Correlations of Molecular Weights of ß-Glucans from Qingke (Tibetan Hulless Barley) to Their Multiple Bioactivities.

ß-glucans have been considered the major bioactive components in Qingke (Tibetan hulless barley). However, the structure⁻function relationships of ß-glucans from Qingke have seldom been investigated. Whether the bioactivities of Qingke ß-glucans are closely correlated to their molecular weights remains unknown. Therefore, in order to explore Qingke ß-glucans as functional/healthy food ingredients for industrial applications, and to better understand their structure⁻function relationships, correlations of molecular weights of Qingke ß-glucans to their in vitro binding properties, inhibitory activities on digestive enzymes (α-amylase and pancreatic lipase), anti-inflammatory activities, and anticancer activities were systematically investigated. Results showed that the in vitro binding properties and the inhibitory activities on α-amylase and pancreatic lipase of Qingke ß-glucans were positively correlated to their molecular weights. However, the anti-inflammatory activities of Qingke ß-glucans increased as their molecular weights decreased. Furthermore, Qingke ß-glucans exhibited selectively anti-cancer activities in vitro. Positive and negative correlations of molecular weights to inhibitory effects against A549 cells and MDA-MB-231 cells were observed, respectively. However, the inhibitory effects of Qingke ß-glucans against HCT116 cells were not associated with their molecular weights. Results suggested that the molecular weights of Qingke ß-glucans significantly affected their bioactivities, which was beneficial for a better understanding of their structure⁻function relationships. Moreover, results showed that Qingke ß-glucans could be further explored as functional/healthy food ingredients for industrial applications due to their multiple health benefits.

Characterization, in vitro binding properties, and inhibitory activity on pancreatic lipase of ß-glucans from different Qingke (Tibetan hulless barley) cultivars.

In order to explore Qingke ß-glucans as functional food ingredients for prevention of obesity, the physicochemical structures, in vitro binding properties, and inhibitory activities on pancreatic lipase of ß-glucans from three different Qingke cultivars, including Ganyucang (black), Dingqing (blue), and Zangqing 320 (white), were investigated and compared. Results showed that molecular weights, particle sizes, and intrinsic viscosities of ß-glucans from colored (black and blue) Qingke cultivars were much higher than those of white Qingke ß-glucans, respectively. In addition, the constituent monosaccharides of ß-glucans from colored Qingke cultivars were determined as arabinose, xylose, glucose, and galactose, and glucose was the dominant monosaccharide. Furthermore, colored Qingke ß-glucans exerted strong fat binding, cholesterol binding, and bile-acid binding capacities, as well as inhibitory activities on pancreatic lipase, which were much higher than those of white Qingke ß-glucans. Indeed, the fat binding, cholesterol binding, and bile-acid binding capacities, as well as the inhibitory activities on pancreatic lipase of Qingke ß-glucans were positively associated with their molecular weights and intrinsic viscosities. Results are beneficial for better understanding of the structure-function relationship of Qingke ß-glucans, and ß-glucans from colored Qingke cultivars (Ganyucang and Dingqing) could be further explored as functional food ingredients for prevention of obesity.