molecules Review Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity Valery M. Dembitsky 1,2,*, Ekaterina Ermolenko 2, Nick Savidov 1, Tatyana A. Gloriozova 3 and Vladimir V. Poroikov 3 1 Centre for Applied Research, Innovation and Entrepreneurship, Lethbridge College, 3000 College Drive South, Lethbridge, AB T1K 1L6, Canada;
[email protected] 2 A.V. Zhirmunsky National Scientific Center of Marine Biology, 17 Palchevsky Str., 690041 Vladivostok, Russia;
[email protected] 3 Institute of Biomedical Chemistry, 10 Pogodinskaya Str., 119121 Moscow, Russia;
[email protected] (T.A.G.);
[email protected] (V.V.P.) * Correspondence:
[email protected]; Tel.: +1-403-320-3202 (ext. 5463); Fax: +1-888-858-8517 Abstract: Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, Citation: Dembitsky, V.M.; which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, Ermolenko, E.; Savidov, N.; the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with Gloriozova, T.A.; Poroikov, V.V.