title: Accumulation of a bioactive triterpene saponin fraction of Quillaja brasiliensis leaves is associated with abiotic and biotic stresses.
abstract: The saponins from leaves of Quillaja brasiliensis, a native species from Southern Brazil, show structural and functional similarities to those of Quillaja saponaria barks, which are currently used as adjuvants in vaccine formulations. The accumulation patterns of an immunoadjuvant fraction of leaf triterpene saponins (QB-90) in response to stress factors were examined, aiming at understanding the regulation of accumulation of these metabolites. The content of QB-90 in leaf disks was significantly increased by application of different osmotic stress agents, such as sorbitol, sodium chloride and polyethylene glycol in isosmotic concentrations. Higher yields of bioactive saponins were also observed upon exposure to salicylic acid, jasmonic acid, ultrasound and UV-C light. Experiments with shoots indicated a significant increase in QB-90 yields with moderate increases in white light irradiance and by mechanical damage applied to leaves. The increased accumulation of these terpenes may be part of a defense response. The results herein described may contribute to further advance knowledge on the regulation of accumulation of bioactive saponins, and at defining strategies to improve yields of these useful metabolites.
authors.affiliation: Department of Botany, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. fernandadecosta@yahoo.com.br
authors.forename: Fernanda
authors.initials: F
authors.lastname: de Costa
authors.forename: Anna Carolina Alves
authors.initials: AC
authors.lastname: Yendo
authors.forename: Juliane Deise
authors.initials: JD
authors.lastname: Fleck
authors.forename: Grace
authors.initials: G
authors.lastname: Gosmann
authors.forename: Arthur Germano
authors.initials: AG
authors.lastname: Fett-Neto
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D011092:Polyethylene Glycols / Q000378:metabolism; D031990:Quillaja / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D062605:Quillaja Saponins / Q000378:metabolism*; D020156:Salicylic Acid / Q000494:pharmacology; D012503:Saponins / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013012:Sorbitol / Q000494:pharmacology; D013016:Sound; D013314:Stress, Mechanical; D013312:Stress, Physiological; D014315:Triterpenes / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D000276:Adjuvants, Immunologic; D003517:Cyclopentanes; D054883:Oxylipins; C570176:QB 90U; D062605:Quillaja Saponins; D012503:Saponins; D014315:Triterpenes; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D013012:Sorbitol; C011006:jasmonic acid; D020156:Salicylic Acid