Paulownia as a Medicinal Tree: Traditional Uses and Current Advances

Paulownia is one of the most useful and sought after trees, in China and elsewhere, due to its multipurpose status. Though not regarded as a regular medicinal plant species, various plant parts (leaves, flowers, fruits, wood, bark, roots and seeds) of Paulownia have been used for treating a variety of ailments and diseases. Each of these parts has been shown to contain one or more bioactive components, such as ursolic acid and matteucinol in the leaves; paulownin and d-sesamin in the wood/xylem; syringin and catalpinoside in the bark. The fruits contain fatty oils, alkaloids, flavonones as well as flavonoids with antioxidant properties. The flavonoid contents and TROLOX Equivalent Antioxidant Capacity (TEAC) value in fresh and dry leaf extracts of Paulownia elongata suggest that this species has potential for advanced medicinal use. In vitro grown Paulownia fortunei Hemsl. seedlings, inoculated with Agrobacterium rhizogenes have a potential to produce hairy roots and synthesize bioactive compounds such as acteosides (verbascosides). With various new studies describing isolation of therapeutic compounds and their probable application in human health, it is an opportune moment to revisit medicinal potential of this tree. In this review, the usage of Paulownia in traditional medicine has been revisited and current advances in various fields of research in the genus Paulownia are summarized.