Polyphenol and Anthocyanin Composition and Activity of Highland Barley with Different Colors

Abstract

In this research, the composition of free phenols, bound phenols, and anthocyanins and their in vitro antioxidant activity and in vitro α-glucosidase inhibiting activity were observed in different barley colors. The outcomes revealed that the contents of total phenols (570.78 mg/100 gDW), total flavonoids (47.08 mg/100 gDW), and anthocyanins (48.07 mg/100 g) were the highest in purple barley. Furthermore, the structure, composition, and concentration of phenolics differed depending on the colors of barley. The types and contents of bound total phenolic acids and flavonoids were greater than those of free total phenolic acids and flavonoids. The main phenolic acids in blue barley were cinnamic acid polyphenols, whereas in black, yellow, and purple barley, benzoic acid polyphenols were the main phenolic acids, and the main types of flavonoids in black and blue barley were chalcones and flavanones, respectively, whereas flavonol was the main type of flavonoid in yellow and purple barley. Moreover, cornflower pigment-3-glucoside was the major anthocyanin in blue, yellow, and purple barley, whereas the main anthocyanin in black barley was delphinidin-3-glucoside. The dark color of barley indicated richness in the anthocyanins. In addition, the free polyphenol fractions had stronger DPPH and ABTS radical scavenging capacity as compared to the bound ones. In vitro α-glucosidase-inhibiting activity was greater in bound polyphenols than in free polyphenols, with differences between different varieties of barley. Purple barley phenolic fractions had the greatest ABTS radical scavenging and iron ion reduction capacities, as well as the highest α-glucosidase-inhibiting activity. The strongest DPPH radical scavenging capacity was found in yellow barley, while the strongest in vitro α-glucosidase-inhibiting activity was found in anthocyanins isolated from black barley. Furthermore, in different colors of barley, there was a strong association between the concentration of specific phenolic compounds and antioxidant and α-glucosidase-inhibiting activities. The outcomes of this study revealed that all colored barley seeds tested were high in phenolic compounds, and had a good antioxidant impact and α-glucosidase-inhibiting activity. As a result, colored barley can serve as an antioxidant and hypoglycemic food. Polyphenols extracted from purple barley and anthocyanins extracted from black barley stand out among them.

Phenolic Profile and Antioxidant, Anti-Inflammatory Activity of <i>Annona senegalensis, Ipomoea batatas, Terminalia superba</i> and <i>Psidium guajava</i> Linn Extracts Used in Benin

“…In fact, the phytochemical screening and HPLC analysis make by Kengni revealed the presence of several phenolic compounds including phenol (o/p-coumaric acid; syringic acid), anthocyanins, tannins, and flavonoids (vanillic acid) [29]. These different compounds are known for their strong antioxidant activity [31].…”

Polyphenol Profile and In Vitro Antioxidant and Enzyme Inhibitory Activities of Different Solvent Extracts of Highland Barley Bran

“…Active compounds from plant extracts are shown to be potent α-glucosidase and α-amylase inhibitors [ 10 , 37 ]. Polyphenol compounds have an inhibitory activity in plant extracts [ 12 , 38 ]. The inhibition rate of α-glucosidase from bound phenol was greater than that of free phenol in highland barley with different grain colors.…”

“…Moreover, differences were observed between different highland barley varieties, with the polyphenol extract from purple highland barley and the anthocyanin extract from the black highland barley having the strongest α-glucosidase inhibitory activity. Furthermore, a strong relationship was observed between specific polyphenol compounds and α-glucosidase activity [ 12 ]. Among various phenolic compounds, ferulic acid and catechin have been proven to possess obvious inhibitory activity toward α-glucosidase and α-amylase via specific action sites, such as Arg 407 , Asp 326 , Arg 197 residues, etc., in α-glucosidase and Asp 197 , Glu 233 , Asp 300 residues, etc., in α-amylase [ 39 ].…”

“…The correlation coefficients between benzoic acid content and α-glucosidase and α-amylase inhibition rate were 0.730 and 0.828, respectively, indicating that benzoic acid might be the main contributor to the extract’s enzyme inhibitory ability. Jin et al discovered compounds in polyphenol extracts of colored-grain highland barley, such as o -coumaric acid, vanillic acid, pelargonidin-3-glucoside, and petunidin, which were closely correlated to α-glucosidase inhibitory activity [ 12 ]. Verbascoside has been shown to be a major contributor to α-amylase inhibitory activity in Symphytum anatolicum solvent extracts [ 9 ].…”

“…Polyphenols, a class of aromatic hydroxy derivatives, have strong antioxidant activity and can inhibit free radical-induced polymerization chain reactions. They are natural, efficient, safe, low-cost antioxidants and enzyme inhibitors compared to synthetic antioxidants, ideal for naturally preventing and improving these diseases [ 12 , 13 ]. Polyphenol compounds (such as flavonoids, anthocyanins, and phenolic acids, among others) in highland barley are primarily concentrated in the bran portion, providing exceptional biological activity and the potential to be used as an excellent dietary polyphenol supplement, with increasing interest in functional food development [ 14 , 15 , 16 ].…”