Plants used in by traditional African healers could stop blindness caused by diabetes, being born prematurely or old age, a new study found.
A compound from the Hyacinthaceae plant family could treat the causes of a range of eye diseases that involves damage to the back of the eye, the retina.
The naturally occurring homoisoflavonoids or its synthetic derivatives could provide the answer by stopping the growth on new blood vessels in the retina.
Professor Dulcie Mulholland, Head of Department of Chemistry at the University of Surrey said: “Abnormal formation of new blood vessels in the eye is associated with blindness in many ocular diseases such as retinopathy of prematurity (ROP) affecting children, proliferative diabetic retinopathy (PDR), the wet form of age-related macular degeneration (AMD) and neovascular glaucoma affecting adults and elderly people, respectively.
“The newly formed vasculature is fragile and leaky, causing haemorrhage and accumulation of fluids in the retina.
“If left untreated, the resulting edema and fibrotic scarring can lead to irreversible vision loss.”
She added the main treatment is drugs targeting the vascular endothelial growth factor (VEGF) such as bevacizumab, ranibizumab, and aflibercept.
But they require hospital visits for injections into the eye and have side effects and in cases of wet AMD, nearly a third are resistant to treatment.
Prof Mulholland added: “Therefore, there is an unmet need to develop novel and
specific antiangiogenic small molecule therapies to complement and combine with existing drugs for ROP, PDR, and wet AMD.
“Natural products continue to provide appealing lead compounds for treatment of diseases.
“Naturally occurring homoisoflavonoids are reported to have diverse biological
activities including antioxidant, anti-inflammatory, and antiangiogenic activities.
“The Hyacinthaceae is one of the families rich in homoisoflavonoids distributed in different parts of the plants.
“The Hyacinthaceae (sensu APGII) consists of approximately 900 species, in about 70 genera.
“The family can be divided into four subfamilies, the widespread Hyacinthoideae, Urgineoideae, and Ornithogaloideae and the small subfamily Oziroeoideae which is restricted to South ̈America.
“Members of the Hyacinthoideae subfamily have a long tradition of being used by traditional healers to treat a wide range of complaints.”
So together with researchers from Kingston University and the Indiana University School of Medicine tested how well these compounds were able to stop the growth of new blood vessels.
They found one synthetic derivative in particular could be used to develop future treatments while further work continues to synthesise more related compounds.
Professor Mulholland said: “It goes without saying that losing your eyesight is a devastating experience.
“We believe that our results hint at possible future treatments for many degenerative eye conditions and it appears that nature still has many secrets to reveal.”
Dr Sianne Schwikkard at Kingston’s School of Life Sciences, Pharmacy and Chemistry said: “The discovery of new and innovative treatments from natural sources for life-altering diseases has huge potential.
“This work has produced a real opportunity to further collaboration and has the potential to bring new breakthroughs in the treatment of degenerative eye-diseases.”
Professor Tim Corson, at Indiana’s Eugene and Marilyn Glick Eye Institute added: “Existing therapies for these diseases must be injected into the eye, and do not work in all patients.
“Our findings are a first step towards therapies that might avoid these shortcomings.”
Great Ormond Street Hospital said retinopathy of prematurity affects around a fifth of premature babies and mainly occurs in those who are born before 32weeks or weigh less than 1500g.
Diabetic retinopathy is caused by high blood sugar levels damaging the back of the eye – causing blindness if left untreated.
It is estimated to affect 28 million people worldwide.
Wet age-related macular degeneration is one of the world’s leading causes of blindness – affecting 20 million older adults worldwide.
The study was published in the Journal of Natural Products.