Purification of L-alpha glycerylphosphorylcholine by column chromatography

Flow Synthesis of L-α-Glycerylphosphorylcholine: Studies on Synthetic Routes Applicable to a Flow Reactor and Optimization of Reaction Conditions

L-α-Glycerylphosphorylcholine (L-α-GPC) has mainly been produced by two methods: extraction from plants rich in phosphatidylcholine and chemical synthesis. However, production through extraction involves difficult processes, such as fermentation, extractions and ripening, and conventional chemical synthesis methods with high-cost reactants and a batch reactor. These methods are not ideal for large-quantity production. Thus, it is important to develop a simple production method of L-α-GPC, which is suitable for mass production without the need for expensive reactants. Here, we studied synthetic L-α-GPC methods that are applicable to a flow synthesis system, which can provide selectivity, reproducibility, scalability, and a high yield in short reaction time using inexpensive starting materials. We developed a two-step synthetic route to produce L-α-GPC, including the synthesis of phosphoryl choline using choline chloride and phosphoryl oxychloride (POCl₃) as a first step and synthesis of L-α-GPC by reacting phosphoryl choline with (R)-(-)-3-chloro-1,2-propanediol (CPD) as a second step under basic conditions. Both steps were separately performed in a customized flow reactor, and reaction conditions were optimized. Finally, phosphoryl choline and L-α-GPC, the products first and second reactions, were successfully synthesized with high conversion yields of 97% and 79%, respectively.

Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

A practical and fast isolation of 12 cyclolinopeptides (linusorbs) from flaxseed oil via preparative HPLC with phenyl-hexyl column

Linusorbs, known as cyclolinopeptides, are a group of cyclic hydrophobic peptides derived from flaxseed oil with various health benefits. However, the current research efforts on both the biological activities and antioxidant capacities of linusorbs are limited because of existing issues with their purification and characterization. A practical method based on preparative HPLC for isolating 12 linusorbs simultaneously was developed and factors such as the solvent selection, gradient elution program, flow rate, loaded mass, and loading concentration, were optimized. The optimum conditions were an initial acetonitrile (ACN) to water ratio of 40%, final ACN ratio of 80%, eluting time of 21 min, a flow rate of 16 mL/min, sample load of 12.5 mg, and concentration of 80 mg/mL (in methanol). The 12 linusorbs obtained were verified using off-line MS/MS, recording purities of above 95.5%. The method could serve as a practical and fast isolation method enabling further investigation of minor linusorbs.

Intrinsic stability study of L-α-glycerylphosphorylcholine with HPLC method development and validation

L-α-Glycerylphosphorylcholine (L-α-GPC) is effective to control the symptoms of cognitive decline for the patients of Alzheimer's disease. In this study, an HPLC method coupled with a refractive index detector was developed to evaluate the intrinsic stability of L-α-GPC. The separation of L-α-GPC and its major potential degradation products was achieved on a normal-phase silica gel column (4.6 mm × 250 mm) with the mobile phase consisting of methanol-20 mM ammonium formate aqueous solution (pH 3.2) (65:35, v/v) in isocratic mode. The HPLC method was validated satisfactorily with respect to precision, accuracy and robustness. It is found that L-α-GPC is stable under the photolytic, thermal, oxidative and acidic conditions, while relatively sensitive to alkaline condition due to the specific breakage of phosphate ester bond in the moiety of L-α-GPC. A preliminary kinetics study for the alkaline degradation was conducted with the corresponding kinetics parameters obtained. It can be concluded that the developed HPLC method is capable of distinguishing the stability difference between the two phosphate ester bonds characterized on the L-α-GPC chemical structure.

Production of α-Glycerylphosphorylcholine and Other Compounds from Wheat Fermentation

The liquified mash of milled grains from the Canadian wheat cultivar, AC Andrew, was fermented to determine whether α-glycerylphosphorylcholine (α-GPC) accumulated and whether the accumulation was dependent on fermentation-related factors. Fermentation was conducted at a temperature of 37 °C for 7 days (168 h) with samples collected every 24 h. The samples were analyzed using a proton nuclear magnetic resonance water suppression pulse sequence to allow the quantitation of ethanol, acetic acid, lactic acid, succinic acid, glycerol, phenethyl alcohol, betaine, and α-GPC. A Gompertz model was used to interpret fermentation kinetics for each analyte, and during fermentation, ethanol accumulated to a concentration of 72.1 g/L while α-GPC accumulated to a concentration of 1.68 g/L over 72 h. There were significant and positive correlations between the accumulation of α-GPC, ethanol, lactic acid, and glycerol and acetic acid production. Furthermore, there were no significant negative correlations between the productions of these compounds; hence, all the compounds accumulated during fermentation were produced simultaneously with no observed decrease measured in any compound. This indicates that α-GPC can be successfully produced industrially without any negative impact on ethanol or other useful compounds.

Preparation and purification of novel phosphatidyl prodrug and performance modulation of phosphatidyl nanoprodrug

Background

A novel phosphatidyl nanoprodrug system can be selectively released parent drugs in cancer cells, triggered by the local overexpression of phospholipase D (PLD). This system significantly reduces the intrinsic disadvantages of conventional chemotherapeutic drugs. However, the separation and purification processes of phosphatidyl prodrug, the precursor of phosphatidyl nanoprodrug, have not been established, and the preparation of nanocrystals with good stability and tumor-targeting capability is still challenging.

Results

In this study, we established a successive elution procedure for the phosphatidyl prodrug—phosphatidyl mitoxantrone (PMA), using an initial ten-bed volume of chloroform/methanol/glacial acetic acid/water (26/10/0.8/0.7) (v/v/v/v) followed by a five-bed volume (26/10/0.8/3), with which purity rates of 96.93% and overall yields of 50.35% of PMA were obtained. Moreover, to reduce the intrinsic disadvantages of conventional chemotherapeutic drugs, phosphatidyl nanoprodrug—PMA nanoprodrug (NP@PMA)—was prepared. To enhance their stability, nanoparticles were modified with polyethylene glycol (PEG). We found that nanoprodrugs modified by PEG (NP@PEG–PMA) were stably present in RPMI-1640 medium containing 10% FBS, compared with unmodified nanoprodrug (NP@PMA). To enhance active tumor-targeting efficiency, we modified nanoparticles with an arginine-glycine-aspartic acid (RGD) peptide (NP@RGD–PEG–PMA). In vitro cytotoxicity assays showed that, compared with the cytotoxicity of NP@PEG–PMA against tumor cells, that of NP@RGD–PEG–PMA was enhanced. Thus, RGD modification may serve to enhance the active tumor-targeting efficiency of a nanoprodrug, thereby increasing its cytotoxicity.

Conclusions

A process for the preparation and purification of novel phosphatidyl prodrugs was successfully established, and the nanoprodrug was modified using PEG for enhanced nanoparticle stability, and using RGD peptide for enhanced active tumor-targeting efficiency. These procedures offer considerable potential in the development of functional antitumor prodrugs.