Identification of moracin N in mulberry leaf and evaluation of antioxidant activity.

Mulberry leaf is a newly accepted vegetable for daily diet. It tastes good and has multiple health benefits, including antioxidant and anti-inflammatory activities. However, the chemicals responsible for these health benefits remain unveiled. Prenylated phenolics are characteristic bioactive compounds in mulberry leaf, which are recognized as good antioxidants. In this work, moracin N was purified from mulberry leaf. It showed better antioxidant activities than resveratrol. The EC50 value of cellular antioxidant activity was 24.92 μM, and the IC50 value against DPPH radical was 40.00 μM. The prenyl group rendered the molecule more membrane affinity which improved the bioavailability. The furan ring was critical for the antioxidant behaviour. The cell viability test revealed that moracin N had a good safety. These results pointed out that moracin N contributed to the antioxidant activity of mulberry leaf.