Extraction of chili, black pepper, and ginger with near-critical CO2, propane, and dimethyl ether: analysis of the extracts by quantitative nuclear magnetic resonance

Extraction and Separation of Natural Products from Microalgae and Other Natural Sources Using Liquefied Dimethyl Ether, a Green Solvent: A Review

Microalgae are a sustainable source for the production of biofuels and bioactive compounds. This review discusses significant research on innovative extraction techniques using dimethyl ether (DME) as a green subcritical fluid. DME, which is characterized by its low boiling point and safety as an organic solvent, exhibits remarkable properties that enable high extraction rates of various active compounds, including lipids and bioactive compounds, from high-water-content microalgae without the need for drying. In this review, the superiority of liquefied DME extraction technology for microalgae over conventional methods is discussed in detail. In addition, we elucidate the extraction mechanism of this technology and address its safety for human health and the environment. This review also covers aspects related to extraction equipment, various applications of different extraction processes, and the estimation and trend analysis of the Hansen solubility parameters. In addition, we anticipate a promising trajectory for the expansion of this technology for the extraction of various resources.

Supercritical fluids and fluid mixtures to obtain high-value compounds from Capsicum peppers

Peppers of the Capsicum genus have a rich nutritional composition and are widely consumed worldwide. Thus, they find numerous applications in the food, pharmaceutical and cosmetic industries. One commercial application is oleoresin production, a nonpolar fraction rich in bioactive compounds, including capsaicinoids and carotenoids. Among the technologies for pepper processing, special attention is given to supercritical fluid technologies, such as supercritical fluid extraction (SFE) with pure solvents and CO2 plus modifiers, and SFE assisted by ultrasound. Supercritical fluid-based processes present advantages over the classical extraction techniques like using less solvents, short extraction times, specificity and scalability. In this review, we present a brief overview of the nutritional aspects of peppers, followed by studies that apply supercritical fluid technologies to produce extracts and concentrate bioactives, besides oleoresin encapsulation. Furthermore, we present related phase equilibrium, cost estimation, and the gaps and needs for the full use of peppers from a sustainable perspective.

Green Extraction of Bioactive Compounds from Plant Biomass and Their Application in Meat as Natural Antioxidant

Plant extracts are rich in various bioactive compounds exerting antioxidants effects, such as phenolics, catechins, flavonoids, quercetin, anthocyanin, tocopherol, rutin, chlorogenic acid, lycopene, caffeic acid, ferulic acid, p-coumaric acid, vitamin C, protocatechuic acid, vitamin E, carotenoids, β-carotene, myricetin, kaempferol, carnosine, zeaxanthin, sesamol, rosmarinic acid, carnosic acid, and carnosol. The extraction processing protocols such as solvent, time, temperature, and plant powder should be optimized to obtain the optimum yield with the maximum concentration of active ingredients. The application of novel green extraction technologies has improved extraction yields with a high concentration of active compounds, heat-labile compounds at a lower environmental cost, in a short duration, and with efficient utilization of the solvent. The application of various combinations of extraction technologies has proved to exert a synergistic effect or to act as an adjunct. There is a need for proper identification, segregation, and purification of the active ingredients in plant extracts for their efficient utilization in the meat industry, as natural antioxidants. The present review has critically analyzed the conventional and green extraction technologies in extracting bioactive compounds from plant biomass and their utilization in meat as natural antioxidants.

Preparation of Liposomes from Soy Lecithin Using Liquefied Dimethyl Ether

We investigated a method to prepare liposomes; soy lecithin was dissolved in liquefied dimethyl ether (DME) at 0.56 MPa, which was then injected into warm water. Liposomes can be successfully prepared at warm water temperatures above 45 °C. The transmission electron microscopy (TEM) images of the obtained liposomes, size distribution, ζ-potential measurements by dynamic light scattering and the amount of residual medium were compared by gas chromatography using the conventional medium, diethyl ether. The size of the obtained liposomes was approximately 60-300 nm and the ζ-potential was approximately -57 mV, which was almost the same as that of the conventional medium. Additionally, for the conventional media, a large amount remained in the liposome dispersion even after removal by depressurization and dialysis membrane treatment; however, liquefied DME, owing to its considerably low boiling point, was completely removed by depressurization. Liquefied DME is a very attractive medium for the preparation of liposomes because it does not have the toxicity and residue problems of conventional solvents or the hazards of ethanol addition and high pressure of supercritical carbon dioxide; it is also environmentally friendly.

