| Magnoliae Officinalis Cortex has been extensively used as a traditional Chinese medicine for the treatment of abdominal distention and pain, dyspepsia, and phlegm of cough with asthma. Chemical study was currently focused on its nonpolar ingredients, such as lignans, alkaloids and volatile oil. Honokiol and magnolol were identified to be the major lipophilic compounds, and their contents were used as the index to evaluate the quality of Magnoliae Officinalis Cortex. Traditionally, Magnoliae Officinalis Cortex was taken in water decoction, hydrophilic ingredients were thus regarded to have relation with its clinic effect.Subsequently, in an attempt to search for more active substances from water-soluble portion of Magnoliae Officinalis Cortex, a series of systematic extraction, isolation, and structural elucidation experiments were performed, which resulted in the characterization of four new phenylethanoid glycosides,1-4, six new phenolic glycosides,5-10, and four known compounds. Most of the new compounds contain a rarely occurring allopyranose, which is hardly found in other plants.The compounds were identified as:2-(3,4-dihydroxyphenyl) ethanol 1-O-[4-O-caffeoyl-α-L-rhamnopyranosyl-(1'2)-β-D-glucopyranosyl-(1'6)]-β-D-all opyranoside (1)、2-(3,4-dihydroxyphenyl) ethanol 1-O-[4-O-caffeoyl-β-D-apiofurano-syl-(1'2)-β-D-glucopyranosyl-(1'6)]-β-D-allopyranoside (2) 2-(3,4-dihydroxyphenyl)ethanol1-O-[3-O-caffeoyl-β-D-apiofuranosyl-(1'2)-β-D-g-lucopyranosyl-(1'6)]-β-D-allopyranoside (3)、2-(3-hydroxy-4-Oβ-D-glucopyranos-ylphenyl) ethanol 1-O-[3-O-caffeoyl-α-L-rhamnopyranosyl-(1'2)-β-D-glucopyrano-syl-(1'6)]-β-D-allopyranoside (4)、3,4-dihydroxy-allylbenzene-3-O-[β-D-glucopyra-nosyl-(1'4)-α-Z-rhamnopyranosyl-(1'6)]-β-D-glucopyranoside (5)、 3,4-dihydroxy-allylbenzene-3-O-[β-D-glucopyranosyl-(1'4)-α-L-rhamnopyranosyl-( 1'6)]-β-D-allopyranoside (6)、3,4,5-trimethoxyphenyl-1-O-[β-D-apiofuranosyl-(1' 4)]-β-D-glucopyranoside (7)、3,4,5-trimethoxyphenyl-1-O-[β-D)-apiofuranosyl-(1' 2)]-β-D-allopyranoside (8),1,1’-dibenzene-8’,9’-dihydroxy-3-allyl-(6’-O-β-D-glucopy- ranosyl)-4-O-β-D-gluc-opyranoside (9)、4-(1,2-dihydroxypropyl)-phenol 1-O-{6-O-[4-O-β-D-allopyranosyl]-vanilloyl}-β-D-allopyranoside (10) 2-(3,4-dihydroxyphenyl) ethanol 1-O-[4-O-caffeoyl-α-L-rhamnopyranosyl-(1'2)-α-L-rhamnopyranosyl-(1'3)-β-D-glucopyranosyl-(1'6)]-β-D-glucopyranoside (11)、 icarisides E3 (12)、(-)-8’-epilyoniresin-4-yl/β-glucopyranoside (13)、magnoloside B (14). Among them,1-10 are new compounds, and 11,13 are firstly isolated from Magnolia officinalis.In in vitro tests, compounds 1-3,11, and 14 showed more potent a-glucosidase inhibitory effects (IC50 values in the range 0.29-0.78 mM). Compounds 1-3,11,14 exhib～ited cytotoxic activity against MGC-803, HepG2 cells with IC50 values of 13.5938.51 μM and 27.58-52.20 μM. All the evaluated compounds, except 1 and 14, showed no cytotoxic activity against Vero normal cells.The systematic phytochemistry study resulted in the characterization of six phenylethanoid glycosides and eight phenolic glycosides, which indicatd the glycosides are the main compounds in Magnoliae Officinalis Cortex. The results of in vitro tests showed that the a-glucosidase inhibitory effects and cytotoxic activities of phenylethanoid glycosides were stronger than those of phenolic glycosides, and the phenylethanoid glycosides are the active compouns in Magnoliae Officinalis Cortex. Meanwhile, the ortho phenolic hydroxyls in aglycone contributed to the activities of the phenylethanoid glycosides. |
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