Composition of Flavonoids and Nutritional Evaluation in Leaves of Different Sea-Buckthorn Germplasm Resources

Sea-buckthorn leaves contain various active components, and research, development, and utilization of sea-buckthorn leaves have broad application prospects in the fields of food, medicine, and feed. The comprehensive quality of different sea-buckthorn germplasm resources was evaluated by determining 17 major nutrients, such as flavone composition, polysaccharides, total flavonoids, total polyphenols, and so on in 26 different varieties of sea buckthorn leaves, and then the comprehensive quality of different sea-buckthorn germplasm resources was evaluated by factor analysis, principal component analysis, and cluster analysis. The results showed that flavonols, mainly quercetin-like flavonols and isorhamnetin-like flavonols, were detected in the leaves of 26 sea-buckthorns. Through comprehensive analysis of its nutritional quality, it was found that the leaves of sea-buckthorn germplasm resources had highly significant genetic differences and germplasm diversity, and the total polyphenol content, polysaccharide content, VC content, total flavonoids content, and crude fat content of sea-buckthorn leaves were comparable to those of some commercially available high-quality famous teas. The higher crude protein content in the leaves of 'S1', the higher crude fiber content in the leaves of 'S4' and 'S13'. The higher crude fat content in the leaves of 'S8' and the relatively higher polysaccharide content in the leaves of 'S4', 'S22', 'S5', 'S18' and 'S7' suggest to a certain extent that the leaves of these sea-buckthorn lines seem to serve as a botanical resource for the extraction of sea-buckthorn crude protein, crude fiber, crude fat, and polysaccharide, respectively. The contents of flavonoids in 'S21' and 'S24' leaves were relatively high, and the contents of total polyphenols in 'S1', 'S8' and 'S21' were relatively high, suggesting that these sea buckthorns could be used as plant resources for extracting flavonoids and total polyphenols from sea buckthorns to a certain extent. Factor analysis and principal component analysis showed that 'S3', 'S16', and 'S10' leaves had the highest comprehensive ranking. The results of this study laid a good foundation for the screening of sea buckthorn germplasm resources and the breeding, processing, and utilization of new varieties of sea-buckthorn leaves.