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Sustainable biocatalytic synthesis of L-homophenylalanine as pharmaceutical drug precursor

Ahmad AL, Oh PC, Abd Shukor SR

Biotechnol Adv, 2009 May-Jun;27(3):286-96.
PMID: 19500550 DOI: 10.1016/j.biotechadv.2009.01.003

Over the past decade, L-homophenylalanine is extensively used in the pharmaceutical industry as a precursor for production of angiotensin-converting enzyme (ACE) inhibitor, which possesses significant clinical application in the management of hypertension and congestive heart failure (CHF). A number of chemical methods have been reported thus far for the synthesis of L-homophenylalanine. However, chemical methods generally suffer from process complexity, high cost, and environmental pollution. On the other hand, enantiomerically pure L-homophenylalanine can be obtained elegantly and efficiently by employing biocatalytic methods, where it appears to be the most attractive process in terms of potential industrial applications, green chemistry and sustainability. Herein we review the biocatalytic synthesis of vital L-homophenylalanine as potentially useful intermediate in the production of pharmaceutical drugs in environmentally friendly conditions, using membrane bioreactor for sustainable biotransformation process. One envisages the future prospects of developing an integrated membrane bioreactor system with improved performance for L-homophenylalanine production.

Matched MeSH terms: Aminobutyrates/chemical synthesis; Aminobutyrates/metabolism*
Troubleshooting and maintenance of high-performance liquid chromatography during herbicide analysis: an overview

Tayeb MA, Ismail BS, Khairiatul Mardiana J, Goh CT

Sains Malaysiana, 2016;45:237-245.

Glufosinate ammonium or ammonium salt (ammonium-(2RS)-2-amino-4- (methylphosphinato) butyric acid; C5H15N2O4P) is a commonly used polar herbicide in Malaysia and present in a variety of environmental waters at the sub-ppb level. Thus, glufosinate ammonium is analyzed in soil and water using high-performance liquid chromatography (HPLC), which is a complex yet the most powerful analysis tool. HPLC is tremendously sensitive and highly automated and HPLC instrumentation and machinery have improved over the years. However, typical problems are still encountered. HPLC users and advanced learners require help in identifying, separating and correcting typical problems. All HPLC systems consist of similar basic components. Although it is a modular system, trouble can occur in each component and change the overall performance. Resolving these problems may be expensive. This review describes the different aspects of HPLC, particularly troubleshooting, common problems and easy guidelines for maintenance.

Matched MeSH terms: Aminobutyrates
Direct Analysis of Glyphosate, Glufosinate, and Their Metabolites in Palm Oil Using Liquid Chromatography with Tandem Mass Spectrometry

Shinde R, Halim N, Banerjee AK

J AOAC Int, 2020 Nov 01;103(6):1528-1533.
PMID: 33247748 DOI: 10.1093/jaoacint/qsaa066

BACKGROUND: Glyphosate and glufosinate are broad-spectrum herbicides which are frequently used in palm oil plantations for weed control. Metabolites of these herbicides are known to have environmental and food safety implications. As there is no validated method for multiresidue testing of these herbicides and their metabolites in palm oil products, a new method was needed for the purpose of regulatory analysis.
OBJECTIVE: In this study, we endeavored to develop a rapid method for multiresidue analysis of glyphosate (+aminomethylphosphonic acid) and glufosinate (+3-methylphosphinicopropionic acid and N-acetyl-glufosinate) in refined and crude palm oil matrices using liquid chromatography (LC) tandem mass spectrometry (MS/MS).
METHOD: The optimized sample preparation workflow included extraction of refined or crude palm oil (10 g) with acidified water (0.1 M HCl), cleanup by phase separation with dichloromethane, and analysis by LC-MS/MS with multiple reaction monitoring.
RESULTS: The use of a Torus-DEA LC column ensured simultaneous analysis of these compounds within a runtime of 10 min. The LOQ of these analytes was 0.01 mg/kg, except that of aminomethylphosphonic acid which was 0.02 mg/kg. The method sensitivity complied with the national maximum residue limits of Malaysia and the European Union. Also, the method selectivity, sensitivity, accuracy, and precision were aligned with the SANTE/12682/2019 guidelines of analytical quality control.
CONCLUSIONS: The potentiality of the optimized method lies in a high throughput direct analysis of glyphosate and glufosinate with their metabolites in a single chromatographic run. The method is fit for purpose for regulatory testing of these residues in a broad range of palm oil matrices.
HIGHLIGHTS: The study reports for the first time a validated method for simultaneous analysis of glyphosate, glufosinate, and their metabolites in a range of palm oil products. The method did not require a derivatization step and provided a high throughput analysis of these compounds with satisfactory selectivity, sensitivity, accuracy, and precision.

