Phenolic constituents, pharmacological activities, quality control, and metabolism of Dracaena species: A review.

Dragon's blood (Chinese name: Xuejie), which comprises red resins obtained from several plants (27 species from 4 families), is drawing worldwide interests in medicinal applications owing to its broad pharmacological spectrum such as promoting blood circulation, regenerating muscle, relieving swelling and pain, maintaining hemostasis, etc. AIM OF THE STUDY: This work aims to evaluate current research progress on phenolic constituents, pharmacological activities, quality control, and metabolism of six Dracaena plants, namely, Dracaena cochinchinensis (Lour.) S.C.Chen, D. cambodiana Pierre ex Gagnep., D. cinnabari Balf. f., D. draco (L.) L., D. loureiroi Gagnep., and D. schizantha Baker, figure out the shortcomings of existing studies, and provide meaningful guidelines for future investigations.Extensive database retrieval, such as SciFinder, PubMed, CNKI, ChemSpider, etc., was performed by using the keywords "Dracaena," "dragon's blood," as well as the Latin names of the six Dracaena species. In addition, relevant textbooks, patents, reviews, and documents were also employed to ensure sufficient information is collected.Flavonoids and their oligomers are the primary chemical clusters distributed in Dracaena plants. Pharmacological activities including analgesic, anti-inflammatory, antibacterial, hypolipidemic, hypoglycemic, and cytotoxic effects; bi-directional regulation effects on hemorheology; and cardiovascular and cerebrovascular effects have been disclosed by modern pharmacological evaluations. The chemical and metabolic profiles after oral administration of dragon's blood extract were preliminarily characterized. However, some of the pharmacological investigations reported only elementary methodologies and unreliable findings, and even worse, some important aspects were questionable or missing in these articles.Dragon's blood is a valuable source of bioactive compounds, mainly flavonoids and their oligomers. Its potential therapeutic effects on different diseases are attractive, such as the notable effect on cardiovascular diseases. In future studies, there is an urgent need to test the effect of this extract on appropriate cell lines and animal models to analyze its ethnopharmacological applications; moreover, "composition-effect correlation" methods and omics technologies are demanded for identifying the effective material basis and therapeutic mechanisms before entering into clinical trials. Moreover, attention should be paid to the chemical profiling and quality evaluation of this precious herbal medicine.