Figure 1 . FT-IR spectra of P. Nagi kernel oil in the frequency range 4000-500cm-1
3.4 In vitro biological evaluation
3.4.1 Antioxidant effect ofP. nagi kernel oil
The radical scavenging ability of P. nagi kernel oil was evaluated in the conventional system of DPPH⸱. Firstly, we added 40μLP. nagi kernel oil to different concentrations of DPPH respectively and studied the scavenging ability to optimize the best experimental conditions. The results (Figure 2 ) showed that the optimized DPPH concentration is 0.036mg/mL and the scavenging ability is 86.56%; Then, we also added different amounts of P. nagi kernel oil to 5mL DPPH solution to optimize the optimal concentration of P. nagi kernel oil with the highest scavenging ability. The results (Figure 3 ) showed that the P. nagi kernel oil exhibited the scavenging ability in a concentration-dependent manner from 5μL to 40μL and exhibited the highest scavenging ability at 40μL with 85.56%. Then, we tested the scavenging ability of P. nagi kernel oil at the optimized conditions: 5 mL of 0.036mg/mL DPPH solution, P. nagi kernel oil 40μL, the three times of scavenging abilities are: 85.07%, 85.67% and 84.80%; the average scavenging ability is 85.18%.