| Abstract: | Phytochemical investigations on the ethyl acetate soluble fraction of the whole plant of Isatis costata Linn. (Brassicaseae) led to the isolation of the oxindole alkaloids costinones A (1), B (2), isatinones A (3), B (4), indirubin (5), and trisindoline (6). Compounds 1–6 displayed significant to moderate inhibition against xanthine oxidase enzyme with IC50 values ranging from 90.3?±?0.06 to 179.6?±?0.04 µM, whereas the standard inhibitor of xanthine oxidase (allopurinol) had an IC50 value of 7.4?±?0.07 µM. Compounds 1 (IC50 7.21?±?0.05 µM), 2 (IC50 9.40?±?0.03 µM), 3 (IC50 11.51?±?0.07 µM), 4 (IC50 12.53?±?0.06 µM), 5 (IC50 14.29?±?0.09 µM), and 6 (IC50 17.34?±?0.04 µM) exhibited pronounced activities when compared with the standard tyrosinase inhibitor l-mimosine (IC50 3.70?±?0.03 µM), along with DPPH radical scavenging activity with IC50 226, 270, 300, 320, 401, and 431 µM, respectively. The crude extract and compounds 1, 2, 5, and 6 showed significant antifungal activity against Trichophyton schoen leinii, Aspergillus niger, Candida albicans, Trichophyton simii, and Macrophomina phaseolina. |
