Table 1.
IC50 values of Stemphylium loti fractions 1.9, 1.10, 2.6 and 2.7 and tenuazonic acid (TeA) in ATP hydrolysis assays using Spinacia oleracea plasma membrane (PM) H+‐ATPases.
| Stemphylium loti extract | IC50 (µg µg−1 protein) | Ratio: IC50 of extract/IC50 of TeA |
|---|---|---|
| Fraction 1.9 | 0.82 (0.69–0.97) | 102.7 |
| Fraction 1.10 | 0.65 (0.55–0.76) | 80.7 |
| Fraction 2.6 | 0.77 (0.68–0.87) | 96.3 |
| Fraction 2.7 | 0.33 (0.28–0.38) | 40.9 |
| TeA (commercial) | 0.008 (0.007–0.009) | 1 |
ATP hydrolysis was analyzed using nonlinear regression and fitted to log[inhibitor] vs the normalized response to determine IC50 values. For S. oleracea PMs treated with fractions 1.9, 1.10, 2.6 and 2.7, n = 3. For S. oleracea PMs treated with TeA, n = 9.