Traditional uses, ten-years research progress on phytochemistry and pharmacology, and clinical studies of the genus Scutellaria

Scutellaria (Lamiaceae), which includes approximately 360–469 accepted species, is widespread in Europe, North America, East Asia, and South America. Several species have a long history being used as traditional medicines to treat respiratory, peptic, neurological, and hepatic and gall diseases. The phytochemistry and pharmacology of the genus Scutellaria have been developed dramatically in the past ten years, and the traditional uses and clinical studies of the genus have not been systematically summarized. Therefore, it is especially valuable to review the current state of knowledge to provide a basis for further exploration of its medicinal potential. The review aims to provide updated information on the ethnopharmacology, the ten-year research progress of phytochemistry and pharmacology, and clinical studies of Scutellaria and to explore the potential medicinal values and further studies of Scutellaria. This review is based on published studies and books from the library and electronic sources, including SciFinder, Scopus, PubMed, Web of Science, Baidu Scholar, CNKI, the online ethnobotanical database, and ethnobotanical monographs. This literature is related to ethnopharmacology, the ten-year research progress on the phytochemistry and pharmacology, and clinical studies of Scutellaria. A total of 50 species, 5 subspecies and 17 varieties of the genus Scutellaria are used as traditional medicine with various biological activities. In the past ten years, 208 chemical constituents have been identified from 16 species and 1 variety of the genus Scutellaria, such as neo-clerodane diterpenoids, sesterterpenoids, terpenoids, flavonoids. Pharmacological research has demonstrated that the extracts and compounds identified from this genus exhibit extensive biological activities, including anticancer, antioxidant, anti-inflammatory, antiviral and antibacterial activities, effects on cardiovascular, cerebrovascular diseases as well as hepatoprotective and neuroprotective effects. The species S. baicalensis, S. barbata, and S. lateriflora and the main compounds baicalein, baicalin and wogonin are involved in clinical trials, which point the way for us to conduct further studies, such as study on the anticancer, antihypertensive, anti-infective, anti-inflammatory, neuroprotective and other effects of Scutellaria. The species included in the genus Scutellaria can be used to treat cancer, infection, hepatic disorders, cardiovascular and cerebrovascular diseases, neurodegenerative diseases, and other diseases. Some indications in traditional medicines have been confirmed by modern pharmacological studies, such as anticancer, anti-inflammatory, anti-infective activity, and hepatoprotective and neuroprotective effects. The available literature indicated that most of the bioactivities could be attributed to flavonoids and neo-clerodane diterpenoids. Although there are some uses of Scutellaria in clinical practice, the existing research on this genus is still limited. In order to expand the development of medicinal resources of Scutellaria, the already studied species in this genus are recommended for more comprehensive investigation on their active substances, pharmacological mechanisms, quality control, clinical use and new drug research. Additionally, it is necessary to study species that their chemical composition or pharmacological activity have not yet been investigated, especially those used in folk medicine.