The variability of terpenoids and flavonoids in native Lindera umbellata from the same region

Abstract

The leaves and twigs of Lindera spp. have long been used as a herbal medicine and toothpicks in Japan. However, little is known about individual variations in the extractives of these species, because many previous studies have not distinguished extractives between individuals. In this study, we investigated the extractives of L. umbellata at the individual level. The detailed identification of the inter- and intra-individual variations in the major terpenoids and flavonoids in native L. umbellata may greatly contribute to the development of cultivation techniques and the effective use of forest resources. The contents of major components of L. umbellata, including four terpenoids (1,8-cineole, linalool, geraniol, and geranyl acetate) and five low-molecular-weight phenolics (pinocembrin chalcone, pinocembrin, pinostrobin chalcone, pinostrobin, and 5,6-dehydrokawain), were analyzed in leaves and twigs seasonally (June, August, and October). The compositions of the major terpenoids were strongly dependent on the properties of each individual and were generally independent of leaves and twigs. Moreover, geranyl acetate was characteristically present in the twigs of some individuals. As new findings regarding linalool, some individuals showed characteristic enantiomeric excesses, presumably because of biotic factors, and the proportion of these enantiomers was kept constant in each individual, regardless of the season. The total phenolic contents in leaves were more than twice those detected in twigs, and the leaves tended to contain more chalcones and twigs more flavanones. Furthermore, the contents of chalcones (pinocembrin chalcone vs. pinostrobin chalcone) and flavanones (pinocembrin vs. pinostrobin) were positively correlated in both leaves and twigs. The coefficient of variation (CV) clearly showed that the content of the major terpenoids was determined by inter-individual rather than intra-individual differences. Although the results obtained in this study should at present only be applicable to a limited population native to specific regions, our findings provide key knowledge in considering the sustainable use of L. umbellata.