Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS

Use of carbonyldiimidazole as a derivatization agent for the detection of pinacolyl alcohol, a forensic marker for Soman, by EI-GC-MS and LC-HRMS in official OPCW proficiency test matrices

Pinacolyl alcohol (PA), a key forensic marker for the nerve agent Soman (GD), is a particularly difficult analyte to detect by various analytical methods. In this work, we have explored the reaction between PA and 1,1'-carbonyldiimidazole (CDI) to yield pinacolyl 1H-imidazole-1-carboxylate (PIC), a product that can be conveniently detected by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Regarding its GC-MS profile, this new carbamate derivative of PA possesses favorable chromatographic features such as a sharp peak and a longer retention time (RT = 16.62 min) relative to PA (broad peak and short retention time, RT = 4.1 min). The derivative can also be detected by LC-HRMS, providing an avenue for the analysis of this chemical using this technique where PA is virtually undetectable unless present in large concentrations. From a forensic science standpoint, detection of this low molecular weight alcohol signals the past or latent presence of the nerve agent Soman (GD) in a given matrix (i.e., environmental or biological). The efficiency of the protocol was tested separately in the analysis and detection of PA by EI-GC-MS and LC-HRMS when present at a 10 μg/mL in a soil matrix featured in the 44th PT and in a glycerol-rich liquid matrix featured in the 48th Official Organization for the Prohibition of Chemical Weapons (OPCW) Proficiency Test when present at a 5 μg/mL concentration. In both scenarios, PA was successfully transformed into PIC, establishing the protocol as an additional tool for the analysis of this unnatural and unique nerve agent marker by GC-MS and LC-HRMS.

Description of Solvent-Extractable Chemicals in Thermal Receipts and Toxicological Assessment of Bisphenol S and Diphenyl Sulfone

Research on thermal receipts has previously focused on the toxic effects of dermal exposure from the most publicized developers (e.g., bisphenol A (BPA) and bisphenol S (BPS)), while no studies have reported on the other solvent-extractable compounds therein. Diphenyl sulfone (DPS) is a sensitizer added to thermal receipts, but little is known about DPS concentrations in receipts or potential toxicity. Here, we quantified BPA, BPS, and DPS concentrations and tentatively identified the solvent-extractable compounds of thermal receipts collected from three South Dakota (USA) cities during 2016-2017. An immortalized chicken hepatic cell line, cultured as 3D spheroids, was used to screen effects of DPS, BPS, and 17ß estradiol (E2; 0.1-1000 µM) on cell viability and gene expression changes. These chemicals elicited limited cytotoxicity with LC50 values ranging from 113 to 143 µM, and induced dysregulation in genes associated with lipid and bile acid homeostasis. Taken together, this study generated novel information on solvent-extractable chemicals from thermal receipts and toxicity data for DPS.

Contaminants of emerging concern: Silylation procedures, evaluation of the stability of silyl derivatives and associated measurement uncertainty

