Fortified S-Allyl L-Cysteine: Animal Safety, Effect on Retinal Ischemia, and Role of Wnt in the Underlying Therapeutic Mechanism

The Effect of S-Allyl L-Cysteine on Retinal Ischemia: The Contributions of MCP-1 and PKM2 in the Underlying Medicinal Properties

Retinal ischemia plays a vital role in vision-threatening retinal ischemic disorders, such as diabetic retinopathy, age-related macular degeneration, glaucoma, etc. The aim of this study was to investigate the effects of S-allyl L-cysteine (SAC) and its associated therapeutic mechanism. Oxidative stress was induced by administration of 500 μM H2O2 for 24 h; SAC demonstrated a dose-dependent neuroprotective effect with significant cell viability effects at 100 μM, and it concurrently downregulated angiogenesis factor PKM2 and inflammatory biomarker MCP-1. In a Wistar rat model of high intraocular pressure (HIOP)-induced retinal ischemia and reperfusion (I/R), post-administration of 100 μM SAC counteracted the ischemic-associated reduction of ERG b-wave amplitude and fluorogold-labeled RGC reduction. This study supports that SAC could protect against retinal ischemia through its anti-oxidative, anti-angiogenic, anti-inflammatory, and neuroprotective properties.

Evaluation of the Effect of Garlic Tablet as a Complementary Treatment for Patients with Diabetic Retinopathy

PURPOSE

The aim of this study was to investigate the effectiveness of garlic (Allium sativum L.) tablets as a complimentary herbal medication in diabetic macular edema.

METHODS

A total of 91 diabetic participants (117 eyes) with central involved macular edema underwent a double-blind randomized trial. The patients used garlic tablets (500 mg) (2 tab/day) or placebo for 4 weeks and subsequently were examined by an expert ophthalmologist. Clinical manifestations including the best-corrected visual acuity (BCVA, logMAR), central macular thickness (CMT, μm), and intraocular pressure (IOP) were measured as the main outcomes.

RESULTS

BCVA was significantly improved by a 0.18 decrease in mean logMAR value in the garlic-treated patients in comparison with 0.06 in the control ones (P value = 0.027). CMT was decreased in both groups by a 102.99 μm decrease in the garlic group compared to 52.67 μm in the placebo group, albeit in a nonsignificant manner (P value: 0.094). IOP was decreased in the garlic group by 1.03 mmHg (P value: 0.024) and increased by 0.3 mmHg (P value: 0.468) in the placebo group.

CONCLUSION

Our trial suggests that garlic supplements can improve visual acuity, decrease the CMT and lower the IOP, and can be considered as an adjuvant treatment in patients with diabetic macular edema. Garlic was satisfactorily tolerated in diabetic patients, and no significant adverse effect interrupting the safety profile was observed.