The Phloroglucinols of Dryopteris aitoniana PICHI SERM. (Dryopteridaceae, Pteridophyta)

Abstract

The phenolic compounds of the fern Dryopteris aitoniana were analyzed by improved methods avoiding alcaline reagents and contact with unbuffered SO,, which can cause deterioration. We confirmed the presence of five of the formerly (1971) reported six compounds, while the sixth, formerly incorrectly assumed to be aspidin (based on a spot in TLC), has now been isolated as cristals (TR-1579). It has the empirical formula C2,H5,O,, but its structure is still unknown. Five other compounds were isolated in pure form, tetra-albaspidin BBBB (25-BBBB) a known but rare phloroglucinol, and four new compounds: penta-albaspidin BBBBB (37-BBBBB), hexa-albaspidin BBBBBB (38-BBBBBB), tetraflavaspidic acid BBBB (26-BBBB) and hexaflavaspidic acid BBBBBB (39-BBBBBB). The structures were established by degradation NMR and partly by field-desorption and fast-atombombardment (FAB) mass spectra. The oligoflavaspidic acids are very unstable compounds, deteriorating during isolation procedures using the older 'standard method'.

Antibacterial Prenylated Acylphloroglucinols from the Fern Elaphoglossum yungense

“…Its 1 H NMR spectrum showed evidence of two methylene bridges (δ 3.60, d, J = 15.6 Hz; δ 3.55, d, J = 15.6 Hz; and δ 3.80, 2H, s), indicating that this acylphloroglucinol has three ring systems. The chemical shift of the signals assigned to CH 2 -7 is characteristic of a methylene group located between a hexadienone and an aromatic ring, while the signal at δ 3.80 indicates that the other methylene bridge connects two aromatic rings . Comparison of the 1D NMR data of this compound with those of yungensins A−F indicated that one of the rings was the same prenylated filicinic acid of the previously described compounds, the second was an acylphloroglucinol-type ring, and the third was a dimethylchromene-type ring.…”

“…Powdered rhizomes and extracts from these plants have been used in the past as vermifuges for humans as well as for animals. − Although their use in herbal medicine is regarded as obsolete today, their strong biological activity has brought attention to acylphloroglucinols. So far, a wide variety of bioactive acylphloroglucinols have been isolated from Hypericum species − as well as from the ferns of the genus Dryopteris , and Elaphoglossum . , …”

Prenylated Acylphloroglucinols with Leishmanicidal Activity from the Fern Elaphoglossum lindbergii

“…It was observed previously for other acylphloroglucinols that the chemical shift of the methyl group of a butanoyl residue is typically located at 0.96–1.02 ppm, whereas the methyl group of a hexanoyl residue is shifted upfield (0.90–0.93 ppm). − ,− The chemical shifts of the terminal methyl groups of the two butanoyl moieties present in lindbergin E ( 1 ) (δ H 1.01 and 0.99) were used to confirm this observation. Moreover, while the shape of the triplet arising from the terminal methyl group of a butanoyl residue is well defined, that of a hexanoyl moiety is distorted (second-order signal) (Figure S49, Supporting Information).…”