Abstract: Aiming to determine the contents of nutrients and active ingredients of mulberry leaves in Ankang City, and promote their development and utilization, 24 mulberry varieties were subjected as the research object, the contents of 11 indicators including nutritional components, medicinal components, and mineral elements in the up- and mid- position leaves were measured, the quality of mulberry leaves was comprehensively evaluated using principal component analysis, and the correlation between the quality indexes of mulberry leaves of different varieties was also analyzed. The results showed that nutritional and bioactive substances in 24 kinds of mulberry leaves presented a certain extent of differences. Using the coefficient of variation to calculate the dispersion of each component, the results showed that the coefficient of variation of selenium content was the maximum in varieties of mulberry, representing that different varieties of mulberry had significant differences in selenium accumulation ability. The cumulative contribution rate of the four principal components extracted from up- and mid-mulberry leaves was 76.551% and 78.114%, respectively, which was used to calculate the comprehensive score of mulberry leaf quality. The results showed that the up-leaves of Luyou 7, Jinshi and Hongguo 2, or mid-leaves of Fengtian 2, 711 and Luyou 7 had relatively high scores. Correlation analysis showed that various physical and chemical indicators in up- and mid-leaves had different correlation scores.

Key words: mulberry, nutritional composition, medicinal components, selenium content, principal component analysis