Analyte range of gas chromatography-mass spectrometry (GC-MS), widely used in environmental analysis, can be significantly broadened by derivatization. Silyl derivatives have improved volatility and thermal stability, chromatographic and mass spectrometric behaviors, and thus detection, structural elucidation and quantification. However, silylation use is often hindered by the stability of generated derivatives and the need to optimize silylation conditions. In this study, we optimized the derivatization conditions for 70 selected contaminants of emerging concern (CEC) using chemometrics approaches. N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), N, O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and BSTFA + 1 % trimethylchlorosilane (TMCS) were investigated, among which the latter gave the best yield. CEC were grouped in three derivatization protocols: 60 °C/45 min, 70 °C/90 min, and 70 °C/45 min. The short- and long-term stability of the CEC-trimethylsilyl (TMS) derivatives, i.e. for 28 days and up to 20 weeks were examined in a solvent and artificial wastewater (AWW) extract at 25 °C, 4 °C and - 18 °C, and during repeated five freeze-thaw (F/T) cycles, at two concentration levels: 100 μg/L and 1000 μg/L. Except for TMS derivatives of shikimic acid (SHA), quinic acid (QA) and sulfanilamide (SFA), the remaining derivatized compounds were stable in solvent (EtAc) for 28 days. In AWW extract, TMS derivatives of citric acid (CA), 17β-estradiol (E2), estriol (E3) and 17α-ethinyl estradiol (EE2) were unstable at 25 °C and 4 °C. Within up to 20 weeks, only the TMS derivatives of CA, meso-erythritol (ERY) and bisphenol BP (BPBP) were unstable. The most significant hydrolytic breakdown was observed during repeated F/T cycles. After three cycles, ≤ 20 % of the initial concentration of six and nine CEC-TMS derivatives had degraded in solvent and AWW extracts, respectively. According to the deep statistical comparison (DSC) approach, the most prominent degradation was observed for TMS derivatives of E2, CA, 9-hydroxyfluorene (9-HF), estrone (E1) and trans-3'-hydroxycotinine (T3HC) in solvent; E2, CA, 9-HF, E3 and E1 in AWW extracts and ERY, E2, CA, 9-HF and E1 in both matrices. Finally, the sample concentration of CEC accounted for most of the measurement uncertainty (MU). Based on our findings, we recommend the derivatized samples to be stored at -18 °C for up to 20 weeks to ensure the stability of their TMS derivatives. Sample freezing and thawing of not more than twice is allowed to maintain ≥80 % of the initial CEC-TMS concentration.

Catharanthus roseus (L.) G. Don: A review of its ethnobotany, phytochemistry, ethnopharmacology and toxicities

ETHNOPHARMACOLOGICAL RELEVANCE

Catharanthus roseus (L.) G. Don is a well known medicinal plant belonging to family Apocynaceae that have been traditionally used as medicine since ancient times. C. roseus is a well-recognized herbal medicine due to its anticancer bisindole alkaloids (vinblastine (111), vincristine (112) and vindesine (121)). In the Ayurvedic system of medicine, different parts of C. roseus are used in folklore herbal medicine for treatment of many types of cancer, diabetes, stomach disorders, kidney, liver and cardiovascular diseases.

AIM OF THE STUDY

The main idea behind this communication is to update comprehensively and analyze critically the traditional applications, phytochemistry, pharmacological activities, and toxicity of various extracts and isolated compounds from C. roseus.

MATERIALS AND METHODS

The presented data covers scientific works on C. roseus published across the world between 1967 and 2021 was searched from various international publishing houses using search engines as well as several traditional texts like Ayurveda and relevant books. Collected data from different sources was comprehensively summarized/analyzed for ethnomedicinal uses, phytochemistry, analytical chemistry, biological activities and toxicity studies of C. roseus.

RESULTS AND DISCUSSION

C. roseus has a wide range of applications in the traditional system of medicine especially in cancer and diabetes. During phytochemical investigation, total of 344 compounds including monoterpene indole alkaloids (MIAs) (110), bisindole alkaloids (35), flavonoids (34), phenolic acids (9) and volatile constituents (156) have been reported in the various extracts and fractions of different plant parts of C. roseus. The extracts and isolated compounds of C. roseus have to exhibit many pharmacological activities such as anticancer/cytotoxic, antidiabetic, antimicrobial, antioxidant, larvicidal and pupicidal. The comparative toxicity of extracts and bioactive compounds investigated in dose dependent manner. The investigation of toxicity showed that the both extracts and isolated compounds are safe to a certain limit beyond that they cause adverse effects.