Efficacy and sustainability of natural products in COVID-19 treatment development: opportunities and challenges in using agro-industrial waste from Citrus and apple

Natural products have been used in the treatment of illnesses throughout the history of humankind. Exploitation of bioactive compounds from natural sources can aid in the discovery of new drugs, provide the scaffold of new medicines. In the face of challenging diseases, such as the COVID-19 pandemic, for which there was no effective treatment, nature could offer insights as to novel therapeutic options for control measures. However, the environmental impact and supply chain of bioactive production must be carefully evaluated to ensure the detrimental effects will not outweigh the potential benefits gained. History has already proven that highly bioactive compounds can be rare and not suitable for medicinal exploitation; therefore, the sustainability must be accessed before expensive, time-demanding, and large trials can be initialized. A sustainable option to readily produce a phytotherapy with minimal environmental stress is the use of agro-industry wastes, a by-product produced in high quantities. In this review we evaluate the sustainability issues associated with the production of phytotherapy as a readily available tool for pandemic control.

Enhancement of Lipid Extraction from Soya Bean by Addition of Dimethyl Ether as Entrainer into Supercritical Carbon Dioxide

Soya beans contain a variety of lipids, and it is important to selectively separate neutral lipids from other lipids. Supercritical carbon dioxide extraction has been used as an alternative to the selective separation of neutral lipids from soya beans, usually using non-polar hexane. However, supercritical carbon dioxide extraction has a high operating pressure of over 40 MPa. On the other hand, liquefied dimethyl ether extraction, which has attracted attention in recent years, requires an operating pressure of only 0.5 MPa, but there is concern about the possibility of an explosion during operation because it is a flammable liquefied gas. Therefore, this study aims to reduce the operating pressure by using a non-flammable solvent, supercritical carbon dioxide extraction mixed with liquefied dimethyl ether as an entrainer. The extraction rate and the amount of neutral lipids extracted increased with increasing amounts of added liquefied dimethyl ether. In the mixed solvent, the amount of neutral lipids extracted was higher at an operating pressure of 20 MPa than in pure supercritical carbon dioxide extraction at 40 MPa. The mixing of liquefied dimethyl ether with supercritical carbon dioxide allowed an improvement in the extraction of neutral lipids while remaining non-flammable.

Surfactant-Free Decellularization of Porcine Aortic Tissue by Subcritical Dimethyl Ether

Porcine aortic tissue was decellularized by subcritical dimethyl ether (DME) used as an alternative to the surfactant sodium dodecyl sulfate. The process included three steps. For the first step, lipids were extracted from the porcine aorta using subcritical DME at 23 °C with a DME pressure of 0.56 MPa. Next, DME was evaporated from the aorta under atmospheric pressure and temperature. The second step involved DNA fragmentation by DNase, which was primarily identical to the common method. For the third step, similar to the common method, DNA fragments were removed by washing with water and ethanol. After 3 days of DNase treatment, the amount of DNA remaining in the porcine aorta was 40 ng/dry-mg, which was lower than the standard value of 50 ng/mg-dry. Hematoxylin and eosin staining showed that most cell nuclei were removed from the aorta. These results demonstrate that subcritical DME eliminates the need to utilize surfactants.

Ethanol-free antisolvent crystallization of glycine by liquefied dimethyl ether

Liquefied dimethyl ether (DME) was employed as an antisolvent to crystallize glycine from its aqueous solution. The proposed method can be performed at 20–25 °C and has the potential to reduce the energy consumption of drying or crystallizing using ethanol. α-Glycine crystals were successfully obtained from glycine aqueous solutions by mixing in liquefied DME, which was easily removed from the crystals by decompression. Contact with a liquefied DME/water mixture and small γ-glycine crystals resulted in the α-glycine converting to γ-glycine. This was only observed for saturated glycine solutions. We speculated that this conversion occurs via a solution-mediated transition. Pure liquefied DME is not capable of promoting solvent-mediated transitions, so saturated glycine solutions treated with the pure antisolvent can give α-glycine as the sole product.

