Estudio químico y biológico de especies del género Azorella

143 p.El presente estudio tuvo por finalidad aislar e identificar los metabolitos mayoritarios a partir de algunas plantas del género Azorella, (A.spinosa, A. madreporica) cuyas especies forman parte de la familia Apiaceae, además de obtener derivados semisintéticos en la medida que fue posible y probar la actividad biológica de estos compuestos. Investigaciones realizadas en otros géneros de Azorella han permitido la identificación de varios compuestos diterpenicos del tipo azorellano y mulinano, algunos de estos diterpenos han sido responsables de distintas actividades biológicas, tales como antibacteriana, antiinflamatoria, inhibición de la acetilcolinesterasa, entre otras. El estudio químico de las partes aéreas de la especie A. spinosa permitió aislar diterpenos, un triterpeno, cumarina e isoflavonas. A partir del extracto etéreo fueron aislados cuatro diterpenos dos de ellos reportados previamente en literatura, en otras especies 13α-hidroxiazorellano, ácido mulinólico y dos compuestos nuevos 2-acetoxi-13-hidroxi-mulin-11-eno, 2-acetoxi-mulin-11,13-dieno, a partir de 2-acetoxi-13-hidroxi-mulin-11-eno se obtuvo el compuesto hidrolizado 2,13-dihidroxi-mulin-11-eno. Por otra parte del extracto metanólico se aisló un triterpeno, que resulto ser la lactona del ácido ursólico siendo este compuesto nuevo en esta especie pero ya reportado en otras plantas, de este mismo extracto se aisló quercetina y 7-hidroxicumarina.A partir del estudio químico de la A. madreporica fueron aisladas tres isoflavonas las cuales corresponden a alpinumisoflavona, licoisoflavona A y angustona C, compuestos reportados por primera vez en esta especie. A partir de la alpinumisoflavona se obtuvo el derivado diacetilado 4´,4´´-diacetoxi-alpinumisoflavona y de la acetilación de licoisoflavona se obtuvo el derivado monoacetilado 7-acetoxi-licoisoflavona A. Todos los compuestos aislados que resultaron ser nuevos o informados por primera vez en estas especies, como también los derivados semisintéticos preparados, fueron evaluados mediante el ensayo de microdilución en microplacas como agentes antibacterianos frente a Escherichia coli, Acinetobacter baumanni, Pseudomonas aeuroginosa y Staphilococcus aureus. Solo las isoflavonas alpinumisoflavona y licoisoflavona A fueron activas y selectivos sobre E. coli. Los diterpenos 2-acetoxi-13-hidroxi-mulin-11-eno, 2-acetoxi-mulin-11,13-dieno y el derivado 2,13-dihidroxi-mulin-11-eno, fueron evaluados en el ensayo de inhibición de la enzima acetilcolinesterasa (AChE) y la butirilcolinesterasa (BuChE) y sobre la actividad antioxidante empleando el ensayo DPPH. Por otro lado, el extracto metanólico de A. spinosa recolectada en la zona de Constitución (Región del Maule) y tres extractos metanólicos de A. monantha recolectadas en tres localidades distintas Paso Vergara y Enladrillado (Región del Maule), y Torres del Paine (Región de Magallanes) se evaluaron sobre todas las actividades biológicas anteriormente descritas, incluyendo la actividad antiplaquetaria, siendo los extractos de A. spinosa y A. monantha (Paso Vergara) las que mostraron mejores resultados./ABSTRACT: The aim of this study was to isolate and to identify the main metabolites from some plants of the Azorella (A.spinosa, A. madreporica) genre whose species are part of the Apiaceae family. Also, this study helped to obtain semisynthetic derivatives as possible as far and to test the biological activity of these compounds. Research in other Azorella genres have allowed the identification of several diterpene compounds of the mulinane and azorellane type. Some of these diterpenes have been responsible of the various biological activities such as antibacterial, anti-inflammatory, inhibition of acetylcholinesterase, and others. The chemical study of the aerial parts of the species A. spinosa allowed to isolate diterpenes, triterpenes, isoflavones and coumarin. From the ethereal extract, four diterpenes were isolated, two of them were previously reported in literature, in other species like the 13α-hydroxyazorellane and mulinolic acid, and the other two new compounds, 2-acetoxy-13-hydroxy- mulin-11-en, 2-acetoxy-mulin 11,13-diene, starting from the 2-acetoxy-13-hydroxy- mulin-11-en compound was obtained the 2,13-dihydroxy-mulin-11-en. By the other side, a triterpene was isolated from the methanol extract, which has proved to be the lactone of the ursolic acid being this a new compound in this specie but already reported in other plants. From the same extract was isolated quercetin and 7-hydroxycoumarin. From the chemical study of the A. madreprica, three isoflavones were isolated which correspond to alpinumisoflavone, angustone C and licoisoflavone A, compounds reported by the first time in this species. Starting from the alpinumisoflavone, the diacetyl derivative was obtained 4',4''-diacetoxy-alpinumisoflavoe and from the licoisoflavone acetylation, 7-acetoxy-licoisoflavone A monoacetylated derivative was obtained. All these compounds were elucidated using conventional spectroscopic techniques and by mean of the comparison with literature data. All those isolated compounds were found to be new or reported by first time in these species. Also, semisynthetic derivatives were evaluated by the microdilution in assay microplates as antibacterial against Escherichia coli, Acinetobacter baumanni, Pseudomonas aeruginosa and Staphylococcus aureus. Only the alpinumisoflavone and licoisoflavone A isoflavones were active and selective over the E. coli. The diterpenes 2-acetoxy-13-hydroxy-mulin-11-en, 2-acetoxy-mulin-11,13-diene and 2,13-dihydroxy mulin-11-en derivative were evaluated in the inhibition assay of the acetylcholinesterase (AChE) enzyme and the butyrylcholinesterase (BuChE). Also, the antioxidant activity were evaluated using the DPPH assay.By the other hand, the methanolic extract of A. spinosa collected from Constitución zone (Region of Maule) and the three methanol extracts of A. monantha collected from three different locations like Paso Vergara and Enladrillado (Region of Maule), and Torres del Paine (Region of Magallanes) were evaluated on over all the biological activities described above, including antiplatelet activity, being the extracts of A. spinosa and A. monantha (Paso Vergara) that showed the best result

