Tyrosinase inhibitory effect and inhibitory mechanism of tiliroside from raspberry

Figures & data

Figure 1.  Process curves for the inhibition of monophenolase of mushroom tyrosinase by tiliroside. Tyrosine was a substrate. The reaction was done in 50 mM Na₂HPO₄-NaH₂PO₄ buffer, pH 6.6, at 30 °C in the presence of different concentrations of tiliroside for curves 1–6 were 0, 0.021, 0.042, 0.084, 0.168 and 0.337 mM, respectively. The final concentration of mushroom tyrosinase was 14.934 μg/mL.

Figure 2.  The structural similarity of tyrosine and tiliroside.

Figure 3.  Lineweaver-Burk plots for inhibition of tiliroside on the oxidation of tyrosine by mushroom tyrosinase. Tyrosine was a substrate. The reaction was done in 50 mM Na₂HPO₄-NaH₂PO₄ buffer, pH 6.6 and at 30 °C in the presence of different concentrations of tiliroside for curves 1–5 was 0, 0.042, 0.084, 0.168 and 0.337 mM, respectively. The final concentration of mushroom tyrosinase was 14.934 μg/mL. The inset was the secondary plot of the slope versus concentration of inhibitor (tiliroside).

Figure 4.  Lineweaver-Burk plots for inhibition of tiliroside on the oxidation of L-DOPA by mushroom tyrosinase. L-DOPA was a substrate. The reaction was done in 50 mM Na₂HPO₄-NaH₂PO₄ buffer, pH 6.6, at 30 °C in the presence of different concentrations of tiliroside for curves 1–5 was 0, 0.042, 0.084, 0.168 and 0.337 mM, respectively. The final concentration of mushroom tyrosinase was 3.000 μg/mL. The inset was the secondary plot of the slope versus concentration of inhibitor (tiliroside).

Table 1.  The cell viability of tiliroside and arbutin on B16 cells (Mean ± SD, %).

Concentration (mM)	Cell survival (Mean ± SD, %)
	Tiliroside	Arbutin
0	100 ± 0.00	100 ± 0.00
0.011	97.4 ± 0.02	99.7 ± 0.03
0.021	96.8 ± 0.20	97.2 ± 0.30
0.042	93.8 ± 0.01^*	97.0 ± 0.40
0.084	89.5 ± 0.02^*	92.1 ± 0.03^*
0.168	78.9 ± 0.01^*	82.9 ± 0.01*

Viability of medium-treated cells was set to 100%.

Differences in data were evaluated for statistical significance (p < 0.05) using the t-test.

Table 2.  The tyrosinase- and melanin-reducing activities of tiliroside on B16 cells.

Sample	Concentration (mM)	Intracellular tyrosinase inhibition (Mean ± SD, %)	Melanin production inhibition (Mean ± SD, %)
Tiliroside	0.011	5.7 ± 0.15^*	14.5 ± 0.02^*
	0.021	12.9 ± 0.01^*	17.5 ± 0.01^*
	0.042	14.8 ± 0.04^*	21.2 ± 0.02^*
	0.084	24.5 ± 0.03^*	40.4 ± 0.03^*
	0.168	34.5 ± 0.01^*	54.1 ± 0.04^*
arbutin	0.011	5.2 ± 0.04^*	2.2 ± 0.02
	0.021	6.0 ± 0.03^*	12.2 ± 0.04^*
	0.042	7.1 ± 0.02^*	15.8 ± 0.03^*
	0.084	7.6 ± 0.04^*	18.0 ± 0.01^*
	0.168	9.1 ± 0.02^*	29.5 ± 0.01^*

Percentage of tyrosinase inhibition and melanin production inhibition were result from compared with medium-treated group.

Differences in data were evaluated for statistical significance (p < 0.05) using the t-test.