Extract of Morus alba fruits
The dried fruits of M. alba L. were purchased from a local herbal market in Jeonbuk, Korea. The fruits were pulverized into powder and extracted twice with hot water (70 ˚C) for 3 hours. The solvent was removed under reduced pressure in an RV10 rotary evaporator (IKA, Staufen, Germany) to yield an M. alba fruit hot water extract (59.3%, w/w). The extract was dried to a powder and kept in a closed container until use. To avoid variations in activity for different preparations, enough extract was obtained in one batch for use throughout the experiments. The content of the marker pyrrole alkaloid, 2-formyl-5-(methoxymethyl)-1H -pyrrole-1-butanoic acid, inMorus alba L. was quantitated using high-performance liquid chromatography (HPLC) (Chang et al., 2015).