Evaluation of the chemical composition, antioxidant and anti-inflammatory activities of distillate and residue fractions of sweet basil essential oil.

In this study, the chemical composition and antioxidant and anti-inflammatory activities of sweet basil (Ocimum basilicum L. Lamiaceae family) were evaluated. Sweet basil is a food-related plant that is widely used in traditional Chinese medicine. Sweet basil crude oil was processed via molecular distillation and further characterized using gas chromatography-mass spectrometry (GC-MS) to screen for new compounds. The GC-MS analysis identified thirty-eight compounds. The major constituents of the residue fraction were estragole (17.06%), methyl eugenol (11.35%) and linoleic acid (11.40%), while the distillate fraction primarily contained methyl eugenol (16.96%), α-cadinol (16.24%) and α-bergamotene (11.92%). The antioxidant (DPPH and ABTS assays) and anti-inflammatory (in Raw264.7 cells) activities were evaluated. The residue fraction markedly scavenged the DPPH (IC50 = 1.092 ± 0.066 mg/mL) and ABTS (IC50 = 0.707 ± 0.042 mg/mL) radicals. Meanwhile, the distillate fraction distinctly suppressed the production of cytokines (TNF-α, IL-β, IL-6) and their gene expression in LPS-induced Raw264.7 cells and suppressed NO and iNOS in an in vitro model when compared with the crude oil. In conclusion, the fractions obtained from sweet basil crude oil showed different antioxidant and anti-inflammatory properties, and they could be used as an effective source of natural antioxidant and anti-inflammatory agents after molecular distillation. Thus, the properties of essential oils in natural herbal medicines may be maximized to provide a valuable therapeutic strategy for treating various disorders caused by extreme oxidative stress.