BioScience Trends. 2017;11(1):41-46. (DOI: 10.5582/ddt.2016.01071)

Olive and ginkgo extracts as potential cataract therapy with differential inhibitory activity on aldose reductase.

Elimam DM, Ibrahim AS, Liou GI, Badria FA


SUMMARY

Aldose reductase (AR) has been the leading target in the treatment of diabetic cataract. Although numerous synthetic AR inhibitors (ARI) have been identified, their adverse side effects currently preclude their use. Olive leaf extract (OLE) as well as ginkgo leaf extract (GLE) are natural supplements that have wide therapeutic indices and a plethora of salutary effects during diabetes that so far untested on sugar cataract progression. As such, the present study sought to evaluate the AR-inhibiting properties of OLE and GLE using the isolated enzyme from rabbit lens. Biochemical analyses revealed that both OLE and GLE inhibited rabbit lens AR activity in a concentration-dependent manner with half maximal inhibitory concentration (IC50) 65 ?g/mL and 72.5 ?g/mL, respectively. Interestingly, the results of kinetic studies exhibited a differential pattern of inhibition by these two extracts. While an non-competitive inhibition of AR was promoted by OLE recognized by significant decrease in the apparent maximum velocity (Vmax) (0.12


KEYWORDS: Rabbit lenses, polyol pathway, aldose reductase, NADPH, enzyme inhibiting, cataract, olive extract, ginkgo extract

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