Deprea cuyacensis, (N. W. Sawyer & S. Leiva) S. Leiva & Lezama (N. W. Sawyer & S. Leiva) S. Leiva & Lezama

Casero, Carina N., Oberti, Juan C., Orozco, Clara I., Cárdenas, Alejandro, Brito, Iván, Barboza, Gloria E. & Nicotra, Viviana E., 2015, Withanolides from three species of the genus Deprea (Solanaceae). Chemotaxonomical considerations, Phytochemistry 110, pp. 83-90 : 85

2.2. Withanolides isolated from D. cuyacensis

Following a similar procedure, the EtOH extract of D. cuyacensis was analyzed and two 13,14-seco withaphysalins were isolated, namely the previously determined withaphysalin C isolated from Physalis minima ( Kirson et al., 1976) and compound 3, named withaphysalin X. Compound 3 had a molecular formula of C 28 H 36 O 8 by HRESIMS. Inspection of the 1D and 2D NMR spectroscopic data indicated that compound 3 possessed a 13,14-seco-ergostane nucleus closely related to that of withaphysalin C ( Kirson et al., 1976) and its 18-acetyl derivative ( Ma et al., 2007) ( Tables 1 and 3 ). Compound 3 (C-18 R) was characterized from a mixture of epimers C-18 R /C-18 S in a 2:1 ratio, and was found to contain the following moieties in common with withaphysalin C: a 1-oxo-2,5-diene system in rings A/B, an hemiacetal arrangement involving C-18 and C-20 positions, a 13 b,14 b -epoxy function, and a δ -lactone in the side chain, in agreement with the 1 H– 1 H COSY, HSQC, and HMBC experiments. The only difference observed between 3 and withaphysalin C was the missing C-27 methyl signal and the resonance at δ 4.40 m and 4.33 m, assigned to H-27a and H-27b, respectively, indicating that C-27 was oxidized to a hydroxymethyl group. This was consistent with the methylene carbon resonance at δ 56.8 in the 13 C NMR and DEPT spectra.