Putative Anticataract Properties of Honey Studied by the Action of Flavonoids on a Lens Culture Model

Abstract

Stingless bee (Meliponini) honey is a bioresource used to treat cataracts in traditional medicine. The anticataract activity of twenty flavonoids was explored in an osmotic cataract model, to find a probable link between the putative anti-cataract properties of stingless bee honey eyedrops and their flavonoids. Osmotic cataracts were induced in ovine lenses to produce a model to test anti-cataract drugs in cultured lenses by digital image analysis. Digital images were taken every 4 hr to monitor progressive opacification by measurements of grey level. In 24 hr. the opacification was stable. Osmotic cataracts were induced by incubating ovine lenses in 45% hypotonic HBS for 24 hr to test the anticataract action of twenty synthetic flavonoids at a concentration of 10^-5 M. Luteolin tetramethyl ether, luteolin 4'-glucoside, luteolin 3'-7-diglucoside and orientin, significantly inhibited cataracts induced in ovine lenses incubated in 45% hypotonic HBS for 24 hr. Different degrees of opacification were produced by hypotonic stress in ovine lenses. The significant inhibition of cataracts caused by four derivatives of luteolin in vitro may be considered as a preliminary evidence for the putative anticataract properties of stingless bee honeys.