Botany, traditional use, phytochemistry, pharmacology, quality control, and authentication of Radix Gentianae Macrophyllae -A traditional medicine: A review

Radix Gentianae Macrophyllae, commonly known as Qinjiao (in Chinese), is dried roots of medicinal plants that belong to Gentianaceae family and Gentiana genus. It has medically been used for the treatment of various diseases such as arthritis, stroke, facial paralysis, and scapulohumeral periarthritis in China since ancient times.The aim of this paper is to provide a comprehensive and constructive overview of Qinjiao mainly containing Gentiana macrophylla Pall., Gentiana straminea Maxim., Gentiana crasicaulis Duthie ex Burk., and Gentiana daurica Fisch. in botany, traditional use, phytochemicals, pharmacology (biological activities and pharmacokinetics), quality control, and authentication according to the up-to-date data of available scientific literatures.All information regarding these four plants was collected from various academic search engines for example Google, Google Scholar, Web of Science, SciFinder, Pubmed, CNKI, and Wanfang. Additional information was obtained from botanical books, Chinese classic texts, and medical monographs.So far 166 compounds have been isolated and identified from Qinjiao plants together with Gentiana tibetica King ex Hook. f., Gentiana siphonantha Maxim., Gentiana officinalis H. Smith, and Gentiana waltonii Burk. Their constituents are mainly classified into iridoid glycosides, triterpenes, flavones, sterols, benzene derivatives, etc. The pharmacological studies demonstrate that Qinjiao plants display a wide range of bioactivities e.g. anti-inflammatory, anti-oxidant, hepato-protective, cardio- and neuro-protective, insecticidal, and anti-influenza effects. The conventional quality control is performed by determination of the concentration of some compounds, e.g., gentiopicroside, or establishment of the fingerprint. In addition to seed propagation, tissue culture technology has been used to address the limited supplies and guarantee the sustainable development of Qinjiao in the experimental scale.Although the identification of compounds from Qinjiao and demonstration of medicinal uses in vitro and in vivo have been carried out, various other studies on these plants should deserve our more attention. More efforts should be concentrated on the underlying mechanisms of their beneficial bioactivities. The proper toxic evaluation is indispensable to guarantee the safety, efficacy, and eligibility for medical use. To sum up, the summarized achievements could highlight the importance of Qinjiao and provide a solid foundation for scientists not only to further exploit the therapeutic potentials, but also possibly develop novel drugs in the subsequent research.