Plant growth regulation activity of steviol and derivatives.
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.
de Oliveira
Brás Heleno
BH
Universidade Federal do Paraná, Departamento de Química, Curitiba, PR, Brazil. bho@ufpr.br
Stiirmer
Júlio César
JC
de Souza Filho
José D
JD
Ayub
Ricardo Antonio
RA
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
D045786:Diterpenes, Kaurane; D005960:Glucosides; D010937:Plant Growth Regulators; C012043:stevioside; C012042:steviol