NEURITE ELONGATION AGENT, MEMORY-IMPROVING AGENT AND ANTI-ALZHEIMER AGENT COMPRISING 4-DEMETHYLNOBILETIN OR 4-DEMETHYLTANGERETIN AS ACTIVE INGREDIENT, AND PROCESS FOR PRODUCTION OF THE COMPOUND
A method for producing 4′-demethylnobiletin or 4′-demethyltangeretin including fermenting a skin derived from at least one citrus fruit selected from citrus fruits belonging to section Acrumen in subgenus Metacitrus in genus Citrus or citrus fruits belonging to section Aurantium in subgenus Archicitrus in genus Citrus, or a water extract product thereof using one or more Aspergillus molds selected from Aspergillus kawachii, Aspergillus awamori, Aspergillus oryzae, Aspergillus sojae, Aspergillus saitoi, and Aspergillus usamii to obtain a fermented product.