The antitumour activity of C21 steroidal glycosides and their derivatives of Baishouwu: A review

Baishouwu has been used in China for thousands of years since it was first discovered in the late Tang Dynasty and flourished in the Song and Ming Dynasties. The Chinese herbal medicines named Baishouwu include Cynanchum auriculatum Royle ex Wight., Cynanchum bungei Decne. and Cynanchum wilfordii Hemsl. It is described in the Sign of Materia Medica as "sweet, bitter, reinforce liver and kidney, and non-toxic". It is widely used for nourishing the blood to expel wind, reinforcing liver and kidney, strengthening bones and muscles. In this review, the current research status of the C21 steroidal glycosides and their derivatives of Baishouwu for malignant tumours and their anti-tumour mechanisms are discussed. This may lay the ground for potential application of Baishouwu and its active ingredients in the treatment of tumours. Scientific databases, including PubMed, Elsevier, Science Direct, Google Scholar, CNKI, WANFANG DATA and VIP were searched to gather data about Baishouwu and its C21 steroidal glycosides and their derivatives. Prior literature indicates that Baishouwu has important biological activities such as anti-tumour, anti-epileptic, reducing cholesterol, protection of liver and kidney and immunomodulatory, which are of increasing interest, especially its anti-tumour activity. Recent studies demonstrate that the C21 steroidal glycosides of Baishouwu, which have prominent antitumour efficacy, are one of its main active ingredients. Presently, a variety of C21 steroidal glycosides have been isolated from Baishouwu medicinal part, the tuberous root. This review summarizes the various antitumour activities of the C21 steroidal glycosides and their derivatives of Baishouwu. In this review, the antitumour effects and mechanisms of total C21 steroidal glycosides and monomers and derivatives of Baishouwu in vitro and in vivo were summarized. Baishouwu can inhibit tumourigenesis by blocking tumour cell cycle progression, regulating numerous signaling pathways, promoting apoptosis, inhibiting tumour cells proliferation and metastasis, improving immunity and so on. This review provides a theoretical basis for inheriting and developing the medical heritage of the motherland, exploring the resources of traditional Chinese medicine for ethnic minorities and clinical rational drug use.