The Studies On The Chemical Constituents From The Fruits Of Melia Toosendan Sieb.et Zucc.and Biological Activities

ObjectiveTo study the chemical constituents from the dried fruits of Melia toosendan Sieb.et Zucc.To evaluate theα-glucosidase inhibitory activities and anti-tumor activities in vitro.MethodsAir-dried fruits of M.toosendan were extracted three times with 95%Et OH under reflux conditions.After evaporation of the ethanol under reduced pressure,the crude extract was suspended in H₂O and then partitioned with petroleum ether（PE）,ethyl acetate（EA）,n-butanol（n-Bu OH）,successively.The EA-soluble fraction was isolated systematically and purified by silica gel column chromatography,ODS column chromatography,thin layer chromatography（TLC）,high performance liquid chromatography（HPLC）and preparative high performance liquid chromatography（Pre-HPLC）.The structures of compounds were identified by nuclear magnetic resonance spectra(¹H NMR,¹³C NMR,HSQC,HMBC,¹H-¹H COSY,NOESY),high resolution electrospray ionization mass spectroscopy（HRESIMS）,ultraviolet spectra（UV）.The isolated triterpenoids were evaluated for theirα-glucosidase inhibitory activities and anti-breast cancer cell（MCF-7）activities.ResultsThe 29 triterpenoids were isolated from the ethyl acetate part of 95%ethanol extract of fruits of M.toosendan and identified as 12α-ethoxyl nimbolinin A（1）,Meliatoosenin T（2）,Nimbolinin G（3）,Meliatoosenin U（4）,Nimbolinin H（5）,Nimbolinin I（6）,12α-ethoxyMeliatooseninL（7）,NimbolininJ（8）,1α,7α-ditigloyloxy-3α-acetoxyl-12α-ethoxyl-nimbolinin（9）,12-O-ethyl nimbolinin B（10）,12-O-methyl nimbolinin B（11）,12-O-methyl-1-O-deacetyl nimbolinin B（12）,12-O-ethyl-1-O-deacetyl nimbolinin B（13）,12-ethoxy nimbolinin B（14）,12α/β-1-O-tigloyl-1-O-deacetyl-nimbolinin B（15）,Toosendansin M（16）,Toosendansin N（17）,Ohchinolal（18）,Spirosendan M（19）,Mesendanin K（20）,Meliatoosin D（21）,21β-ethoxyl agladupol E（22）,Meliatirucallane M（23）,Mesendanin V（24）,isoxylocarpol D（25）,Cinamodiol（26）,MeliaseninG（27）,21R,23R-epoxy-21α-ethoxy-24S,25-dihydroxy-apotirucall-7-en-3-one（28）,Toosendine E（29）.Compounds 25 and 26 showed inhibitory activity againstα-glucosidase with IC₅₀values of 120.3±5.8 and 104.9±7.1μM.The limonoids showed weak inhibitory effect on breast cancer cells,with IC₅₀values greater than 50μM.ConclusionsThe 29 triterpenoids isolated from the M.toosendan,of which 16 were unreported compounds,were classified into six structural types.Compounds 1-15 were nimbolinin-type limonoids;compounds 16-18 were nimbin-type limonoids;compound 19was spiro-type limonoid;compounds 20,21 were havanensin-type limonoids;and compounds 22-29 were tirucallane-type triterpenoids.Among them,compounds 1-8,16,17,19,20,22-25 were new compounds.Compounds 25 and 26 showed inhibitory effects onα-glucosidase in vitro.The results of anti-tumor activity showed that limonoids had almost no inhibitory effect on breast cancer cells.