Antibacterial Activity and Metabolomics Profiling of Torch Ginger (Etlingera elatior Jack) Flower Oil Extracted Using Subcritical Carbon Dioxide (CO2)

The aim of this study was to identify the bioactive compound and evaluate the antibacterial activity of torch ginger flower oil extracted using subcritical carbon dioxide. The antibacterial activity was evaluated in agar diffusion assay, while MIC and MBC were determined using the microdilution broth assay. The essential oil was subjected to metabolomics profiling using GC-MS and 1H-NMR techniques. The results demonstrated strong antibacterial activity towards Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli. The MIC values were 0.0625, 0.25, and 0.25 mg/mL, and the MBC values were 0.25, 0.5, and 1 mg/mL towards S. typhimurium, S. aureus, and E. coli, respectively. A total of 33 compounds were identified using GC-MS including 15 compounds (45%) known for their antimicrobial activity. In addition, sixteen metabolites were identified using NMR analysis and 8 out of the sixteen metabolites (50%) have antibacterial activity. The extracted oil demonstrated broad range for antibacterial activity and has high potential for applications in pharmaceutical and food industries. Practical Applications. The oil extracted from the torch ginger flower was found very stable and has promising applications as antibacterial agent for food and pharmaceutical industries.

Intensification of Catalytic Processes through the Pellet Structuring: Steady-State Properties of a Bifunctional Catalyst Pellet Applied to Generic Chemical Reactions and the Direct Synthesis of DME

Structuring of different types of catalytic active centers at a single-pellet level appears to be a promising and powerful tool for integration and intensification of multistep solid-catalyzed chemical reactions. However, the enhancement in the product yield and selectivity strongly depends on the proper choice of the distribution of different catalysts within the pellet. To demonstrate potential benefits from properly designed catalyst pellet, numerical studies were conducted with the aid of the mathematical model of a single spherical bifunctional catalyst pellet. The analysis was performed both for a system of two generic chemical reactions and for a real process, i.e., direct synthesis of dimethyl ether (DME) from synthesis gas via methanol. Evaluation of the pellet performance was done for three arrangements of the catalytic active sites within the pellet, i.e., a uniform distribution of two types of catalytic active centers in the entire volume of the pellet, and two core–shell structures. It was demonstrated that, especially for the larger pellets typical for fixed-bed applications, the product yield might be significantly improved by selecting proper catalyst arrangements within the pellet.

Cross-talk between 10-gingerol and its anti-cancerous potential: a recent update

Since time immortal, ginger, as an ancient herb, has been used throughout the world in foods and beverages due to its typical strong and pungent flavor. Besides its use as a spice, it also serves as an excellent source of several bioactive phenolics, including nonvolatile pungent compounds, such as gingerols, paradols, shogaols, and gingerones. Gingerols constitute key ingredients in fresh ginger, with the most abundant being 6-gingerol (6-G), 8-gingerol (8-G), and 10-gingerol (10-G). Many studies have investigated the various valuable pharmacological properties of these ingredients and experimentally verified the mechanistic aspects of their health effects; however, to date, most research on the anti-cancerous activities of gingerols have focused largely on 6-G. Thus, the present article deals with the number of recent studies that have indicated and highlighted the role of 10-G with respect to its cancer prevention attributes in particular and its anti-inflammatory, anti-oxidant, anti-microbial, and gastrointestinal tract protective potential in general. The purpose of this review is to provide an overview of all the experimentally validated health benefits of 10-G for nutraceutical applications. The various findings have warranted the further investigation of 10-G and its possible use in various cancer treatments as well as its promising role as a chemo-preventive agent.

