Insight into tetrahydrofuran lignans from Isatis indigotica fortune with neuroprotective and acetylcholinesterase inhibitor activity Author Xi, Yu-Fei , Ming Bai &, Xin Zhang &, Zi-Lin Hou &, Bin Lin &, Li-Li Lou & *, &, Xiao-Xiao Huang & ** & Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research & Development, Liaoning Province; Engineering Research Center of Natural &, Ming Bai &, Xin Zhang Author Bai, Ming Author Zhang, Xin Author Hou, Zi-Lin Author Lin, Bin Author Yao, Guo-Dong Author Lou, Li-Li Author Wang, Xiao-Bo Author Song, Shao-Jiang Author Huang, Xiao-Xiao text Phytochemistry 2023 113609 2023-04-30 208 113609 113609 http://dx.doi.org/10.1016/j.phytochem.2023.113609 journal article 10.1016/j.phytochem.2023.113609 1873-3700 8160720

Table 1 1 H (400 MHz) and 13 C NMR (100 MHz) spectroscopic data of 1 and 2 in DMSO‑ d 6.

Position	1		2
	δ H (multi, J in Hz)	δ C	δ H (multi, J in	δ C
			Hz)
1	–	133.6	–	133.7
2	7.07, d (1.4)	110.7	7.05, d (1.4)	110.8
3	–	147.4	–	147.4
4	–	145.9	–	145.9
5	6.76, overlapped	115.1	6.76, d (8.1)	115.2
6	6.88, overlapped	119.0	6.91, dd (8.1,	118.8
			1.4)
7	5.00, d (9.5)	81.9	5.01, d (9.4)	81.0
8	2.72, m	59.8	2.77, m	60.3
9	3.22, dd (10.5, 5.2); 3.16, dd	58.1	3.24, m	58.3
(10.5, 5.0)
1′	–	51.9	–	52.0
2′	6.14, s	113.1	6.24, s	114.5
3′	–	151.0	–	150.3
4′	–	175.4	–	175.7
5′	–	150.4	–	151.3
6′	6.11, s	119.0	6.18, s	118.6
7′	4.67, overlapped	83.8	4.70, d (4.9)	84.4
8′	4.34, m	78.3	4.10,	78.0
			overlapped
9′	3.72, m; 3.57, m	60.8	3.40, m	59.4
1′′	–	129.4	–	130.0
2′′	6.87, overlapped	108.9	6.99, d (1.3)	109.9
3′′	–	148.9	–	149.5
4′′	–	146.4	–	147.1
5′′	6.77, overlapped	113.4	6.84, d (8.4)	114.8
6′′	6.72, d (8.2)	118.5	6.82, dd (8.4,	119.0
			1.3)
7′′	6.39, d (15.9)	128.8	6.42, d (15.9)	128.5
8′′	6.19, dt (15.9, 5.3)	128.1	6.22,	128.5
			overlapped
9′′	4.07, br s	61.7	4.07, d (5.2)	61.6
4-OH	8.91, br s	–	8.94, br s	–
9-OH	4.37, overlapped	–	No observed	–
9′-OH	4.67, overlapped	–	No observed	–
9′′ -OH	4.78, t (5.1)	–	No observed	–
3-OCH3	3.80, s	55.6	3.79, s	55.6
3′-OCH3	3.54, s	54.5	3.48, s	54.4
5′-OCH3	3.55, s	54.5	3.59, s	54.9
3′′ -	3.64, s	55.0	3.74, s	55.6
OCH3