Matched MeSH terms: Aminobutyrates
Rapid and direct determination of glyphosate, glufosinate, and aminophosphonic acid by online preconcentration CE with contactless conductivity detection

See HH, Hauser PC, Ibrahim WA, Sanagi MM

Electrophoresis, 2010 Jan;31(3):575-82.
PMID: 20119968 DOI: 10.1002/elps.200900380

Rapid and direct online preconcentration followed by CE with capacitively coupled contactless conductivity detection (CE-C(4)D) is evaluated as a new approach for the determination of glyphosate, glufosinate (GLUF), and aminophosphonic acid (AMPA) in drinking water. Two online preconcentration techniques, namely large volume sample stacking without polarity switching and field-enhanced sample injection, coupled with CE-C(4)D were successfully developed and optimized. Under optimized conditions, LODs in the range of 0.01-0.1 microM (1.7-11.1 microg/L) and sensitivity enhancements of 48- to 53-fold were achieved with the large volume sample stacking-CE-C(4)D method. By performing the field-enhanced sample injection-CE-C(4)D procedure, excellent LODs down to 0.0005-0.02 microM (0.1-2.2 microg/L) as well as sensitivity enhancements of up to 245- to 1002-fold were obtained. Both techniques showed satisfactory reproducibility with RSDs of peak height of better than 10%. The newly established approaches were successfully applied to the analysis of glyphosate, glufosinate, and aminophosphonic acid in spiked tap drinking water.

Matched MeSH terms: Aminobutyrates/analysis*
Runoff of the herbicides triclopyr and glufosinate ammonium from oil palm plantation soil

Tayeb MA, Ismail BS, Khairiatul-Mardiana J

Environ Monit Assess, 2017 Oct 11;189(11):551.
PMID: 29022154 DOI: 10.1007/s10661-017-6236-4

This study focused on the residue detection of the herbicides triclopyr and glufosinate ammonium in the runoff losses from the Tasik Chini oil palm plantation area and the Tasik Chini Lake under natural rainfall conditions in the Malaysian tropical environment. Triclopyr and glufosinate ammonium are post-emergence herbicides. Both herbicides were foliar-sprayed on 0.5 ha of oil palm plantation plots, which were individualized by an uneven slope of 10-15%. Samples were collected at 1, 3, 7, 15, 30, 45, 60, 90, and 120 days after treatment. The concentrations of both herbicides quickly diminished from those in the analyzed sample by the time of collection. The highest residue levels found in the field surface leachate were 0.031 (single dosage, triclopyr), 0.041 (single dosage, glufosinate ammonium), 0.017 (double dosage, triclopyr), and 0.037 μg/kg (double dosage, glufosinate ammonium). The chromatographic peaks were observed at "0" day treatment (2 h after herbicide application). From the applied active ingredients, the triclopyr and glufosinate losses were 0.025 and 0.055%, respectively. The experimental results showed that both herbicides are less potent than other herbicides in polluting water systems because of their short persistence and strong adsorption onto soil clay particles.

