Chemistry and Biological Activity of Tetrahydrocannabinol and its Derivatives -- Quantitative Structure–Activity Relationships of Heterocyclic Topoisomerase I and II Inhibitors -- Molecular Modeling of the Biologically Active Alkaloids -- Microbial Transformation of Nitrogenous Compounds -- Synthesis of Triazole and Coumarin Compounds and Their Physiological Activity -- Protoberberine Alkaloids: Physicochemical and Nucleic Acid Binding Properties -- Polycyclic Diamine Alkaloids from Marine Sponges -- Catechins and Proanthocyanidins: Naturally Occurring O-Heterocycles with Antimicrobial Activity -- Benzofuroxan and Furoxan. Chemistry and Biology.