Establishment of a rapid method to quantify eight flavonol glycosides for quality assessment of red toon using UPLC

Abstract

Red Toon is a popular vegetable of favorable health benefits over Asia and Russia regions. In this study, isolation and identification of chemical constituents were performed to assess the quality of this functional food cultivated in various origins or harvested in different months. As a result, eight flavonol glycosides including rutin (I), myricitrin (II), quercetin-3-O-β-d-galactoranoside (III), quercetin-3-O-β-d-glucopyranose (IV), quercetin-3-O-α-l-arabinopyranoside (V), astragalin (VI), quercetin-3-O-α-l-rhamopyranoside (VII), and kaempferol-3-O-α-l-rhamopyranoside (VIII) were obtained. Among these, compounds III and V were isolated from Toona genus for the first time. Importantly, a rapid and convenient ultra-performance liquid chromatography (UPLC) method was developed to quantify the flavonol glycosides in Red Toon and validated for linearity, precision, stability, repeatability, and accuracy successively. In addition, it was found that total flavonoid glycosides (about 2.6%) in the food were kept at a higher level from April to June than other months of the year. Furthermore, their content in the Red Toon collected from ten different origins was also determined and compared, and the results suggested that the total flavonoid glycosides from Shandong Yantai were the highest, followed by Shandong Ximou, supporting a well-recognized viewpoint that Red Toon cultivated in Shandong Province, China, is considered genuine due to the best health benefits and flavor.

Integrated extraction and purification of total bioactive flavonoids from Toona sinensis leaves

“…The flavonoids existing in the purified products were analyzed using a UPLC-ESI-MS system (Shimadzu LCMS-8050, Japan). The chromatographic separation was performed on a C 18 column (2.1 mm × 150 mm, 1.7 μm, Waters, Ireland) according to previous study (Shen et al 2018). The column temperature was kept at 35℃.…”

Flavonol profiles of mature leaves allow discriminating Toona sinensis Roem from different north-south geographical origins across China with varied antioxidant activities

“…However, once the buds grow longer than 20 cm, the leaves are no longer edible as they are high in fibre and have reduced flavour [ 19 ]. Notably, the flavonoid content of T. sinensis leaves is among the highest level across hundreds of vegetables and fruits [ 9 , 22 ], and its accumulation is increased alongside leaf maturation [ 23 , 24 ]. The flavonoid content and antioxidant activity of mature leaves (grown for over three months) of T. sinensis have been reported to be even higher than that of Ginkgo biloba leaves [ 25 ].…”

“…Moreover, the estimated biomass of mature leaves from T. sinensis with a diameter breast height (DBH) of 10–19 cm was measured to be 8–11 kg/tree, and with a DBH of 20–45 cm, the level increased to 18–23 kg/tree [ 26 ]. Flavonoids in plant leaves are primarily flavonols, including T. sinensis [ 1 , 23 , 27 ]. Thus, mature leaves of T. sinensis hold great industrial potential to act as quality resources for the extraction and refining of natural flavonols.…”

“…However, the specific flavonol composition of mature T. sinensis leaves is rarely analysed, and only 10 glycosyl derivatives of quercetin and kaempferol have been identified [ 20 , 23 , 28 , 29 ]. Additionally, T. sinensis has a high genetic differentiation across populations [ 30 , 31 ], but little knowledge related to flavonol distribution within the species has been uncovered.…”

Differences and Correlations of Morphological Characteristics and Fatty Acid Profiles of Seeds of Toona sinensis

“…In addition, the bark and roots of T. sinensis are used in traditional medicines for the treatments of dysentery, enteritis, flatulence and itchiness [1,5] . In recent years, increasing numbers of studies report that T. sinensis is rich in bioactive compounds, such as phenolics, [6] polysaccharides, [7] and triterpenoids, [8] and exhibits various beneficial functions for human health, such as antioxidant, anticancer, anti‐angiogenesis, anti‐inflammatory, anti‐fatigue and anti‐nociceptive effects [5] . Thus, T. sinensis has been extensively planted, and its total acreage has already exceeded 133,000 hectares in China [9]…”