ACIDO ASCÓRBICO: DESDE LA QUIMICA HASTA SU CRUCIAL FUNCIÓN PROTECTIVA EN OJO"

SERRA H.M; CAFARO T

ACTA BIOQUíMICA CLíNICA LATINOAMERICANA

Año: 2007 vol. 41 p. 525 - 532

0325-2957

Vitamin C or L-ascorbic acid (AA) is an essential vitamin and a water solubleimportant antioxidant agent, chemically synthesized from glucose, by enzymaticreactions, being the L-gulono γ lactone oxidase (GLO) the last enzymeinvolved. The inability to synthesize AA by some species, due to the absenceof GLO seems to have happened hundreds of millions years ago. The degradationof the AA is carried out by oxidative processes which involve thehydrolysis of the lactona ring to produce 2,3 - diketogulonic acid (DCG) thatis later degraded by decarboxilation, generating colored products, found insome ocular pathologies. Among the different properties of the AA, it is worthmentioning its capacity to absorb ultraviolet radiation (RUV) and to avoid the photochemicaldamage of exposed tissues. In humans and in some animals (guinea pigs, primates, etc) theaqueous humor has bigger concentrations of AA than plasma. This responds to a mechanismof specialized active transport in the ciliary body that transfers AA from the blood towards theaqueous humor and from there to the corneal epithelium, transforming the cornea into thestructure of the eye responsible for the biggest absorption of RUV.