, and antidiabetic properties. Among these, β-glucan and polyphenols are the most valuable bioactive components, contributing to the three most prominent functions of HB: hypoglycemic, lipid-lowering, and antioxidant activities. Nowadays, the application of HB in developing novel value-added products has been impeded by the incomplete understanding of its phytochemistry, bioactivity, and pharmacology. In light of the potential benefits of HB, we systematically summarized up-to-date information on the nutrients and functional active ingredients in HB and focused on introducing their pharmacological characteristics as well as the specific biological effects. This review will promote the comprehensive utilization of HB to develop healthcare products to support the improvement of human well-being.