Phenolic Characterization and Antioxidant Activity of Chrysanthemum indicum and Opisthopappus Shih during Different Growth Stages

Recently, much attention has been devoted to natural phenolics because of their ideal structure and chemistry for free radical scavenging activities, which may play important roles in long-term health and a reduction in the risk of developing chronic degenerative diseases. Chrysanthemum indicum (C. indicum) has been widely used as a health food and as a popular herb in China for many centuries. Opisthopappus Shih (O. shih) often takes the place of its related genera, C. indicum, in functional tea or medicine prescriptions in place of origin. In this article, a comparative study on the phenolics and antioxidant activity of C. indicum and O. shih during different growth stages was investigated. The antioxidant properties of plant extracts were tested using DPPH and ABTS assays. The characterization of potential phytochemicals was carried out using Fourier transform infrared (FT-IR) spectroscopy. Total phenolics (TPC) and total flavonoid content (TFC) were measured using Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. An HPLC method was used to simultaneously quantify five phenolic compounds, including chlorogenic acid, luteolin, rutin, quercetin, and apigenin. Results indicated that the Trolox equivalent antioxidant activity (TEAC) values of C. indicum and O. shih had extremely large variations at different growth stages. The most abundant phenolics and potent antioxidant activity of two related plants appear at the early vegetative and then flowering stages. Antioxidant activities and phenolic content of O. shih were higher than those of corresponding organs of C. indicum at the same collection time. The whole plant of O. shih, especially its leaves and flowers, are good candidates for obtaining nutraceuticals and functional food ingredients.