*3.4. ECD and 13C NMR Calculation*

The conformational searches of the compounds were carried out by means of the Spartan'14 software and at Molecular Merck force field (MMFF) and DFT/TD-DFT calculations. Furthermore, Gaussian 05 program was used to generate and optimize the conformer at B3LYP/3-21G (d) level. Conformers with a Boltzmann distribution of over 1% were chosen for optimization at B3LYP/6-31+G (d, p), meanwhile, ECD calculation were conducted with the TD-DFT method at the B3LYP/6-31+G (d, p) level and the 13C NMR calculation at mPW1PW91-SCRF/6-311+g (2d, p). The ECD spectra were generated using the SpecDis 3.0 (University of Würzburg, Würzburg, Germany) and Origin Pro 8.0 (Origin Lab, Ltd., Northampton, MA, USA) from dipole length rotational strengths by applying Gaussian band shapes with sigma = 0.30 eV. Then, the calculated and theoretical values of 13C were analyzed by DP4+ [30].

## *3.5. Anti-Inflammatory Assays*

The RAW 264.7 mouse macrophage cell line was purchased from the Cell Bank of Shanghai Institute of Biochemistry and Cell Biology (Chinese Academy of Sciences, Shanghai, China). Murine macrophage RAW 264.7 cells were cultured in DMEM (high glucose) medium supplemented with 10% (*v/v*) fetal bovine serum, 100 <sup>μ</sup>g·mL−<sup>1</sup> penicillin and streptomycin, and 10 mM HEPES buffer at 37◦C in 5% CO2 in air for 1 h. Cells were pretreated with different concentrations of samples (10, 5, 2.5, 1.25, and 0.625 μM) dissolved in serum-free medium containing 0.5% DMSO for 4 h, followed by stimulation with <sup>1</sup> <sup>μ</sup>g·mL−<sup>1</sup> LPS for 24 h. A total of 50 <sup>μ</sup>L cell culture medium was mixed with 100 <sup>μ</sup><sup>L</sup> Griess reagents I and II and incubated horizontally at room temperature for 10 min. The absorbance was measured at 570 nm [31,32].
