RESUMO
A new alkaloid, named (±)-preisomide (1), together with five known polyketides (2-6), were isolated from an endophytic fungus Preussia isomera in Panax notoginseng by using one strain-many compounds (OSMAC) strategy. Their structures were identified by extensive spectroscopic experiments and comparison with literature data. Structurally, compound 1 possessed a rare naturally occurring tetrahydro-2H-1,2-oxazin ring. Compound 6 displayed significant antibacterial activity against multidrug-resistant Enterococcus faecium, methicinllin-resistant Staphylococcus aureus and multidrug-resistant Enterococcus faecalis with an MIC value of 25 µg/mL, as well as moderate antifungal activity against Gibberella saubinetii with an MIC value of 50 µg/mL.
Assuntos
Alcaloides/química , Ascomicetos/química , Endófitos , Panax notoginseng/microbiologiaRESUMO
A pair of enantiomeric norsesquiterpenoids, (+)- and (-)-preuisolactone A (1) [(+)-1 and (-)-1)] featuring an unprecedented tricyclo[4.4.01,6.02,8]decane carbon scaffold were isolated from Preussia isomera. Their structures were determined by spectroscopic and computed methods and X-ray crystallography. Compounds (+)-1 and (-)-1 are two rare naturally occurring sesquiterpenoidal enantiomers. A plausible biosynthetic pathway for 1 is proposed. Additionally, (±)-1 exhibited remarkable antibacterial activity against Micrococcus luteus with an MIC value of 10.2 µM.
Assuntos
Antibacterianos/farmacologia , Ascomicetos/química , Compostos Heterocíclicos/farmacologia , Micrococcus luteus/efeitos dos fármacos , Sesquiterpenos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Compostos Heterocíclicos/química , Compostos Heterocíclicos/isolamento & purificação , Testes de Sensibilidade Microbiana , Conformação Molecular , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , EstereoisomerismoRESUMO
Five new polyphenolic derivatives, sepiumols A-E (1-5), were isolated from the root barks of Periploca sepium. Their structures were elucidated by interpretation of NMR spectroscopic and mass spectrometric data. Compounds 1, 3 and 5 were found to exhibit significant antifungal activity, particularly for 3 with the remarkable activity against Gibberella saubinetii and Alternaria longipes with MIC values of 1.56 and 3.13⯵g/mL (ketoconazole: 0.78⯵g/mL), respectively. In addition, compounds 1, 3 and 5 also displayed significant antibacterial activity against methicillin-resistant Staphylococcus aureu with MIC values of 12.50-25⯵g/mL (ciprofloxacin: 0.78⯵g/mL).
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Periploca/química , Polifenóis/farmacologia , Alternaria/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Gibberella/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Casca de Planta/química , Raízes de Plantas/química , Polifenóis/isolamento & purificaçãoRESUMO
Three new hopane-type triterpenoids (1-3), fern-7(8)-en-19α, 28-diol (1), pteron-14-ene-7α,19α,28-triol (2) and 3ß,4α,25-trihydroxyfilican (3), were isolated from the aerial parts of Adiantum capillus-veneris. Their structures were determined by NMR spectroscopic and mass spectrometric data. Compounds 2 and 3 exhibited remarkable antifungal activity against Helminthosporium maydis and Alternaria alternata with MIC values of 12.5-3.125⯵g/mL, and compound 3 also against Verticillium dahliae Kleb with an MIC value of 3.125⯵g/mL. In addition, compounds 1-3 also displayed weak antibacterial activity against Micrococcus lysodeikticus, Bacterium paratyphosum B and Pseudomonas aeruginosa with an MIC value of 100⯵g/mL.
Assuntos
Adiantum/química , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Triterpenos/farmacologia , Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Testes de Sensibilidade Microbiana , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Componentes Aéreos da Planta/química , Triterpenos/isolamento & purificaçãoRESUMO
2-Oxoglutaric acid (2-OG), a Krebs cycle intermediate, is a signaling molecule in many organisms. To determine which form of 2-OG, the ketone or the ketal form, is responsible for its signaling function, we have synthesized and characterized various 2-OG analogs. Only 2-methylenepentanedioic acid (2-MPA), which resembles closely the ketone form of 2-OG, is able to elicit cell responses in the cyanobacterium Anabaena by inducing nitrogen-fixing cells called heterocysts. None of the analogs mimicking the ketal form of 2-OG are able to induce heterocysts because none of them are able to interact with NtcA, a 2-OG sensor. NtcA interacts with 2-MPA and 2-OG in a similar manner, and it is necessary for heterocyst differentiation induced by 2-MPA. Therefore, it is primarily the ketone form that is responsible for the signaling role of 2-OG in Anabaena.
Assuntos
Ácidos Dicarboxílicos/química , Ácidos Cetoglutáricos/química , Ácidos Cetoglutáricos/farmacologia , Cetonas/química , Transdução de Sinais/efeitos dos fármacos , Anabaena/efeitos dos fármacos , Anabaena/crescimento & desenvolvimento , Anabaena/fisiologia , Cristalografia por Raios X , Ácidos Cetoglutáricos/síntese química , Modelos Moleculares , Mimetismo Molecular , Estrutura Molecular , Transdução de Sinais/fisiologiaRESUMO
In the present article, the authors, in the light of their research in recent a decade of years, make an overall summary on the regularities of clinical acupuncture from the stimulated points, the superficial and deep layers, the literature basis and the innovation points. These basic regularities include symmetry or corresponding, segmental innervation, center or central axis, superiority of distal limbs, ending-stimulation accelerating analgesia, periphery-stimulation accelerating easiness and smooth, local feed back, specific feed back, selection of the stimulated points, acupuncture of different layers, etc.. They also discuss the possibility of integration of traditional Chinese and Western medicine from the view-points of neuroanatomy, neurophysiology and rehabilitation medicine. Systematic analysis on the regularities of clinical acupuncture makes the ancient meridian-collateral theory and abundant clinical experience summed up in definite concepts, simplifies the complicated theory system of acupuncture learning, and favors the communication about the terminology of Chinese medicine and Western medicine.