Chemical Constituents And Anti-AD Activity Of Two Medicinal Plants

Curcuma longa L(Turmeric.)is a rhizomatous herbaceous perennial plant of the Curcuma genus,Zingiberaceae family.It is native to tropical South Asia but is now widely cultivated in the tropical and subtropical regions of the world.There are50 species in the world,and 16 species were mainly distributed in Guangxi province in China.Modern pharmacological researches revealed that C.longa L possesses antioxidant,anti-inflammatory,anti-tumor,treating Alzheimer's disease,and anti-AIDS activities.Nardostachys chinensis Batal,belonging to the genus Nardostachys(Valerianaceae),is a perennial herbal plant and distributes in Gansu,Qinghai,Sichuan,Yunnan provinces,which exhibits antimalarial,antinociceptive,neurotrophic and cytotoxic activities.In this paper,the ethyl acetate extracts of two medicinal plants were systematically isolated and purified,and 42 compounds were identified by extensive spectrographic techniques.There were 5 novel compounds in N.chinensis Batal.Nardochinin A(1)possessed a norsesquiterpene skeleton with an unusual 3/6/5/5 tetracyclic ring system,which had not appeared in natural products.Nardochinins B(2)and C(3)were the first time found naturally occurring sesquiterpenoids with a 4,5-seco-nardosinane skeleton.Besides,compound 3represented an unprecedented 4,5-seco-nardosinane type norsesquiterpenoid with losing an isopropenyl at C-6 compared with 2 in the structural framework.Nardochinin D(4)was a novel,highly oxygenated valerenane-type sesquiterpenoid possessing a rare 3,12-epoxy group and an unusual 9,11-epoxy group.(?)-Neonardochinone A(5)was a novel lignan-derived compound,it was worth noting that the crystal of 5 had a p21/c space group,indicating a racemic mixture,which was in accordance with its[?]_D value(0).Therefore,chiral HPLC analysis and isolation of 5 was carried out on the chiral chromatography column to afford the two anticipated enantionmers.The anti-Alzheimer's disease(AD)activities of 1–5were also evaluated using the transgenic Caenorhabditis elegans expressing human A?pathological model,nardochinin B(2)and(?)-neonardochinone A(5)had the excellent anti-AD activity.