Research On Phloroglucinol Derivatives And Their Antibacterial Activity Of Hypericum Curvisepalum

The plants of the Hypericum genus manifested various pharmacological activities,such as antidepressant,antitumor,antiviral,bacteriostatic,antioxidant,neuroprotective effects,etc.Many of these plants,such as Hypericum ascyron,Hypericum scabrum,Hypericum attenuatum,are widely used at home and abroad.The chemical constituents of Hypericum are mainly flavonoids,dianthrones,xanthones,terpenes and phloroglucinol derivatives,among which phloroglucinol derivatives possessing complex and changeable structures and multiple biological activities such as antibacterial,antiviral,anticytotoxic,antioxidant,and nerve cell protection activities,which have attracted wide interest.Hypericum curvisepalum N.Robson is a plant of the genus Hypericum in the family Hypericaceae,mainly located in the south of Sichuan,the southwest of Guizhou and Yunnan.As far as we know,no phytochemical investigation has been conducted on this plant.In order to find new structures and strong pharmacological activity of phloroglucinol derivatives,lay the foundation for the development and utilization of Hypericum resources.In this paper,the phloroglucinol derivatives in the petroleum ether eluting fraction of the methanol extract from H.curvisepalum were systematically separated,purified and structurally identified.The silica gel column chromatography,medium-pressure liquid chromatography,Sephadfex LH-20 column chromatography,high-performance liquid chromatography,circulating preparative liquid chromatography and other separation methods were adopted in this study.Their structures of all the isolated were elucidated by the physiochemical properties and spectroscopic data.As a result,fifteen phloroglucinol derivatives were isolated and their structures were elucidated as curvisepalumione A(1),curvisepalumione B(2),Curvisepalumione C(3),attenuatumione H(4),oxepahyperforin(5),furoadhyperforin(6),uraloiain A(7),uralione H(8),uralodin B(9),furoadhyperforin isomerA(10),furoadhyperforin isomer B(11),uralione G(12),uralodin C(13),hypercohin E(14),hypercohin F(15).Among them,compounds 1-3 are previously undescribed.The semi-quantitative microplate method was used to reflect the antibacterial activity that the crude extract petroleum ether fraction,ethyl acetate fraction,methanol fraction and compounds 4-9,14 and 15 from Hypericum curvisepalum against Staphylococcus aureus,Escherichia coli,and Bacillus subtilis by color change of resazurin.The results showed that the MIC values of petroleum ether fraction,ethyl acetate fraction,methanol fraction and compounds 4-9,14 and 15 against Bacillus subtilis were 31.25 ?g/mL,31.25 ?g/mL,1.95?g/mL,1.95 ?g/mL,500 ?g/mL,62.5 ?g/mL,125 ?g/mL,250 ?g/mL,1.95 ?g/mL,31.25?g/mL,respectively.