Structures and Spasmolytic Activities of Derivatives from Sesquiterpenes of Alpinia speciosa and Alpinia japonica.

Sesquiterpenes isolated from Alpinia speciosa and Alpinia japonica, and their derivatives were found to inhibit histamine- or barium chloride-induced contraction of excised guinea pig ileum when tested by the Magnus method. Major spasmolytic principles contained in those extracts were the sesquiterpenes, β-eudesmol, nerolidol, humulene epoxide II and 4α-hydroxydihydroagarofuran. Relationships between the chemical structures of the sesquiterpenes and their derivatives, and their spasmolytic activities were discussed.