Contrasting Dihydronaphthoquinone Patterns in Closely Related Drosera (Sundew) Species Enable Taxonomic Distinction and Identification

Abstract

Dihydronaphthoquinones are described as constituents of sundews (Drosera), Venus flytraps (Dionaea), and dewy pines (Drosophyllum) for the first time. As in the corresponding naphthoquinones, these reduced derivatives may occur in two regio-isomeric series distinguished by the relative position of a methyl group (at position 2 or 7 in the naphthalene skeleton), depending on the taxon. Species producing plumbagin (2-methyljuglone, 1) do commonly contain the corresponding dihydroplumbagin (5), while species containing ramentaceone (7-methyljuglone, 2) also contain dihydroramentaceone (7-methyl-β-dihydrojuglone, 6). So far, only few species containing plumbagin (1) and dihydroplumbagin (5) additionally form dihydroramentaceone (6) but not ramentaceone (2). Thus, subtle but constant differences in the chemism of closely related and morphologically similar species reliably define and distinguish taxa within D. sect. Arachnopus, which is taken to exemplify their chemotaxonomic utility. The joint presence of quinones and hydroquinones allows observations and predictions on the chemical structures and the reactions of these intriguing natural products.

Bait, not reward: CO2-enrichedNepenthespitchers secrete toxic nectar

“…Isoshinanolone has been reported from other Nepenthes species/hybrids, N. gracilis (Aung et al ., 2002), N. thorelii (Likhitwitayawuid et al ., 1998), N. mirabilis (Thanh et al ., 2015), N. thorellii x ( ventricosa x maxima ) (Ou-Yang et al ., 2019) and in other genera viz. , Drosera indica , D. serpens , D. finlaysoniana , Dionaea , and Drosophyllum (Schlauer et al ., 2021). AChE inhibition assay ( in vivo and in vitro ) showed (+)-isoshinanolone as a neuroactive compound which manipulates insect behavior and flight.…”

Refined taxon sampling discloses new quinone patterns and relationships among Sundews (Drosera, Droseraceae)

“…; Schlauer et al 2019b)). The morphologically similar D. finlaysoniana is apparently invariably characterized by formation of the M-precursor dihydroramentaceone while P is the main quinone with M remaining below detection (Schlauer et al 2021). D. sections Drosera, Ptycnostigma Planch., and Brasilianae Rivadavia, Gonella & A.Fleischm.…”

Quality parameters for the medicinal plant Drosera rotundifolia L.: A new approach with established techniques

“…Previous studies have indicated that D. intermedia has a higher naphthoquinone content compared to D. rotundifolia, a finding confirmed in this study. [27,35] Both species are native to Europe and have been used as medicinal plants. In the past, naphthoquinones were attributed to the therapeutic effects of sundew, but it is now known that flavonoids also play a role in the effects.…”