The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,...The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.展开更多
A new perylenequinone, named hypomycin A, was isolated from the mycelia of Hypomyces sp.. Its structure was elucidated on the basis of spectroscopic methods.
Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the peryle...Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the perylenequinone molecule is of stable structure. and all substituents may cause the decrease of barriers for the hydrogen transfer reaction.展开更多
Perylenequinones(PQs)from bambusicolous Shiraia fungi serve as excellent photosensitizers for photodynamic therapy.However,the lower yield of PQ production in mycelium cultures is an important bottleneck for their cli...Perylenequinones(PQs)from bambusicolous Shiraia fungi serve as excellent photosensitizers for photodynamic therapy.However,the lower yield of PQ production in mycelium cultures is an important bottleneck for their clinical application.Light has long been recognized as a pivotal regulatory signal for fungal secondary metabolite biosynthesis.In this study,we explored the role of nitric oxide(NO)in the growth and PQ biosynthesis in mycelium cultures of Shiraia sp.S9 exposed to red light.The continuous irradiation with red light(627 nm,200 lx)suppressed fungal conidiation,promoted hyphal branching,and elicited a notable increase in PQ accumulation.Red light exposure induced NO generation,peaking to 81.7μmol/g FW on day 8 of the culture,with the involvement of nitric oxide synthase(NOS)-or nitrate reductase(NR)-dependent pathways.The application of a NO donor sodium nitroprusside(SNP)restored conidiation of Shiraia sp.S9 under red light and stimulated PQ production,which was mitigated upon the introduction of NO scavenger carboxy-PTIO or soluble guanylate cyclase inhibitor NS-2028.These results showed that red light-induced NO,as a signaling molecule,was involved in the regulation of growth and PQ production in Shiraia sp.S9 through the NO-cGMP-PKG signaling pathway.While mycelial H2O2 content exhibited no significant alternations,a transient increase of intracellular Ca2+and extracellular ATP(eATP)content was detected upon exposure to red light.The generation of NO was found to be interdependent on cytosolic Ca2+and eATP concentration.These signal molecules cooperated synergistically to enhance membrane permeability and elevate the transcript levels of PQ biosynthetic genes in Shiraia sp.S9.Notably,the combined treatment of red light with 5μM SNP yielded a synergistic effect,resulting in a substantially higher level of hypocrellin A(HA,254 mg/L),about 3.0-fold over the dark control.Our findings provide valuable insights into the regulation of NO on fungal secondary metabolite biosynthesis and present a promising strategy involving the combined elicitation with SNP for enhanced production of photoactive PQs and other valuable secondary metabolites in fungi.展开更多
By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds o...By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.展开更多
AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, single...AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers a-gainst the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79. 91 kJ/mol, respectively, (iii) Barriers against the IPT of cation and anion radical of PQ (PQ,+ and PC,-) are 65. 94 and 59.29 kJ/ mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89. 24 and 88. 07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven-membered side ring of HA has no marked influence on its barrier against IPT.展开更多
Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone(PQ)in intramolecular proton transfer(IPT)process.It was found that there existed a maximum of dipole moment in all ...Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone(PQ)in intramolecular proton transfer(IPT)process.It was found that there existed a maximum of dipole moment in all IPT process except PQ anion(PQ)which possessed a minimum.Moreover,almost all states of PQ except ground state had high changes in dipole moment.All of these laid foundations to clarify solvent effects in IPT of PQ.展开更多
文摘The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.
文摘A new perylenequinone, named hypomycin A, was isolated from the mycelia of Hypomyces sp.. Its structure was elucidated on the basis of spectroscopic methods.
文摘Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the perylenequinone molecule is of stable structure. and all substituents may cause the decrease of barriers for the hydrogen transfer reaction.
基金supported by the National Natural Science Foundation of China(No.82073955 and 81773696)the Priority Academic Program Development of the Jiangsu Higher Education Institutes(PAPD).
文摘Perylenequinones(PQs)from bambusicolous Shiraia fungi serve as excellent photosensitizers for photodynamic therapy.However,the lower yield of PQ production in mycelium cultures is an important bottleneck for their clinical application.Light has long been recognized as a pivotal regulatory signal for fungal secondary metabolite biosynthesis.In this study,we explored the role of nitric oxide(NO)in the growth and PQ biosynthesis in mycelium cultures of Shiraia sp.S9 exposed to red light.The continuous irradiation with red light(627 nm,200 lx)suppressed fungal conidiation,promoted hyphal branching,and elicited a notable increase in PQ accumulation.Red light exposure induced NO generation,peaking to 81.7μmol/g FW on day 8 of the culture,with the involvement of nitric oxide synthase(NOS)-or nitrate reductase(NR)-dependent pathways.The application of a NO donor sodium nitroprusside(SNP)restored conidiation of Shiraia sp.S9 under red light and stimulated PQ production,which was mitigated upon the introduction of NO scavenger carboxy-PTIO or soluble guanylate cyclase inhibitor NS-2028.These results showed that red light-induced NO,as a signaling molecule,was involved in the regulation of growth and PQ production in Shiraia sp.S9 through the NO-cGMP-PKG signaling pathway.While mycelial H2O2 content exhibited no significant alternations,a transient increase of intracellular Ca2+and extracellular ATP(eATP)content was detected upon exposure to red light.The generation of NO was found to be interdependent on cytosolic Ca2+and eATP concentration.These signal molecules cooperated synergistically to enhance membrane permeability and elevate the transcript levels of PQ biosynthetic genes in Shiraia sp.S9.Notably,the combined treatment of red light with 5μM SNP yielded a synergistic effect,resulting in a substantially higher level of hypocrellin A(HA,254 mg/L),about 3.0-fold over the dark control.Our findings provide valuable insights into the regulation of NO on fungal secondary metabolite biosynthesis and present a promising strategy involving the combined elicitation with SNP for enhanced production of photoactive PQs and other valuable secondary metabolites in fungi.
基金Project supported by the National Natural Science Foundation of China.
文摘By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.
文摘AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers a-gainst the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79. 91 kJ/mol, respectively, (iii) Barriers against the IPT of cation and anion radical of PQ (PQ,+ and PC,-) are 65. 94 and 59.29 kJ/ mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89. 24 and 88. 07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven-membered side ring of HA has no marked influence on its barrier against IPT.
基金supported by Doctoral Foundation of Science of Shandong Teachers University.
文摘Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone(PQ)in intramolecular proton transfer(IPT)process.It was found that there existed a maximum of dipole moment in all IPT process except PQ anion(PQ)which possessed a minimum.Moreover,almost all states of PQ except ground state had high changes in dipole moment.All of these laid foundations to clarify solvent effects in IPT of PQ.
