## 3 Material and Method
### Extraction and Isolation  
The gum resin of _B. carterii_ (4.7 kg) was first powdered and extracted sequentially with petroleum ether and methanol to obtain two fractions. The methanolic extract (607.0 g) was chromatographed on a silica gel CC eluted by gradient PE-EtOAc-MeOH (100:0:0-0:100:0-0:0:100) to obtain eight fractions (Fr.1-Fr.8). The Fr. 4 (103.0 g) was separated by MPLC equipped with an MCI column using a gradient mobile phase of McN-H\({}_{2}\)O (40:60-0:100) to give eight fractions (Fr.4-a-Fr.4-h). Fr.4-a (2.9 g) was further separated by MPLC on a C18 column eluted with McN-H\({}_{2}\)O (38:62-0:100) to obtain 11 sub-fractions (Fr.4-a-1-Fr.4-a-11). Fr.4-a-9 (202.0 mg) was subjected to the HPLC eluted with MeOH-H\({}_{2}\)O (25:75) at a flow rate of 3.0 mL/min to give 5 (2.5 mg, t\({}_{\text{R}}\) = 23.3 min).  
Fr.4-b (3.3 g) was separated by MPLC on a C18 column eluted with McN-H\({}_{2}\)O (40:60-0:100) to obtain nine sub-fractions (Fr.4-b-1-Fr.4-a-9). Fr.4-b-4 (214.0 mg) was purified by HPLC eluted by MeOH-H\({}_{2}\)O (55:45) to produce 10 (9.0 mg, t\({}_{\text{R}}\) = 18.5 min). Fr.4-b-6 (147.0 mg) was purified by HPLC eluted with McNN-H\({}_{2}\)O (65:35) to obtain 6 (6.2 mg, t\({}_{\text{R}}\) = 15.0 min). Fr.4-b-7 (102.5 mg) yielded 7 (4.2 mg, t\({}_{\text{R}}\) = 11.7 min) through the HPLC purification using a mobile phase of McN-H\({}_{2}\)O (46:54).  
Fr.4-c (8.5 g) was subjected to the MPLC system constructed with RP-C18 CC eluted McN-H\({}_{2}\)O (30:70-80:20) to obtain 20 products. Compound 9 (1.7 mg) was isolated from Fr.4-c-7 (138.6 mg) by repeated HPLC purification using mobile phases of MeOH-H\({}_{2}\)O (57:43) and MeOH-MeCN-H\({}_{2}\)O (28:28:44). Fr.4-c-10 (512.0 mg) was separated by HPLC eluted with McNN-H\({}_{2}\)O (30:70) and then purified by HPLC eluted with MeOH-MeCN-H\({}_{2}\)O (19:19:62) and MeOH-H\({}_{2}\)O (60:40) to obtain 1 (0.7 mg, t\({}_{\text{R}}\) = 29.0 min) and 4 (4.3 mg, t\({}_{\text{R}}\) = 16.1 min), respectively. Fr.4-c-11 (1.2 g) was repeatedly purified by RP-HPLC eluted with MeOH-MeCN-H\({}_{2}\)O (15:15:70) and MeOH-H\({}_{2}\)O (70:30) to yield 11 (7.0 mg, t\({}_{\text{R}}\) = 20.9 min). Fr.4-c-12 (1.2 g) was chromatographed on a semi-preparative HPLC to obtain Fr.4-c-12-1-Fr.4-c-12-3. Subsequently, Fr.4-c-12-1 (118.0 mg) was purified by the semi-preparative HPLC eluted with MeOH-MeCN-H\({}_{2}\)O (18:18:62) to produce 2 (2.3 mg, t\({}_{\text{R}}\) = 31.0 min) and 3 (2.5 mg, t\({}_{\text{R}}\) = 32.0 min). Compound 12 (10.0 mg, t\({}_{\text{R}}\) = 30.5 min) was isolated from Fr.4-c-12-1-3 (130.0 mg) by HPLC eluted with MeOH-H\({}_{2}\)O (65:35). Fr.4-c-14 (790.0 mg) was purified by the HPLC eluted with McNN-H\({}_{2}\)O (43:57) and MeOH-H\({}_{2}\)O (70:30) to obtain 8 (4.9 mg, t\({}_{\text{R}}\) = 25.0 min).  
_Boswellianol A_ (1). Yellow oil; \([\alpha]^{25}_{\text{D}}\) -12.3 (\(c\) 0.5, MeOH); IR (KBr) \(\
u_{\text{max}}\) 2927, 2870, 1693, 1454, 1384, 1076, 1037 cm\({}^{-1}\); UV (MeOH) \(\lambda_{\text{max}}\) (log \(\varepsilon\)): 258.9 (1.21), 305.2 (1.57) nm;ECD (MeOH) \(\lambda_{\rm max}\) (\(\Delta\varepsilon\)): 236.0 (1.27), 303.8 (1.57) nm; \({}^{1}\)H (CDCl\({}_{3}\), 600 MHz) and \({}^{13}\)C NMR (CDCl\({}_{3}\), 150 MHz) data, see Tables 1 and 3; HR-ESI-MS \(m/z\) 357.2625 [M + H]\({}^{+}\) (calculated for C\({}_{20}\)H\({}_{37}\)O\({}_{5}\) as 357.2636) and 379.2452 [M + Na]\({}^{+}  
(RIPA) buffer with protease inhibitor cocktail (Roche). Total protein was separated by 10% SDS-PAGE Gel and transferred to polyvinylidene dilluoride (PVDF) membranes (Millipore, Burlington, MA, USA). Primary antibodies against Smad2/3, N-cad, and GAPDH were purchased from CST, USA, and pSmad3 and FN were obtained from Abclonal, Wuhan, China. Western blots were imaged using an LI-COR Odyssey imaging system (Lincoln, NE, USA).