The present invention relates to a natural antibacterial and antioxidant composition of an extract rich in phenol compounds obtained from seedlings of A. Chilensis, also known as maqui, cultured in vitro. Specifically, a method is described for generating plant biomass in a sustainable manner, without needing to use materials grown in natural conditions, thereby reducing the impact on the exploitation of the species. The biomass generated is used to obtain a hydroalcoholic extract having antioxidant and antibacterial properties, owing to which the composition can be added directly to food products, cosmetics, pharmaceuticals for human consumption, or a combination of same.