Isolation,Purification And Identification Of Chemical Constituents From The Twigs Of Morus Nigra L.,a Traditional Uygur Medicine

Object:1.The chemical components of the ethyl acetate part of the 95%ethanol extract of the twigs of M.nigra were studied to provide a material basis for screening its biological activity.2.The preliminary determination of the activity of some of the isolated monomeric compounds provides some data support for the screening of active compounds.Methods:1.The ethyl acetate part of the twigs of M.nigra was separated and purified by HP20 macroporous resin column chromatography,normal phase silica gel column chromatography,Sephadex LH-20 gel column chromatography and semi-preparative liquid chromatography.2.The structure of the compounds was identified using ultraviolet spectroscopy（UV）,High-resolution electrospray ionization mass spectroscopy（HR-ESI-MS）,one-dimensional nuclear magnetic technology(¹H-NMR,¹³C-NMR,DEPT135)and two-dimensional nuclear magnetic technology（HSQC,HMBC,¹H-¹H COSY）in combination with literature and databases.3.The antioxidant activity and cancer cell inhibitory activity of some compounds were determined by DPPH radical scavenging and MTT assay,respectively.Results:1.34 monomer compounds were isolated and identified from the twigs of M.nigra,including five new compounds:2’,4’,2’’-trihydroxychalcone-4’’-O-β-D-glucopyranoside（1）,3,7-dihydroxy-4-prenylcoumarin（2）,mornigrol J（3）,mornigrol I（4）,mornigrol K（5）。29 known compounds:quercetin（6）,2,4-dihydroxybenzaldehyde（7）,Isolariciresinol（8）,Dihydrodehydrodiconiferyl alcohol（9）,2,4-Dihydroxybenzoic acid（10）,aromadedrin（11）,1,3-bis（2,4-dihydroxyphenyl）-1-acetone（12）,resveratrol（13）,moracin M（14）,Eriodictyol（15）,Steppogenin（16）,taxifolin（17）,3-O-methylquercetin（18）,3-O-methylquercetin-7-O-β-D-glucopyranoside（19）,Morin（20）,quercetin-3’-O-β-D-glucopyranoside（21）,quercetin-4’-O-β-D-glucopyranoside（22）,Linolenic acid（23）,ethyl linoleate（24）,ethyl 2,4-dihydroxybenzoate（25）,nigranol A（26）,moracin B（27）,7-Hydroxycoumarin（28）,syringaresinol（29）,Pinoresinol（30）,Nigrasin D（31）,Nigrasin C（32）,nigragenon E（33）,davidigenin（34）.2.All the selected compounds in the antioxidant activity experiments had an antioxidant ability,and the scavenging ability of DPPH radicals was compound 20>27>16>9>19>1>11,and the scavenging ability of compounds 20 and 27 was comparable to that of the positive control drug Trolox.The results of the cancer cell growth inhibitory activity assay showed that compounds 9,14 and 27 all had a dose-dependent inhibitory effect on the growth of gastric cancer cells MGC-803,and the inhibitory ability showed that compound 14>27>9.Compound 14 may be a good inhibitor of gastric cancer cell growth.Conclusions:1.The 34 monomeric compounds obtained contained one chalcone,seven flavonols,three dihydroflavonols,two dihydroflavonoids,one stilbene,four benzofurans,four sanggenon-type flavanones,two coumarins,three lignans,five benzene ring derivatives,and two long-chain fatty acid esters.2.Compounds 1,2,3,4,and 5 are new compounds,and compounds 1,2,3,4,5,8,9,10,12,15,16,18,19,22,25,27,34 are isolated from M.nigra for the first time.3.The 34 monomeric compounds obtained were dominated by the number and content of flavonoids,suggesting that flavonoids may be the main material basis for the pharmacological activity of M.nigra.4.There are certain pharmacological activities of antioxidation and inhibiting the growth of gastric cancer cells of the twigs of M.nigra,and it is expected to find some chemical components with good biological activity from it.