title: Plant growth regulation activity of steviol and derivatives.
abstract: This work describes the preparation of tetracyclic diterpenoids and determination of their plant growth regulator properties. Stevioside (2) was used as starting material and the derivatives 13-hydroxy-ent-kaur-16-en-19-oic acid (steviol, 3), ent-7alpha,13-dihydroxy-kaur-16-en-19-oic acid (4), 13-hydroxy, ent-kaur-16,17-epoxi-19-oic acid (steviol epoxide, 5), 17-hydroxy-16-ketobayeran-19-oic acid (17-hydroxyisosteviol, 6), 17-hydroxy-16-hydroxyiminobayeran-19-oic acid (7), 16-ketobayeran-19-oic acid (isosteviol, 9), 16,17-dihydroxybeyeran-19-oic acid (8), and 16-hydroxyiminobayeran-19-oic acid (isosteviol oxime, 10) were obtained by simple chemical procedures. Another derivative, ent-7alpha,13-dihydroxycaur-15-en-19-oic acid (4), was obtained by biotransformation of steviol (3) by Penicillium citrinum. In order to determine the plant growth regulator activity the compounds were submitted to the lettuce hypocotyl and barley aleurone bioassays. All compounds showed significant activities in both bioassays. Steviol (3) and isosteviol (9) were also tested in field-grown grapes resulting in an increase in berry weight and size.
authors.affiliation: Universidade Federal do Paraná, Departamento de Química, Curitiba, PR, Brazil. bho@ufpr.br
authors.forename: Brás Heleno
authors.initials: BH
authors.lastname: de Oliveira
authors.forename: Júlio César
authors.initials: JC
authors.lastname: Stiirmer
authors.forename: José D
authors.initials: JD
authors.lastname: de Souza Filho
authors.forename: Ricardo Antonio
authors.initials: RA
authors.lastname: Ayub
mesh_terms: D045786:Diterpenes, Kaurane / Q000737:chemistry* / Q000494:pharmacology; D005960:Glucosides / Q000737:chemistry* / Q000494:pharmacology; D001467:Hordeum / Q000187:drug effects / Q000254:growth & development; D018545:Lactuca / Q000187:drug effects / Q000254:growth & development; D015394:Molecular Structure; D010937:Plant Growth Regulators / Q000737:chemistry* / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D045786:Diterpenes, Kaurane; D005960:Glucosides; D010937:Plant Growth Regulators; C012043:stevioside; C012042:steviol