Limonin is a triterpenoid enriched in citrus fruits, which has antivirus and antitumor ability. IC50 Value: Target: HIV; anticancer Limonin is a triterpenoid aglycone that is a bitter principle of citrus fruits. Limonin is chemically induced carcinogenesis inhibitor and HIV-1 replication inhibitor. Limonin has anti-proliferative, proapoptotic activity on several cancer cell lines and inhibits azoxymethane-induced colon cancer in rats. Limonin also inhibits HIV-1 replication in culturedf monocytes, macrophages, and mononuclear cells, perhaps by inhibition of HIV-1 protease activity.