Study On The Chemical Constituents Of The Aerial Parts Of Hypericum Sampsonii

Hypericum sampsonii belongs to the Hypericum genus of Guttiferae family.The whole herbs of H.sampsonii has been used as folk medicine for the treatment of hematemesis,hemoptysis,bleeding wounds,due to its various therapentic effects,including cooling blood for hemostasis,clearing heat-toxicity,promoting blood flow for regulating menstruation and dispelling pathogenic wind for dredging channels.Modern pharmacological study indicated that the extracts of H.sampsonii possessed antitumor,antidepressant and antiviral activities.In our investigation on the chemical constituents of the 60%EtOH extract of the aerial parts of H.sampsonii,a total of 44 compounds were isolated from the subfraction HSD(95%EtOH eluate over HP20 macroporous resin)through various chromatographic techniques.According to physicochemical property and spectroscopic analysis(IR,UV,MS,NMR,CD),their structures were identified as:norsampsones A-E(1-5)*,dioxasampsones A-B(6-7)*,hypersampsone N(8)*,hypersampsone O(9)*,hypersampsone P(10)*,hypersampsone M(11)*,hypersampsone Q(12)*,sampsonione G(13),plukenetion B(14),hypercohone A(15),sampsonione R(16),sampsonione B(17),sampsonione A(18),plukenetione A(19),otogirinin A(20),28,29-epoxyplukenetione A(21),sampsonione Q(22),hyperisampsin G(23),hyperisampsin E(24),hypersampsone S(25)*,hypersampsone T(26)*,hypersampsone R(27)*,hypersampsone U(28)*,hypersampsone V(29)*,hypersampsone W(30)*,sampsonione O(31),sampsonione N(32),sampsonione L(33),sampsonione P(34),hyperattenin E(35),hyperibone I(36),hypersampsone H(37),otogirinin E(38),(±)-sampsone D(39a*,39b*),(±)-sampsone E(40a*,40b),sampsone F(41)*,sampsone G(42)*,otogirinin F(43),otogirinin G(44).All compounds were polyprenylated acylphloroglucinols(PPAPs),and 21 of them were new ones.Compounds 1-5 featured an unprecedented carbon skeleton with the loss of a carbonyl in phloroglucinol ring,while compounds 6-7 possessed an unusual epoxy-ring-fused skeleton.The absolute configurations of most of the new compounds were determined by various experiments including single crystal X-ray,ECD calculations,modified mosher's and Snatzke's methods.The isolated PPAPs were investigated for their effects on RXRa transcriptional-inhibitory activities as well as cytotoxicity against HeLa cells.As a result,the PPAPs with bicyclo[3.3.1]nonane skeleton showed better activities than other types.Among them,compounds 31?32 and 34 showed potent effects in both two bioassay in a dose dependent manner.The MS fragmentation patterns of PPAPs with bicyclo[3.3.1]nonane skeleton were investigated,and the proper fragmentation pathways were also proposed.Using the UPLC-Q/TOF-MS technique,the rapid indentification of chemical constituents of subfraction HSD was achieved.As a result,a total of 35 PPAPs were identified,which were futher confirmed by the isolated standards,and the structure types of 21 PPAPs were speculated.It suggested that there were numbers of undiscovered PPAPs existed in H.sampsonii,which need further investigation.The work laid a chemical foundation for revealing the bioactive ingredients of the active parts of H.sampsonii with RXRa transcriptional-inhibitory activities,and provide scientific basis for further rational utilization of H.sampsonii.