Studies On The Chemical And Bioactive Constituents Of Gynostemma Pentaphyllum And Alisma Orientalis

Two traditional Chinese medicines(TCMs),Gynostemma pentaphyllum (Cucurbitaceae) and Alisma orientalis(Alismataceae),have been chemically and biologically investigated.Five new and twenty-four known compounds were isolated using column chromatography(CC) over silica gel,macroporous resin,polyamide resin,MCI gel,Sephadex LH-20,Toyopearl HW-40s,and semipreparative HPLC. Their structures,especially the absolute stereochemistry of the new compounds,were characterized on the basis of extensive spectroscopic methods(IR,UV,1D-/2D-NMR, LR-/HR-ESIMS,Circular Dichroism) and some chemical transformations.From the whole plant of Gynostemma Pentaphyllum,five new megastigmane glycosides(1-5) together with seven(6-12) related known compounds were isolated. The new structures were elucidated to be(3R,4R,5S,6S,7E)-3,4,6-trihydroxymegastigmane-7-en-9-one-3-O-β-D-glucopyranoside(gynostemoside A,1), (3S,4S,5R,6R,7E,9R)-3,4,6,9-tetrahydroxy-megastigmane-7-en-3-O-β-D-glucopyranoside (gynostemoside B,2),(3S,4S,5S,6S,7E,9R)-3,4, 9-trihydroxymegastigmane-7-en-9-O-β-D-glucopyranoside(gynostemoside C,3),(3S, 4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-3-O-β-D-glucopyranoside (gynostemoside D,4),and(3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-4-O-β-D-glucopyranoside(gynostemoside E,5).The known compounds 6-12 were all isolated from this plant for the first time.Compounds 1-12 were subjected to the cellular-based klotho promoter bioassay,but were found inactive.In addition,the isolated compounds were tested against human lung adenocarcinoma(A549,H460), human glioma(U251),human osteosarcoma(U2OS),and human breast(MCF-7) cancer cells,but none of them was found to have cytotoxic effects.Using a bioassay-guided isolation procedure,seventeen compounds(13-29) were obtained from the methanol extract of the rhizome of Alisma orientalis.Their structures were determined to beα-D-fructofuranose(13),β-D-fructofuranose(14), ethylα-D-fructofuranoside(15),ethylβ-D-fructofuranoside(16),5-hydroxymethyl-furaldehyde (17),sucrose(18),raffinose(19),stachyose(20),verbascose(21), manninotriose(22),verbascotetraose(23),sulfoorientalol A(24),adenosine(25), uridine(26),adenine(27),and glycerol(29).Compounds 15,16 and 19-23 were isolated from this plant for the first time.A hypothetical biosynthesis pathway among the isolated carbohydrates(13-23) was briefly introduced.All the purified compounds were subjected to the cellular-based M₁ receptor bioassay,and only compound 24 was found to show primary bioactivity.