In recent years, a number of natural products isolated from Chinese herbs have been found to inhibit proliferation, induce apoptosis, suppress angiogenesis, retard metastasis and enhance chemotherapy, exhibiting anti-cancer potential both in vitro and in vivo. This article summarizes recent advances in in vitro and in vivo research on the anti-cancer effects and related mechanisms of some promising natural products. These natural products are also reviewed for their therapeutic potentials, including flavonoids (gambogic acid, curcumin, wogonin and silibinin), alkaloids (berberine), terpenes (artemisinin, β-elemene, oridonin, triptolide, and ursolic acid), quinones (shikonin and emodin) and saponins (ginsenoside Rg₃), which are isolated from Chinese medicinal herbs. In particular, the discovery of the new use of artemisinin derivatives as excellent anti-cancer drugs is also reviewed.

Introduction: Terpenoids constitute the largest class of natural products and are a rich reservoir of candidate compounds for drug discovery. Recent efforts into the research and development of anti-cancer drugs derived from natural products have led to the identification of a variety of terpenoids that inhibit cancer cell proliferation and metastasis via various mechanisms. Despite the increasing number of research reports, there lacks a comprehensive review of anti-cancer activity of terpenoids. Areas covered: The present article provides an overview of the recent progress in the anti-cancer studies on terpenoids. Over a dozen naturally originated terpenoid compounds, in particular those derived from traditional Chinese medicine, were classified into five categories according to the structures, namely monoterpenoids, sesquiterpenoids, diterpenoids, triterpenoids and tetraterpenoids. The anti-cancer activities and relevant mechanistic insights of these compounds are discussed in this review. Expert opinion: The anti-cancer activity of terpenoids appears promising and will potentially open more opportunities for cancer therapy. However, current studies are restricted to descriptive findings and lack mechanistic insights and systematic structure–activity relationship (SAR) studies. Future efforts into the systematic identification of the targets of terpenoids are believed to increase chances of gaining breakthrough insights in the field.

Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloids isolated from natural herbs exhibit antiproliferation and antimetastasis effects on various types of cancers bothin vitroandin vivo. Alkaloids, such as camptothecin and vinblastine, have already been successfully developed into anticancer drugs. This paper focuses on the naturally derived alkaloids with prospective anticancer properties, such as berberine, evodiamine, matrine, piperine, sanguinarine, and tetrandrine, and summarizes the mechanisms of action of these compounds. Based on the information in the literature that is summarized in this paper, the use of alkaloids as anticancer agents is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloids can be made.

Summarizing the status of drugs in the market and examining the trend of drug research and development is important in drug discovery. In this study, we compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009. Two networks, namely, the target–target and drug–drug networks, have been set up using the network analysis tools. The multi-target drugs have much more potential, as shown by the network visualization and the market trends. We discussed the possible reasons and proposed the rational strategies for drug research and development in the future.