Natural products have gained popularity worldwide for promoting healthcare, as well as disease prevention. Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloids isolated from natural herbs exhibit antiproliferation, antibacterial, antiviral, insecticidal, and antimetastatic effects on various types of cancers both in vitro and in vivo. This paper focuses on the naturally-derived alkaloids such as berberine, matrine, piperine, fritillarine, and rhynchophylline, etc., and summarizes the action mechanisms of these compounds. Based on the information in the literature that is summarized in this paper, the use of alkaloids as drugs is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloids can be made. Following this, it is hoped that as a result of this review, there will be a greater awareness of the excellent promise that natural alkaloids show for use in the therapy of diseases.
