Differences in the flavonoid composition of the leaves, fruits, and branches of mulberry are distinguished based on a plant metabolomics approach

Abstract

Mulberry is a common crop rich in flavonoids, and its leaves (ML), fruits (M), and branches (Ramulus Mori, RM) have medicinal value. In the present study, a total of 118 flavonoid metabolites (47 flavone, 23 flavonol, 16 flavonoid, 8 anthocyanins, 8 isoflavone, 14 flavanone, and 2 proanthocyanidins) and 12 polyphenols were identified by ultra-performance liquid chromatography–electrospray ionization-tandem mass spectrometry. The most abundant in ML were 8- C-hexosyl-hesperetin O-hexoside and astragalin, the most abundant in M were 8- C-hexosyl-hesperetin O-hexoside and naringenin, and the most abundant in RM were cyanidin 3- O-galactoside and gallocatechin–gallocatechin. The total flavonoid compositions of ML and RM were essentially the same, but the contents of flavonoid metabolite in more than half of them were higher than those in M. Compared with ML, the contents of flavone and flavonoid in RM and M were generally down-regulated. Each tissue part had a unique flavonoid, which could be used as a marker to distinguish different tissue parts. In this study, the differences between flavonoid metabolite among RM, ML, and M were studied, which provided a theoretical basis for making full use of mulberry resources.