Prebiotic effect of diosgenin, an immunoactive steroidal sapogenin of the Chinese yam

► Prebiotic effects of diosgenin on lactobacilli were investigated. ► Diosgenin restored the diminished density of faecal lactobacilli associated with food allergy in mice. ► Diosgenin enhanced the growth of lactobacilli in culture. ► Steroidal sapogenins represent a novel class of phytochemicals with prebiotic activity on lactobacilli.