RESUMEN
Recent studies into gibberellin A(1) (GA(1)) showed it to be physiologically more active than GA(3) in plants of great agricultural interest, such as tomatoes, rice, peas, and sweet cherries. We describe here a simple procedure for obtaining large quantities of GA(1) (1,500 mg/l) by incubating the FKMC1995 strain of Fusarium fujikuroi in a standard complex medium (SCM). We also compare the GA production of this strain with that of two other wild-type strains of F. fujikuroi (IMI58289, m567) in SCM and low-nitrogen medium and discuss the possible biogenetic mechanisms involved in the over-accumulation of GA(1) by FKMC1995.
Asunto(s)
Fusarium/metabolismo , Giberelinas/biosíntesis , Medios de Cultivo , Fusarium/citología , Giberelinas/químicaRESUMEN
As lactonas sesquiterpênicas licnofólido (1) e eremantólido C (2) e alguns derivados: 1 ,2 -epóxieremantólido C (3), 1 β -hidróxi-2,3-diidroeremantólido C (4), 3 - hidróxieremantólido C (5), cloreto de 4,5-diidroeremantólido-5-n-propilamônio (6) e 1 β -hidróxi- 2,3-diidrolicnofólido (7) foram testadas contra as bactérias Enterococus faecalis S48, Bacillus subtilis CECT 397, Staphylococus aureus ATCC 8, Salmonella typhymurium LT2, Escherichia coli U9 e Proteus sp. Os compostos 1, 4, 5 e 7 apresentaram atividade antibacteriana.
Sesquiterpene lactones lychnopholide (1) and eremantholide C (2) and some derivatives: 1 ,2 -epoxyeremantholide C (3), 1 β -hidroxy-2,3-dihydroeremantolide C (4), 3 -hydroxyeremantholide C (5), 5-n- propylamonium- 4,5-dihydroeremantholide C chloride (6) and 1 β -hydroxy-2,3- dihydrolychnopholide (7) were tested against Enterococus faecalis S48, Bacillus subtilis CECT 397, Staphylococus aureus ATCC 8, Salmonella typhymurium LT2, Escherichia coli U9 e Proteus sp. Compounds 1, 4, 5 and 7 showed activity.
RESUMEN
Feeding experiments with ent-kaurenoic acid (4), 15 alpha-hydroxy-ent-kaurenoic acid (5), 15 beta-hydroxy-ent-kaurenoic acid (6), and mixtures of 4 plus 5 and 4 plus 6 were conducted using the SG138 mutant of Gibberella fujikuroi, to gain information about the phenotype of this unique strain. The biotransformation of 5 gave 7 beta,15 alpha-dihydroxykaurenolide (9) and 7 beta,15 alpha-dihydroxy-ent-kaurenoic acid (13). The incubation of 6 produced 7 beta,15 beta-dihydroxy-ent-kaurenoic acid (7) and 7 beta,15 beta-dihydroxykaurenolide (10). No 15-hydroxylated gibberellins were detected in any of these experiments. The results indicated that a hydroxy group at C-15 does not inhibit 7 beta-hydroxylase activity but in the SG138 strain obstructs the enzymatic ring-B contraction of ent-kaurenoids to gibberellins. Exogenous 4 stimulated both the excretion of ent-kaurene and the fungal metabolism of 5 and 6.
Asunto(s)
Diterpenos/metabolismo , Gibberella/metabolismo , Biotransformación , Gibberella/genética , Hidroxilación , Modelos Químicos , MutaciónRESUMEN
The semisyntheses of melampolides 1 and 2, previously found in Mikania minima, were carried out in order to confirm their chemical structures and to establish their absolute configurations. Their conformational analyses, performed using molecular mechanics, experimental (1)H NMR coupling constants, and NOE experiments, showed a preferred DU conformer in solution at room temperature. The cytotoxic activities of 1 and 2 against three tumor cell lines were also determined. Conjugated aldehyde 2 showed higher activity than alcohol 1.
Asunto(s)
Antineoplásicos Fitogénicos/aislamiento & purificación , Plantas/química , Sesquiterpenos/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Estructura Molecular , Sesquiterpenos/química , Sesquiterpenos/farmacología , Análisis Espectral , Estereoisomerismo , Células Tumorales CultivadasRESUMEN
In the search for new sources of sesquiterpene lactones, six Centaurea species have been analyzed. The activity against the fungus Cunninghamella echinulata of (+)-cnicin (1) and (+)-salonitenolide (2), isolated from the Centaurea plants, as well as that of (+)-costunolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5) and (-)-eremantholide C (6), has been evaluated. Compounds 3 and 4 showed noticeable EC50 values, whilst more polar lactones were inactive. These results suggest that a relatively low polarity is one of the molecular requirements for the antifungal activity of sesquiterpene lactones.
Asunto(s)
Antifúngicos/farmacología , Asteraceae , Cunninghamella/efectos de los fármacos , Lactonas/farmacología , Plantas Medicinales , Sesquiterpenos/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/farmacologíaRESUMEN
In the search for novel bioactive products from filamentous fungi, sterols and triterpenoids found in Phycomyces blakesleeanus were analyzed using semipreparative HPLC, GC-MS, and NMR techniques. Structures proposed for the three new compounds identified, phycomysterol A (1), phycomysterol B (2), and neoergosterol (3), were confirmed by chemical synthesis. Phycomysterols possess a new natural 19-norergostane skeleton with an aromatic B ring. Phycomysterol A showed anti-HIV activity.
Asunto(s)
Fármacos Anti-VIH/química , Phycomyces/química , Esteroles/química , Animales , Fármacos Anti-VIH/aislamiento & purificación , Fármacos Anti-VIH/farmacología , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Células Cultivadas , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ratones , Esteroles/aislamiento & purificación , Esteroles/farmacología , Ensayo de Placa ViralRESUMEN
Malacitanolide (2), a new eudesmanolide isolated from the aerial parts of Centaurea malacitana, was characterized spectroscopically. The synthesis of 2 from cnicin (1), via the epoxide 3, confirmed the structure and stereochemistry of malacitanolide, as well as its biogenetic relationship with 1. Cytotoxic activity values for 2 are significantly higher than for 1.