Careyarboside A: A New Flavan-3-ol Glycoside from the Stems of Careya arborea (Lecythidaceae)

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Plant Material.
In September 2015, stems of C. arborea were taken from Cambodia's Seima Protection Forest for the present investigation.Botanical identifcation was made by one of the authors (Dr.H. E. Keo Omaliss), and a voucher specimen (CA101) of the plant was placed at the laboratory of natural products research team, Gyeonggido Business & Science Accelerator.

Acid Hydrolysis.
A solution of compound 1 (2 mg) in 2 M HCl/MeOH (4 : 1, 5 mL) was heated in a water bath for 6 h with the temperature at 80 °C.Te reaction mixture was cooled, then diluted with water (15 mL), neutralized with NaHCO 3 , and extracted with EtOAc (3 × 15 mL).For sugar analysis, the aqueous layer was concentrated to an adequate level (1 mL) and analyzed by TLC (silica gel) using the solvent system CHCl 3 /MeOH/H 2 O (70 : 30 : 1).Using a vanillin-sulfuric acid spray followed by heating, a spot was detected.Te R f value of glucose was 0.25.Tus, the sugar component was identifed as glucose.Te optical rotation of the water solution was determined to be [α]  [20].On the other hand, the aglycone migrated into the EtOAc layer.Te combined EtOAc-soluble extracts were evaporated to dryness to yield the aglycone.For further purifcation, the aglycone was subjected to fash column chromatography on RP-18 and eluted with an MeCN -H 2 O gradient system (10 :

Figure 4 :
Figure 4: HPLC-PDA chromatographic profle of the EtOH extract from Careya arborea stems was recorded at 210 nm.
Figure S5: HSQC spectrum of the compound 1.
Figure S13: ESI-MS spectrum of the compound 2.
Figure S16: ESI-MS spectrum of the compound 3.
Figure S19: ESI-MS spectrum of the compound 4.
Figure S21: 13 C-NMR spectrum of the compound 5. Figure S22: ESI-MS spectrum of the compound 5.
Figure S25: ESI-MS spectrum of the compound 6.
a Assignments confrmed by1H-1 H COSY, HSQC, and HMBC experiments.b Measured for pyridine-d 5 solution.c Measured for CD 3 OD solution.d Carbon multiplicity deduced by HSQC and DEPT.