Antioxidant and DNA-Protective Activity of an Extract Originated from Kalamon Olives Debittering

The Bioactivity of a Hydroxytyrosol-Enriched Extract Originated after Direct Hydrolysis of Olive Leaves from Greek Cultivars

Nowadays, olive leaf polyphenols have been at the center of scientific interest due to their beneficial effects on human health. The most abundant polyphenol in olive leaves is oleuropein. The biological properties of oleuropein are mainly due to the hydroxytyrosol moiety, a drastic catechol group, whose biological activity has been mentioned many times in the literature. Hence, in recent years, many nutritional supplements, food products, and cosmetics enriched in hydroxytyrosol have been developed and marketed, with unexpectedly positive results. However, the concentration levels of hydroxytyrosol in olive leaves are low, as it depends on several agricultural factors. In this study, a rapid and easy methodology for the production of hydroxytyrosol-enriched extracts from olive leaves was described. The proposed method is based on the direct acidic hydrolysis of olive leaves, where the extraction procedure and the hydrolysis of oleuropein are carried out in one step. Furthermore, we tested the in vitro bioactivity of this extract using cell-free and cell-based methods, evaluating its antioxidant and DNA-protective properties. Our results showed that the hydroxytyrosol-enriched extract produced after direct hydrolysis of olive leaves exerted significant in vitro antioxidant and geno-protective activity, and potentially these extracts could have various applications in the pharmaceutical, food, and cosmetic industries.

Development of a Holistic In Vitro Cell-Free Approach to Determine the Redox Bioactivity of Agricultural Products

In recent years, there has been a strong consumer demand for food products that provide nutritional benefits to human health. Therefore, the assessment of the biological activity is considered as an important parameter for the promotion of high-quality food products. Herein, we introduce a novel methodology comprising a complete set of in vitro cell-free screening techniques for the evaluation of the bioactivity of various food products on the basis of their antioxidant capacity. These assays examine the free radical scavenging activities, the reducing properties, and the protective ability against oxidative damage to biomolecules. The adoption of the proposed battery of antioxidant assays is anticipated to contribute to the holistic characterization of the bioactivity of the food product under examination. Consumer motivations and expectations with respect to nutritious food products with bio-functional properties drive the global food market toward food certification. Therefore, the development and application of scientific methodologies that examine the quality characteristics of food products could increase consumers' trust and promote their beneficial properties for human health.