Metabolomic characteristics and anthraquinones accumulation patterns of Rhubarb in different tissues and roots from different developmental stages

Abstract

Rhubarb’s multifaceted value in culinary and medicine is renowned, especially Rheum tanguticum (Rhubarb), whose bountiful content of anthraquinones (AQs) makes it increasingly attractive in the realms of dietary supplements and natural edible pigments. Current understanding of the spatiotemporal dynamics of AQs accumulation in Rhubarb remains limited, and the knowledge of other valuable metabolites is even more scarce. This gap limits the ability to fully explore Rhubarb's potential as a food ingredient and hinders its efficient use in food development, potentially leading to unnecessary resource waste. This study integrated widely targeted metabolomics and AQs quantification to determine the metabolic profiles in four tissues and the roots at three developmental stages in Rhubarb. The high levels of malic and citric acids in the stems paved the way for their use in flavored beverages and substantiated the practice of traditional consumption. The abundance of flavonoids in the leaves and seeds, and the AQs, phenolic acids of the seeds, which potentially bestowed upon them exceptional antioxidant capabilities, underscore the significant potential of edible product development. The widespread traditional use of roots was mirrored by the preferential accumulation of AQs, and the roots' value escalated in tandem with the time-accumulated increase of AQs. The root bark and root tip with high AQs should be given attention in production and not simply discarded. This research clarifies the chemical composition and spatiotemporal variation patterns of Rhubarb’s characteristic components, offering valuable scientific insights for their efficient use and value enhancement in the food industry.