Bioactive Compounds From Four Medicinal Plants

The organic anion transporters(OATs in humans or Oats in rodents)play key roles in the distribution and excretion of drugs.Specifically,OAT1 and OAT3 play important roles in the renal elimination of a range of substrate molecules.Little is known about natural products that can modulate OAT1 and OAT3 activities.To study the interactions of phytochemicals in Juncus effusus,Primula macrocalyx,and Artemisia lercheana with OAT1 and OAT3,a bioactivity guided phytochemical investigation was performed to obtain a series of compounds,some of which are responsible for the initial observed activities.Sevenpreviouslyundescribedphenanthrenoids,including7-carboxy-2-hydroxy-1-methyl-6-vinyl-9,10-dihydrophenanthrene(JED1),7-carboxy-2-hydroxy-1-methyl-8-vinyl-9,10-dihydrophenanthrene(JED2),6-carboxy-2-hydroxy-1-methyl-8-vinyl-9,10-dihydrophenanthrene(JED3),2-hydroxy-7-hydroxymethyl-1-methyl-8-vinyl-9,10-dihydrophenanthrene(JED4),2-hydroxy-7-hydroxymethyl-1-methyl-8-vinylphenanthrene(JED5),2,7-dimethoxy-1-methyl-5-vinylphenanthrene(JED6),7-hydroxy-2-methoxy-1,6-dimethyl-5-vinyl-phenanthrene(JED7),along with twelve known compounds,including juncusol(JED8),effusol(JED9),7-carboxy-2-hydroxy-1-methyl-5-vinyl-9,10-dihydrophenanthrene(JED10),2,7-dihydroxy-5-(1-methoxyethyl)-1-methyl-9,10-dihydrophenanthrene(JED11),jinflexin A(JED12),dehydrojuncusol(JED13),dehydroeffusol(JED14),2,7-dihydroxy-1,6-dimethylpyrene(JED15),4,4?-dihydroxy-3,3?-dimethoxy-benzophenone(JED16),N-(N-benzoyl-L-phenylalanyl)-L-phenylalanol(JED17),aurantiamide acetate(JED18),and2-(3''-methoxy-4''-hydroxybenzyl)-3-(3'-methoxy-4'-hydroxybenzyl)-?-butyrolactone(JED19),were isolated from the active dichloromethane soluble fraction of a methanol extract of the medullae of J.effusus.Compounds JED16-19 are here initially reported as metabolites of the Juncaceae family.Two previously undescribed flavones,2?-methoxy-5?-hydroxyflavone(PMD5)and 5,6,8,2?,6?-pentamethoxyflavone(PMD11),along with ten known flavones,including 3?-methoxyflavone(PMD1),flavone(PMD2),2?-methoxyflavone(PMD3),2?,5?-dimethoxyflavone(PMD4),3?-hydroxy-4?,5?-dimethoxyflavone(PMD6),5,6,2?,6?-tetramethoxyflavone(PMD7),5,6,2?,3?,6?-pentamethoxyflavone(PMD8),3'-hydroxyflavone(PMD9),2'-hydroxyflavone(PMD10),5,6,2?-trimethoxyflavone(PMD12),Riccardin C(PMD13),5-methoxy-2-?-primverosyloxy-benzoic acid methyl ester(PMB14),4-methoxy-2-?-primverosyloxy-benzoic acid methyl ester(PMB15),and kaempferol-3-O-?-D-[xylopyranosyl-(1?2)-?-D-glucopyranosyl-(1?6)-?-D-glucopy ranoside](PMB16),were isolated from the active dichloromethane soluble fraction and inactive n-butanol soluble fraction of a methanol extract of the entire plant of P.macrocalyx.Nine compounds PMD1-3,PMD6,PMD7,PMD10,and PMB14-16 are reported for the first time from P.macrocalyx.Compounds PMD9 and PMD12 are here initially reported as metabolites of the Primulaceae,and PMD9 is newly described as a natural product.A pair of known isomers,3,5-dicaffeoylquinic acid(ALB1)and4,5-dicaffeoylquinic acid(ALB2),were isolated from an active n-butanol soluble fraction of a methanol extract of the stems and roots of A.lercheana.These two dicaffeoylquinic acids were isolated from