Introduction Collagen hydrolysate is recognized as a safe nutraceutical, whose combination of amino acids stimulates the synthesis of collagen in the extracellular matrix of cartilage and other tissues. Objective to conduct a systematic review of literature on the action of collagen hydrolysate in bone and cartilaginous tissue and its therapeutic use against osteoporosis and osteoarthritis. Method a study of the PubMed, MEDLINE, LILACS, and SciELO databases was performed. Articles published in English and Portuguese in the period of 1994 to 2014 were considered. Results: the sample comprised nine experimental articles with in vivo (animals and humans) and in vitro (human cells) models, which found that the use of different doses of collagen hydrolysate were associated with the maintenance of bone composition and strength, and the proliferation and cell growth of cartilage. Conclusion hydrolyzed collagen has a positive therapeutic effect on osteoporosis and osteoarthritis with a potential increase in bone mineral density, a protective effect on articular cartilage, and especially in the symptomatic relief of pain.

Diabetic retinopathy (DR) is a neurodegenerative and vascular pathology that is considered one of the leading causes of blindness worldwide, resulting from complications of advanced diabetes mellitus (DM). Current therapies consist of protocols aiming to alleviate the existing clinical signs associated with microvascular alterations limited to the advanced disease stages. In response to the low resolution and limitations of the DR treatment, there is an urgent need to develop more effective alternative therapies to optimize glycemic, vascular, and neuronal parameters, including the reduction in the cellular damage promoted by inflammation and oxidative stress. Recent evidence has shown that dietary polyphenols reduce oxidative and inflammatory parameters of various diseases by modulating multiple cell signaling pathways and gene expression, contributing to the improvement of several chronic diseases, including metabolic and neurodegenerative diseases. However, despite the growing evidence for the bioactivities of phenolic compounds, there is still a lack of data, especially from human studies, on the therapeutic potential of these substances. This review aims to comprehensively describe and clarify the effects of dietary phenolic compounds on the pathophysiological mechanisms involved in DR, especially those of oxidative and inflammatory nature, through evidence from experimental studies. Finally, the review highlights the potential of dietary phenolic compounds as a prophylactic and therapeutic strategy and the need for further clinical studies approaching the efficacy of these substances in DR management.