Antioxidant activity of stem and root extracts of Rhubarb (Rheum ribes): An edible medicinal plant |
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Authors: | Mehmet Öztürk Fatma Aydoğmuş-Öztürk Mehmet Emin Duru Gülaçtı Topçu |
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Affiliation: | 1. Department of Analytical Chemistry, Faculty of Pharmacy, University of Istanbul, 34116 Istanbul, Turkey;2. Department of Biology, Faculty of Arts and Sciences, Mugla University, 48187 Mu?la, Turkey;3. Department of Chemistry, Faculty of Arts and Sciences, Mugla University, 48187 Mu?la, Turkey;4. Department of Chemistry, Faculty of Science and Arts, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey |
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Abstract: | The antioxidant activity of chloroform and methanol extract of roots and stems of Rhubarb (Rheum ribes L.), which are used for medicinal purposes and also its fresh stems and petioles are consumed as vegetable, was studied. The antioxidant potential of both extracts of roots and stems were evaluated using different antioxidant tests, namely total antioxidant (lipid peroxidation inhibition activity), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, superoxide anion radical scavenging, ferric reducing power, and cupric reducing power (CUPRAC), and metal chelating activities. Total antioxidant activity was also measured according to the β-carotene bleaching method, and all four extracts exhibited stronger activity than known standards, namely butylated hydroxytoluene (BHT) and α-tocopherol. Particularly, higher activity was exhibited by roots with 93.1% and 84.1% inhibitions of chloroform and methanol extracts, while 82.2% and 82.0% inhibitions by stem extracts, respectively. However, both methanol extracts exhibited higher DPPH radical scavenging activity than the corresponding chloroform extracts, moreover, methanol extract of the stems showed better activity than BHT. In addition, both root extracts showed more potent superoxide anion radical scavenging activity than BHT, and comparable with well known radical scavenger l-ascorbic acid. Except chloroform extract of the roots, the other three extracts exhibited better metal chelating activity than quercetin. Also, total phenolic and flavonoid contents in both extracts of the roots and stems of R. ribes were determined as pyrocatechol and quercetin equivalents, respectively. |
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Keywords: | l-AA l-ascorbic acid EDTA ethylene diamine tetra acetic acid TCA trichloroacetic acid FCR Folin&ndash Ciocalteu&rsquo s reagent DPPH 1 1-diphenyl-2-picrylhydrazyl BHA butylated hydroxyanisole BHT butylated hydroxytoluene TOC α-tocopherol NADH nicotinamide adenine dinucleotide NBT nitrotetrazolium blue chloride PMS N-methylphenazonium methyl sulfate PEs pyrocatechol equivalents QEs quercetin equivalents SD standard deviation CARR chloroform extract of the stems MARR methanol extract of the stems CRRR chloroform extract of the roots MRRR methanol extract of the roots |
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