A.lerchiana for the first time.The structures were established by extensive spectroscopic analysis,including HRESIMS,UPLC-MS,UV,ECD,and 1D and 2D NMR experiments,together with comparison with those in previous reports.The compounds isolated from active fractions were evaluated for inhibition of OAT1 and OAT3 in vitro.Two dihydrophenanthrenes(JED1,JED10),a benzophenone(JED16),and six flavones(PMD2,PMD3,PMD6-8,and PMD12)showed good concentration-dependent inhibition on 6-CF uptake by OAT1 with IC₅₀?10?M.Six dihydrophenanthrenes(JED1-3,JED8,JED10,and JED11),a benzophenone(JED16),and seven flavones(PMD2,PMD3,PMD6-9,and PMD12),showed good concentration-dependent inhibition on 6-CF uptake by OAT3 with IC₅₀<10?M.These compounds account for the inhibitory activities observed in the initial fractions.To our knowledge,this study is the first to evaluate two dicaffeoylquinic acids(ALB1-2),fifteen phenanthrenoids(JED1-15),a benzophenone(JED16),two amides(JED17-18),a lignan(JED19),and twelve flavones(PMD1-12)as inhibitors of the OAT1 and OAT3.In addition,one new dihydrophenanthrene JED1 markedly altered the pharmacokinetic parameters of the diuretic drug,furosemide,a known substrate of both OAT1 and OAT3,in vivo,which may provide a basis for further drug development.In recent years,there has been renewed interest in antimicrobial agents from plants due to their ethnomedicinal uses,and low toxicity and side effects.Herein,antimicrobial activities of crude fractions from the above plants were tested against sixteen microorganisms to screen for potential antimicrobial agents.The dichloromethane fraction of the methanol extract of P.macrocalyx showed marked antifungal activity against the yeast strain,Candida rugosa.Three flavones(PMD7,PMD8,and PMD12)showed marked antifungal activities with MIC<2.0?M.To our knowledge,this study is the first to evaluate twelve flavones(PMD1-12)as antifungal agents against C.rugosa.Phytochemical investigation of the ethyl acetate soluble fraction of Mirabilis himalaica roots has led to the isolation and identification of six previously undescribed flavonoids,including 2S-5-methoxy-6-methyl-7,2?-dihydroxyflavanone(ME1),5,7,2?-trihydroxy-6-methylflavone(ME3),5,7,6?-trihydroxy-6-methylcoumaronochromone(ME4),2,4?,6?-trihydroxy-2?-methoxy-3?-methylchalcone(ME5),6R,11-dimethoxy-9-hydroxyrotenoid(ME6),and6R,11-dimethoxy-9-hydroxy-10-methylrotenoid(ME7),along with eight known flavonoids,including 2S-5-methoxy-6-methyl-7,4?-dihydroxyflavanone(ME2),not previously reported as a natural product,and seven rotenoids,boeravinone A(ME8),boeravinone B(ME9),boeravinone D(ME10),boeravinone P(ME11),boeravinone F(ME12),coccineone B(ME13),and mirabijalone E(ME14).These compounds were evaluated for their cytotoxic activities against three human cancer cell lines:A375(melanoma),A549(lung),and PLC(hepatoma).Results showed that compound ME5 exhibited moderate cytotoxicities for PLC and A375 cells,while compounds ME8 and ME10 exhibited moderate cytotoxicity for A549 cells.For known compounds,this is the first report for the cytotoxicity against A375,A549,and PLC for ME2,ME11,and ME13,and also the first report for the cytotoxicity against A375 and PLC for ME8-10,ME12,and ME14.