The present invention relates to the obtainment, production and use of metabolites with anti-botrytis cinerea properties from natural extracts of Chilean plants. In particular, it comprises an in vitro cultivated quillay extract (Quillaza saponaria Mol.), which allows improving the antifungal activity as the result of the enrichment with some secondary metabolites not found in the in vivo plants. The invention also comprises the in vivo cultivation method, the extraction method, a biocide formulation, and the applications thereof.