Natural products isolation studies of native Australian fern species

Abstract

Natural products isolation studies of 16 native Australian fern species have been undertaken, facilitated by pressurised hot water extraction (PHWE). Fourteen of these fern species have not been the subject of natural products isolation research previously. In total, 14 different compounds were isolated from 12 of these 16 different fern species. This included γ-and δ-lactones; flavonoid glycosides, a dihydrobenzofuran neolignan, in addition to hydroxycinnamate/caffeic acid esters. More specifically, the lactones 5,6-dihydro-5-hydroxy-6-methyl-2H-pyran-2-one, 5-(1hydroxyethyl)-2(5H)-furanone and osmundalin were obtained from Todea barbara, while a dihydrobenzofuran neolignan, (−)-trans-blechnic acid were found in Austroblechnum pennamarina subsp. alpina, and the shikimate ester 5-O-caffeoylshikimic acid was isolated from Parablechnum wattsii. In addition, flavonoids and their glycoside derivatives, kaempferol 3-Oglucopyranoside, 4β-carboxymethyl-(−)-epicatechin, (2R)-eriodictyol-7-O-β-D-glucopyranoside, naringin, quercitrin, quercetin 3-O-(6″-acetyl)-β-D-glucopyranoside, rutin, and tiliroside were isolated from seven other fern species.

Distinctive Arbutin‐Containing Markers: Chemotaxonomic Significance and Insights into the Evolution of Proteaceae Phytochemistry

“…The ensuing solids were loaded onto silica gel plug and eluted to provide 6 fractions: fraction 1 (30 mg; 25 % AcOEt/hexanes elution, 100 mL), fraction 2 (41 mg; 50 % AcOEt elution, 100 mL), fraction 3 (41 mg; 75 % AcOEt elution, 100 mL), fraction 4 (31 mg; 100 % AcOEt elution,100 mL), fraction 5 (89 mg; 10 % MeOH/AcOEt elution, 100 mL), fraction 6 (483 mg; 25 % MeOH/AcOEt elution, 100 mL). Following TLC analysis, fraction 5 was subjected to automated flash column chromatography (4 g silica cartridge, 0–40 % MeOH/AcOEt, 8 min), which robustaside D ( 1 k ) [22] (10 mg) as a tan amorphous solid, arbutin ( 1 a ) [9] (6 mg) as a tan amorphous solid, and rutin ( 3 b ) (2 mg) as a brown amorphous solid [38] . Fraction 6 was subjected to automated flash column chromatography (12 g silica cartridge, 0–60 % MeOH/AcOEt, 10 min), which provided robustaside D ( 1 k ) (8 mg) as a tan amorphous solid, and previously reported glycoside 1 c (2 mg) as a tan amorphous solid [9] .…”

“…After 2 h, the mixture was filtered through a plug of Celite® and the filtrate was concentrated under reduced pressure to provide extract B (420 mg). Extract A (280 mg) was subjected to automated flash column chromatography (4 g silica cartridge, 0–10 % MeOH/CH 2 Cl 2 , 20 min; then 10–40 % MeOH/CH 2 Cl 2 , 4 min), which provided arbutin ( 1 a ) [9] (20 mg), and robustaside D ( 1 k ) [22] (10 mg), rutin ( 3 b ) (20 mg) [38] . Extract B (420 mg) was subjected to automated flash column chromatography (4 g silica cartridge, 0–10 % MeOH/CH 2 Cl 2 , 12 min; then 10–40 % MeOH/CH 2 Cl 2 , 4 min), which provided arbutin ( 1 a ) (12 mg), and robustaside D ( 1 k ) (5 mg).…”

“…Extract A (280 mg) was subjected to automated flash column chromatography (4 g silica cartridge, 0-10 % MeOH/CH 2 Cl 2 , 20 min; then 10-40 % MeOH/CH 2 Cl 2 , 4 min), which provided arbutin (1 a) [9] (20 mg), and robustaside D (1 k) [22] (10 mg), rutin (3 b) (20 mg). [38] Extract B (420 mg) was subjected to automated flash column chromatography (4 g silica cartridge, 0-10 % MeOH/CH 2 Cl 2 , 12 min; then 10-40 % MeOH/CH 2 Cl 2 , 4 min), which provided arbutin (1 a) (12 mg), and robustaside D (1 k) (5 mg). LCMS analysis of extract A also supported the presence of previously reported glycosides 1 c and 1 g. [9]…”

“…Following TLC analysis, fraction 5 was subjected to automated flash column chromatography (4 g silica cartridge, 0-40 % MeOH/AcOEt, 8 min), which robustaside D (1 k) [22] (10 mg) as a tan amorphous solid, arbutin (1 a) [9] (6 mg) as a tan amorphous solid, and rutin (3 b) (2 mg) as a brown amorphous solid. [38] Fraction 6 was subjected to automated flash column chromatography (12 g silica cartridge, 0-60 % MeOH/AcOEt, 10 min), which provided robustaside D (1 k) (8 mg) as a tan amorphous solid, and previously reported glycoside 1 c (2 mg) as a tan amorphous solid. [9] LCMS analysis of fraction 5 also supported the presence of previously reported glycosides 1 d and 1 f. [9]…”

The Norsesquiterpene Glycoside Ptaquiloside as a Poisonous, Carcinogenic Component of Certain Ferns

“…Interestingly, ferns have been used for various purposes throughout history (as food, medicine, ornaments, etc.) The number of edible (or considered as edible) fern species in China is 144 [ 51 ]; the ostrich, bracken and royal ferns are the most popular edible fern species.…”