Phytochemical Composition and Antioxidant Activity of Petals of Six Rosa Species from Iran.

Background: The petals of Rosa species are used in the food industry and various traditional medicinal products, but few studies exist on the phytochemical composition and antioxidant activity of petals of Rosa L. species grown in Iran. Objective: Phytochemical characteristics and antioxidant activity and some phenolic compounds of petals of six Rosa L. species were studied. Methods: Total phenolic content, total flavonoid content, and antioxidant activity were determined using Folin-Ciocalteu reagent, aluminum chloride method, ferric-reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, respectively. An HPLC system was used for quantitative analysis of phytochemical compounds. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were performed among the variables analyzed using Minitab software. Also, heat maps were used to visualize phytochemical characteristics and antioxidant activity in each species using GraphPad Prism software. Results: The amount of total phenol content, total flavonoid content, and antioxidant activity were in the range of 25.13-52.01 mg gallic acid equivalents/g dry weight (DW), 0.61-0.82 mg quercetin equivalents/g DW, 11.47-20.93 µmol Fe++ /g DW (FRAP), and 31.66-74.44% (DPPH), respectively. The p-coumaric acid (647.28 μg/g DW) and chlorogenic acid (24.37-135.23 μg/g DW) were found to be the most abundant phenolic compounds in the extracts of rose petals. The HCA and PCA revealed three distinct categories of species based on phytochemical composition and antioxidant activity. Conclusions: These results showed that phytochemical characteristics of different rose species widely correlated with species type and are promising sources of natural antioxidants beneficial for use in the food or pharmaceutical industries. Highlights: Iran is one of the main centers for genetic diversity of Rosa L. The petals of Rosa species are used in the food industry and various traditional medicinal products, but few studies exist on the phytochemical composition and antioxidant activity of petals of Rosa L. species grown in Iran. Antioxidant activity and phytochemical compound of Six Rosa L. species petals grown in Iran were studied. Phenolic compounds in petals of Rosa were analyzed by HPLC. The color parameters, amount of total phenolic, total flavonoids, antioxidant activity and some individual phenolic compounds were significantly variable amongst Rosa species.