CONCLUSION

This review is a comprehensive, critically analyzed summarization of sufficient baseline information of selected topics in one place undertaken till date on C. roseus for future works and drug discovery. The phytochemical investigation including biosynthetic pathways showed that the MIAs and bisindole alkaloids are major and characteristic class of compounds in this plant. The present data confirm that the extracts/fractions and their isolated alkaloids especially vinblastine (111) and vincristine (112) have a potent anticancer/cytotoxic and antidiabetic property and there is a need for further study with particular attention to the mechanisms of anticancer activity. In biosynthesis pathways of alkaloids especially bisindole alkaloids, some enzymes and rearrangement are unexposed therefore it is required to draw special attention. It also focuses on attracting the attention of scientific communities about the widespread biological activities of this species for its better utilization prospects in the near future.

Identification of organic pollutants with potential ecological and health risks in aquatic environments: Progress and challenges

Thousands of organic pollutants are intentionally and unintentionally discharged into water bodies, adversely affecting the ecological environment and human health. Screening for organic pollutants that pose a potential risk in aquatic environments is essential for risk management. This review evaluates the processes, methods, and technologies used to screen such pollutants in the aquatic environment and discuss their advantages and disadvantages, in addition to the challenges and knowledge gaps in this field. Combining non-target screening, target screening, and suspect screening is often effective for compiling a list of potential risk compounds and enables the quantitative analysis of these compounds. Sample preparation technologies and pollutant detection technologies considerably affect the results of pollutant screening. The limited amount of chemical and toxicological information contained in databases hinders the screening of organic pollutants with potential risk. Machine learning, high-throughput methods, and other technologies will increase the accuracy and convenience of screening for high-risk pollutants. This review provides an important reference for screening these compounds in aquatic environments and can be used in future pollutant screening and risk management.

A chemometric strategy to automatically screen selected ion monitoring ions for gas chromatography-mass spectrometry-based pseudotargeted metabolomics

The pseudotargeted metabolomics based on gas chromatography-mass spectrometry (GC-MS) has the advantage of filtering out artifacts originating from sample treatment and accurately quantifying underlying compounds in the analyzed samples. However, this technique faces the problem of selecting high-quality selective ions for performing selected ion monitoring (SIM) on instruments. In this work, we proposed AntDAS-SIMOpt, an automatic untargeted strategy for SIM ion optimization that was accomplished on the basis of an experimental design combined with advanced chemometric algorithms. First, a group of diluted quality control samples was used to screen underlying compounds in samples automatically. Ions in each of the resolved mass spectrum were then evaluated by using the developed algorithms to identify the SIM ion. A Matlab graphical user interface (GUI) was designed to facilitate routine analysis, which can be obtained from http://www.pmdb.org.cn/antdassimopt. The performance of the developed strategy was comprehensively investigated by using standard and complex plant datasets. Results indicated that AntDAS-SIMOpt may be useful for GC-MS-based metabolomics.

Persistence and removal of trace organic compounds in centralized and decentralized wastewater treatment systems

The persistence of trace organic chemicals in treated effluent derived from both centralized wastewater treatment plants (WWTPs) and decentralized wastewater treatment systems (DEWATS) is of concern due to their potential impacts on human and ecosystem health. Here, we utilize non-targeted analysis (NTA) with comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC × GC/TOF-MS) to conduct an evaluation of the common persistent and removed compounds found in two centralized WWTPs in the USA and South Africa and one DEWATS in South Africa. Overall, removal efficiencies of chemicals were similar between the treatment plants when they were compared according to the number of chemical features detected in the influents and effluents of each treatment plant. However, the DEWATS treatment train, which has longer solids retention and hydraulic residence times than both of the centralized WWTPs and utilizes primarily anaerobic treatment processes, was able to remove 13 additional compounds and showed a greater decrease in normalized peak areas compared to the centralized WWTPs. Of the 111 common compounds tentatively identified in all three influents, 11 compounds were persistent in all replicates, including 5 compounds not previously reported in effluents of WWTPs or water reuse systems. There were no significant differences among the physico-chemical properties of persistent and removed compounds, but significant differences were observed among some of the molecular descriptors. These results have important implications for the treatment of trace organic chemicals in centralized and decentralized WWTPs and the monitoring of new compounds in WWTP effluent.

