Studies On The Steroid Saponins And Activities Of Polygonatum Odoratum (Mil1.) Druce

The rhizomes of Polygonatum odoratum (Mill.) Druce are widely distributed inChina. The main chemical constituents of P. odoratum are steroidal saponins,homoisoflavonoids, polysaccharide, and so on. It has long been used to promote theproduction of body fluid to quench thirst in traditional Chinese medicine.Pharmacological studies demonstrated immunity improvement, hypoglycemic,anti-aging, etc. Our previous study on the chemical constituents of this plant resultedin the isolation of eighteen compounds, including five new steroidal saponins withoutthe determination of absolute configuration. This research is an ongoing investigationon the chemical constituents and activities of P. odoratum.Objectives: To study the chemical constituents of P. odoratum andpharmacological activities of the isolated compounds.Methods: The chemical constituents were isolated from P. odoratum by Silicagel, Sephadex LH-20, ODS column chromatography, re-crystallization and pre-HPLC.The structures of the compounds were identified on the basis of physical properties,chemical evidence and spectroscopic analysis including MS, NMR, UV, IR. Somecompounds were evaluated for their effect on AMPK activation by Western blot andprotective effect on the oxidative damage of PC12cells by MTT.Results: A phytochemical investigation on the50%and70%ethanol extract ofP. odoratum resulted in the isolation of sixteen compounds, Polygoside A (1),Polygoside B (2),(3,14)-3-O-β-D-glucopyranosyl-(12)-[β-D-xylopyranosyl-(13)]--D-glucopyranosyl(14)-β-D-galcopyranosyl-yamogenin (3),(3,14)-3-O-β-D-glucopyranosyl-(12)-[β-D-glucopyranosyl-(13)]-β-D-glucopyranosyl(14)-β-D-galcopyranosyl-14-hydroxy-(25S)-spirost-5-ene (4),3,14-dihydroxy-(25S)-sipirost-5-ene (5), Polygonatone A (6), Polygonatone B (7), Polygonatone C (8), Polygonatone D (9),(3R)-5,7-dihydroxy-6-methyl-8-methoxy-3-(4’-hydroxybenzyl)-chroman-4-one (10),(3R)-5,7-dihydroxy-6,8-dimethyl-3-(4’-hydroxybenzyl)-chroman-4-one (11),(3R)-5,7-dihydroxy-6-methyl-3-(4’-hydroxybenzyl)-chroman-4-one(12),5,4’-dihydroxy-7-methoxy-6-methylflavane (13), Emodin-8-O--D-glucopyranoside (14), N-trans-feruloyltyramine (15) and P-hydroxybenzoic acid (16).Pharmacology experiments showed that compounds9-12can improve the level of thephosphorylated form of AMPK (pAMPK) and its downstream substrate acetyl-CoAcarboxylase (pACC); compounds1and15had favourable protective effect on PC12cells were subjected to cell oxyradical injury oxidative injury by H2O2, compounds1,10and15had favourable protective effect on cell oxygen deficiency by Na2S2O4.Conclusion: Sixteen compounds were isolated from P. odoratum. Among them,compounds1,2and6-9were new compounds, compounds14and16were isolatedfrom the genus for the first time, and also determined the absolute configuration offive new steroidal saponins which were previously obtained from P. odoratum.Pharmacology experiments demonstrated that compounds9-12exhibited significantactivition on AMPK, compounds1,10and15showed antioxidant activity.