Sesquiterpenes, 15-carbon compounds formed from 3 isoprenoid units, are secondary metabolites produced mainly in higher plants but also in fungi and invertebrates. Sesquiterpenes occur in human food, but they are principally taken as components of many folk medicines and dietary supplements. Moreover, sesquiterpenes could become a rich reservoir of candidate compounds for drug discovery as several sesquiterpenes and their derivatives possess interesting biological activities. Recent efforts in the research and development of new drugs derived from natural products have led to the identification of a variety of sesquiterpenes that possess promising anti-inflammatory, antiparasitic and anti-carcinogenic activities. On the other hand, some sesquiterpenes can cause serious toxicity and other adverse effects. Therefore, more and more attention has been paid to the investigation of the mechanisms of biological activities of sesquiterpenes in vitro as well as in vivo. The data collected in this review show that many of sesquiterpenes biological activities are based on antioxidant or pro-oxidant actions of sesquiterpenes. Structure, concentration, metabolism as well as type of cells determine if sesquiterpene acts as anti-oxidant or pro-oxidant. Therefore, detailed research of sesquiterpenes is very important for evaluation of their efficacy and for their safe use.
Anthracycline antibiotic doxorubicin (DOX) belongs among the most important antineoplastics used in cancer therapy. Unfortunately, its cytostatic effect in therapeutic doses is frequently insufficient; but the use of higher DOX doses is limited by the development of systemic toxicity, especially cardiotoxicity. Therefore, a searching for some possibilities of how to increase DOX efficacy in cancer cells, and minimizing associated toxicities to noncancerous tissues, is in the forefront of scientific research. Many approaches are based on altered DOX metabolism. The classical strategies include an enhancing of DOX uptake by cancer cells and/or an activation of DOX prodrug within cancer cells via liposomal encapsulation or conjugation with antibodies, peptides, or synthetic polymers. The diminishing of DOX deactivation, restriction of DOX efflux from cancer cells, decreased antioxidant defense of cancer cells, changes in cell cycle, or modulation of signaling pathways represent newer approaches in increasing DOX toxicity in tumors. Each way has certain advantages and limitations. The aim of this review was not to collect all reported results, but to bring an overview of various approaches and a summary of their principles. Possible advantages, disadvantages, and further perspectives are discussed and evaluated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.