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Master's Dissertation
DOI
https://doi.org/10.11606/D.46.1998.tde-05052023-160458
Document
Author
Full name
Kênnia Rocha Rezende
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1998
Supervisor
Committee
Kato, Massuo Jorge (President)
Roque, Nidia Franca
Young, Maria Claudia Marx
Title in Portuguese
Estrutura e atividade biológica de lignanas ariltetralônicas e derivados de Virola sebifera
Keywords in Portuguese
Produtos naturais
Química orgânica
Abstract in Portuguese
Os extratos das sementes de Virola sebifera foi fracionado através de técnicas cromatográficas conduzindo ao isolamento de quatro neolignanas ariltetralônicas (7'R,8 'S,8S)-7-hidroxi-3,4,3,4-dimetilenodioxi-7-oxo-2,7-8,8-neolignana(1a); (7'R,8'S,8S)-3,4,3',4 '-dimetilenodioxi-7-oxo-2,7',8,8'-neolignana (1b); (8R,7'S,8'R)-4,5-dimetoxi-3' ,4'metilenodioxi-7-oxo-2,7' ,8.8'-neolignana (2a) e (8R,7'S,8'R)-7'-hidroxi-4,5-dimetoxi-3',4'metilenodioxi-7-oxo-2,7',8.8'-neolignana (2b) e uma neolignana diarilbutânica (8S,7'S,8'S)-7-acetoxi-3,4-dimetoxi-3' ,4'-metilenodioxi-7.1-seco-6.7' ,8.8'-neolignana (4), previamente descritas na literatura. São descritos ainda dois novos produtos naturais com esqueleto ariltetralônico e secotetralínico, respectivamente: (7'R,8'S,8S)-2'-hidroxi-3,4,4' ,5'-dimetilenodioxi-7-oxo-2,7'-8,8'-neolignana (1c) e (8R,8'R)-3,4,3' ,4' ,7.7'dioxo, 8.8'-neolignana (3). As neolignanas isoladas em quantidade foram derivatizadas e avaliadas quanto ao seu potencial biológico. No ensaio antitumoral com leveduras mutantes de Saccharomyces cerevisiae, as neolignanas e os derivados testados foram inativos. No ensaio antifúngico com Cladosporium cladosporioides apenas (1b) e (1c) demonstraram discreta atividade. No ensaio com desovas de Biomphalaria glabrata, a Cl50 para (1b) e (1c) foi 11,7 e 8,5 µg/mL, respectivamente. No ensaio antioxidante, as neolignanas mais ativas apresentaram hidroxilas fenólicas livres 1c, Cat-1a, Cat-2a demonstrando atividade, em média, quarenta vezes maior que o α- tocoferol.
Title in English
Estrutura e atividade biológica de lignanas ariltetralônicas e derivados de Virola sebifera
Keywords in English
Produtos naturais
Química orgânica
Abstract in English
Ethyl acetate extract of Virola sebifera seeds was fractionated by chromatographic techniques yielding four aryltetralonic neolignans previously described: (7'R,8'S,8S)-7-hydroxy-3,4,3',4'-dimethylenedioxy-7-oxo-2,7'-8,8'-neolignan (1a); (7'R,8'S,8S)-3,4,3' ,4'-dimethylenedioxy-7-oxo-2,7',8,8'-neolignan (1b); (8R,7'S,8'R)-4,5-dimethoxy-3',4'-methylenedioxy-7-oxo-2,7' ,8.8'-neolignan (2a) e (7'S,8'R)-7'-hydroxy-4,5-dimethoxy-3',4'-methylenedioxy-7-oxo-2,7',8.8'-neolignan (2b) and one diarylbutanic neolignan (8S,7'S,8 'S)-7-acetoxy-3,4-dimethoxy-3',4'-methylenedioxy-7.1-seco-6.7',8.8'-neolignan (4). Furthermore, a new aryltetralonic and a diarylbutanic neolignans were described: (7'R,8'S,8S)-2'-hydroxy-3,4,4'5'-dimethoxy-7-oxo-2,7'-8,8'neolignan-(1c) and (8R,8'R)-3,4,3',4',7.7'-dioxo,8.8'-neolignan (3). None of the isolated or derivatized neolignans showed antitumoral activity based on the low growth inhibition effect on mutant strains of Saccharomyces cerevisiae. The antifungal assay using Cladosporium cladosporioides showed slight activity for (1b) and (1c) . The moluscicidal assay on Biomphalaria glabrata indicated high activity for (1b)and (1c)with LC50 of 11,7 and 8,5 µg/mL, respectively. As expected, the deprotection of (1a) and (2a) neolignans, yielding the corresponding catechols, increased forty times the antioxidant activity as compared to α-tocopherol. Similar activity was observed to the new neolignan bearing one free hydroxyl group (1c).
 
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2023-05-05
 
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