FIG. 8.
a Some over-the-counter (OTC) formulas of Ginkgo biloba have ototoxic potential. Certain concentrations were significantly ototoxic (one-way ANOVA, Nature’s Bounty (green): F 3, 40 = 4.824, p = 0.006; Nature’s Way (orange): F 3, 39 = 7.013, p < 0.001). b The combination of purified flavonoids was significantly ototoxic (one-way ANOVA, F 7, 68 = 17.49, p < 0.0001). Fish were treated with a combined solution of 20 μM flavonoid (20 μM kaemp, isor, and quer) or a combined solution containing 50 μM of each flavonoid. Pairwise comparisons show that significant hair cell loss was only seen with 50 μM of each flavonoid combined in one treatment. “Both” indicates a combination of DMSO and EtOH as the combined vehicle control. a, b Significance values are denoted by asterisks (*p < 0.05, **p < 0.01, ***p < 0.001). N = 10 fish per group and all bars are +S.E.M. c 1H NMR spectra (950 MHz) of both OTC formulas of G. biloba as compared to quercetin or kaempferol standard compounds. Nature’s Bounty appears to contain both flavonoids, while the flavonoid composition of the Nature’s Way formulation could not be confirmed due to the overlap of NMR signals of other constituents that were present at higher levels. N = 32 experiments for each sample.