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Vitamin K is one of the many health-promoting substances whose impact on the human body has been underestimated until recently. However, recently published research results have changed this situation, prompting some researchers to consider it a new panacea for diseases of old age. The result is a significant increase in interest in the accurate analysis of vitamin K in various types of samples, ranging from food, through dietary supplements, to biological matrices and clinical trials, both observational and interventional. This review summarizes the current state of knowledge about the proven and speculated biological activity of vitamin K and its importance for the world's aging societies, including the methods used for its isolation and analysis in various matrices types. Of all the analytical methods, the currently preferred methods of choice for the direct analysis of vitamin K are chromatographic methods, in particular liquid chromatography-tandem mass spectrometry. This technique, despite its sensitivity and selectivity, requires an appropriate stage of sample preparation. As there is still room for improvement in the efficiency of these methods, especially at the sample preparation stage, this review shows the directions that need to be taken to make these methods faster, more efficient and more environmentally friendly. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present in the most comprehensive way the facts about the application of PLE in the analysis of secondary metabolites in plants. It is true that due to its specific extraction conditions, PLE is one of the most effective and versatile techniques of plant constituents isolation. It is also true that it has popularized the use of aqueous organic mixtures, and even water alone, for the extraction of nonpolar compounds. Yet, the same specific extraction conditions can lead to erroneous results of plant constituent content analysis. Disclosure of new facts about the application of PLE in the analysis of secondary plant metabolites provides an insight into an often overlooked aspect of extraction of active compounds from plants. • This review updates knowledge about the applicability of PLE. • It discusses the effectiveness and usefulness of PLE in the context of its achievements. • It discloses the limitations of PLE in the plant constituents content analysis. • Knowing all these facts can lead to the creation of a perfect method with a good method. [ABSTRACT FROM AUTHOR]

Abstract The aim of this paper was to present the diversity of analytical challenges in which the MSPD technique is useful and the variety of sorbents that are currently applied to meet these challenges with particular emphasis on new research areas in which the MSPD process started to be applied. In addition, the paper presents new tools to improve both the MSPD yields using the MSPD processes supported by centrifugation, ultrasound, microwave and magnetism and its selectivity combining MSPD with other extraction techniques in particular, with microextraction ones, such as liquid-liquid microextraction dispersion or homogeneous liquid-liquid microextraction. Facing the problem of the increased urgency for further reduction of sample preparation costs and organic solvent usage, alternative MSPD approaches such as the solventless MSPD mode and MSPD with sand used as a dispersing material in the so-called sea sand dispersion method were discussed. Highlights • This review updates knowledge about the applicability of MSPD. • It discuss the versatility and flexibility of MSPD in the context of its achievements and limitations. • Indicates new research areas in which MSPD began to be applied. • In addition, indicates those that in the near future should use this simple process. [ABSTRACT FROM AUTHOR]

This study deals with the sea sand disruption method (SSDM) in sample preparation for chromatographic analysis of quercetin in different plants. Several SSDM variables were tested in relation to quercetin recovery: sample to sand mass ratio, type of dispersing liquid, volume of the solvent applied for analyte elution, and the time of grinding. The optimized procedure has been applied for the extraction of quercetin from the edible and inedible parts of different varieties of onion, apples, and tea. The SSDM results are comparable with those obtained by pressurized liquid extraction, regarded as one of the most effective sample preparation techniques. The presented results show that the hydrolysis of quercetin glycoside form in SSDM conditions does not occur or is negligible. Hence, the method is especially useful when the estimation of the real amount of aglycones in plants is required. [ABSTRACT FROM AUTHOR]

Silymarin, a mixture of flavonolignans exhibiting many pharmacological activities, is obtained from the fruits of milk thistle (Silybum marianum L. Gaertner). Due to the high lipid content in thistle fruits, the European Pharmacopoeia recommends a two-step process of its extraction. First, the fruits are defatted for 6 h, using n-hexane; second, silymarin is extracted with methanol for 5 more hours. The presented data show that this extremely long traditional Soxhlet extraction process can be shortened to a few minutes using pressurized liquid extraction (PLE). PLE also allows to eliminate the defatting stage required in the traditional procedure, thus simplifying the silymarin extraction procedure and preventing silymarin loss caused by defatting. The PLE recoveries obtained under the optimized extraction conditions are clearly better than the ones obtained by the Pharmacopoeia-recommended Soxhlet extraction procedure. The PLE yields of silychristin, silydianin, silybin A, silybin B, isosilybin A and isosilybin B in acetone are 3.3, 6.9, 3.3, 5.1, 2.6 and 1.5 mg/g of the non-defatted fruits, respectively. The 5-h Soxhlet extraction with methanol on defatted fruits gives only ∼72% of the silymarin amount obtained in 10 min PLE at 125°C. [ABSTRACT FROM AUTHOR]

Biological properties of menaquinone-7, one of the vitamin K2 vitamers (K2MK-7), both those proven and those that remain to be investigated, arouse extensive interest that goes beyond the strictly scientific framework. The most important of them is the prevention of age-related diseases, considering that we live in the times identified as the era of aging societies and many people are exposed to the vitamin K2MK-7 deficiency. Therefore, an effective analytical protocol that can be adopted as a diagnostic and preventive analytics tool is needed. Herein, a simple sample preparation method followed by the liquid chromatography-tandem mass spectrometry-based method (LC-MS/MS), was used for the selective and sensitive determination of K2MK-7 in serum samples. Under the optimized conditions, using 500 µL of serum and the same amount of n-hexane, the reproducibility and the accuracy were obtained in the ranges of 89–97% and 86–110%, respectively, and the limit of detection value was 0.01 ng/mL. This method was used for the routine analysis. Statistical interpretation of the data from 518 samples obtained during 2 years of practice allowed for obtaining information on the content and distribution of K2MK-7 in the Polish population, broken down by the sex and age groups. [ABSTRACT FROM AUTHOR]