## 4 Materials and Methods
### Extraction and Isolation  
Dried stems and branches of _A. mono_ Maxim. (5.4 kg) were cut into small pieces and extracted with methanol (4 \(\times\) 20 L) under reflux. The MeOH solvent was evaporated under reduced pressure to obtain the MeOH residue (350.0 g), which was subsequently suspended in H\({}_{2}\)O (3 L) and then partitioned with _n_-hexane, CH\({}_{2}\)Cl\({}_{2}\), and EtOAc to obtain the _n_-hexane extract (35.2 g), CH\({}_{2}\)Cl\({}_{2}\) extract (77.8 g), EtOAc extract (62.4 g), and water layer after removing the chemical solvents.  
The CH\({}_{2}\)Cl\({}_{2}\) extract was separated by CC on silica gel using a stepwise eluent of _n_-hexane-acetone (100:1-1:100, _v_/_v_) and CH\({}_{2}\)Cl\({}_{2}\)-MeOH (30:1-1:1, _v_/_v_) to yield seven fractions, 1A-G. Fraction 1D (8.1 g) was chromatographed on silica gel CC, eluted using a gradient mixture of CH\({}_{2}\)Cl\({}_{2}\)-acetone (100:1-1:100, _v_/_v_) and CH\({}_{2}\)Cl\({}_{2}\)-MeOH (20:1-1:1, _v_/_v_), to yield six subfractions, 1D1-6. Subtraction 1D2 (49.7 mg) was separated by RP-18 CC, using a mixture of acetone and H\({}_{2}\)O (1.5:1, _v_/_v_) as the eluent to obtain compound **3** (8.9 mg). Compounds **4** (5.8 mg) and **5** (2.0 mg) were purified from subfractions 1D3 (140.1 mg) and 1D4 (92.2 mg), respectively, by RP-18 CC elution with MeOH-H\({}_{2}\)O (1:1.5, _v_/_v_). Compounds **1** (4.9 mg) and **2** (8.9 mg) were isolated from subfraction 1D6 (223.2 mg) by HPLC using an isocratic mixture of MeOH and distilled H\({}_{2}\)O (40:60, _v_/_v_). Fraction 1E (9.5 g) was separated by silica gel CC, using CH\({}_{2}\)Cl\({}_{2}\)-acetone (gradient 100:1-1:100, _v_/_v_) and then CH\({}_{2}\)Cl\({}_{2}\)-MeOH (gradient 30:1-1:1, _v_/_v_) as the eluent to yield eight subfractions, 1E1\(-\)8. From subfraction 1E7 (239.2 mg), compounds **7** (44.5 mg) and **8** (17.4 mg) were isolated by HPLC, using 52% MeOH in distilled H\({}_{2}\)O as the eluent.  
The water layer was chromatographed by Diaion CC using MeOH-H\({}_{2}\)O (gradient 0:1-1:0, _v_/_v_) as the eluent to yield three fractions, 2A\(-\)C. Fraction 2B (43.7 g) was chromatographed on silica gel and eluted with CH\({}_{2}\)Cl\({}_{2}\)-MeOH (gradient 100:1-1:100, _v_/_v_), followed by RP-18 CC using a MeOH-H\({}_{2}\)O mixture (1.5:1, _v_/_v_) as the mobile phase to obtain four fractions, 2B1\(-\)4. Compound **6** (7.2 mg) was isolated from fraction 2B1 (3.8 g) by HPLC, using an isocratic mixture of MeOH and H\({}_{2}\)O (50:50, _v_/_v_) as the eluent.  
3-(3,4-Dihydrooxyphenyl)-8-hydroxysiocumarin (1), yellow needles, \({}^{1}\)H-NMR (500 MHz, CD\({}_{3}\)OD-4\({}_{4}\)): \(\delta_{\rm H}\) 7.56 (1H, t = 7.9 Hz, H-6), 7.46 (1H, d, \(J\) = 2.0 Hz, H-2'), 7.32 (1H, d, \(J\) = 7.6 Hz, H-5), 7.11 (1H, d, \(J\) = 8.2, 2.0 Hz, H-6), 6.87 (1H, d, \(J\) = 8.1 Hz, H-7), 6.80 (1H, d, \(J\) = 7.6 Hz, H-5'), 6.46 (1H, s, H-4); \({}^{3}\)C-NMR (125 MHz, CD\({}_{3}\)OD-4\({}_{4}\)): \(\delta_{\rm C}\) 167.9 (C-1), 144.1 (C-3), 108.6 (C-4), 116.6 (C-5), 137.8 (C-6), 116.4 (C-7), 158.3 (C-8), 109.9 (C-9), 143.8 (C-10), 126.9 (C-1'), 111.7 (C-2'), 146.5 (C-3'), 147.5 (C-4'), 117.7 (C-5'), 124.2 (C-6').