Abstract:
With the growing popularity of skincare products around the world, cosmetic applications of plant
extracts are gaining continuous attention in cosmeceutical industries. Therefore, this study aims to
investigate the anti-melanogenic effect of Ceylon black tea extracts. In this study five different
black tea extracts were prepared with distilled water (extraction by autoclave, extraction at 80°C for
2 h) and organic solvents (ethanol, methanol, acetone). Each extract of black tea was tested for total
phenol content, total flavonoid content, DPPH radical scavenging activity and tyrosinase inhibitory
activity. Finally, different concentrations of tea extract were tested in B16F10 melanoma cells for
cytotoxicity and protein suppression levels. According to the results of this study, the highest yield
of 42.93% was obtained from the ethanol extraction followed by 40.19% from acetone extraction.
Highest total polyphenol contents were obtained from ethanol and acetone extractions with
240.30±1.40 μg/g and 240.20±4.70 μg/g concentrations. The highest total flavonoid content was
obtained from acetone extraction with the concentration of 57.49±4.70 μg/g. Distilled water extract
of Ceylon black tea exhibited the highest inhibitory activity on tyrosinase with an IC50 value of
0.016±0.001 mg/ml whereas ethanol extract exhibited the highest DPPH radical scavenging activity
with an EC50 value of 0.009±0.000 mg/ml. Treated concentrations of 10 to 50 μg/ml were not
cytotoxic to B16F10 cells and exhibited more than 80% cell viability at all treated concentration.
Further, western blot results revealed the suppression of tyrosinase, TRP-1, TRP-2 and MITF
protein expression levels in dose dependent manner. Therefore, we suggest the applicability of
distilled water extract of black tea as a novel melanogenesis inhibitor and skin-whitening agent in
Sri Lanka cosmeceutical industries.
Keywords: Cosmeceuticals; Black tea; Anti-melanogenic; Green extraction; Tyrosinase
