United States Pharmacopeia comprehensive safety review of Styphnolobium japonicum flower and flower bud

The dried flower and flower bud of Styphnolobium japonicum (L.) Schott (Japanese Sophora flower and Japanese Sophora flower bud, respectively) have long been used as herbal medicines in Asia. Today, they are marketed as dietary supplements in the United States for their anti-oxidative properties and as a source of flavonoids, including rutin and quercetin. This review focused on the safety of S. japonicum flower and flower bud as dietary supplement ingredients. No serious adverse events or toxicity were reported in the clinical or experimental animal studies we reviewed. Although some studies indicated that rutin or quercetin may have potential for drug interactions, none were identified for S. japonicum flower or flower bud. S. japonicum flower and flower bud are not known to have been associated with serious health risks when appropriately consumed in dietary supplements and have been admitted to the U.S. Pharmacopeial Convention monograph development process. However, pregnant and breastfeeding women should seek the advice of a healthcare professional because no data are available on their use by these special populations.