Research On Isolation And Identification Of Catecholamine Derivatives And Nitro Compounds From Portulaca Oleracea L.and Their Bioactivities

Portulaca oleracea L.is an herbaceous succulent annual plant belonging to Portulacaceae family.It is a medicinal herb and also an edible vegetable.The aerial part of P.oleracea is recorded in Chinese Pharmacopoeia,being acidic in taste and cold in nature,possessing heat-clearing and detoxifying,blood-cooling and blood-stopping,as well as dysentery-stopping functions.Pharmacological research demonstrated that extracts of P.oleracea had wide effects,such as anti-bacterial,anti-inflammatory,antioxidant,hypoglycemic,hypolipidemic,anti-tumor,anti-asthma,and immune-modulatory activities.There are several types of chemical constituents in P.oleracea.including alkaloids,organic acids,flavonoids,coumarins,and polysaccharides.However,its bioactive ingredients are not very clear and need to be intensively studied.Our research group previously isolated 30 catecholamine derivatives,including phenylethylamine,isoquinoline,indoline and benzazepine skeleton alkaloids.In addition,a nitro compound was firstly discovered.Thin layer chromatography showed that a lot of unknown catecholamine derivatives and nitro compounds were still present in P.oleracea.Concerning their ?2-adrenergic receptor(AR)agonist and anti-inflammatory dual functions,catecholamine derivatives were hypothesized to be the inflammatory and anti-asthma principles in P.oleracea.The nitro compounds were reported to have anti-microbial activity against Bacillus brevis,Bacillzus subtilis,and Micrococcus luteus,and they were hypothesized to be the anti-bacterial principles in P.oleracea.To date,there are few reports on above two types ofcompounds in P.oleracea.Therefore,in this thesis,we aimed to intensively study the catecholamine derivatives and nitro compounds in P.oleracea,and screen their anti-inflammatory and anti?microbial activities.Compounds were isolated from water extract of P.oleracea through 717 anion exchange resin,silica gel,polyamide and Sephadex LH-20 column chromatography,and their structures were elucidated based on MS,IR,1DNMR,2DNMR data analysis.A total of 21 compounds were isolated and identified,as 2-(3,4-dihydroxy-5-sulfo-6-chlorophenyl)-ethylamine salt(1),2-(3,4-dihydroxy-5-sulfonicphenyl)-ethylamine salt(2),5-sulfonate-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline(3),(2S)-pyroglutamic acid methyl ester(4),(2R)-(-)-2-methoxy-2-(2-sulfonic-3,4-dihydroxyphenyl)-ethyla-mine(5),(1R)-(+)-(1-methanesulfonic)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline(6),adenine(7),(2S)-(-)-2-chloro-3-(3-nitro-4-hydroxyphenyl)-propionic acid(8),(2R)-(+)-2-chloro-3-(3-nitro-4-hydroxyphenyl)-propionic acid methyl ester(9),cis-3-(3-nitro-4-hydroxyphenyl)-methyl acrylate(10),3-methoxy-4,5-dinitrophenol(11),(2S)-(-)-2-chloro-3-(3,5-dinitro-4-hydroxyphenyl)-methyl propionate(12),trans-3-(3-nitro-4-hydroxyphenyl)-methyl acrylate(13),L-threonine(14),(2S)-(-)-2-chloro-3-(3,5-dinitro-4-hydroxyphenyl)-propionic acid(15),trans-3-(3-nitro-4-hydroxyphenyl)-acrylic acid(16),(2R)-(+)-2-hydroxy-3-(3,5-dinitro-4-hydroxyphenyl)-propionic acid methyl ester(17),(1R)-(+)-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline(18,salsolinol),6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline(19),(1R)-(+)-benzyl-6,7-dihydroxy-l,2,3,4-tetrahydroisoquinoline(20),L-tyrosine methyl ester(21).Among them,7 new compounds(1,3,5,6,8,15,17)were named portulacacid A-G;3 compounds(2,13,16)were new natural products;except 4,7,14,18.20,21 other 15 compounds were isolated from P.oleracea for the first time.Anti-inflammatory activity screening indicated that,compounds 8-13,15-17 inhibited NO over-production in different degree in LPS-treated RAW 264.7 macrophage cells,of which compound 10 had the strongest anti-inflammatory activity with the EC50 value of 17.96 ?M.Compounds 8-11 were screened for anti-fungal activity against Candida albicans,using broth microdilution assay.Results showed that only compound 9 showed inhibition against C.albicans,with the MIC value of 64-128 ?g/mL,and other compounds had no activity.Compound 11 was screened for anti-bacterial activity against Staphylococcus aureus,Bacillus subtilis and Shigella sonnei.Results showed that compound 11 only inhibited the growth of S.sonnei and the MIC value was 128-256?g/mL.All of these bioactivities of compounds 9-11 were discovered for the first time.