## 2 Materials and Methods  
### General Information  
The optical rotation was measured on a JASCO DIP-1000 polarimeter (JASCO Co., Tokyo, Japan). Before use, the polarimeter was tested with an aqueous solution of D-glucose (Sigma-Aldrich, St. Louis, MO, USA). when in equilibrium with a stable ratio of \(\alpha\)/\(\beta\)-isomers. Samples were dissolved in methanol for the optical rotation measurements and the concentration was described in g/100 mL. The circular dichroism (CD) measurement was performed for each sample in methanol using a JASCO J-810 CD-ORD spectropolarimeter (JASCO Co., Tokyo, Japan). The CD curves were obtained in a range of 200-400 nm wavelength by 5-fold of accumulation (scanning speed, 100 nm/min; response, 2 s). The NMR experiments were performed on a 600 MHz Varian NMR spectrometer (VNS-600, Palo Alto, CA, USA) and a JNM-ECA 500 MHz NMR instrument (JEOL Ltd., Tokyo, Japan). The acquired \({}^{1}\)H and \({}^{13}\)C NMR data were referenced to \(\delta_{\mathrm{H}}\) 3.31/\(\delta_{\mathrm{C}}\) 49.15 (for methanol-\(d_{4}\) and 1:1 ratio of methanol-\(d_{4}\) and acetone-\(d_{6}\)) and 2.05/29.92 (for acetone-\(d_{6}\)), respectively, and further processed using MestReNova 12.0.1 software (Mestrelab Research SL, Santiago de Compostela, Spain). LR-ESIMS was carried out on an Agilent 6120 series LC-MS system (Agilent Technologies, Santa Clara, CA, USA), equipped with a Luna C18(2) column (3 \(\mathrm{\SIUnitSymbolMicro m}\), 150 mm \(\times\) 4.6 mm i.d., Phenomenex, Torrance, CA, USA). Samples of 0.1 mg/mL in methanol were analyzed, respectively, for 19 min in a gradient solvent system of 5% acetonitrile in water containing 0.05% formic acid and acetonitrile containing 0.05% formic acid at a flow rate of 0.7 mL/min. Mass data were collected over a scan mass range of 100-1000 amu in positive mode. An RP-18 (YMC gel ODS-A, 12 nm, S-75 \(\mathrm{\SIUnitSymbolMicro m}\), YMC Co., Kyoto, Japan) was used for column chromatography (CC). The thin-layer chromatographic (TLC) analysis was performed on a Kieselgel 60 F\({}_{254}\) (Merck, Darmstadt, Germany) and a Kieselgel 60 RP-18-F\({}_{254S}\) device (Merck, Darmstadt, Germany), with visualization under UV light (254 and 365 nm) and by heating at 180 \({}^{\circ}\)C for 2 min after spraying 10% (_v/v_) sulfuric acid. A YMC-Pack ODS-AQ column (5 \(\upmu\)m, 250 mm \(\times\) 20 mm i.d., YMC Co., Tokyo, Japan) and a ChiralPak IF (5 \(\upmu\)m, 250 mm \(\times\) 4.6 mm i.d., Daicel Co., Osaka, Japan) were used for preparative high-performance liquid chromatography (HPLC) that was conducted on a Waters HPLC system (Waters Co., Milford, CT, USA). The medium-pressure liquid chromatography (MPLC) was performed on a CombiFlash Rf200 system (Teledyne ISCO, Lincoln, NE, USA) with RediSep Rf Normal Phase Silica columns. Dulbecco's modified Eagle's medium (DMEM), fetal bovine serum (FBS), and penicillin-streptomycin were purchased from Hyclone (Logan, UT, USA). LPS, dimethyl sulfoxide (DMSO), Griess reagent, and N\({}^{\text{G}}\)-monomethyl-L-arginine acetate salt (L-NMMA) were purchased from Sigma-Aldrich (St. Louis, MO, USA). All other chemicals and solvents used in this study were of analytical grade.