Eight ent-kaurane diterpenoid glycosides named diosmariosides a-h from the leaves of diospyros maritima and their cytotoxic activity

Abstract

From the leaves of Diospyros maritima, collected from Okinawa Island, eight new glycosides based on ent-kaurane-type diterpenoids, entitled diosmariosides A-H, were isolated. The absolute structure of diosmarioside E (5) was determined by X-ray crystallographic analysis. The structure of diosmarioside H was elucidated to be a dimeric compound between diosmarioside A and a sugeroside through a ketal bond. An assay of cytotoxicity towards the lung adenocarcinoma (A549) cell line was performed. Among the compounds isolated, only diosmarioside D (4) and sugeroside 9 showed strong activity. The anti-microbial activity toward multi-drug resistant strains was also determined, but no activity was observed.