Study On The Discovery Of Anti-alzheimer’s Disease Constituets From Radix Aconiti Puberuli

The Traditional Chinese Medicine(TCM)"Radix Aconiti Puberuli",derived from the roots of Aconitum barbatum Pers.var.puberulum Ledeb.,was firstly recorded in the Shennong Bencao Jing as a low-grade one.Now it is used in folk with functions of rheumatism removing,dehumidifying,pain relieving,expectoration,cough suppressing and dyspnea relieving etc.In the strategy of bio-assay guided fractionation,107 compounds were isolated from the active fractions B2,B3&B5,which improved the study and memory ability of transgenic flies with huma Aβ42 gene dramatically.Of these compounds,4 novel skeleton compounds,32 new compounds,3 new natural products and 22 compounds firstly isolated from Aconitum.L are included.Structurally,they are diterpenoid alkaloids(1～44),flavonol glycosides(45～62),anthranilamides(63～71),other types(72～79)and organic acids derivatives(80～107).The 4 novel skeleton compounds are C19 diterpenoid alkaloids puberutine(1),6,17-seco puberutine(2)and C18 diterpenoid alkaloids puberunine(3),puberudine(4).The 32 new compounds are as follows:C18 diterpenoid alkaloids puberudine hydrochloride(5),puberumines A～E(6～10),C19 diterpenoid alkaloids puberumines F～H(14～16),dehydroacosanine hydrochloride(17),puberumine I(23),C20 diterpenoid alkaloids puberumines J～M(25-28),puberumine N hydrochloride(29),lepenine hydrochloride(30),puberumines O～Q(34～36),flavonol glycosides puberulosides A～E(45～49),anthranilamides puberamides A～E(63～67),others types(1,2’-bipyrrolidin)-2,5’-dione(72),puberulin(78).The 3 new natural products are C18 diterpenoid alkaloids puberanine A(11)and anthranilamides puberamides F～G(69～70).The 22 compounds firstly isolated from Aconitum.L are flavonol glycosides juglalin(51),afzelin(52),multiflorin B(53),lepidoside(55),kaempferol 3-O-α-L-arabinopyranosyl-7-O-α-L-rhamnopyrano side(56),kaempferol 3-O-β-D-galactopyranosyl-7-O-α-L-rhamnopyranoside(57),kaempferol 3-O-β-D-glucopyranosyl(1→4)-α-L-rhamnopyranosyl-7-O-α-L-rhamnopyranoside(59),kaempferol 3-O-α-L-rhamnopyranosyl-7-O-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranoside(60),quercetin 3-O-α-L-(4-O-acetyl)-rhamnopyranosyl-7-O-α-L-rhamnopyranoside(62),followed by other types pyroglutamic acid(73),oleracein E(74),iseluxine(75),4(1H)-quinolinone(76),2-(4-hydroxyphe nyl)-2,3-dihydrobenzo[b]furan-3,4,6-triol(79)and organic acid derivatives protocatechuic acid(95),protocatechuic acid methyl ester(96),4-hydroxyisophthalic acid(97),3-(p-hydroxyphenyl)-lactic acid(98),3-(p-hydroxyphenyl)-lactic acid methyl ester(99),Dan Shen Su(101),3-(3,4-dihydroxyphenyl)-lactic acid methyl ester(102).trans-caffeic acid methyl ester(104).The 4 novel skeleton compounds contribute to 2 new types of C19 diterpenoid alkaloids and 2 new subtypes of C18 diterpenoid alkaloids,puberutine(1)and 6,17-seco puberutine(2)contribute as the seventh type,puberutine type and the eighth type 6,17-seco puberutine type of C19 diterpenoid alkaloids.Structurally,the known six types of C19 diterpenoid alkaloids belong to the one same skeleton.Puberunine(3)and puberudine(4)contribute as the third subtype,rearranged subtype and the fourth subtype 1,2-seco subtype in ranaconitine type of C18 diterpenoid alkaloids,which are also the fifth and sixth subtype of the whole C18 diterpenoid alkaloids.The plausible biogenetic pathways of the novel skeleton alkaloids are considered.Furthermore,we point out in practically and theoretically,at least for C18 diterpenoid alkaloids,that the C-3 substituent group adopts a β orientation is exist,while for the reported compounds at present and analysis with traditional theory,they all adopts a a orientation.We discuss the feasibility of the orientation determination according to the C-19 chemical shift value in the condition of containing a 1α-OH.We also discuss the method to determine the esterification site(s)of mono-and di-aconitic acid esters through investigating the chemical shift value difference of the two signals resonance at 167 ppm around,which can be used to resolve the issue on mono-and simple di-esters with 1D NMR,but still difficulty on the mixture di-esters.Two compounds(anthranilamide 68 and trans-aconitic acid derivative 80)were found to show favorable activity on the transgenic flies model.Also,some flavonoids display fine activity on the BV-2 microglia model.Further work is necessary to do for both.In the end,we draw a further work plan to improve this research.Moreover,a notion on how to select a suitable in vitro model in drug discovery from TCM is proposed.