Capsaicin reactivates hMOF in gastric cancer cells and induces cell growth inhibition

Capsaicin (CAP) is the major pungent component of chili pepper and is being evaluated for use against numerous types of tumors. Although CAP is indicated to target multiple signaling pathways, exact mechanisms of how it disturb cancer cell metablism remain obscure. Recent studies revealed Sirtuin 1 (SIRT1) serves as a potential target of CAP in cancer cells, indicating a direct regulation of cancer cell histone acetylation by capsaicin. The present study evaluated the effect of CAP on gastric cancer (GC) cell lines to understand the mechanism of cell growth inhibition. The results showed that CAP could significantly suppress cell growth, while altering histone acetylation in GC cell lines. Further studies found that hMOF, a major histone acetyltranferase for H4K16, is central to CAP-induced epigenetic changes. Reduced hMOF activity was detected in GC tissues, which could be restored by CAP both in vivo and in vitro. These findings revealed an important role of hMOF-mediated histone acetylation in CAP-directed anti-cancer processes, and suggested CAP as a potential drug for use in gastric cancer prevention and therapy.

Nuclear Magnetic Resonance (NMR) Spectroscopy For Metabolic Profiling of Medicinal Plants and Their Products

NMR spectroscopy has multidisciplinary applications, including excellent impact in metabolomics. The analytical capacity of NMR spectroscopy provides information for easy qualitative and quantitative assessment of both endogenous and exogenous metabolites present in biological samples. The complexity of a particular metabolite and its contribution in a biological system are critically important for understanding the functional state that governs the organism's phenotypes. This review covers historical aspects of developments in the NMR field, its applications in chemical profiling, metabolomics, and quality control of plants and their derived medicines, foods, and other products. The bottlenecks of NMR in metabolic profiling are also discussed, keeping in view the future scope and further technological interventions.

Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials

The aim of this study was to assess the clinical efficacy and safety of oral ginger for symptomatic treatment of osteoarthritis (OA) by carrying out a systematic literature search followed by meta-analyses on selected studies. Inclusion criteria were randomized controlled trials (RCTs) comparing oral ginger treatment with placebo in OA patients aged >18 years. Outcomes were reduction in pain and reduction in disability. Harm was assessed as withdrawals due to adverse events. The efficacy effect size was estimated using Hedges' standardized mean difference (SMD), and safety by risk ratio (RR). Standard random-effects meta-analysis was used, and inconsistency was evaluated by the I-squared index (I(2)). Out of 122 retrieved references, 117 were discarded, leaving five trials (593 patients) for meta-analyses. The majority reported relevant randomization procedures and blinding, but an inadequate intention-to-treat (ITT) analysis. Following ginger intake, a statistically significant pain reduction SMD = -0.30 ([95% CI: [(-0.50, -0.09)], P = 0.005]) with a low degree of inconsistency among trials (I(2) = 27%), and a statistically significant reduction in disability SMD = -0.22 ([95% CI: ([-0.39, -0.04)]; P = 0.01; I(2) = 0%]) were seen, both in favor of ginger. Patients given ginger were more than twice as likely to discontinue treatment compared to placebo ([RR = 2.33; 95% CI: (1.04, 5.22)]; P = 0.04; I(2) = 0%]). Ginger was modestly efficacious and reasonably safe for treatment of OA. We judged the evidence to be of moderate quality, based on the small number of participants and inadequate ITT populations. Prospero: CRD42011001777.

Extraction for metabolomics: access to the metabolome

INTRODUCTION

The value of information obtained from a metabolomic study depends on how much of the metabolome is present in analysed samples. Thus, only a comprehensive and reproducible extraction method will provide reliable data because the metabolites that will be measured are those that were extracted and all conclusions will be built around this information.

OBJECTIVE

To discuss the efficiency and reliability of available sample pre-treatment methods and their application in different fields of metabolomics.

METHODS

The review has three sections: the first deals with pre-extraction techniques, the second discusses the choice of extraction solvents and their main features and the third includes a brief description of the most used extraction techniques: microwave-assisted extraction, solid-phase extraction, supercritical fluid extraction, Soxhlet and a new method developed in our laboratory--the comprehensive extraction method.

