A Fat-Soluble Growth Factor of Silkworm

Abstract

The absolute methanol extract of mulberry leaf powder contains a previously unknown fat-soluble growth promoting factor for the silkworm, Bombyx mori. This factor was purified and identified as the mixture of palmitic acid and linolenic acid. The addition of each of the acids individually rather inhibited the larval growth. The combination of stearic, oleic, or linoleic acid with linolenic acid also showed growth stimulating effect. The activity of the mixture of methyl palmitate and methyl linolenate was very slight.