Isolation and characterisation of 13 pterosins and pterosides from bracken (Pteridium aquilinum (L.) Kuhn) rhizome

Abstract

Thirteen previously undescribed pterosins and pterosides were isolated from bracken rhizomes in north of Wales. Their structures were elucidated using NMR spectroscopic and high resolution FT-ICR-MS data. were assessed for their anti-diabetic activity using an intestinal glucose uptake assay; all were found to be inactive at 300 µM. Isolation and characterisation of 13 pterosins and pterosides from bracken (Pteridium aquilinum (L.) Kuhn) rhizome

Four New Pterosins from Pteris cretica and Their Cytotoxic Activities

“…Comparison of the UV and NMR spectroscopic data of 4 (Table 2) with those of spelosin showed several differences, the main one being the presence of an additional hexose sugar moiety having a signal for an anomeric-H at δ H 4.57 (d, J = 7.8 Hz) and remaining sugar proton signals at δ H 3.27–3.85. The 13 C-NMR spectrum of 4 contained an anomeric carbon signal of a hexose moiety at δ H 105.8 and signals for remaining five sugar carbons at δ H 62.8–78.2, which were in good agreement with those reported for glucoside compounds [22]. Furthermore, the coupling constant ( J = 7.8 Hz) is consistent with a trans 3 J H-H , showing that the glucose moiety is in a β-configuration [20].…”

“…This was further confirmed by the HMBC spectrum that showed the correlations from H-15 ( δ H 5.08) to C-14 ( δ C 65.6) and from H-14 ( δ H 3.98) to C-15 ( δ C 67.5). The absolute configuration of 3 was also determined as 2 S by the CD spectrum which exhibited vibronic n –π* transition which concurs with C-2 having 2 S configuration [22]. Based on these results, compound 3 was assigned as creticoside A.…”

“…Compound 3 exhibited 1 H- and 13 C-NMR data closely resembling to those of rhedynoside A [22]. The difference between NMR spectroscopic data of 3 (Table 2) and those of rhedynoside A was 3 possesses an ether link.…”

Natural products isolation studies of native Australian fern species

“…[13,14] Distinctive flavonoids that have been isolated include neoflavonoids, calomelanols A-J (5-14) from farinose of Pityrogramma calomelanos (L.) Link, [15,16] bioflavonoids such as hinokiflavone (15), 7″-O-methylhinokiflavone (16) amentoflavone (17) and 7,7″-di-Omethylamentoflavone (18) from Selaginella tamariscina Examples of secondary metabolites isolated from ferns and lycophytes: alkaloids (1-4), complex flavonoids , sesquiterpenoids (29)(30)(31)(32) and miscellaneous natural products (33)(34)(35)(36)(37); *stereogenic centres were not assigned in these molecules www.publish.csiro.au/ch Australian Journal of Chemistry (P.Beauv.) Spring, [17] involvenflavones A-F (19)(20)(21)(22)(23)(24) from S. involven (Sw.) Spring [18] and prenylated flavonoids (25)(26)(27)(28) from Helminthostachys zeylanica (L.) Hook. [19] Many sesquiterpenoid compounds with indane or cadinene skeletons are found in ferns.…”

“…[10] Sesquiterpenyl indanones, known as pterosins, and their glycosides (pterosides) have been isolated from bracken fern species and polypodiaceous ferns. [20] For example, multifidosides A-C (29-31) have been isolated from Pteris multifida Poir. [14] and the carcinogenic pteroside, ptaquiloside (32) has been isolated from Pteridium aquilinium (L.) Kuhn.…”