(+)-Abscisic acid

Abscisic acid ((S)​-​(+)​-​Abscisic acid) is a plant hormone which is as a growth inhibitor. Abscisic acid has been shown to regulate many aspects of plant growth and development including embryo maturation, seed dormancy, germination, cell division and elongation, floral induction, and responses to environmental stresses such as drought, salinity, cold, pathogen attack and UV radiation[1].

(+)-Abscisic acid (pure substance) is a colorless crystalline solid. It has a melting point of 160–161°C and sublimes at 120°C. The partition coefficients are 1.8 for the electrically neutral form and 0.94 for the ionic form. Its relative density is 1.21. The solubility in water is 3102 mg/L (at pH 4). The specific rotation is [α]²⁰D = +40.997° (c = 10.1 mg/mL in ethanol, at 20°C). The pKa is 4.61. It is soluble in chloroform, acetone, ethyl acetate, and diethyl ether but only sparingly soluble in benzene and water. The UV maximum absorption wavelength (in methanol) is 252 nm.

ChEBI: The naturally occurring (1'S)-(+) enantiomer of abscisic acid. It is an important sesquiterpenoid plant hormone which acts as a regulator of plant responses to environmental stresses such as drought and cold.

Crystallise the acid from CCl4/pet ether, EtOH/hexane and sublime it at 120o. Also purify it by dissolving ~30g in 30mL of EtOAc, adding 100mL of hexane and allow to crystallise overnight (yield 8.4g), m 156-158o, 161-163o, [] D +426o (c 0.005M H2SO4 in MeOH). [Cornforth et al. Nature (London) 206 715 1965, Soukemp et al. Helv Chim Acta 72 361 1989.] The RS-isomer was purified on a Kieselgel F254 plate with toluene/EtOAc/AcOH (50:50:3) and has m 188-190o [Cornforth et al. Aust J Chem 45 179 1992]. [Beilstein 17/3 V 13.]

Abscisic acid can stimulate the production of ethylene and promote fruit ripening. It inhibits the synthesis of DNA and protein. The physiological functions of abscisic acid are as follows: 1. Inhibit and promote growth. When the concentration of externally applied abscisic acid is high, the growth of stems, hypocotyls, roots, coleoptiles or leaves is inhibited. When the concentration is low, it promotes the rooting of the isolated cucumber cotyledons and the elongation of the hypocotyls, accelerates the reproduction of duckweed, and stimulates the development of parthenocarpy seeds. 2. Maintain dormancy of buds and seeds. Dormancy is related to the balance of gibberellin and abscisic acid in the body. 3. Promote the shedding of fruits and leaves. 4. Promote the closure of stomata. Abscisic acid can close the stomata quickly, is non-toxic to plants, and is a good anti-transpirant. A biological test method for testing the concentration of abscisic acid is to float the epidermis of detached leaves on the surface of various concentrations of abscisic acid solution. Within a certain range, the degree of stomata opening and closing is inversely proportional to the concentration of abscisic acid. 5. Affect flowering. Under long-day conditions, abscisic acid can make the top buds of strawberries and blackberries dormant and promote flowering. 6. Affect sexual differentiation. Gibberellin can make female plants of cannabis form male flowers. This effect can be reversed by abscisic acid, but abscisic acid cannot make male plants form female flowers. The natural isomer of abscisic acid. A plant growth regulator that has a high affinity binding site for abscisic acid on the plasma membrane of broad bean guard cells. And a variety of physiological mechanisms such as seed dormancy, leaf shedding, stomatal movement and plant stress response. Through complex interactions with a variety of intracellular signaling systems, shedding isoforms can regulate the expression of hundreds of plant genes.

(+)-Abscisic acid is the natural isomer of the abscission-accelerating plant hormone and a plant growth regulator that exhibits multiple physiological effects, including inducing plant dormancy, inhibiting seed germination and plant growth, and stimulating stomatal closure.

Molecular Weight:264.32
XLogP3:1.6
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:264.13615911
Monoisotopic Mass:264.13615911
Topological Polar Surface Area:74.6
Heavy Atom Count:19
Complexity:494
Defined Atom Stereocenter Count:1
Undefined Bond Stereocenter Count:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes