Metabolomics Study and Evaluation of Antioxidant and Anti-Inflammatory Activities of Essential Oils From Rosa rubus...

Many species of the genus Rosa were renowned for their high ornamental or edible value. Among them, Rosa rubus, a native species in China, boasts a pleasant aroma of its flowers that distinguishes it from roses, offering significant potential for further exploration. Nevertheless, research on the characteristics of the aroma components of its flowers remains scarce. This study initially utilized the headspace solid-phase microextraction (HS-SPME) coupling with gas chromatography-mass spectrometry (GC-MS) method to investigate the volatile components of fresh R. rubus flowers (RHS). Meanwhile, for comparison, the GC-MS method was also employed to analyze the aroma components of essential oil (REO) and hydrosol (REH) extracted from fresh R. rubus flowers via steam distillation. Multivariate statistical methods were applied to compare and analyze the variations in volatile components between pairs. The antioxidant activities of the REO and REH were assessed using the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), and ferric reducing antioxidant power (FRAP) methods, and their anti-inflammatory activities using the Griess method. 265 volatile compounds were authenticated from R. rubus flowers, mainly including terpenoids, alcohols, aldehydes, etc. Among these, 184 compounds were identified from REO, 84 from RHS, and 98 from REH. These three extracts showed significant differences in metabolites. Among them, REO was dominated by terpenoids (34.60%) and alkanes (26.16%), RHS was dominated by aldehydes (30.94%) and terpenoids (27.41%), and REH was dominated by alcohols (58.76%). The aromatic characteristics of volatile compounds in REO, RHS, and REH were primarily retrieved from the Odor and FlavorDB databases. REO and REH were characterized by stronger woody and sweet notes, while RHS exhibited more prominent floral, green, and fresh profiles. The DPPH, ABTS, and FRAP assays were used to evaluate the antioxidant activities of the REO and REH. The results showed that REO exhibited higher antioxidant activity than REH. Correspondingly, in vitro anti-inflammatory activity screening showed that REO exhibited more significant inhibitory activity on nitric oxide production compared to REH in the LPS-induced RAW 264.7 cell model, with the IC₅₀ value of 12.22 ± 0.03 µg/mL. The above results suggested that REO possesses a greater potential for development into health supplements and cosmetic products with antioxidant and anti-inflammatory properties compared to REH. This study revealed the unique aroma components, aroma characteristics, and biological activity of R. rubus flowers, providing insights for its broader commercial applications.