Study On Chemical Constituents And Biological Activity Of Phymatopteris Hastata

Phymatopteris hastata（Thunb.）Pic.Serm.,changed to Selliguea hastata in the latest edition of Flora of China,is distributed over many provinces of southern China.P.hastata is used as a folk herb in traditional Chinese medicine for the treatment of a wide range of ailments such as bronchitis,fever,urinary tract infection,and it is especially useful in the external treatment of carbuncles,furunculosis and viper bites.Previous phytochemical investigations of Phymatopteris have reported the identification of 33 natural compounds,including four novel compounds.The types of these compounds mainly include steroids,triterpenoids,polyphenols,flavonoids,and fatty acid derivatives.Some of these compounds were identified as varied biological activities,including anti-diabetic and antioxidative activities.Although many phytochemical studies have been conducted since 1928,the effective components of P.hastata are not yet fully clarified.In continuation of our investigation on medicinal ferns,herein,we report the structural elucidation,and biological activity of one enantiomeric pair of new dihydroflavones（7a/7b）and one novel protocatechuic acid methyl ester（11）（Fig.2-10）,together with eighteen known compounds（1-6,8-10,and 12-20）isolated from P.hastata by a series of column chromatographic separations.Their complete structures were identified by a combination of HR-ESI-MS,1D and 2D-NMR,ORD and acidic hydrolysis,while the known compounds were identified by comparisons of the physical data with those reported in the literature.Some compounds were evaluated for their inhibitory activities againstα-glucosidase,antioxidant activity,antimicrobial activity.Furthermore,the essential oil of P.hastata was studied by GC-MS,and some compounds isolated from PE and EA fraction were identified on the based of the GC-MS profile.1.By a series of column chromatographic separations,20 compounds were isolated from Et OH extract（95%）of P.hastata.The structures of known compounds were determined by compared with literature data.The structures of new compounds were determined by HR-ESI-MS、1D and 2D NMR、ORD and acid hydrolysis.The compounds are as followed:coumarin（1）,trans-O-coumaric acid（2）,trans-caffeic acid（3）,β-sitosterol（4）,tetracosanol（5）,juglanin（6）,（-）-/（+）-naringenin-7-O-α-L-rhamnopyranoside（7）,hexadecanoic acid（8）,kaempferol 3-O-α-rhamnopyranoside（9）,atroside（10）,protocatechuic acid methyl ester-4-O-（6’-O-protocatechuoyl）-β-D-glucopyranoside（11）,1,3-dimyristin（12）,kaempferol-7-O-α-L-rhamnopyranoside（13）,1-O-heptatriacontanoyl glycerol（14）,zeaxanthin（15）,avicularin（16）,kaempferol-3-O-α-L-arabinofuranosyl-7-O-α-L-rhamnopyranoside（17）,kaempferol3-O-[α-D-apiofuranosyl-（1-2）-α-L-arabinofuranoside]-7-O-α-L-rhamnopyranoside（18）,β-ecdysterone（19）,trans-melilotoside（20）.Compounds 7 and 11 are the novel compounds and compounds 2,9,13,15,18,and 19 are isolated from the genus for the first time.2.To explore the undiscovered and potential pharmacological activities of the crude extracts and some compounds of P.hastata,theα-glucosidase inhibition assy were evaluated by p-NPG method and the structure-activity of the related compounds were discussed,too.On the basis of that,the effects of reaction times and the kinetic experiments were investigated.Compounds 1,10,11,and 12 showed a significantα-glucosidase inhibitory activity(IC₅₀ value as 96±2.9,99±8.9,88±3.6,and 168±1.7μg/m L,respectively)and the inhibition rate of compound was decreased over time and reached the lowest level after 25 minutes.Compound 11 was noncompetitive with Ki value of 0.46±0.06 m M and compound 3 was uncompetitive inhibition by the kinetic result.3.The antioxidant activities of various solvent extracts from P.hastata and compounds were investigated by DPPH and ABTS free radical scavenging assay.The n-Bu OH phase have a lower IC₅₀ value（46.6±12.1μg/m L,0.0045μg/m L）in this experiment,indicating a good effect in antioxidant activity of this plant.Furthermore,compound 7 and 8 exhibited outstanding antioxidant activities with an IC₅₀ value（0.0038 and 0.0048μg/m L;36.0±8.3 and 0.0049μg/m L,respectively）.4.The inhibition of bacterial activity of the compounds isolated from P.hastata was evaluated by E.coli and S.aureus.A.niger,P.notatum and shnu20200520 were used as screening models to investigate their inhibitory activity against fungi.Compound 15 showed a significant antimicrobial activity against S.aureus,P.notatum and shnu20200520,compound 13 had a potential antimicrobial activity against S.aureus,and P.notatum,compound 1,2,and 5 had the activity against S.aureus,and compound 8 and 14 displayed antimicrobial activity of P.notatum.5.The volatile components of P.hastata were studied by GC-MS,and the results of n-hexane automatic injection mode and solid phase microextraction（SPME）mode were investigated.It was found that the sensitivity of spme mode was significantly higher than that of n-hexane automatic injection mode.n-Hexane automatic injection mode detected 40 components from the volatile oil of the plant in 57.5 min,while the SPME mode detected 162 volatile components in 45.0 min.In addition,based on the GC-MS guidance,some compounds of the PE fraction of P.hastata were identified.