Variations in the halogenated monoterpene metabolites of plocamium cartilagineum of the chilean coast

Examination of six samples of the red alga P. cartilagineum collected along 1600 km of Central Chilean coast yielded a number of polyhalogenated monocyclic monoterpenes. Acyclic compounds were not found. Two common compounds for all samples have been found. By means of their chemical composition, the samples can be separated into two main groups. © 1986

Halogenated sesquiterpenes pacifenol and pacifenol derivatives on the aphid Schizaphis graminum

Pacifenol, a halogenated sesquiterpene was isolated from Laurencia claviformis. The effects of pacifenol and two derivatives on survival and feeding behaviour of the aphid Schizaphis graminum were studied. Toxicity of pacifenol was lower than the other compounds, and the dibromo derivative was more toxic than pacifidiene. At concentrations higher than 250 and 750 ppm, respectively, both compounds acted as antifeedants on aphids. © 1993

Two chemical types of the red alga Plocamium cartilagineum from Chile

Examination of two close collections of Plocamium cartilagineum separated into plants bearing carposporophyte, tetrasporophyte and gametophyte yielded the same qualitative chemical composition, but the three reproductive phases have quantitative differences. We designate chemotype β to the collection which contains brominated monoterpenes and chemotype α to the group which lacks the enzymatic system which incorporates bromine. © 1988

Insecticide and acaricide activities of polyhalogenated monoterpenes from chilean Plocamium cartilagineum

Four new alicyclic monoterpenes based on the 1-(2-chlorovinyl)-2,4,5-trichloro-1,5-dimethylcyclohexane skeleton were isolated from Plocamium cartilagineum from the Chilean coast, together with four known cyclic monoterpenes. The structure of the new compounds were determined by comparison of the spectral data with those of known compounds. The insecticide/acaricide and fungicide activities of some of the isolated monoterpenes were determined. © 1991

Diterpenoids from Baccharis tola

Erythroxylol-A, oleanolic acid, erythroxylol-A oxide, scopolatine, 4-hydroxy-3-methoxyacetophenone and two new diterpenes, ent-beyer-14-en-18-ol and 19-hydroxy-13-epimanoyl oxide, were isolated from B. tola. © 1980

Isoepitaondiol, a diterpenoid of Stypopodium flabelliforme and the insecticidal activity of stypotriol, epitaondiol and derivatives

A new diterpenoid of mixed biogenesis; isoepitaondiol, has been isolated together with known diterpenoids and two chromones from the alga Stypopodium flabelliforme collected at Easter Island. © 1992

Unusual polyoxygenated monoterpenes from the Antarctic alga Pantoneura plocamioides

Six new polyoxygenated marine monoterpenes have been isolated from the Antarctic alga Pantoneura plocamioides. The structure and relative stereochemistry of these compounds, denominated pantopyranoids A-C (1-3), and pantoisofuranoids A-C (4-6) were determined on basis of spectroscopic evidence