Lomatia polymorpha (Labill.) R. Br

Deans, Bianca J., Tedone, Laura, Bissember, Alex C. & Smith, Jason A., 2018, Phytochemical profile of the rare, ancient clone Lomatia tasmanica and comparison to other endemic Tasmanian species L. tinctoria and L. polymorpha, Phytochemistry 153, pp. 74-78 : 77

4.4. Extraction of Lomatia polymorpha

Diethyl ether maceration. Fresh leaves including petiole of L. polymorpha (18.3 g) were removed from the stems (to form an even layer of material in the extraction vessel). The plant material was then completely submerged in diethyl ether (250 mL) and the vessel was sealed and maintained at room temperature. After 5 h, the leaves were observed to change to a darker green/black color, while the solution displayed a vibrant yellow color. The mixture was filtered, dried (Na 2 SO 4), filtered, and evaporated under reduced pressure to provide an orange residue (149 mg). This mixture was purified by automated flash chromatography to deliver juglone (60 mg, 0.32% w/w) as red/ orange crystalline solid and a colorless semi-solid (13 mg, 0.07% w/w) containing a mixture of the three n -alcohols tetracosan-1-ol (C 24 H 50 O), hexacosan-1-ol (C 26 H 54 O) and octacosan-1-ol (C 28 H 58 O).

Tetracosan-1-ol. EIC (m / z): 336 [M–18] +. Hexacosan-1-ol. EIC (m / z): 364 [M–18] +, 336. Octacosan-1-ol. EIC (m / z): 392 [M–18] +, 364, 336. See Supporting Information for the 1 H NMR spectrum, as well as GC-MS data (retention time, LRI, TIC, and EIC for selected diagnostic ions) of the mixture containing the three n -alcohols.

PHWE. Immediately following the above-mentioned diethyl ether maceration, residual solvent was allowed to evaporate from the leaf material that remained (∼10 min). The ensuing L. polymorpha leaves (14.5 g) were then coarsely ground in a spice grinder, mixed with sand (2 g), and extracted using the identical espresso PHWE method detailed previously. The ensuing extract was then concentrated under reduced pressure on a rotary evaporator (50 ̊C bath temperature) to remove EtOH. The extract was then extracted with EtOAc (3 × 60 mL), with the organic extracts combined, dried over Na 2 SO 4, filtered and evaporated under reduced pressured to provide a solid dark green residue (149 mg). This residue was purified by flash chromatography (0 → 30% CH 2 Cl 2 /MeOH; 11 min) to afford dihydroquercetin 3- O -β- D-xyloside (4) as a dark yellow film (21 mg) and quercetin 3- O -β- D- glucose (5) as a yellow solid (17 mg) and A fraction of co-eluted compounds (60 mg) was purified further by flash chromatography (20% MeOH/ CH 2 Cl 2), to also afford dihydroquercetin 3- O -β- D-xyloside (4) (11 mg, overall yield 0.22% w/w). Fractions which contained a mixture of quercetin 3- O -β- D- glucose (5) with two minor components were combined and subsequently purified by automated reverse phase chromatography (0 → 50% MeCN/H 2 O; 13 min), to also provide quercetin 3- O -β- D- glucose (5) (3 mg, overall yield 0.14% w/w), 1,4,8-trihydroxynaphthalene-1- O -β- D- glucose (6) (6 mg, 0.04% w/w) as a clear film, and 4- O -p - coumaroyl-D- glucose (7) (5 mg, 0.03% w/w) as a pale yellow solid. NMR spectroscopic data for compounds 4–7 is provided in the Supporting Information.

Peracetylation of saccharides obtained from PHWE. The aqueous phase from the above-mentioned EtOAc extraction step, was evaporated and a portion of the crude residue (176 mg), thus obtained, was dissolved in pyridine (1.5 mL) and cooled to 0 ̊C. Acetic anhydride (1.5 mL) was then added dropwise to this mixture and the magnetically stirred mixture maintained at room temperature. After 21 h, the mixture was concentrated under reduced pressure to afford a brown gum (242 mg), which was loaded onto a silica plug (50% EtOAc/hexanes elution), to remove CH 2 Cl 2 -insoluble by-products. This provided a light brown mixture of non-polar components (70 mg). Purification by automated flash column chromatography (0 → 100% EtOAc/hexanes; 10 min) provided α- and β- glucose pentaacetate (16 mg).