“…The 1 H NMR (500 MHz, CDCl3) showed a spectra of δ 1 H: 6.19 (1H, d, J = 3.5 Hz, H-13a), 5.46 (1H, d, J = 3.2 Hz, H-13b), 5.24 (1H, brs, J = 2.4, 1.5 Hz, H-15a), 5.04 (1H, brs, H-15b), 4.87 (1H, brs, H-14a), 4.79 (1H, brs, H-14b), 3.94 (1H, t, J = 9.3 Hz, H-6), 2.93 (1H , m, H-5), 2.89 -2.79 (2H, m, H-4, 7), 2.59 -2.41 (3H, m, H-3a, 9a, 3b), 2.22 (1H, m, H-9b ), 2.13 (1H, m, H-2a), 1.97 -1.79 (2H, m, H-2b,8a), 1.39 (1H, m, H-8b) (Figure 3). From the spectral analysis and comparisons with the literature [22] [23], the structure of Ek-cpd1 was characterized as dehydrocostus lactone, which is a sesquiterpene lactone with guaianolides class (Figure 4).…”