Determination of secondary metabolites including curcumin in Rheum ribes L. and surveying of its antioxidant and anticancer activity

Dry stem and root of Rheum ribes are used for the treatment of different diseases. In this study, the organic components in the root of R. ribes were extracted by three extraction methods (soxhlet, ultrasonic and maceration) and the efficiencies of these methods were calculated. To validate the existence of Curcumin, analysis such as UV–Vis (Ultraviolet–Visible), HPLC (High Performance Liquid Chromatography), GC (Gas Chromatography) and GC/Mass were performed and in order to separate Curcuminoids, TLC (Thin Layer Chromatography) technique was implemented on the extract which had the highest yield. Total phenolic, flavonoid and flavonol contents of three kinds of extract were measured. For studying antioxidant activity, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging was done. Finally, for investigating anticancer activity, MTT (Methyl Thiazolyl Tetrazolium), NBT (Nitro Blue Tetrazolium) and DNA-Binding tests were done. The most yield was belonged to soxhlet extract. The results showed the presence of Curcumin in soxhlet extract has not been reported previously. Furthermore, the total phenolic, flavonoid and flavonol contents were belonged to ultrasonic extract. As well as the maximum antioxidants properties were belonged to ultrasonic and maceration extraction. The MTT assay showed the lowest IC₅₀ in the ultrasonic extract. At NBT test, the highest NBT reduction percentage was belonged to maceration extraction. DNA-binding test revealed that all the extracts have shown some degree of fragmentation. Due to the presence of Curcumin in R. ribes and the notable features that the results showed, it can be a good source for Curcumin extraction and use in the drug industry.