Functional evaluation of yuzu (Citrus junos) extracts containing limonoids and polyamine for life extension

- Quantitative of limonoid, polyamine, and arginine were determined in citrus junos fruits for the first time.
- Intake of limonoid aglycone and spermine alleviated inflammation of the central nervous system in SD mice.
- Ingestion of limonoid aglycones and spermine by SD mice extended their longevity by about 10-12%.
- Ingestion of fruits containing limonoid or polyamine may be improving intestinal health and increasing lifespan.

We determined high concentrations of arginine and polyamines (putrescine, spermidine, and spermine) in yuzu (Citrus junos) seeds. Yuzu produces large quantities of limonoids. We fed limonoid aglycones extracted from yuzu seeds and commercial spermine as a polyamine to Sandhoff disease (SD) mice with abnormal glycolipid metabolism and autosomal recessive inheritance, as found in humans. Ingestion of limonoid aglycones and spermine by SD mice extended their longevity by about 10-12%, where it alleviated inflammation of the central nervous system. After administering limonoid aglycones or limonoid aglycones/spermine, analyses of the bacterial flora in the feces based on 16S rDNA indicated changes in the relative ratio between Bacteroidetes (Bacteroidales and Lactobacillus) and Firmicutes (Clostridiales and Erysipelotrichaceae). In both SD and wild-type mice, the amount of short-chain fatty acids produced by the bacterial flora increased according to the intake of limonoid aglycones and spermine.