Oxidation of 8′-hydroxy abscisic acid in Black Mexican Sweet maize cell suspension cultures

• Published in: Phytochemistry (Oxford) Vol. 65; no. 24; pp. 3199 - 3209
• Main Authors: Irina Zaharia, L., Gai, Yuanzhu, Nelson, Ken M., Ambrose, Stephen J., Abrams, Suzanne R.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.12.2004; Elsevier
• Subjects: 8′-HydroxyABA; abscisic acid; Abscisic Acid - chemistry; Abscisic Acid - metabolism; Abscisic acid, ABA; biochemical pathways; Biochemistry & Molecular Biology; Biological and medical sciences; biotransformation; cell suspension culture; Cells, Cultured; Chemical constitution; corn; cultured cells; Deuterium - chemistry; Deuterium labelled ABA metabolites; Fundamental and applied biological sciences. Psychology; grain crops; Gramineae; Hydroxylation; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; Metabolism; Models, Chemical; Molecular Structure; oxidation; Oxidation-Reduction; plant biochemistry; Plant Growth Regulators - chemistry; Plant Growth Regulators - metabolism; plant physiology; Plant physiology and development; Plant Sciences; Science & Technology; spectral analysis; Synthesis; Tissue cultures, protoplasts; Zea mays; Zea mays - cytology; Zea mays - metabolism; Zea mays L. cv. Black Mexican Sweet; Synthesis; Zea mays L. cv. Black Mexican Sweet; Gramineae; Abscisic acid, ABA; 8′-HydroxyABA; Metabolism; Deuterium labelled ABA metabolites; ABA; synthesis; DIHYDROPHASEIC ACID; ANALOG; L; MASS-SPECTROMETRY; SEEDS; deuterium labelled ABA metabolites; BIOLOGICAL-ACTIVITY; abscisic acid; metabolism; 8 '-HydroxyABA; (+)-ABSCISIC ACID; Deuterium; Cell culture; Monocotyledones; Incorporation; Zea mays; Metabolite; Aldehyde; ABA; 8'-HydroxyABA; Deuterium labelled ABA metabolites; Synthesis; Suspension culture; Zea mays L. cv. Black Mexican Sweet; Gramineae; Metabolism; Abscisic acid; Biotransformation; Angiospermae; Abscisic acid; Isolation; Spermatophyta; Oxidation; Chemical synthesis
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2004.09.007

Metabolism studies of deuterated abscisic acid in maize tissue cultures uncovered a further oxidation pathway of 8′-hydroxyABA, with isolation of catabolites derived from the 8′-alcohol, aldehyde and acid. In a biotransformation study to prepare deuterium labelled phaseic acid (PA) from deuterated abscisic acid (ABA), the product contained fewer deuterium atoms than expected. Thus, spectroscopic data of isolated deuterated PA prepared from biotransformation of (+)-5,8′,8′,8′-d 4-ABA in maize ( Zea mays L. cv. Black Mexican Sweet) cell suspension cultures showed 83% deuterium incorporation at the 8′- exo position. Also, metabolism studies of (+)-4,5-d 2-ABA in maize resulted in the isolation of deuterium labelled ABA derivatives, namely PA, dihydrophaseic acid (DPA), 4′- O-β- d-glucopyranosylDPA, 8′-hydroxyPA, 8′-hydroxyDPA and 8′-oxoDPA, as deduced from spectroscopic methods. These combined results suggested the presence of an aldehyde intermediate which is either: (a) reduced to 8′-hydroxyABA and cyclized to PA, or (b) is hydrated and cyclized to 8′-hydroxyPA or (c) is further oxidized to the acid and cyclized to 8′-oxoPA. The chemical synthesis of this intermediate, as well as its biotransformation in maize cell cultures is presented.