RESULTS

Examination of over 200 studies showed that sample collection, homogenisation, grinding and storage could affect the yield and reproducibility of results. They also revealed that apart from the solvent used for extraction, the extraction techniques have a decisive role on the metabolites available for analysis.

CONCLUSION

It is essential to evaluate efficacy and reproducibility of sample pre-treatment as a first step to ensure the reliability of a metabolomic study. Among the reviewed methods, the comprehensive extraction method appears to provide a promising approach for extracting diverse types of metabolites.

Optimization of subcritical fluid extraction of carotenoids and chlorophyll a from Laminaria japonica Aresch by response surface methodology

BACKGROUND

The carotenoids and chlorophyll a of Laminaria japonica Aresch were extracted using ethanol-modified subcritical 1,1,1,2-tetrafluoroethane (R134a). In the present study, the effects of pressure (5-17 MPa), temperature (303-333 K) and the amount of cosolvent(2-6% R134a, w/w)were investigated. Response surface methodology (RSM) combined with a Box-Behnken design was applied to evaluate the significance of the three independent variables on each response. A desirability function was conducted to simultaneously optimize the multiple responses.

RESULTS

The optimum extraction conditions were as follows: extraction temperature 324.13 K, extraction pressure 17 MPa and a cosolvent amount of 4.73%. Under these conditions, the yields of carotenoids and chlorophyll a were predicted to be 0.239 and 2.326 g kg(-1), respectively.

CONCLUSION

It has been proved that subcritical R134a is a potential solvent, which can be an alternative to supercritical CO2 for extraction of natural ingredients under mild conditions.

Supercritical fluid extraction of plant flavors and fragrances

Supercritical fluid extraction (SFE) of plant material with solvents like CO₂, propane, butane, or ethylene is a topic of growing interest. SFE allows the processing of plant material at low temperatures, hence limiting thermal degradation, and avoids the use of toxic solvents. Although today SFE is mainly used for decaffeination of coffee and tea as well as production of hop extracts on a large scale, there is also a growing interest in this extraction method for other industrial applications operating at different scales. In this review we update the literature data on SFE technology, with particular reference to flavors and fragrance, by comparing traditional extraction techniques of some industrial medicinal and aromatic crops with SFE. Moreover, we describe the biological activity of SFE extracts by describing their insecticidal, acaricidal, antimycotic, antimicrobial, cytotoxic and antioxidant properties. Finally, we discuss the process modelling, mass-transfer mechanisms, kinetics parameters and thermodynamic by giving an overview of SFE potential in the flavors and fragrances arena.

Supercritical fluid extraction in natural products analyses

Supercritical fluids (SCFs) are increasingly replacing the organic solvents, e.g., n-hexane, chloroform, dichloromethane, or methanol, that are conventionally used in industrial extraction, purification, and recrystallization operations because of regulatory and environmental pressures on hydrocarbon and ozone-depleting emissions. In natural products extraction and isolation, supercritical fluid extraction (SFE), especially employing supercritical CO(2), has become a popular choice. Sophisticated modern technologies allow precise regulation of changes in temperature and pressure, and thus manipulation of solvating property of the SCF, which helps the extraction of natural products of a wide range of polarities. This chapter deals mainly with the application of the SFE technology in the natural products extraction and isolation, and outlines various methodologies with specific examples.

Analysis by HPLC and LC/MS of pungent piperamides in commercial black, white, green, and red whole and ground peppercorns

