Screening of antitopoisomerase, antioxidant, and antimicrobial activities of selected triterpenes and saponins

A baccharane-type triterpene (1), four oleanane-type triterpenes (2-5) and twelve oleanane-type bidesmodic saponins (6-17) were subjected to antioxidant, antimicrobial and antitopoisomerase evaluation. Moderate antimicrobial activity was observed (zone of inhibition in millimeters); triterpenes 2-4 were toxic to Staphylococcus epidermidis (13.20 ± 0.00; 11.75 ± 0.07; 9.85 ± 0.21, respectively), while baccharis oxide (1) inhibited the growth of S. epidermidis (14.75 ± 0.35), Candida albicans (20.55 ± 0.92), Escherichia coli (14.80 ± 1.13) and Klebsiella pneumoniae (16.35 ± 0.49). Polygalacic acid (4), 6, 7, 15 and 16 showed growth inhibition of C. albicans (13.50 ± 0.71; 11.00 ± 00; 8.50 ± 0.71; 11.70 ± 0.14; 10.50 ± 0.71, respectively). The growth inhibition of S. epidermidis was achieved by 8 (9.00 ± 1.41) and 15 (9.00 ± 0.00); while the last compound inhibited the growth of K. pneumoniae (9.50 ± 0.71). The tested compound concentration for antitopoisomerase activity was between 1.8-13.8 times of those used as positive controls (CPT= 0.1435 μM, ETP = 0.0849 μM), showing that 1 (1.1726 μM), is topoisomerase I inhibitor. Methylated oleanolic acid (3a, 0.7128 μM), together with 9 (0.3650 μM), 13 (0.3294 μM) and 14 (0.3691 μM) showed antitopoisomerase II activity. None of all tested compounds showed significant antioxidant activity using the DPPH method.