The antioxidant, cytotoxic and antimicrobial effects of fermented and non-fermented extracts of ‘the Korean shrub’ Dendropanax morbifera and sweet potato were compared to assess the potential utility of these species in the development of health-oriented food. Non-fermented extract (NFDSE) was obtained from the leaves and branches of D. morbifera and the bodies of sweet potato using distilled water. The fermented extract (FDSE) was prepared by inoculating the above-obtained extracts with Lactobacillus plantarum and Lactobacillus brevis. The extracts of the two species combined D. morbifera and sweet potato exhibited substantial antioxidant activity. Moreover, NFDSE at 24 h exerted more antioxidant effects than FDSE (72.57% vs. 71.08%, respectively) at a concentration of 100 mg/ml. Comparison of the effects of the non-fermented and fermented extracts on HaCaT keratinocyte cell viability revealed that FDSE had a slightly higher cytotoxicity than NFDSE (94.8% vs. 102.7% viability, respectively) at a concentration of 500 g/ml. It was further found that NFDSE and FDSE had the strongest antimicrobial effects against Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis (a Gram-positive coccidium). Therefore, it is obvious that extracts of D. morbifera and sweet potato represent ‘novel candidates’ for the production of functional anti-aging agents with minimal side effects.
Key words: Dendropanax morbifera and sweet potato, antioxidant activity, cytotoxicity, antimicrobial effects, health-oriented food.