Unlocking the potential antioxidant and anti-inflammatory activities of Rhododendron molle G. Don.

Rhododendron molle G. Don is an important traditional Chinese medicinal plant, which has been applied to treat some inflammatory diseases. In the present study, ethanol extracts of R. molle flower (RFE) and leaf (RLE) were used for phytochemical, antioxidant and anti-inflammatory analysis. The antioxidant activity was investigated using the free radicals of 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH-)-scavenging activity, super oxide anion radical (O2.-)-scavenging activity and iron reducing power (FRAP). Production of nitric oxide (NO) was an indicator to evaluate the anti-inflammatory activity. The results showed that compared with RFE, RLE was more active against DPPH (56.66%), FRAP (51.29%) and hydroxyl radical (OH-) (69.66%) at 100μg/mL. In the same time, RLE and RFE had significant anti-inflammatory activity which could reduce nitrite production from 8.76μM to 5.08μM and 6.01μM, respectively. In addition, GC-MS analysis showed that 43 compounds were identified in R. molle. Among them, 11 compounds had antioxidant and 5 compounds had anti-inflammatory effect. Results showed that ethanol extracts of R. molle have significant antioxidant and anti-inflammatory activity. These results would be helpful for further investigation on the anti-inflammatory mechanism of R. molle.