A new stereoisomer of 8-O-4′ system neolignan, (7R,8S)-1-(3,4- dimethoxyphenyl)-2-[4-(3-hydroxy-1-propenyl)-2-methoxyphenoxy]-propane-1,3-diol (1) and a new stereoisomer of tetrahydrofuranoid lignan, (7R,8S,7'S,8'R)-(3,4,5, 3′,4′)-pentamethoxy-9,7′-dihydroxy-8.8′,7.0. 9′-lignan (2) along with seven known lignans and neolignans (3-9) were isolated from the methanol extracts of the flower buds of Magnolia fargesii. The structures of these compounds (1-9) were elucidated by spectroscopic methods including 1D- and 2D-NMR as well as by comparison with reported values. Absolute configurations of new stereoisomers 1 and 2 were determined by circular dichroism (CD) spectra. The absolute configuration of (S,8S,10S)-[tetrahydro-4- hydroxy-2-(3,4,5-tri-methoxyphenyl)furan-3-yl]methyl 3,4-dimethoxy benzoate (3) was determined by Mosher's esterification method for the first time in this study. Three lignans, tanegool (4), (+)-dehydrodiconiferyl alcohol (5), and epieudes-min (6), were isolated from this plant for the first time. Superoxide radical scavenging activities of the isolates (1-9) were measured by irradiated riboflavin/ethylenediaminetetraacetic acid (EDTA)/Nitroblue tetrazolium (NBT) system, and their in vitro rat lens aldose reductase (RLAR) inhibitory activities were also evaluated.
Bibliographical noteFunding Information:
This work was supported, in part, by Field Technology Research Project through the Korea South-East Power Co., Ltd. (KOEN), Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry (IPET) through Animal Disease Management Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) ( 319078-2 ), and a grant from the Ministry of Science and ICT ( MSIT ) through the National Research Foundation ( NRF ) of Korea [ NRF-2019R1C1C1004572 ; NRF-2019R1A4A1029125 ].
- Aldose reductase
- Diabetic complication
- Magnolia fargesii
- Superoxide radical