Figure 2. Inhibitory effect of combination of Morinda citrifolia seed extract (MCS-ext) and cannabidiol (CBD) in lipopolysaccharide (LPS)- stimulated RAW 264 cells. MCS-ext was added to cells 0.5 h before incubation with cannabidiol (CBD) (2.5 μM) and lipopolysaccharides (LPS) (200 ng/ml). The final concentration of MCS-ext in samples incubated with LPS is indicated. A: The level of nitric oxide (NO) in the culture medium was measured using the Griess reaction. B: Cell viability was measured using Cell Counting Kit-8 assay. C: Total RNA was isolated using Isogen II after LPS stimulation. Inducible nitric oxide synthase (Nos2) messenger RNA (mRNA) expression level was analyzed by real-time reverse transcriptase-polymerase chain reaction. Relative mRNA levels were determined using 2^−ΔΔCt method and normalized to Actb expression. The relative mRNA level of the nontreated samples was set to 1. Data are presented as the mean±SD (n=3-4). Significantly different at: *p<0.05, **p<0.01, and ***p<0.001 as determined by Student’s t-test except for comparisons with CBD alone and MCS-ext alone.