Figure 1.

Red extract is as effective as acetyl salicylic acid (ASA) in reverting trigeminal allodynia. (A) Schematic representation of the experimental protocol utilized in this study. See “Materials and Methods” section for details. (B) Evaluation of facial allodynia in rats drinking water, Yellow or Red extracts and exposed to trigeminal sensitization by Complete Freund’s Adjuvant (CFA) injection in the temporomandibular joint (TMJ). The head withdrawal threshold was evaluated at 24, 48 and 72 h post CFA injection in the morning (see (A)), in 25 rats for the Water group and 33 rats each for the Yellow and Red groups. ^###p < 0.001 with respect to corresponding “PRE” values, one-way ANOVA followed by Tukey’s test; **p < 0.01 ***p < 0.001 with respect to purple corn supplement, one-way ANOVA followed by Bonferroni test. (C) Evaluation of facial allodynia in CFA-injected animals drinking water, Yellow or Red extracts and treated with ASA or saline. For each condition (i.e., rats drinking water, yellow or purple corn supplements), light colored-bars represent the head withdrawal threshold evaluated at 48 h post CFA injection in the morning, whereas the dark colored-bars represent the head withdrawal threshold evaluated in the afternoon, 30 min after i.p. saline or 50 mg/kg ASA. Similar results have been obtained at 24 and 72 h post CFA injection (not shown). N = 8 (Water) and 9 (Yellow and Red) rats treated with saline, and 8 (Water) and 11 (Yellow and Red) rats treated with ASA. **p < 0.01 with respect to Red extract, two-way ANOVA followed by Bonferroni test; ^#p < 0.05 with respect to corresponding value in the morning, Students’ t-test.