Thiosemicarbazones (TSCs) are the condensed products of carbonyl compounds (aldehydes, ketones) and thiosemicarbazide. Thiosemicarbazones and their metal complexes attract both the analytical as well as biological researchers due to their vast applications in binding to the metal ions and also biological applications. Few authors reviewed the analytical applications of thiosemicarbazones 1-3. The recent review 3 discussed the analytical and biological applications of thio and phenyl thiosemicarbazones, but mainly focused on the analytical applications. Wood et al. 4 reviewed the usage of Cu(II)-diacetyl-bis(N 4methyl-thiosemicarbazones) as a radiotracer for tumor hypoxia. Garoufis et al. 5 reviewed antiviral, antifungal, antimicrobial and antitumor activities of Pd(II) coordination compounds including thiosemicarbazone complexes. Few authors 6,7 reviewed the therapeutic activities of transition metal complexes of thiosemicarbazones. Kathiravan et al. 8 reported the biology and chemistry of antifungal agents, including thiosemicarbazones. This present review extensively discusses the biological applications such as, antimalarial, antibacterial, antitrypanosomal and antiviral properties of thiosemicarbazones and their metal complexes reported since 2008. RESULTS AND DISCUSSION Antimalarial activity: The activity of compounds or agents, which will inhibit the growth and spread malarial parasites and the biological effect, is known as antimalarial activity. Various species of Plasmodium are the causative agents of malaria. Plasmodium, the parasite responsible for human

Chromium is a very important trace element in regarding both environmental and biological point of view. Most of the research about chromium focused on the biological activity of trivalent chromium and carcinogenicity of hexavalent chromium. It is a lustrous and hard metal that takes high polish and have high melting point 1 . In 1798, a French chemist Nicholas-Louis Vauquelin successfully isolated metallic chromium by heating chromic oxide with charcoal by means of chemical reduction 2 .Chromium oxidation states are ranging from -2 to +6. But in nature it exists in only three oxidation states. Those three oxidation states of Cr are 0, +3 and +6. It exists in 0 oxidation state in metallic Cr, in chromic compounds it is in +3 states and in CrO 4 2-, Cr 2 O 7 2compounds it exists in +6 oxidation state. Among all oxidation states, +3 and +6 states are more commonly observed in chromium compounds but the remaining oxidation states are rare 3 .According to the International Minerals Association, 82 minerals were recognized for chromium. Among these, the important chromium mineral is chromite. The concentration of chromium in chromite mineral is 46.46 % on average 2 . Most

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