Quality characterization of flavonoids from flowers, stems and leaves of Chrysanthemum morifolium Ramat. ‘Chuju’

Chrysanthemum morifolium Ramat. ‘Chuju’ is a plant with dual edible and medicinal values. While the bioactive constituents of Chuju flowers have been extensively investigated, the flavonoid composition and quality characteristics in its stems and leaves remain systematically uncharacterized. This study employed ultrasound-assisted ethanol extraction to obtain flavonoid extracts from flowers, stems, and leaves during the flowering period, followed by comprehensive analysis of total flavonoid content, antioxidant capacity, and stability. The results showed that the total flavonoid content in the flowers, stems and leaves of Chuju was relatively high. The total flavonoid content in the flowers was 73.99 mg/g DW, followed by leaves (51.95 mg/g DW) and stems (32.72 mg/g DW). HPLC analysis revealed that the flowers, stems and leaves of Chuju all contained four types of flavonoids and phenolic acids: chlorogenic acid, rutin, luteolin-7-O-glucoside, and 3,5-O-dicaffeoylquinic acid. The content of these components varied in different parts, with the highest content of chlorogenic acid being in the flowers (3.51 mg/g DW), followed by the stems (1.56 mg/g DW). The content of luteolin-7-O-glucoside was the highest in the leaves (0.69 mg/g DW), significantly higher than that of the other components. The extracts from flowers, stems, and leaves demonstrated strong DPPH and ABTS radical scavenging activities. Stability tests indicated flavonoids from flowers, stems, and leaves were sensitive to light, oxygen, high temperature, and extreme pH conditions. These findings have revealed the potential of the stems and leaves of Chuju as a new source of flavonoids.