Studies On The Chemical Constituents Of Leonurus Macranthus Maxim

Leonurus macranthus Maxim(family Lamiaceae),is mainly distributed in Liaoning,Jilin,and north of Hebei provinces of China.The aerial parts of L.macranthus are used in traditional Chinese medicine for the treatment of menoxenia,dysmenorrhea,and oliguresis.Our previous study indicated the CH2Cl2 portion from acetone extract of the aerial parts of L.macranthus showed inhibition of nitric oxide(NO)production in lipopolysaccharide-activated BV-2 microglial cells.Diterpenoids were detected in the CH2Cl2 portion by LCMS-IT-TOF analysis.In order to clarify the efficacy material basis and its action mechanism,the chemical constituents of CH2Cl2 portion were investigated.Meanwhile,the inhibitory effects of the isolated compounds on NO production in LPS-stimulated BV-2 microglial cells were evaluated in vitro.The results are listed as below.1.The research progress of chemical constituents and bioactivities of Leonurus plants have been reviewed.The main chemical constituents of the plants from this genus are alkaloids,diterpenoids,favonoids,phenolic glycosides,iridoid glycosides,triterpenoids,cyclic peptides,megastigmanes,sesquiterpenoids,among others;The crude extracts and pure compounds from Leonurus plants have been found to exhibit a wide array of biological activities including cardioprotective,neuroprotective,hepatoprotective,anti-inflammatory,analgesic,antioxidative,antioxidant,antiplatelet aggregation,antibacterial,antitumor,and cytotoxic activities.2.The chemical constituents were separated and purified by various column chromatography including silica gel,Sephadex LH-20,ODS,and semipreparative HPLC.Their structures were elucidated on the basis of spectroscopic analysis and physiochemical properties.Fifty-one compounds were identified from the dichloromethane layer of acetone extract of this plant,including 24 diterpenoids:macranthin A(1),6-O-deacetylmacranthin A(2),3-O-acetylmacranthin A(3),15-O-deacetylmacranthin A(4),isomacranthin A(5),6-O-deacetylisomacranthin A(6),19-Odeacetylisomacranthin A(7),macranthin B(8),macranthin C(9),isomacranthin C(10),6-O-deacetylmacranthin C(11),macranthin D(12),15-O-deacetylmacranthin D(13),macranthin E(14),macranthin F(15),3-O-acetyl macranthin F(16),isomacranthin F(17),6-O-acetylmacranthin F(18),6,15-O-diacetyl macranthin F(19),3,6-O-diacetylmacranthin F(20),3,6,15-O-triacetylmacranthin F(21),macranthin G(22),macranthin H(23),macranthin Ⅰ(24);eight nor-sesquiterpenes:(7E,6R,9S)-9-hydroxy-4,7-megastigmadien-3-one(25),(6S,7E)-hydroxy-4,7-megastigma dien-3,9-dione(26),vomifoliol(27),(3S,5R,6S,7E)-3,5,6-trihydroxy-7-megastigmen-9-one(28),(3S,5R,6S,7E,9R)-5,6-epoxy-3,9-dihydroxy-7-megastigmene(29),3,4-dihydroxy-7,8-dihydro-β-ionone(30),loliolide(31),(-)loliolide(32);six lignans:(+)-syringaresinol(33),(+)-1-hydroxysyringaresinol(34),rayalinol(35),erythro-guaiacylglycerol-β-O-4’-coniferyl ether(36),(7R,7’R,7"S,8S,8’S,8"S)-3’,4"-dihydroxy-3,5,4’,5"-tetramethoxy-7,9’:7’,9-diepoxy-4,8"-oxy-8,8’-sesquineo-lignan-7",9"-diol(37),(7R,7’R,7"S,8S,8’S,8"S)-4’,5"-dihydroxy-3,5,3’,4"-tetramethoxy-7,9’:7’,9-diepoxy-4,8"-oxy-8,8’-sesquineo-lignan-7",9"-diol(38);three flavonoids:4,5-dihydroxy-7-methoxyflavone(39),eriodictyol(40),and 3’-hydroxy-genkwanin(41);and 10 other types of compounds:isoscopoletin(42),p-coumaric acid(43),methyl caffeate(44),trans-ferulic acid(45),syringic aldehyde(46),3-hydroxy-4-methoxybenzoic acid(47),oct-1-en-3-yl β-glucopyranoside(48),5-hydroxy-2-pyrrolidone(49),pterolactam(50),and nicotinamide(51).Among the isolates,compounds 1-24 are new ones.3.The NO inhibitory activities of the isolated compounds were evaluated in LPS-stimulated BV-2 microglial cells in vitro.Compounds 1-3,5-10,13,15,21,40,and 41 showed moderate inhibition of nitric oxide production in LPS-stimulated BV-2 cells.