Compounds
HSG4112 and all other glabridin-derivative compounds were prepared at
Glaceum Inc. (Suwon, Republic of Korea) following the protocols from
US9783551B2 (Yoo, 2017). Glaceum Inc. holds all IPs for synthesis,
method, and use of all compounds in this paper as well as other
unmentioned glabridin-derivatives. Commercially available glabridin
(Sigma-Aldrich Co., St. Lousi, MO, USA) was used. Absolute configuration
nomenclature (R /S ) was used instead of optical rotation
nomenclature (+/−) because (R ) form of C-4’ methylated
dihydro-glabridin and HSG4112 showed levorotary (−) optical rotation
while (R ) form of glabridin and 3”,4”-dihydro-glabridin showed
dextrorotary (+). The preparation of vehicle and test substances were
carried out once a week during the administration period.