| The main contents of this dissertation include the chemical constituents investigation of the genuine Yunnan medicinal herb Knoxia valerianoides and its fermentation study with Aleurodiscus mirabilis TJ-8.In the first chapter of this paper,the progress of the chemical constituents and bioactivities of Knoxia are summarized.In the second chapter,the chemical constituents of K.valerianoides were studied.Twenty compounds were isolate and identified as: one diterpene: 2-O-[2-O-Isovaleryl-?-D-glucopyranosyl]-4-epi-atractyligenin(1);two cycloene ether terpene glycosides: asperuloside(2),asperuloside acid(3);one triterpenes: arjunolic acid(4);two sterol: ?-sitosterol(5),stigmasterol(6);six anthraquinone: 3-hydroxy-1-methoxy-2-methoxymethyl-9,10-anthraquinone(7),1,3,5,6-tetrahydroxy-2-methyl-9,10-anthraquinone(8),lucidin ?-methyl ether(9),1,3,5-trihydroxy-6-methoxy-2-methoxymethyl-9,10-anthraquinone(10),6-hydroxxyrubiadin(11),rubiadin(12);and eight other types of compounds: D-glucopyanoside-2-phenylethenyl(13),1-(2-ethylphenyl)ethane-1,2-diol(14),p-hydroxy-benzoic acid ethyl eater(15),5-hydroxymethyl-2-furfural(16),5-hydroxymethyl-furfural(17),3-methoxy-4-hydroxy benzoic acid(18),3,4-dihydroxyacetophenone(19)and vanillic acid(20).The contents of 5 anthraquinone compounds were determined,and the acetylcholinesterase(AChE)inhibitory effects and antibacterial activities of all the isolated compounds were tested.The results showed that compounds 9 and 13 exhibited medium inhibitory effects on AChE with inhibitory rates of 31.40% and 33.98% when the concentration of the sample is 50 ?mol/L,respectively,the inhibition rate of tacrine in the positive control was 92.37%.Compound 10 had medium antibacterial activity against Candida albicans with a MIC of 128 ?g/mL,the MIC of nystatin in the positive control was 1 ?g/mL.Compound 13 showed medium antibacterial activity against Bacillus subtilis,the minimum inhibitory concertration(MIC)was 128 ?g/mL.Compound 13 exhibited medium antibacterial activity against Staphylococcus aureudihydroxys with a MIC of 128 ?g/mL,the MIC of kanamycin in the positive control was 1 ?g/mL.The third chapter described the fermentation screening of K.valerianoides with 35 fungi,and biotransformation of 1,8-dihydroxyanthraquinone with Aleurodiscus mirabilis TJ-8.1,8-Dihydroxyanthraquinone was transformed into the benzophenone derivative peniphenone(11)by A.mirabilis liquid fermentation.The conversion rate was 8.86%.Using fresh potato as culture medium for solid fermentation.The secondary metabolites of A.mirabilis were investigated.Ten known compounds were obtained from this fungi: including five cytochalasin compounds:(11)-cytochalasa-6(12),13,19-triene-1,21-dione-16,18-dimethyl-7-hydroxy-10-phenyl-(7S*,13 E,16S*,18R*,19E)(1),cytochalasin J(2),diaporthichalasin C(3),cytochalasin R1(4),cytochalasin Z10(5);two dimer tetrahydroxy anthrones: dicerandrols B(6),dicerandrols A(7);two sterols: ergosterol(8),cerevisterol(9);and a benzophenone derivative: monodictyphenone(10).Due to the structural similarity between compounds 10 and 11,combining with the report on the biosynthesis pathway of compound 10,the transformation pathway of 1,8-dihydroxyanthraquinone was supposed to be motivated by P450 enzyme in A.mirabilis.Therefore,the P450 enzyme accelerator n-tetracane,inhibitor 1-aminobenzotriazole(ABT),piperomyl butoxide(PBO)were used in the fermentation experiment,which confirmed that P450 enzyme in A.mirabilis plays an important role in 1,8-dihydroxyanthraquinone transformation.All the isolated compounds were tested for antimicrobial activity,the results showed that compounds 6 and 7 had strong inhibitory effects on all three bacteria(B.subtilis,E.coli,S.aureus),the MIC were 2 ?g/mL and 8 ?g/mL(B.subtilis),16 ?g/mL and 256 ?g/mL(E.coli),2 ?g/mL and 4 ?g/mL(S.aureus),respectively,the MIC of kanamycin in the positive control was 1 ?g/mL. |
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