With regard to the progress of modern medical approaches, a new logic-based combination of modern medicine, with existing facilities in the fields of traditional medicine, has resulted in complementary medicine. Thus, modern medicine will face new challenges using valuable and harmless alternative methods based on complementary medical findings.
In times past, traditional medicine/complementary alternative medicine (TM/CAM) played a special role in the treatment of eye diseases. Moreover, ophthalmology was paid a great deal of attention in traditional literature, especially in Iranian traditional medicine. Among old civilizations, unproven treatments were used to treat different types of ophthalmological diseases, including; injecting cobra venom for macular degeneration, and biogenic stimulation with tissues such as placenta, injected sub conjunctivally for incurable eye diseases (
1). New CAM approaches in ophthalmology employ various methods, including; acupuncture, dietary supplements, herbal remedies and homeopathy.
In Iranian traditional medical literature, the medicinal values of onion (
Allium cepa) are frequently mentioned. Avicenna (980 – 1037 AD), in the ‘Canon of Medicine,’ brought detailed discussions of ophthalmic disease, such as the diagnosis and treatment of cataracts ( 2), and noted the beneficial effects of onion on the eye. As described, ‘the extract of edible basl (onion) is useful for cataracts and clears vision, collyrium of powdered seeds with honey is useful in corneal opacity’( 3).
About two centuries ago in,‘Makhzan-O-L Advieh,’a famous Iranian traditional pharmacopoeia, written by Mohammad Hossein Aghili Khorasani Shirazi (d. 1772 AD), one of the most significant Persian physicians, onion was prescribed for the prevention and treatment of a number of eye diseases, including; cataract, epiphora and blepharitis (
Onion is one of the oldest cultivated plants, and it has been used for many centuries as a natural flavoring, herbal medicine, and among some civilizations it even hadreligious connotations (
5). Onions contain; allins, flavonoids, steroid saponins, polysaccahrides, fructosans, saccharose and other sugars ( 6). These compounds have strong antioxidant, antibacterial and anti-inflammatory properties ( 5- 7). Thiosulfinates are the best studied volatile compounds arising from alliums. In addition to its pungency and flavoring characteristics, it also exhibits antimicrobial effects ( 6). Flavonoids, are another compound of onions, and their significant antioxidant properties inhibit free-radical mediated events in cells that lead to tissue inflammation ( 7- 9). Steroid saponins are another important component, which have medicinal value and these have been studied in animal models ( 10).
Unfortunately, antibiotic resistance continues to increase.
Streptococcus pneumonia and Staphylococcus aureusare the most common ocular pathogens that quickly develop resistance to ophthalmic antibiotics ( 11). Therefore, novel compounds as alternative agents are critically needed. One of the recent approaches is to focus on traditional herbal medicine in order to develop new medications.