Study on Compounds from Fraxinus Mandshurica Rpur.
|Course||Medical and Biological Engineering|
|Keywords||Oleaceae Fraxinus mandshurica Rupr. Coumarin Phenylethanoid Glycoside target isolation secondary metabolite|
The bark of Fraxinus mandshurica Rupr. can be used as substitutes for Qinpi in Traditional Chinese Medicine. The bark is used for anti-inflammatory and analgesic, popularly on Chinese people only in folk. Consider various aspects of chemical constituents in the bark, study the chemical constituents in the bark is necessary. The Bark of Fraxinus mandshurica Rupr was collected from Changbai Mountain in 2002, identified by professor Jing-min Zhang from Jilin University. In this paper, we infer and research the unknown secondary metabolites, isolate and identify the chemical constituents from the bark.According the known compounds from the Fraxinus species, and on basis of studying the biosynthetic pathway, it is necessary for inferring the unknown chemical constituents. Then design the biosynthesis link contained the known or unknown chemical constituents, which of the new one is the isolated target. For example, the 7-hydroxys of coumarins are from the former of tyrosine, the other hydroxyl groups are biosynthesis on the basis Abstract of enzyme, methylated further. Therefore, if find a coumarin with one hydroxyl group or methoxyl group in a plant, maybe there are other coumarins with multi-hydroxyl groups or methoxyl groups in the plant. On this basis, we can infer the former of one compound or the secondary metabolites in the biosynthesis link.The constituents of the ether-soluble portion, EtOAc-soluble portion and n-butanol soluble portion in the 95% ethanol extract were isolated and purified by means of chromatography. Compounds were identified by ESI-MS, 1H-NMR, 13C-NMR, HMQC and HMBC. They were identified as fraxinol, isofraxidin, fraxetin, aesculetin, mandshurin, isofraxidin-β-D-glycoside, fraxin, isoscopoletin-β-D-glycoside, fraxidin,β-sitosterol, balanophonin, daucosterol, ligsroside, Calceolarioside A, Calceolarioside B, D-galactitol, Calceolarioside A-2’-α-L-rhamnopyranoside, D-man- nitol, 2,2’-(3-methoxy-4-β-Dglucosyl)phenyl-3,3’-bicyclooxaetane, 4-(2-β-D-glucosyl)-benzene-3,4-diol, and 4-(2-β-D-glucosyl) benzene-3,4-dimethoxyl. Among them, there were 2 new compounds in the world, they are 2,2’-(3-methoxy-4-β- Dglucosyl)phenyl-3,3’-bicyclooxaetane, Calceolarioside A-2’-α- L-rhamnopyranoside, and 4-(2-β-D-glucosyl)benzene- 3,4-dimeth- oxyl. 19 compounds were found in the bark of Fraxinus mandshurica Rupr. for the first time.To establish chromatographic fingerprints of Fraxinus mandshurica Rupr., HPLC was used for control its quality. HPLC was employed for study the chromatographic fingerprints of coumarins from Fraxinus mandshurica Rupr. The HPLC fingerprint profiles of Fraxinus mandshurica Rupr. contains 10 common peaks.The relative retention time and the relative area of the common peaks were determined. The fingerprint profile can be used for the identification and quality control of Fraxinus mandshurica Rupr..Due to the pharmacological study, it indicated that the extract of the bark by 95% ethanol could release the pain, and significantly inhibit acute and chronic inflammatory, too. The compound mandshurin is anticancer, effective for SGC 7901.In conclusion, 30 compounds were separated and identified with 2 new compounds. The results suggest that the method used in this experiment is feasible. In addition, this method can be further expanded. According to the reported information of compounds from the plants (such as the structures, activity of the known chemical constituents), which are in the biosynthesis link, infer the structures, physical-chemical characters, ever activity of the unknown secondary metabolites. It was used on this basis to design the method to isolate of the unknown compounds. Based on the structure, polarity, solubility, stability of the predicted compounds, it can infer what is appropriate to isolate the compounds, such as solvent system.