Abstract:
This study utilized a chiral liquid chromatography-mass spectrometry (LC
-MS)-guided isolation strategy to accurately capture angular-type pyranocoumarins (APs) in Peucedani Radix (Chinese name: Qianhu). Sixteen APs were successfully purified from the ethyl acetate extract of Peucedani Radix through deploying various techniques such as silica gel, ODS, Sephadex LH-20, and achiral (chiral) semi-preparative liquid chromatography. After extensive structural measurements, such as
1H and
13C NMR spectroscopy, their structures were identified as (3′
S)-3′-(2-methyl-butyroyl)-4′-oxo-3′, 4′-dihydroseselin (
1A), (3′
R)-3′-(2-methyl-butyroyl)-4′-oxo-3′, 4′-dihydroseselin (
1B), (3′
S)-3′-isovaleryl-4′-oxo-lomatin (
2A), (3′
R)-3′-isovaleryl-4′-oxo-lomatin (
2B), (3′
S)-3′-angeloyloxy-4′-oxo-3′, 4′-dihydroseselin (
3A), (3′
R)-3′-angeloyloxy-4′-oxo-3′, 4′-dihydroseselin (
3B), (3′
S, 4′
S)-praeruptorin B (
4A), (3′
R, 4′
R)-praeruptorin B (
4B), (3′
S, 4′
S)-praeruptorin E (
5A), (3′
R, 4′
R)-praeruptorin E (
5B), 3′-isovaleryl-4′-angeloyl-
cis-khellactone (
6), 3′-angeloyl-4′-(2-methyl-butyroyl)-
cis-khellactone (
7), (3′
S, 4′
S)-praeruptorin A (
8A), (3′
R, 4′
R)-praeruptorin A (
8B), (3′
S, 4′
S)-khellactone (
9A), and (3′
R, 4′
R)-khellactone (
9B), respectively. Thereof, compounds
1A and
1B were new compounds, while compound
2A represents a new configuration for a known planar structure. Compounds
2A and
2B were isolated for the first time from Peucedani Radix. Above all, chiral LC
-MS-guided isolation strategy is advantageous at rapid capturing new compounds from herbal medicines, providing an effective means for the separation of novel structures, especially new enantiomers.