Evaluation of Antibacterial and Antioxidant of Thiosemicarbazide Derivatives: A Preliminary Study on Antitubercular Activities
Abstract
Tuberculosis (TB) has been classified as a global problem by the WHO. TB is initiated by the bacterium Mycobacterium tuberculosis , with high infectious power. Indonesia ranks fourth in Southeast Asia with an increase in cases by 2022 of 63.41%. Heterocyclic compounds have broad bioactivity, making them good as pharmacological agents. Furanoyl (furan-containing carbonyl) combined in the thiosemicarbazide structure has activity in inhibiting the growth of M. tuberculosis , but its performance is still in the moderate category. The lipophilic character plays an important role for TB drugs, as this character helps the transfer of drugs into body cells and bacteria. TB drugs do not only depend on lipophilic character, but the penetration rate of drugs into bacterial cells needs to be considered. Efforts to increase the penetration rate of drugs into M. tuberculosis cells can be made by adding furan-2-carboxamide groups to the structure of drug compounds. Qualitative antibacterial activity tests were carried out for compounds (10), (12), (13), and (14) and antioxidant tests were carried out using the DPPH assay. The results showed that all test compounds were specifically active on P. aeruginosa , which is a Gram-negative bacterium, with inhibition zones of 0, 7.5, 11.5, and 9 mm, respectively. In the approach of antibacterial activity, the test compounds should be more active in inhibiting Gram-positive bacteria. Compounds (13) and (14) were used as comparators to confirm the correlation between antibacterial and antitubercular. The results obtained were different; compounds (13) and (14) have been tested for antitubercular activity ( M. tuberculosis H37Rv) with satisfactory results. The tested compounds didn’t show any potential for antioxidant activity because they have different structures than antioxidant-active compounds. In the future, thiosemicarbazide could be combined with a hydroxyl group to enhance its antitubercular activity. Antitubercular screening was carried out on the next step by in silico and in vitro study.