Matched MeSH terms: Aminobutyrates/analysis*
Serine-rich protein is a novel positive regulator for silicon accumulation in mangrove

Sahebi M, Hanafi MM, Siti Nor Akmar A, Rafii MY, Azizi P, Idris AS

Gene, 2015 Feb 10;556(2):170-81.
PMID: 25479011 DOI: 10.1016/j.gene.2014.11.055

Silicon (Si) plays an important role in reducing plant susceptibility against a variety of different biotic and abiotic stresses; and also has an important regulatory role in soil to avoid heavy metal toxicity and providing suitable growing conditions for plants. A full-length cDNAs of 696bp of serine-rich protein was cloned from mangrove plant (Rhizophora apiculata) by amplification of cDNA ends from an expressed sequence tag homologous to groundnut (Arachis hypogaea), submitted to NCBI (KF211374). This serine-rich protein gene encodes a deduced protein of 223 amino acids. The transcript titre of the serine-rich protein was found to be strongly enriched in roots compared with the leaves of two month old mangrove plants and expression level of this serine-rich protein was found to be strongly induced when the mangrove seedlings were exposed to SiO2. Expression of the serine-rich protein transgenic was detected in transgenic Arabidopsis thaliana, where the amount of serine increased from 1.02 to 37.8mg/g. The same trend was also seen in Si content in the roots (14.3%) and leaves (7.4%) of the transgenic A. thaliana compared to the wild-type plants under Si treatment. The biological results demonstrated that the accumulation of the serine amino acid in the vegetative tissues of the transgenic plants enhanced their ability to absorb and accumulate more Si in the roots and leaves and suggests that the serine-rich protein gene has potential for use in genetic engineering of different stress tolerance characteristics.

Matched MeSH terms: Aminobutyrates/pharmacology
Transformation of oil palm using Agrobacterium tumefaciens

Izawati AM, Parveez GK, Masani MY

Methods Mol Biol, 2012;847:177-88.
PMID: 22351008 DOI: 10.1007/978-1-61779-558-9_15

Transgenic oil palm (Elaeis guineensis Jacq.) plantlets are regenerated after Agrobacterium tumefaciens-mediated transformation of embryogenic calli derived from young leaves of oil palm. The calli are transformed with an Agrobacterium strain, LBA4404, harboring the plasmid pUBA, which carries a selectable marker gene (bar) for resistance to the herbicide Basta and is driven by a maize ubiquitin promoter. Modifications of the transformation method, treatment of the target tissues using acetosyringone, exposure to a plasmolysis medium, and physical injury via biolistics are applied. The main reasons for such modifications are to activate the bacterial virulence system and, subsequently, to increase the transformation efficiency. Transgenic oil palm cells are selected and regenerated on a medium containing herbicide Basta. Molecular analyses revealed the presence and integration of the introduced bar gene into the genome of the transformants.

Matched MeSH terms: Aminobutyrates/pharmacology*
Fulltext Angiotensin receptor neprilysin inhibitor as a novel antihypertensive drug: Evidence from Asia and around the globe

Lin DS, Wang TD, Buranakitjaroen P, Chen CH, Cheng HM, Chia YC, et al.

J Clin Hypertens (Greenwich), 2021 Mar;23(3):556-567.
PMID: 33305531 DOI: 10.1111/jch.14120

Hypertension is a worldwide epidemic that continues to grow, with a subset of patients responding poorly to current treatment available. This is especially relevant in Asia, which constitutes 61% of the global population. Hypertension in Asia is a unique entity that is often salt-sensitive, nocturnal, and systolic predominant. Sacubitril/valsartan is a first-in-class angiotensin receptor neprilysin inhibitor that was first used in heart failure with reduced ejection fraction. Sacubitril inhibits neprilysin, a metallopeptidase that degrades natriuretic peptides (NPs). NPs exert sympatholytic, diuretic, natriuretic, vasodilatory, and insulin-sensitizing effects mostly via cyclic guanosine monophosphate (cGMP)-mediated pathways. As an antihypertensive agent, sacubitril/valsartan has outperformed angiotensin II receptor type 1 blockers (ARBs), with additional reductions of office systolic blood pressures ranging between 5 and 7 mmHg, in multiple studies in Asia and around the globe. The drug was well tolerated even in the elderly or those with chronic kidney disease. Its mechanisms of actions are particularly attractive for treatment of hypertension in Asia. Sacubitril/valsartan offers a novel, dual class, single-molecule property that may be considered as first-line antihypertensive therapy. Further investigations are needed to validate its safety for long-term use and to explore other potentials such as in the management of insulin resistance and obesity, which often coexist with hypertension in Asia.

Matched MeSH terms: Aminobutyrates