Cocrystals of Natural Products: Improving the Dissolution Performance of Flavonoids Using Betaine

Flavonoids are a class of important natural chemicals that can be isolated from a wide range of plants. Flavonoids exhibit diverse pharmacological activities, although most of them are slightly soluble or insoluble in water, resulting in low bioavailability after oral administration. To improve the dissolution performance of these compounds, we selected a natural sweetener, betaine (BTN), to form cocrystals with flavonoids. In this study, cocrystallization trials between BTN and three flavonoid compounds, baicalein (BAI), phioretin (PHL), and quercetin (QUE), were successfully performed. These three newly obtained cocrystals were characterized by a range of analytical methods. All cocrystal forms exhibit improved equilibrium solubilities relative to their parent compounds. The compounds used in this investigation belong to flavone, dihydrochalcone, and flavonol subclasses of flavonoids, respectively. Such results indicate BTN might show potential as a promising coformer to form performance-enhancing cocrystals with flavonoids.