Iridoids from the flowers of Gardenia jasminoides Ellis and their chemotaxonomic significance

•Fifteen iridoids were isolated from the flowers of Gardenia jasminoides for the first time.•Four iridoid aglycones were reported for the first time from the genus Gardenia.•The chemotaxonomic significance and biosynthetic pathways of iridoid were summarized.•Iridoid were considered as important chemotaxonomic markers in Rubiaceae.

Phytochemical investigation of the flowers of Gardenia jasminoides Ellis (Rubiaceae Gardenia) resulted in the isolation and identification of four iridoid aglycones (1–4) and eleven iridoid glycosides (5–15). This is the first report of the occurrence of these compounds in the genus Gardenia: garjasmine (1), dunnisin (2), α-gardiol (3), β-gardiol (4), diffusoside A (6), diffusoside B (7), genameside C (13), and deacetylasperulosidic acid (14). The chemotaxonomic significance and biosynthetic pathways of these iridoid aglycones (1–4) and iridoid glycosides (5–15) are summarized. Iridoid aglycones and iridoid glycosides are considered as important chemotaxonomic markers in Rubiaceae and this work indicates that the iridoid aglycones (1–4) have a limited distribution in the Rubiaceae.

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