Stefania Romandini

Antioxidant and antimicrobial capacity of several monofloral Cuban honeys and their correlation with color, polyphenol content and other chemical compounds.

Several monofloral Cuban honeys were analyzed to determine their total phenolic, flavonoid, ascorbic acid, amino acid, protein and carotenoid contents as well as their radical-scavenging activity and antimicrobial capacities. The total phenolic, flavonoid and carotenoid contents varied considerably, and the highest values were obtained for Linen vine (Govania polygama (Jack) Urb) honey, which is classified as an amber honey. The highest amino acid content was found in Morning glory (Ipomoea triloba L.) while Liven vine had the highest protein content. Similarly Linen vine honey had the highest antioxidant activity while the lowest was found in Christmas vine (Turbina corymbosa (L.) Raf). Ascorbic acid was absent. Hydroxyl radical formation was studied by EPR and spin trapping, and it was found in all honeys tested. The antimicrobial activity was screened using two Gram-positive and Gram-negative bacteria. S. aureus was the most sensitive microorganism while Pseudomonas aeruginosa presented higher minimum active dilution values. Bacillus subtilis and Escherichia coli were both moderately sensitive to honey antimicrobial activity. A correlation between radical-scavenging activity and total phenolic content was found. Correlation existed also between color vs phenolics content, vs flavonoid content or between phenolic vs flavonoid.

Methodological Aspects about Determination of Phenolic Compounds and In Vitro Evaluation of Antioxidant Capacity in the Honey: A Review

The antioxidant activity of honey varies greatly depending on the honeys floral source. There is little knowl- edge about the profiles of antioxidant substances in honey from different floral sources. The variation in these profiles might be responsible for the widely varying ability of honey to protect against oxidative reactions. Honey is rich in poly- phenol compounds, which act as natural antioxidants, and are becoming increasingly popular because of their potential role in contributing to human health. These compounds can also be used as indicators in studies about the floral and geo- graphical origin of the honey. Therefore, we overviewed the current analytical methods for measuring polyphenols and antioxidant capacity in honey. The analytical procedure to determine individual phenolic compounds involves their ex- traction from the sample, analytical separation and quantification. The analytical separation techniques widely employed are gas chromatography, high-pressure liquid chromatography and capillary electrophoresis. The techniques to evaluate the antioxidant capacity are based on colorimetric assays such as DPPH, FRAP, TEAC (ABTS) and microplate fluores- cence reader like ORAC assay.

The potential impact of strawberry on human health

The strawberry (Fragaria X ananassa, Duch.) represents a relevant source of micronutrients, such as minerals, vitamin C, folate and phenolic substances, most of which are natural antioxidants and contribute to the high nutritional quality of the fruit. All these compounds are essential for health and, in particular, strawberry phenolics are best known for their antioxidant and anti-inflammatory action, and possess directly and indirectly antimicrobial, anti-allergy and anti-hypertensive properties, as well as the capacity to inhibit the activities of some physiological enzymes and receptor properties. The main objective of this article is to review and update the current knowledge on the potential impact of the strawberry on human health, with particular attention on compounds and their possible mechanisms of action.