The Isolation And Identification Of Diterpenoids From Rabdosia Rubescens

ObjectiveRabdosia rubescens(Hemls.)Hara,a perennial herb of the genus Isodon that is widely distributed in Henan,Hubei,Guizhou,Anhui.The dry aerial part of R.rubescens was developed into a drug,which has anti-inflammatory,anti-bacterial,anti-tumor and antioxidant biological activities.Diterpenoids,flavonoids,steroids and other compounds have been isolated from R.rubescens,among which diterpenes are the main components.In this paper,the chemical constituents and anti-inflammatory activities of Rabdosia rubescens were studied to lay the foundation for elucidating the mechanism in the treatment of inflammatory diseases.MethodsThe dry aerial part of Rabdosia rubescens 20kg was extracted with 95%ethanol at 78℃,and then extracted with petroleum ether,ethyl acetate,and n-butanol in sequence to obtain 242g,510g,and 372g of extracts,respectively.The compounds were isolated and purified by normal phase silica gel,ODS,hydroxypropyl glucan gel,high performance liquid chromatography and other chromatographic methods from ethyl acetate extract.The structures of the compounds were determined by nuclear magnetic resonance,infrared spectroscopy,ultraviolet spectroscopy,high resolution mass spectrometry and rotary spectroscopy,etc.ResultsForty compounds were isolated from the ethyl acetate extract of Rabdosia rube scens,which were 16(S)-1α,6β,7β-trihydro-xy-17-ethyloxy-7α,20:14α,20-diepoxy-ent-ka ur-15-one(RR-1)、16(R)-1α,6β,7β-trihydroxy-17-ethyloxy-7α,20:14α,20-diepoxy-ent-kau r-15-one(RR-2)、3α,6β,14β,15β-tetrahydroxy-20-nor-ent-kaur-16(17)-en-7-one(RR-3)、1α,6β,15β-trihydroxy-20-ethyloxy-11α,20-epoxy-ent-kaur-16(17)-en-7-one(RR-4)、1α,6β,15β-trihydroxy-14α,20-olide-ent-kaur-16(17)-en-7-one(RR-5)、6β,7β,14β-trihydroxy-15Acetoxy-7α,20-epoxy-ent-kaur-16-ene(RR-6)、1α,6β-dihydroxy-7,16,20-trioxo-ent-abiet a-15-en-7-one(RR-7)、1β,6β-dihydroxy-7,16,20-trioxo-abieta-5(6),15(17)-diene-7-one(R R-8)、1α,7β-dihydroxy-6,16,20-trioxo-ent-abieta-7(8),15(17)-diene-6-one(RR-9)、(3α,14β)-14,16-epoxy-3,18-[1’(S)-(2’,5’-N-hetero)butane-3’(4’)-5’-one]dioxy-ent-abieta-7,15(17)diene(RR-10)、(3α,14β)-14,16-epoxy-3,18-[1’(S)-(2’,6’-N-hetero)pentane-3’(4’)-5’-one]dio xy-ent-abieta-7,15(17)-diene(RR-11)、isodonhenrin E(RR-12)、rabdoternin A(RR-13)、rabdoternin B(RR-14)、15α-hydroxy-6,7-seco-1α,7:11α,6-diolide-ent-kaur-16-ene(R R-15)、rubescensin B(RR-16)、Isorosthornin A(RR-17)、6β,7β,14β,15β-tetrahydroxy-7α,20-epoxy-ent-kaur-16-ene(RR-18)、hebeiabinin C(RR-19)、lushanrubescensin I(R R-20)、Jianshirubesin I(RR-21)、rabdolasional(RR-22)、rubescensin W(RR-23)、t richokaurin(RR-24)、hebeirubescensin L(RR-25)、rabdoternin C(RR-26)、(-)-loliol ide(RR-27)、chakyunglupulin A(RR-28)、5,3’,4’-trihydroxy-6,7,8-trimethoxyflavone(R R-29)、5,4’-dihydroxy-6,7,8,3’-tetramethoxyflavone(RR-30)、(+)-pinoresinol(RR-31)、3-(3,4-dihydroxyphenyl)-acrylic acid 1-(3,4-dihydroxyphenyl)-2-methoxycarbon-ylethyl ester(RR-32)、Ethyl rosmarinate(RR-33)、Nepetoidin B(RR-34)、Ethyl 3,4-Dihydr oxycinnamate(RR-35)、caffeic acid ethylene ester(RR-36)、oresbiusin A(RR-37)、Ferulic acid(RR-38)、1-(-4-hydroxy-3-methoxy)-phenyl-1,2,3-propanetriol(RR-39)、c affeic acid(RR-40)。ConclusionAmong them,RR-1～RR-11 are new diterpenes,and RR-12～RR-14,RR-16～RR-18,RR-21～RR-26 are ent-Kaurene diterpenes,RR-15 and RR-22 are 6,7 fragmentation ent-kaureane diterpenes,RR-19 is ent-Abietane diterpene,RR-20 is spiral fragmentation 6,7 ent-kaurene diterpene.RR-27～RR-28 are sesquiterpenes,RR-29～RR-30 are flavonoids,and RR-31～RR-40 are phenylpropanoids.