Anti-Melanogenesis Effect of Daniellic Acid Isolated from Daniellia oliveri (Rolfe) Hutch. & Dalziel (Leguminosae) Oleoresin of Burkina Faso

Abstract
Over the past years, natural products have been used as useful candidates for prevention and treatment of skin disorders such as skin darkening. In this current research, Daniellia oliveri which was a potential source of cosmeceutical agent was selected to investigate its active components. Daniellic acid isolated from the oleoresin was characterized by using data from 1H-NMR, 13C-NMR, HSQC, IR, and online chemo-informatic analysis. The daniellic acid antioxidant, anti-proliferative, and tyrosinase inhibition capabilities were evaluated. This compound possessed an anti-DPPH and iron (III) reducing effect compared to quercetin. It was able to inhibit 9 tumor cells with IC50 going from 0.03 mM (U373) to 0.14 mM (Malme-3M). Interestingly daniellic acid inhibits tyrosinase activity with 1.20 mM as IC50. The tyrosinase inhibition mechanism was noncompetitive mixed-type with un-significant effect on cell melanogenesis. Daniellic acids induced a half-reduction of melanin production in B16F10 cell in IBMX stimulation (p 0.05). The same observation was effective in Malme-3M melanin production with a significant daniellic acid action than kojic acid (p 0.05) without reducing cell viabilities. This bioactive daniellic acid could explain the traditional uses of oleoresins from Daniellia oliveri for genitor-urinary tract diseases treatments, wound healing, and skin ailments in Burkina Faso.