New insights into the exploitation of vitis vinifera l. Cv. aglianico leaf extracts for nutraceutical purposes

The leaves of Vitis vinifera L. have been used for a long time in traditional medicine for the treatment of many ailments. Grape polyphenols, indeed, have been demonstrated to be able to defend against oxidative stress, responsible for various disorders such as cancer, diabetes and neurodegenerative diseases. The effects of different extraction techniques, Soxhlet (SOX), Accelerated Solvent (ASE 40, ASE 50) and Ultrasound Assisted Extraction (UAE) were studied in this work to evaluate their impact on the chemical profile and bioactive potential of Vitis vinifera L. (cv. Aglianico) leaf extracts. The phytochemical profile was investigated by HPLC-DAD and 9 phenolic compounds were identified and quantified in the extract. Moreover, the antioxidant, anticholinesterase and antityrosinase activities were evaluated. In detail, the total polyphenol content and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, Oxygen Radical Absorbance Capacities and β-Carotene Bleaching assays) were evaluated and compared to assess the Relative Antioxidant Capacity Index (RACI). To test the inhibitory activity of extracts towards cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition assays were performed. SOX and ASE 50 have shown the highest value of RACI, 0.76 and 0.65, respectively. Regarding enzymatic inhibitory activity, ASE 50 (IC50 = 107.16 ± 8.12 µg/mL) and SOX (IC50 = 171.34 ± 12.12 µg/mL) extracts exhibited the highest AChE and BChE inhibitory activity, respectively, while UAE (IC50 = 293.2 ± 25.6 µg/mL, followed by SOX (IC50 = 302.5 ± 38.3 µg/mL) showed the highest tyrosinase inhibition value. Our results demonstrated for the first time that Aglianico leaves are important sources of phenols that could be used to prevent oxidative stress and be potentially helpful in diseases treatable with tyrosinase and cholinesterase inhibitors, like myasthenia gravis or Alzheimer’s

Anthocyanins in Blueberries Grown in Hot Climate Exert Strong Antioxidant Activity and May Be Effective Against Urinary Tract Bacteria

Anthocyanins are extensively studied for their health-related properties, including antibacterial activity against urinary tract infections (UTI). Among common fruits, blueberries, with their remarkable antioxidant capacity, are one of the richest sources. Anthocyanin-rich extracts were obtained from four varieties: Snowchaser, Star, Stella Blue and Cristina Blue, grown in the hot climate of Southern Spain. Their total anthocyanins contents (TAC) were determined spectrophotometrically, and the anthocyanin profile by ultra high performance liquid chromatography - tandem mass spectrometer (UHPLC-MS/MS). Their antioxidant activity was assessed by oxygen radical absorbance capacity (ORAC) assay, while antibacterial activity against strains isolated from UTI patients was assessed in vitro, helping to select the varieties with the highest bioactive potential. Star showed the highest TAC and antioxidant activity (1663 ± 159 mg of cyanidin-3-O-glucoside (cy-3-O-glu) equivalents/100 g fresh weight (FW), 6345 ± 601 μmol Trolox equivalents (TE)/100 g FW, respectively), followed by Cristina Blue, Stella Blue and Snowchaser. As far as we know, this is the first time that cyanidin-3-rutinoside has been identified in blueberries. The extracts inhibited all the tested strains, MICs ranging from 0.4 mg/mL (for Stella Blue extract against UTI P. aeruginosa) to 9.5 mg/mL (for all extracts against UTI K. pneumoniae ssp. pneumoniae). This is the first study that assessed in vitro the antibacterial activity of blueberries against Klebsiella pneumoniae, Providencia stuartii and Micrococcus spp. strains isolated from UTI.España, University of Sevilla, VI Plan Propio de Investigación y Transferencia (VIPPIT‐2019‐I.5

Phytochemical profiles, antioxidant and cholinesterase inhibition activity of Vitis vinifera L. cv. Aglianico leaf extracts

Previous reports revealed that grape polyphenol compounds defend against oxidative stress, responsible of various disorders, such as cancer, diabetes and neurodegenerative diseases [1]. Among these, Alzheimer’s disease (AD), the most common human neurodegenerative disorder, is a clinical syndrome of dementia and the therapeutic targets for ameliorating the characteristic cholinergic deficit are acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes [2]. Therefore, AChE inhibitors, such as galantamine, are the drugs mainly used for the AD pharmacological treatment [1]. The purpose of this research is to analyze the effects that different extraction techniques have shown on the quali-quantitative phenolic profile, on antioxidant and on cholinesterase inhibition activities of Vitis vinifera L. (cv. Aglianico) leaf extracts. Leaves of Aglianico were collected in Basilicata Region and the samples were subjected to Soxhlet extraction (SOX), Ultrasound Assisted Extraction (UAE) and Accelerated Solvent Extraction at 40°C (ASE 40) and 50°C (ASE 50). The phenolic profile of extracts were studied by LC-DAD and the method used allowed the identification and quantification of 12 phenolics. The obtained extracts were also subjected to the Total Polyphenols Content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Oxygen Radical Absorbance Capacities (ORAC) and β-Carotene Bleaching (BCB) in vitro assays to evaluate their secondary metabolite content and antioxidant activity [3, 4]. The Relative Antioxidant Capacity Index (RACI) was calculated to compare data obtained by different assays. Moreover the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition assays were performed to test their enzymatic inhibition activity [5]. Data demonstrated that the best extraction technique in terms of yield was the Soxhlet method. Further, SOX extract showed the highest RACI value (0.76), followed by ASE 50 extract (0.65). As regards enzymatic inhibitory activity, ASE 50 extract exhibited good AChE inhibitory activity with an IC50 of 107.16 ± 8.12 μg/mL. In the BChE assay, instead, SOX extract showed the best BChE inhibitory activity with IC50 of 171.34 ± 12.12 μg/mL. In conclusion, our results demonstrated for the first time as Aglianico leaves are important sources of phenolics that could be used to prevent oxidative stress and potentially be helpful in Alzheimer’s disease treatment