ABSTRACT
Four pyrazines were isolated from the n-butanol fraction of Hypecoum erectum L. by using various chromatographic methods, including MCI gel, ODS, silica gel and semi-preparative HPLC. The structures of the isolated compounds were identified as hyperectpyrazin A (1), 1′S-(6-methylpyrazin-2-yl)-ethane-1′,2′-diol (2), 2-hydroxymethyl-6-methylpyrazin (3) and pyrazine-2-carboxylic acid (4) by spectroscopy methods (1D NMR, 2D NMR, UV, IR, MS, etc.). The absolute configuration of compound 2 was determined by using the Mo2(OAc)4 induced CD analysis for the first time. Compound 1 was a new compound, compounds 2-4 were isolated from H. erectum for the first time. Compounds 1-4 were evaluated for their inhibition against acetylcholinesterase and nitric oxide generation induced by lipopolysaccharide-RAW264.7 macrophage cells. At a concentration of 50 μmol·L-1, compounds 2 and 4 displayed inhibitory effects on acetylcholinesterase with the inhibition rates of 44.40% and 43.99%, respectively.
ABSTRACT
Ten alkaloids(1-10) were isolated from the ethyl acetate extract of the fruit of Lycium chinense var. potaninii by silica gel, ODS, and preparative high performance liquid chromatography(HPLC), and identified by NMR and MS as methyl(2S)-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]-3-(phenyl)propanoate(1), methyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]-3-(phenyl)propanoate(2), 3-hydroxy-4-ethyl ketone pyridine(3), indolyl-3-carbaldehyde(4),(R)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde(5),(R)-4-isopropyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-car-baldehyde(6), methyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]-3-(4-hydroxyphenyl)propanoate(7), dimethyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanedioate(8), 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoate(9), 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid(10). All the compounds were isolated from the plant for the first time. Among them, compounds 1-3 were new compounds. Compounds 1-9 were evaluated for hypoglycemic activity in vitro with the palmitic acid-induced insulin resistance in HepG2 cells. At 10 μmol·L~(-1), compounds 4, 6, 7, and 9 can promote the glucose consumption of HepG2 cells with insulin resistance.
Subject(s)
Lycium/chemistry , Fruit/chemistry , Insulin Resistance , Propionates , Alkaloids/pharmacologyABSTRACT
To prepare composite phospholipid liposomes containing total alkaloids of Strychnos nux-vomica with hydrogenated soybean phosphatidylcholine (HSPC) and 1, 2-dipalmitoyl-sn-glycero-3-phosphacholine (DPPC), and compare with normal DPPC thermosensitive liposomes for thermosensitive release property. Total alkaloids were extracted from S. nux-vomica with the impregnation method and further purified. Liposomes containing total alkaloids, thermosensitive liposomes and conventional thermosensitive liposomes without thermosensitive release property were prepared by ammonium sulfate transmembrane gradients and stealth liposome technique. Their encapsulation efficiency (EE), grain size, zeta potential and drug release behavior were compared. Their EEs and zeta potentials were almost identical; but the grain sizes of composite phospholipid liposomes and thermosensitive liposomes were significantly smaller than conventional liposomes. After comparing release behaviors of the three liposomes at 37, 43 degrees C, we found that the release of composite phospholipid liposomes was significantly lower than that of thermosensitive liposomes at 37 degrees C, but higher than that of thermosensitive liposomes at 43 degrees C. Meanwhile, conventional liposomes, with a very high phase-transition temperature, showed only slight release behavior at both temperatures. The study results showed that composite phospholipid liposomes had a better thermosensitive release behavior when the dosage of lysophosphatidic was reduced by 2. 5 times.