Emerging contaminants in South African water environment- a critical review of their occurrence, sources and ecotoxicological risks

The release of emerging contaminants (ECs) to the environment is a serious concern due to its health implications on humans, aquatic species, and the development of anti-microbial resistance. This review focuses on the critical analysis of available literature on the prevalence of ECs in the aquatic environment and their removal from wastewater treatment plants (WWTPs) in South Africa. Besides, a risk assessment is performed on the reported ECs from the South African surface water to augment the knowledge towards mitigation of EC pollution, and prioritisation of ECs to assist future monitoring plans and regulation framework. A zone wise classification approach was carried out to identify the spatial inferences and data deficiencies that revealed a non-uniformity in the monitoring of ECs throughout South Africa, with few zones rendering no data. The overarching data mining further revealed that unmanaged urine diverted toilets could be a potential source of EC pollution to groundwater in South Africa. Based on the available literature, it can be deduced that the complete adoption of EC management practices from developed countries might only contribute partly in the mitigation of EC pollution in South Africa. Therefore, an EC monitoring programme specific to the country is recommended which should be based on their occurrence levels, sources and removal in WWTPs.

Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction

Pharmaceuticals and personal care products (PPCPs) are abundantly used by people, and some of them are excreted unaltered or as metabolites through urine, with the sewage being the most important source to their release to the environment. These compounds are in almost all types of water (wastewater, surface water, groundwater, etc.) at concentrations ranging from ng/L to µg/L. The isolation and concentration of the PPCPs from water achieves the appropriate sensitivity. This step is mostly based on solid-phase extraction (SPE) but also includes other approaches (dispersive liquid-liquid microextraction (DLLME), buckypaper, SPE using multicartridges, etc.). In this review article, we aim to discuss the procedures employed to extract PPCPs from any type of water sample prior to their determination via an instrumental analytical technique. Furthermore, we put forward not only the merits of the different methods available but also a number of inconsistencies, divergences, weaknesses and disadvantages of the procedures found in literature, as well as the systems proposed to overcome them and to improve the methodology. Environmental applications of the developed techniques are also discussed. The pressing need for new analytical innovations, emerging trends and future prospects was also considered.

Isolation and Characterization of a New Endophytic Actinobacterium Streptomyces californicus Strain ADR1 as a Promising Source of Anti-Bacterial, Anti-Biofilm and Antioxidant Metabolites

In view of the fast depleting armamentarium of drugs against significant pathogens, like methicillin-resistant Staphylococcus aureus (MRSA) and others due to rapidly emerging drug-resistance, the discovery and development of new drugs need urgent action. In this endeavor, a new strain of endophytic actinobacterium was isolated from the plant Datura metel, which produced secondary metabolites with potent anti-infective activities. The isolate was identified as Streptomyces californicus strain ADR1 based on 16S rRNA gene sequence analysis. Metabolites produced by the isolate had been investigated for their antibacterial attributes against important pathogens: S. aureus, MRSA, S. epidermis, Enterococcus faecium and E. faecalis. Minimum inhibitory concentration (MIC₉₀) values against these pathogens varied from 0.23 ± 0.01 to 5.68 ± 0.20 μg/mL. The metabolites inhibited biofilm formation by the strains of S. aureus and MRSA (Biofilm inhibitory concentration [BIC₉₀] values: 0.74 ± 0.08–4.92 ± 0.49 μg/mL). The BIC₉₀ values increased in the case of pre-formed biofilms. Additionally, the metabolites possessed good antioxidant properties, with an inhibitory concentration (IC₉₀) value of 217.24 ± 6.77 µg/mL for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. An insight into different classes of compounds produced by the strain ADR1 was obtained by chemical profiling and GC-MS analysis, wherein several therapeutic classes, for example, alkaloids, phenolics, terpenes, terpenoids and glycosides, were discovered.