Isolation, structural properties, and bioactivities of polysaccharides from Althaea officinalis Linn.: A review

Althaea officinalis Linn. (AO) is a widely distributed herbaceous plant with a long history of medicinal and food functions in Europe and Western Asia. Althaea officinalis polysaccharide (AOP), as one of the main components and a crucial bioactive substance of AO, has a variety of pharmacological activities, including antitussive, antioxidant, antibacterial, anticancer, wound healing, immunomodulatory, and infertility therapy effects. Many polysaccharides have been successfully obtained in the last five decades from AO. However, there is currently no review available concerning AOP. Considering the importance of AOP for biological study and drug discovery, the present review aims to systematically summarize the recent major studies on extraction and purification methods of polysaccharides from different AO parts (seeds, roots, leaves and flowers), as well as the characterization of their chemical structure, biological activity, structure-activity relationship, and the application of AOP in different fields. Meanwhile, the shortcomings of AOP research are further discussed in detail, and new valuable insights for future AOP research as therapeutic agents and functional foods are proposed.