Scientists from the China Agricultural University report that PACs from sea buckthorn protected the retina of rabbits against light-induced damage via antioxidant, anti-inflammatory and anti-apoptotic mechanisms.
“Supplementing with PACs may be a useful dietary approach to prevent [age-related macular degeneration] and other diseases related to retinal photo-oxidative damage,” wrote the researchers in Nutrients.
Sea buckthorn (Hippophae rhamnoides L.) has been gaining increasing attention, particularly for extracts of its berries which are known to contain omega-7 fatty acids. The plant is nutrient dense and also contains vitamins A, K, E, C, B1 and B2, amino acids, carbohydrates, folic acid, tocopherols and flavonoids, phenols, terpenes, and tannins.
The new study focused on extracts from sea buckthorn seeds, which are reported to be a rich source of PACs.
The researchers gave lab rabbits extracts of sea buckthorn seeds with PACs levels of 50 or 100 mg/kg/day for two weeks before putting them in a light cage. After this, supplementation was continued for another seven days.
“The sea buckthorn seed extract containing 38.9% PACs was used in this study,” explained the researchers. “Thus, the dose of 50 mg/kg sea buckthorn seed PACs used in rabbits could be considered a moderate dose. A human diet with foods rich in PACs, such as red wine, baking chocolate, apples and dried fruits, could reach dosages up to 700–800 mg/day of PACs, which would be about 100 mg/kg in rabbits using the BSA conversion. Thus, 100 mg/kg sea buckthorn seed PACs can be considered a high nutritional dose.”
Results showed that sea buckthorn seed PACs protected the structure of the retina and significantly attenuated any retinal damage.
While the control animals also displayed significant increases in various inflammatory markers like IL-1beta, IL-6, and TNF-alpha, the animals fed the sea buckthorn seed PACs did not experience these increases.
“PACs from sea buckthorn seed possess a protective effect against light-induced retinal degeneration through antioxidant, anti-inflammatory and anti-apoptotic mechanisms,” wrote the researchers.
“In addition, the gut-derived microbial metabolites of PACs are the main circulating forms in the blood and accumulation in the retinas. The efficacy of PACs is either via small molecular metabolite(s) and/or mediated by a distant upstream step in the defenses against light-induced retinal degeneration.
“Therefore, future studies are required to explore which specific forms of PC metabolites are active in the retina.”
2016, 8(5), 245; doi: 10.3390/nu8050245
“Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L.) Seed against Visible Light-Induced Retinal Degeneration in Vivo”
Authors: Y. Wang