ANTIOXIDANT PROPERTIES OF FERMENTED MANGO LEAF EXTRACTS 9 production of melanin, which increases the immunity of the skin but may also accelerate skin damage in excessive amounts (35). Table III shows the increase in tyrosinase inhibitory activity from 7.89% to 15.78% and from 8.64% to 29.82%, with increasing concentrations of the MLFE and the MEFE, respectively. Both fermentation extracts had increasingly stronger tyrosinase inhibitory activity with increasing concentrations. All concentrations of the MEFE demonstrated statistically signifi cant increase in tyrosinase inhibitory activity com- pared to the MLFE (Figure 6). NITRITE-SCAVENGING ABILITY Nitrites can react with secondary amines (e.g., having a substituted hydrocarbon group R for two of the hydrogen atoms, and forming a R1 –R2–NH compound), to produce a Figure 3. Effects of mango leaf extracts MEFE vs. Control on RAW 264.7 cell viability measured by MTT assay. Data expressed as mean ± S.D. (n = 3). Figure 4. Effects of MLFE on the generation of ROS in LPS-stimulated macrophage cells. The data are rep- resentative of three independent experiments.

JOURNAL OF COSMETIC SCIENCE 10 carcinogenic substance, nitrosamine (R1–N–R2–N=O). However, nitrite scavenging can effectively suppress the formation of these carcinogenic compounds (36). Higher concen- trations of phenolic compounds at lower pH values increase nitrite scavenging, whereas this effect diminishes at high pH (37). Table IV shows that the nitrite-scavenging activity increased from 0.08 ± 0.12% at 0.4 mg/ml to 94.97 ± 0.06% at 50 mg/ml in the MLFE, and from 0.19 ± 0.08% at 0.4 mg/ml to 95.89 ± 0.03% at 50 mg/ml in the MEFE, thereby demonstrated that higher concen- trations of fermentation extracts resulted in enhanced scavenging ability. EM-fermentation imparted a superior effect versus lactobacillus fermentation at all concentrations. The statistically signifi cant differences were observed between the two fermentation agents except at a low concentration level of 0.4 mg/ml, in supporting suppression of nitrosa- mine production by mango leaf extracts. Mango leaves, which are high in phenols, effectively break down nitrites at a low pH of 2.5. CONCLUSIONS We evaluated the concentration-dependent antioxidative properties of lactobacillus and EM fermentations of mango leaf extracts. We measured DPPH-radical inhibitory activity and ROS production to estimate the concentration-dependent activity of lactobacillus and EM fermentations. It was confi rmed that the antioxidative activity signifi cantly increased with increasing concentrations of the sample. Total phenolic and fl avonoid contents also increased in a dose-dependent manner. EM fermentation exhibited higher antioxidative activity than lactobacillus fermentation, as well as the synthetic antioxidant, BHT. Figure 5. Effects of MEFE on the generation of ROS in LPS-stimulated macrophage cells. The data are representative of three independent experiments. Table III Tyrosinase Inhibitory Activity in Percentage for MLFE and the MEFE (n = 3) MLFE concentration (mg/ml) Tyrosinase inhibition(%) t p-Value MLFE MEFE 0.4 7.89 ± 0.90 8.64 ± 0.89 −2.387 0.037 2 10.52 ± 1.80 18.42 ± 2.1 −4.943 0.003 10 11.40 ± 2.30 23.68 ± 1.8 −7.282 0.001 50 15.78 ± 1.5 29.82 ± 0.7 −14.68 0.000