Comparative chemical profiling of Rosa damascena flowers at unopened and open stages via spectrophotometry and GC-MS

Flowers of Rosa damascena are used for food, medicine, and perfumery purposes. Thus, it is important to know their chemical profile. In this study, flowers of R. damascena at unopened and open stages were collected and analyzed after drying using a spectrophotometer and GC-MS. The results demonstrated that unopened flowers had the highest total phenols (0.5 mg g−1), total flavonoids (0.21 mg g−1), ascorbic acid (0.37 mg g−1), anthocyanins (0.19 mg g−1), and carotenoids (0.022 mg g−1). Similarly, unopened flowers contained more diverse compounds (48 compounds) than open flowers (38 compounds) regarding GC-MS analysis. Esters and alkenes were the most frequent chemical groups at both stages, but their numbers were the highest at the unopened stage. The most concentrated compounds at the unopened stage were octyl-β-D-glucopyranoside (19.76%) and phenylethyl alcohol (17.32%), but open flowers contained the maximum β-D-ribopyranoside, methyl (30.52%), and 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl (13.20%). The same compound exhibited different concentrations at both stages. Many detected compounds are known to have health effects, and most act as antimicrobial, anti-inflammatory, and antioxidant agents. Generally, diversity and concentration of the compounds in the flowers of R. damascena were influenced by the development stage, and the unopened stage was the richest in the compounds.