Studies On The Chemical Constituents And Bioactivities Of Morus Wittiorum

Morus wittiorum is the species belonging to the genus Morus of Moraceae.As the relative of the cultivated mulberry,it mostly distributes in the southern area of China.Its roots,twigs,leaves and fruits as well are used as the folk medicine.The bioactive screening on the 95%ethanol extract and water extract of the stem bark of M.wittiorum resulted in:the ethyl acetate fraction from the 95%ethanol extract displayed significant anti-oxidative activity;the acetone fraction and methanol fraction of the 95%ethanol extract and the water extract as well showed remarkable inhibitory activity againstα-glucosidase.The 95%ethanol extract and water extract of the stem bark of M.wittiorum were investigated respectively on their chemical constituents systematically by various kinds of chromatographic methods.The isolates were elucidated on the basis of spectroscopic analysis and chemical methods as well.Some of them in sufficient amount were assayed for their bioactivities.The stem bark of M.wittiorum were collected from Jinxiu county of Guangxi province and identified by professor Shou-Yang Liu,Guangxi College of Traditional Chinese Medicine.Among the seventy-four compounds isolated from the stem bark of M.wittiorum, thirty-one compounds(1-31) are new compounds,and the rest were isolated from this plant for the first time.Sixty-three compounds were isolated and identified from the 95% ethanol extract of the stem bark of M.wittiorum,including twenty-four Diels-Alder type adducts,thirty 2-arylbenzofuran derivatives,six flavonoids,three stilbenes.These compounds are listed as follows:wittiorumin A(1),wittiorumin B(2),wittiorumin C(3), wittiorumin D(4),wittiorumin E(5),wittiorumin F(6),wittiorumin G(7),wittifuran A (8),wittifuran B(9),wittifuran C(10),wittifuran D(11),wittifuran E(12),wittifuran F (13),wittifuran G(14),wittifuran H(15),wittifuran I(16),wittifuran J(17),wittifuran K (18),wittifuran L(19),wittifuran M(20),wittifuran N(21),wittifuran O(22),wittifuran P(23),wittifuran Q(24),wittifuran R(25),wittifuran S(26),wittifuran T(27),wittifuran U(28),wittifuran V(29),wittifuran W(30),wittifuran X(31),chalcomoracin(32), mongolicin F(33),mulberrofuran J(34),mulberrofuran K(35X mulberrofuran G(36), guangsangon L(37),kuwanon J(38),kuwanon X(39),guangsangon G(40), guangsangon B(41),guangsangon D(42),kuwanon P(43),albafuran C(44),sorocein A (45),mulberrofuran E(46),mulberrofuran F(47),mulberrofuran O(48),moracin M(49), moracin C(50),2-(3,5-dihydroxyphenyl)-5,6-dihydroxybenzofuran(51),moracin P(52), mulberroside C(53),austrafuran C(54),quercetin(55),5,7,3',4'-tetrahydroxy-3-metho-xyflavone (56),norartocarpanone(57),dihydrokaempferol(58),euchrenone a₇(59), morachalcone A(60),resveratrol(61),oxyresveratrol(62),4'-prenyloxyresveratrol(63).Eleven compounds were obtained and identified from the water extract of the stem bark of M.wittiorum,including seven polyhydroxyalkalines,two acylamides,one amino acid and betaine.The corresponding compounds are displayed as 1-deoxynojirimycin (64),fagomine(65),3-epi-fagomine(66),1,4-dideoxy-1,4-imino-D-arabinitol(67), 2-O-α-D-galactopyranosyl-1 -deoxynojirimycin(68),4-O-β-D-glucopyranosyl-fagomine (69),1,4-dideoxy-1,4-imino-(2-O-β-D-glucopyranosyl)-D-arabinitol(70),(2S)-citrullina-mide (71),grateloupinamide(72),asparagic acid(73),betaine(74).In addition,the investigations under the guiding of bioassay on the acetone fraction and methanol fraction of 95%ethanol extract respectively indicated that polyhydroxyalkalines were bioactive substances possessing inhibitory activity againstα-glucosidase.The positive ESI-MS/MSⁿ spectra of fifteen 2-arylbenzofuran derivatives (compounds 8-11,13-14,17-18,21-27) were studied.Based on the data analysis,some fragmentation patterns were found.2-arylbenzofuran derivatives with substituents such as isoprenyls,geranyls and so on,usually performed the benzyl fragmentation.Moreover, the substituents often formed the pyran or dihydropyran ring with vicinal hydoxy,which resulted in different fragmentation.In addition,different fragmentation pathway produced various diagnostic ions,which were found for the first time in this thesis,could be used to detect or characterize 2-arylbenzofuran derivatives rapidly.Within the compounds isolated from the stem bark of M.wittiorum,twenty-nine compounds(compounds 1-3,8,10,12-14,16-17,21-23,25-26,33-36,39-41,43,45,47, 49-51,56) inhibited the production of the lipid peroxide induced by Fe²⁺-Cys system in the liver microsomal obviously,with inhibitory rates more than 50%at a concentration of 10^-5 M.On the pharmacological model of release ofβ-glucuronidase from rat PMNs induced by PAF,eleven compounds(compounds 10-11,16,32,34,49-51,54,60,62) displayed antiinflammatory activity with the inhibitory rates more than 50%at a concentration of 10^-5 M.Twenty-six compounds(compounds 8,10-11,13-14,16,21-26,29,32-36,39,47, 50-52,56,61-62) obtained from the stem bark of M.wittiorum displayed moderate inhibitory activity against five human tumor cells(A549,Bel-7402,BGC-823,HCT-8 and A2780) by MTT method.However,compounds isolated from water extract (compounds 64-73) did not show inhibitory activity against any of the five tumor cells (IC₅₀>10μg/ml).The inhibition againstα-glucosidase was performed for ten compounds isolated from water extract of the stem bark of M.wittiorum.The resulst showed that seven polyhydroxyalkalines(compounds 64-70) and one acylamide(compound 72) possessed significant inhibition agaistα-glucosidase,with inhibitory rates over 80%at a concentration of 40μg/mL.Especially for compound 64,IC₅₀= 0.07μM;the IC₅₀ values of compound 68 was 0.39μM,which was comparative to the positive control acarbose (IC₅₀ = 0.52μM).And the IC₅₀ values of compounds 69,70,72 were within 1-5μM.