Coreopsis tinctoria Nutt. is a medicinal plant that is cultivated in many countries around the world. The major bioactives of C. tinctoria include marein, flavanomarein, okanin, isookanin and others; among them, marein and flavanomarein are the dominant components, whereas the others present in minor amounts, although they have demonstrated significant biological activities. Continued pharmacological research of flavanomarein, okanin, and isookanin requires sufficient amounts of these components, therefore, this study investigated the efficient biotransformation of marein to flavanomarein, okanin, and isookanin. By screening different enzyme types and optimizing reaction conditions (temperature, concentration, time, and pH), the optimal enzymatic conditions for converting marein to its corresponding cyclic isomer and aglycone were determined. Under enzymatic catalysis, marein and flavanomarein were transformed into their aglycones, okanin and isookanin, respectively. The optimal conditions were as follows: enzyme activity 25 U/mL (VinoTaste^® proline enzyme), 37 ℃, pH 8.0, and a reaction time of 2 h. Under these conditions, marein yielded 34.56% okanin and 18.31% isookanin, while flavanomarein yielded 92.25% isookanin. This study reports, for the first time, the efficient enzymatic conversion of Coreopsis tinctoria flavonoid glycosides into their aglycones.

Coreopsis tinctoria Nutt (C. tinctoria) or a common name ‘Snow chrysanthemum’ because of its growing condition at high altitude,is one of the popular medicinal-food plants, mainly grows in the northwest area of China. Because of its rich nutrients, particularly polyphenols (majorly flavonoids), and volatile oils among others, C. tinctoria has become a research hotspot in recent years. In addition, the flavonoids of C. tinctoria, especially the flavanomarein, marein, okanin and other bioactive phytochemicals, have effective biological activity. They possess good antioxidant and anti-inflammatory effects, also have significant effects on lowering blood pressure, hypoglycemia and reducing levels of triglycerides and cholesterol. However, at present, studies on the bioactivity of C. tinctoria are mainly focused on crude extracts or total flavonoids. The study of monomer components is largely limited to the isolation and purification process, which is difficult for a systematic study because of the chemical-physical nature of marein, flavanomarein and other compounds in C. tinctoria. Therefore, to have an updated isolation of C. tinctoria bioactive components, this paper reviewed the current research status of the separation and purification methods of flavonoids from C. tinctoria, by analyzing and comparing the technical characteristics of these methods, and providing prospects on the development and application of the separation and purification methods of C. tinctoria.

Rhodiola (Rhodiola rosea) grows worldwide, particularly in Europe, North America and several Asia countries like China and Kazakhstan. As a functional food and medicinal herb and broadly used in healthy foods and beverages, R. rosea possesses antioxidant, antifatigue, anti-ageing, inhibitory effects of inflammation, anticancer and other pharmacological properties. There are more than 90 species of Rhodiola distributed in Asia, Europe and North America and R. rosea is one of the major species. China is one of the most producing countries.Same as other plants, the bioactive components of R. rosea vary with growing location and conditions. Phenylpropanoids in R. rosea are a group of main bioactive phytochemicals and their contents are usually used as a quality indicator. Hence it is of great importance to characterize phenylpropanoids in R. rosea from different sources to ensure their effectiveness and efficacy. In this study, 18 R. rosea samples from Kazakhstan and 4 regions of China were collected and further characterized for their contents of rosavin, rosarin and rosin, the major biomarkers of R. rosea quality and pharmacological effects. ANOVA analysis showed that there were significant differences in the contents of three phenylpropanoids, particularly, rosavin among different regions. As an example, the content of total rosavins in R. rosea from Kazakhstan was more than three times that from Bazhou, Xinjiang province of China.