New reports on flavonoids, benzoic- and chlorogenic acids as rare features in the Psychotria alliance (Rubiaceae). (June 2016) - Berger, Andreas
Abstract: Five flavonoid glycosides, three chlorogenic and one benzoic acid were isolated from leaves of seven species belonging to the genera Notopleura, Palicourea and Psychotria. In most species, common flavonol glycosides based upon quercetin and kaempferol were recorded, which corresponds well to literature data on other species of the Psychotria alliance. From Notopleura polyphlebia, however, the new dihydroflavonol glycoside ( 2R, 3R )-7, 4′- O -dimethyl-aromadendrin 5- O -β-d -apiofuranosyl-(1→6)-β-d -glucopyranoside (1 ) was isolated, which is remarkable in terms of both the structure of the aglycone as well as the rarity of apiose as sugar moiety. In addition to flavonoids, benzoic and chlorogenic acids are a common and frequently neglected feature in the alliance, but all appear to be of limited chemosystematic significance when compared to tryptamine-iridoid alkaloids prominently known from this group. Graphical abstract: Highlights: Five flavonoid glycosides were isolated from six species out of 3 genera of the Psychotria alliance. A new dihydroflavonol 5- O -glycoside was isolated from Notopleura polyphlebia . Chlorogenic acids and flavone glycosides were isolated for the first time from the Psychotria alliance. The relevance of phenolic compound accumulation and biosynthetic capacity is discussed.