Background & Aims: Plants contain high antioxidant activities due to their redox and the chemical properties are affluent in secondary metabolites such as phenols, flavonoids, and other components. Rheum turkestanicum Janisch is a plant from polygonaceae that is widely used for diabetes. At this project that is a part of national thesis, relative levels of antioxidant activity, total phenols, total flavonoid, total anthocyanin, soluble and non-soluble sugar content of Rheum turkestanicum were measured. Materials & Methods: The shoots of Rheum turkestanicum were collected and verified from Dargaz region in north-east of Iran and then they were dried at room temperature. The aerial portion of the plant was powdered by grinding, and five grams of the herbal powder were mixed with 300 mL of deionized water and after 24 h, the resulting mixture was filtered using Whatman No. 1 filter paper. Determination of total phenol, total flavonoid, anthocyanin, soluble sugars and antioxidant properties of aqueous extract was performed by standard Folin chicaletto, aluminum chloride colorimeter, Wagner, phenolic sulfuric acid, DPPH methods using a spectrophotometer. Results: The results of this project showed that the amount of total phenolic and flavonoid acids in Rheum turkestanicum extract was high at 123.8 and 116 mg/g dry weight, respectively. DPPH scavenging activity was observed to be 6.42 mg/g dry weight of ascorbic acid. The results of this project showed that DPPH scavenging activity was observed to be 6.42 mg/g ascorbic acid dry weight. Total phenolic acid and total flavonoid content of the investigated Rheum turkestanicum were higher in comparison to other components. Conclusion: This fact indicates that phenolic acids and flavonoids play a major role in the antioxidant and anti-diabetic properties of Rheum turkestanicum. The results also indicate that Rheum turkestanicum can be used as an important source of antioxidants in the food and pharmaceutical industries due to its high levels of secondary metabolites such as phenols and flavonoids.

Keywords