1. A method for differentiating mesenchymal stem cells into neurons, comprising the steps of: (a) adding 100-400 μg/ml of an Ecklonia cava extract and purified deionized water containing SiO 2 , Al 2 O 3 , TiO 3 , Fe 2 O 3 , CaO, Na 2 O K 2 O, and LiO to a cell culture medium; (b) dedifferentiating mesenchymal stem cells in the medium; and (c) differentiating the induced pluripotent stem cells into neurons by culturing in a neuron differentiation medium.