DNA Barcoding of St. John's wort (Hypericum spp.) Growing Wild in North-Eastern Greece

Plants of the genus Hypericum, commonly known as St. Johnes wort (spathohorto or valsamo in Greek), have been used since antiquity for their therapeutic properties. Wild-harvested Hypericum plants are still popular today in herbal medicines, commercially exploited due to their bioactive compounds, hypericin and hyperforin, which have antidepressant, antimicrobial and antiviral activity. Species identification of commercial products is therefore important and DNA barcoding, a molecular method that uses small sequences of organismse genome as barcodes, can be useful in this direction. In this study, we collected plants of the genus Hypericum that grow wild in North-Eastern Greece and explored the efficiency of matK, and trnH-psbA regions as DNA barcodes for their identification. We focused on 5 taxa, namely H. aucheri, H. montbretii, H. olympicum, H. perforatum subsp. perforatum, and H. thasium, the latter a rare Balkan endemic species collected for the first time from mainland Greece. matK (using the genus-specific primers designed herein), trnH-psbA, and their combination were effectively used for the identification of the 5 Hypericum taxa and the discrimination of different H. perforatum subsp. perforatum populations. These barcodes were also able to discriminate Greek populations of H. perforatum, H. aucheri, H. montbretii, and H. olympicum from populations of the same species growing in other countries.</p

Effects of Dietary Supplementation of a Resin-Purified Aqueous-Isopropanol Olive Leaf Extract on Meat and Liver Antioxidant Parameters in Broilers

Olive leaves are byproducts οf the agro-industrial sector and are rich in bioactive compounds with antioxidant properties. They could be supplemented in poultry diets powdered or less frequently as extracts to improve performance, health and product quality. The objective of this study was to investigate the possible beneficial effects of an aqueous isopropanol olive leaf extract—purified through filtration (250–25 µm) and a resin (XAD-4)—when supplemented in broiler chickens’ diets, on meat quality parameters, focusing mainly on antioxidant parameters as there is limited published information. For this purpose, four-hundred-and-eighty-day-old broilers were randomly assigned to four dietary treatments: T1 (control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (positive control: 0.1% encapsulated oregano oil commercially used as feed additive). At the end of the experimental period (day 42), the birds were slaughtered, and samples from breast, thigh meat and liver were collected for antioxidant parameters evaluation. On day 1, after slaughter, in thigh meat, Malondialdehyde (MDA) was lower in T2 compared to T3, and total phenolic content (TPC) was higher in T2 compared to T3 and T4. Total antioxidant capacity (TAC) was increased in T2 and T4 breast meat compared to the control. In liver, T4 treatment resulted in higher TPC. The lack of dose-dependent effect for olive leaf extract may be attributed to the pro-oxidant effects of some bioactive compounds found in olive leaves, such as oleuropein, when supplemented at higher levels. In summary, it can be inferred that the inclusion of 1% olive leaf extract in the feed of broilers has the potential to mitigate oxidation in broiler meat and maybe enhance its quality

Effects of Enriched-in-Oleuropein Olive Leaf Extract Dietary Supplementation on Egg Quality and Antioxidant Parameters in Laying Hens

The objective of the present study was to evaluate the effects of an olive leaf extract obtained with an up-to-date laboratory method, when supplemented at different levels in laying hens’ diets, on egg quality, egg yolk antioxidant parameters, fatty acid content, and liver pathology characteristics. Thus, 96 laying hens of the ISA-Brown breed were allocated to 48 experimental cages with two hens in each cage, resulting in 12 replicates per treatment. Treatments were: T1 (Control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (Positive control: 0.1% encapsulated oregano oil). Eggshell weight and thickness were improved in all treatments compared to the control, with T2 being significantly higher till the end of the experiment (p < 0.001). Egg yolk MDA content was lower for the T2 and T4 groups, while total phenol content and Haugh units were greater in the T2. The most improved fatty acid profile was the one of T3 yolks. The α-tocopherol yolk content was higher in all groups compared to T1. No effect was observed on cholesterol content at any treatment. Based on the findings, it can be inferred that the inclusion of olive leaf extract at a concentration of 1% in the diet leads to enhancements in specific egg quality attributes, accompanied by an augmentation of the antioxidant capacity