Comparison of biofunctional activity of Asparagus cochinchinensis (Lour.) Merr. Extract before and after fermentation with Aspergillus oryzae.

Asparagus cochinchinensis root (ACR) is used in traditional Chinese medicine. In this study, ACR was first extracted with 25% ethyl acetate (EA) and then fermented by Aspergillus oryzae to enhance its antioxidant activity and evaluate its potential antityrosinase activity. The physiological activity and cytotoxicity of A. oryzae-fermented ACR extract, along with its antityrosinase activity and effects on melanogenic factor levels in human epidermal melanocytes (HEMs), were analyzed and compared with those of the unfermented extract. The results showed that the physiological activity of the fermented extract in vitro or in cells was significantly higher than that of the unfermented extract. The IC50 values for 2,2-diphenyl-1-picrylhydrazine radical scavenging activity, reducing power, and antityrosinase activity in vitro for the fermented extract were 250.6 ± 32.5, 25.7 ± 3.5, and 50.6 ± 3.1 mg/L, respectively. The fermented extract favored cellular antityrosinase activity with low melanin production in human melanoma cells compared with the unfermented extract. The inhibitory mechanism of melanin synthesis by unfermented extract was independent of the tested melanogenesis-related proteins. However, the inhibitory mechanism of the fermented extract was possibly caused by synergistic inhibition of these proteins. Thus, A. oryzae-fermented ACR extract may be used for developing new health food or cosmetic ingredients.

Evaluation of tyrosinase inhibitory and antioxidant activities of Angelica dahurica root extracts for four different probiotic bacteria fermentations.

Angelica dahurica root (ADR), which shows strong antioxidant activity, is used in Chinese medicine. This study evaluated the tyrosinase inhibitory and antioxidant activities of ADR extracts fermented by four different probiotic bacteria: Bifidobacterium bifidum, Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus brevis. The ADR was first extracted using distilled water, 70% ethanol, and ethyl acetate, and then fermented by probiotic bacteria. The physiological characteristics of these fermented extracts, namely the antityrosinase activity, antioxidant activity, phenolic composition, and phenolic content, were evaluated and compared with those of unfermented extracts. Results showed that the water extracts after fermentation by probiotic bacteria exhibited the most favorable physiological characteristics. Among the extracts fermented by these probiotic bacteria, L. acidophilus-fermented ADR extract showed the most favorable physiological characteristics. The optimal IC50 values for antityrosinase activity, DPPH radical scavenging activity, and reducing power for L. acidophilus-fermented ADR extract were 0.07 ± 0.03, 0.12 ± 0.01, and 0.68 ± 0.06 mg/mL, respectively. Furthermore, the physiological activities of fermented extracts were considerably higher than those of unfermented extracts. The tyrosinase inhibition and melanin content of B16F10 melanoma cells, and cytotoxicity effects of the fermented ADR extracts on B16F10 cells were also evaluated. We found that the L. acidophilus-fermented ADR extract at 1.5 mg/mL showed significant cellular antityrosinase activity with low melanin production in B16F10 cells and was noncytotoxic to B16F10 cells. Among all probiotic bacteria, water-extracted ADR fermented by L. acidophilus for 48 h was found to be the best skincare agent or antioxidant agent.