Biosynthetic studies on brasiliamides, potently convulsive and bacteriostatic compounds from an endophytic Penicillium brasilianum isolated from Melia azedarach (Meliaceae), confirms their phenylpropanoid origin, which is very uncommon in fungi. Feeding experiments with [$2-^{13}C$]-phenylalanine indicated the incorporation of two units of this amino acid on brasiliamide structures. The first step in the phenylpropanoid pathway to those compounds was evaluated through enzymatic bioassays and confirmed the phenylalanine ammonia-lyase (PAL) participation. The metabolism of phenylalanine in this fungus is discussed.