## 4 Materials and Methods
### Extraction and Isolation of Compounds 1-6  
Dried _G. biloba_ leaves (1.7 kg) were subjected to extraction using 80% aqueous methanol (MeOH, 3.0 L) over a duration of three days, followed by filtration. The resulting extract was concentrated using a rotary evaporator, yielding a green crude extract (293.8 g). This concentrated extract was then suspended in distilled water of 700 mL and subjected to solvent partitioning using hexane, dichloromethane (CH\({}_{2}\)Cl\({}_{2}\)), ethyl acetate (EtOAc), and \(n\)-butanol (\(n\)-BuOH), resulting in the isolation of four fractions: hexane-soluble (31.2 g), CH\({}_{2}\)Cl\({}_{2}\)-soluble (5.5 g), EtOAc-soluble (7.0 g), and \(n\)-BuOH-soluble (37.4 g).  
The hexane-soluble fraction underwent further separation through normal-phase silica open column chromatography, employing a gradient solvent system of MeOH/CH\({}_{2}\)Cl\({}_{2}\) (ranging from 1% to 100% MeOH). This process yielded five fractions denoted as H\({}_{\rm A}\)-H\({}_{\rm F}\).  
Fraction H\({}_{\rm D}\) (5.6 g) was subsequently separated into four fractions (H\({}_{\rm D}\)1-H\({}_{\rm D}\)4) via reversed-phase MPLC using a gradient solvent system of MeOH/H\({}_{2}\)O (ranging from 65% to 75% MeOH). Subfraction H\({}_{\rm D}\)3 (277.0 mg) was further fractionated using preparative reversed-phase HPLC, employing a gradient solvent system of MeOH/H\({}_{2}\)O (ranging from 92% to 100% MeOH), resulting in three fractions (H\({}_{\rm D}\)31-H\({}_{\rm D}\)33). Subfraction H\({}_{\rm D}\)33 (68.2 mg) was purified via semi-preparative HPLC using an isocratic system (60% MeCN) to isolate compounds **1** (6.6 mg, \(t_{R}\) = 32.2 min) and **2** (3.6 mg, \(t_{R}\) = 35.0 min).  
Fraction H\({}_{\rm D}\)4 (3.1 g) was divided into three fractions (H\({}_{\rm D}\)41-H\({}_{\rm D}\)43) via normal-phase MPLC using a gradient solvent system of hexane/EtOAc (ranging from 0% to 100% EtOAc). Subfraction H\({}_{\rm D}\)41 (73.1 mg) was further purified via semi-preparative HPLC with an isocratic system (69% MeCN) to isolate compounds **4** (5.6 mg, \(t_{R}\) = 49.5 min) and **5** (2.1 mg, \(t_{R}\) = 81.0 min). Subfraction H\({}_{\rm D}\)42 (1.41 g) underwent further separation into five fractions, designated as H\({}_{\rm D}\)421-H\({}_{\rm D}\)425, utilizing reversed-phase MPLC with a gradient solvent system of MeOH/H\({}_{2}\)O (ranging from 70% to 100% MeOH). Subfraction H\({}_{\rm D}\)423 (67.3 mg) was subsequently subjected to purification via semi-preparative HPLC, employing an isocratic system with 79% MeOH/H\({}_{2}\)O, resulting in the isolation of compound **3** (15.5 mg, \(t_{R}\) = 70.2 min).  
Fraction H\({}_{\rm E}\) (4.3 g) was fractionated into four fractions (H\({}_{\rm E}\)1-H\({}_{\rm E}\)4) using Sephadex LH-20 column chromatography with MeOH. Subfraction H\({}_{\rm E}\)3 (918 mg) underwent further separation through preparative reversed-phase HPLC, employing a gradient solvent system of MeOH/H\({}_{2}\)O (ranging from 40% to 90% MeOH), resulting in five fractions (H\({}_{\rm E}\)31-H\({}_{\rm E}\)35). Subfraction H\({}_{\rm E}\)34 (13.0 mg) was purified via semi-preparative HPLC with an isocratic system (45% MeCN) to isolate compound **6** (0.5 mg, \(t_{R}\) = 47.2 min).