Figure 3

Structural determination of Fr. 6 as glyceollin I with NMR and TOF-MS. One-dimensional ¹H-NMR (A) and ¹³C-NMR (B) measurements of Fr. 6 were performed in methanol-d₄. (C) Monoisotopic molecular ion of 337.1129 m/z corresponding to C₂₀H₁₇O₅⁻ as [M-H]⁻ (theoretical m/z: 337.1070) by TOF-MS analysis. (D) Chemical structure of glyceollin I.