Preparative enantiomeric separation of potent AMP-activated protein kinase activator by HPLC on amylose-based chiral stationary phase

An overview of the methods for analyzing the chemical forms of metals in plants

Currently, the occurrence of toxic levels of metals in soils is a serious environmental issue worldwide. Phytoremediation is getting much attention to control metals soil pollution because it is economic and environmentally friendly. However, the methods used to detect metals in plants are not uniform and have depicted poor comparability of the research investigations. Therefore, the present overview is designed to discuss the possible chemical forms of metals in various environmental matrixes and the detection methods employed to identify the chemical forms of metals in plants. Moreover, the in situ and indirect methods to detect metals in plants have also been discussed herein. In addition, the pros and cons of the available techniques have also been critically analyzed and discussed. Finally, key points/challenges and future perspectives of these methods have been highlighted for the scientific community.Novelty statementIn the current review, the possible chemical forms of metals in various environmental matrixes are discussed in detail. Various extraction agents and their efficiency for extracting metals from plants have been clearly illustrated. Further, all the available methods for analyzing the chemical forms of metals in plants have been compared.

Reverse-phase HPLC purification for an extremely unstable glucuronide metabolite

A pure β-​D-​Glucopyranosiduronic acid metabolite (≥98.0 % purity and a single impurity ≤0.50 %) was requested for biological studies. Due to its unusual instability, the purification of the glucuronide metabolite was extremely challenging. Initially, the crude sample (89 % HPLC area purity) was purified on a Waters SunFire C₈ OBD column with 40 mM ammonium acetate buffer and acetonitrile as the mobile phase under a gradient program. The purified glucuronide metabolite solid was obtained by evaporation and lyophilization. However, this procedure yielded the target compound with 97.6 % HPLC area purity and did not meet the requirements. Through the investigation, lyophilization was identified as the key step for the purity of the metabolite, and further lyophilization resulted in an increased amount of the degraded impurities. To better understand the compound, stability studies of the purified metabolite were conducted under sample media, organic solvent, acid, base, and light exposure. The compound was observed to be extremely unstable in water, acid, base and methanol, and sensitive to light, but relatively stable in ammonium acetate buffer (pH 5.0). Taking into account compound stability and the initial purification method, the improved purification procedure was successfully developed and the purified glucuronide metabolite was obtained with 99.2 % HPLC area purity and 0.39 % of the largest single impurity.

AMPK activators--potential therapeutics for metabolic and other diseases

AMP-activated protein kinase (AMPK)-mediated cellular metabolic responses to tissue-specific and whole-body stimuli play a vital role in the control of energy homeostasis. As a cellular energy-sensing mechanism, AMPK activation stimulates glucose uptake and fat oxidation, while it suppresses lipogenesis and gluconeogenesis. The cumulative effects of AMPK activation lead to beneficial metabolic states in liver, muscle and other peripheral tissues that are critical in the pathogenesis of obesity, type 2 diabetes and related metabolic disorders. Activators of AMPK that target selected tissues hold potential as novel therapeutics for diseases in which altered energy metabolism contributes to aetiology.