*3.3. Extraction and Isolation*

The dried roots (10 kg) of *E. fischeriana* were crushed, extracted with 95% ethanol (50 L) at room temperature for three times (each for 24 h), the solvent was recovered under reduced pressure to obtain the crude extract. The crude extract was suspended in water (3 L) and then partitioned sequentially with petroleum ether, EtOAc and *n*-BuOH (saturated with water) and dried under reduced pressure to give their corresponding extracts (178.36, 220.82 and 205.43 g, respectively). The EtOAc fraction was subjected to CC (chromatographic column) on silica gel (1.3 kg, 100–200 mesh) using petroleum ether-CH2Cl2 (1:0 to 0:1) and CH2Cl2-MeOH (200:1 to 10:1) as eluents to give fractions 1–3 and 4–10, respectively. Fr. 5 (12.15 g) showed obvious brick-red spots in the TLC and was subjected to ODS CC eluted with MeOH-H2O (40–100%) to obtain 6 fractions (Fr. 5A to Fr. 5F). Fr. 5C (2.42 g) was subsequently loaded on a Sephadex LH-20 column using CH2Cl2-MeOH (1:1) as eluent to obtain 3 fractions (Fr. 5C-a to Fr. 5C-c). Fr. 5C-a (0.69 g) was purified by semipreparative HPLC (ACN-H2O, 87%, 3 mL/min) to obtain compound **3** (6.8 mg, tR = 12.0 min). Compound **1** (4.3 mg, tR = 18.5 min) was isolated from Fr. 5C-b (0.75 g) by preparative HPLC (ACN-H2O, 85%, 3 mL/min). Fr. 5D (1.87 g) was firstly separated by silica gel CC (PE/EtOAc, 5:1) and then by semi-HPLC (ACN-H2O, 90%, 3 mL/min) to afford **2** (3.5 mg, tR = 13.2 min) and **4** (7.2 mg, tR = 16.7 min), respectively.

Euphonoid H (**1**): colorless oil; [α] 20 *<sup>D</sup>* −43.2 (c 0.10, CHCl3); UV (MeOH) *λ*max (log ε) 230 (3.68) nm; IR (KBr) *ν*max 3400, 2932, 1738, 1217, 1033 cm−1; HRESIMS *m*/*z* 445.2213 (calcd. for C23H34O7Na<sup>+</sup> [M + Na]+, 445.2197); 1H and 13C NMR data see Table 1.

Euphonoid I (**2**): colorless oil; [α] 20 *<sup>D</sup>* + 2.8 (c 0.37, CHCl3); UV (MeOH) λmax (log ε) 266 (4.39) nm; IR (KBr) *ν*max 2938, 1788, 1636, 1256, 968 cm−1; HRESIMS *m*/*z* 343.1550 (calcd. for C20H23O5 - [M − H]−, 343.1551); 1H and 13C NMR data see Table 1.

Raserrane A (**3**): colorless oil; [α] 20 *<sup>D</sup>* −42.8 (c 0.10, CHCl3); HRESIMS *m*/*z* 339.2291 (calcd. for C21H32O2Na<sup>+</sup> [M + Na]+, 339.2295).

Raserrane B (**4**): colorless oil; [α] 20 *<sup>D</sup>* −133.4 (c 0.25, CHCl3); HRESIMS *m*/*z* 287.2362 (calcd. for C20H31O<sup>+</sup> [M + H]+, 287.2369).

#### *3.4. Quantum Chemical NMR and ECD Calculations of Compound* **1***–***2**

The random conformational searches were performed by SYBYL X 2.1.1 program using MMFF94s molecular force field. The obtained conformers were subsequently optimized by using Gaussion09 software at the B3LYP/6-31G(d) level in gas phase. The optimized stable conformers were selected for further NMR calculations at the mPW1PW91/6-311 + G(d,p) level in chloroform and ECD calculations at the CAM-B3LYP/6-31 + G(d) level in acetonitrile. The overall theoretical NMR data were analyzed by using linear regression and DP4+ probability. The overall ECD data were weighted by Boltzmann distribution and produced by SpecDis version 1.70.1 software (T. Bruhn; A. Schaumlöffel; Y. Hemberger; G. Pescitelli, Berlin, Germany).
