Vision-restorative okra

Hyaluronic acid (HA), an expensive substance obtained from rooster combs, is currently used to treat cataracts and osteoarthritis as well as for reconstructive surgery. HA is derived from animals, a risky proposition with the rising incidence of avian flu. To add to this, use of raw materials of animal origin in humans requires compliance with existing EU regulations.

The EU-funded OKRAVISION (Replacing the animal source of viscous fluids used in cataract surgery with the okra plant source) project investigated the feasibility of obtaining viscoelastic high molecular weight (HMW) compounds from okra to replace HA in surgical applications. More specifically, they worked on producing HMW rhamnopyranose-galactopyranose-galactopyranosyluronic acid (RGGA) from the okra fruit.

Researchers analysed different okra raw materials from West Africa and south-east Asia. Testing revealed that yield and properties of RGGA obtained from West African okra was better than the Asian variety.

OKRAVISION successfully developed an extraction and purification method and obtained HMW RGGA with higher than expected yield. However, there were issues with the viscosity of the extract during downstream processing, indicating the need for RGGA cross-linking.

The cataract surgery market alone is worth several millions of euros. Other potential applications include aesthetic surgery, joint lubrication, breast implant and the cosmetic industry. Successful and affordable production of HMW RGGA from okra will have significant socioeconomic implications for Europe. Another bonus of using products of plant origin is that the resulting waste could be used in animal food, as biomass for biogas production or as fertiliser.