Pepper plants accumulate pungent bioactive alkaloids called piperamides. To facilitate studies in this area, high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry methods were developed and used to measure the following piperamides in 10 commercial whole (peppercorns) and in 10 ground, black, white, green, and red peppers: piperanine, piperdardine, piperine, piperlonguminine, and piperettine. Structural identification of individual compounds in extracts was performed by associating the HPLC peak of each compound with the corresponding mass spectrum. The piperanine content of the peppers (in mg/g piperine equivalents) ranged from 0.3 for the ground white pepper to 1.4 in black peppercorns. The corresponding range for piperdardine was from 0.0 for seven samples to 1.8 in black peppercorns; for four isomeric piperines, from 0.7 for red to 129 in green peppercorns; for piperlonguminine, from 0.0 in red peppercorns to 1.0 in black peppercorns; and for piperyline, from 0.9 in ground black pepper to 5.9 for red peppercorn. Four well-separated stereoisomeric forms of piperettine with the same molecular weight were present in 19 peppers. The sums of the piperamides ranged from 6.6 for red to 153 for green peppercorns. In contrast to large differences in absolute concentrations among the peppers, the ratios of piperines to total piperamide were quite narrow, ranging from 0.76 for black to 0.90 for white peppercorns, with an average value of 0.84 +/- 0.04 ( n = 19). Thus, on average, the total piperamide content of the peppers consists of 84% piperines and 16% other piperamides. These results demonstrate the utility of the described extraction and analytical methods used to determine the wide-ranging individual and total piperamide contents of widely consumed peppers.

Supercritical fluid extraction in plant essential and volatile oil analysis

The use of supercritical fluids, especially carbon dioxide, in the extraction of plant volatile components has increased during two last decades due to the expected advantages of the supercritical extraction process. Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in the volatile product of plant matrices. Also, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pretreatment technique. This review provides a detailed and updated discussion of the developments, modes and applications of SFE in the isolation of essential oils from plant matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract.

Kinetics of light-induced cis-trans isomerization of four piperines and their levels in ground black peppers as determined by HPLC and LC/MS

The pungent compounds piperine and isomers thereof, secondary metabolites present in black and white pepper fruit, undergo light-induced isomerizations. To facilitate studies in this area, an HPLC method has been developed for analysis and isolation of the following four possible piperine-derived photoinduced isomers: piperine, isopiperine, chavicine, and isochavicine. The limits of detection (LOD) estimated from calibration plots were approximately 15-30 ng for each isomer. Reproducibilities of the analyses were excellent, and recoveries of spiked samples were as follows (average +/- SD; n = 3): chavicine, 98.4 +/- 2.1%; isopiperine, 96.2 +/- 3.2%; piperine, 104 +/- 3.8%; isochavicine, 98.9 +/- 3.0%. To determine the kinetics of these isomerizations, fluorescent light, sunlight, and UV radiation at 254 nm was used to induce cis-trans geometric isomerization as a function of light intensities and time of exposure determined with the aid of high-performance liquid chromatography (HPLC) and liquid chromatography with diode array UV detection-mass spectrometry (LC-DAD/MS). HPLC was also used to determine the distribution of the isomers in four commercial ground black pepper products used as spices in culinary practice. Isomerization increased with light intensities and time of exposure and leveled off at the so-called photostationary phases. The piperine levels of the four products were quite similar, ranging (in wt %) from 10.17 to 11.68. The amounts of the other three isomers ranged from 0.01 to 0.07 of the total for chavicine; from 0.15 to 0.23 for isopiperine; and from 0.37 to 0.42 for isochavicine. The results establish the utility of the HPLC method for simultaneous analysis of the four isomers both in pure form and in black pepper extracts. The dietary significance of the results is discussed.

Multivariate optimisation of microwave-assisted extraction of capsaicin from Capsicum frutescens L. and quantitative analysis by 1H-NMR

A simple and rapid microwave-assisted extraction (MAE) procedure combined with 1H-NMR spectrometry was developed and optimised for the extraction and quantitative determination of capsaicin in Capsicum frutescens. The influence of experimental variables, including irradiation power, extraction temperature and dynamic extraction time before reaching the selected extraction temperature, on the performance of the extraction procedure was systematically studied using a Box-Behnken experimental design followed by a conventional central composite design approach. Statistical treatment of the results together with results from some additional experiments suggested optimum extraction conditions as 120 degrees C and 150 W, for 15 min with acetone as extractant. The optimised MAE method provides extracts that can be analysed quantitatively using 1H-NMR without any preliminary clean-up or derivatisation steps. In the 1H-NMR spectrum of the crude extracts the doublet signal in the delta range 4.349-4.360 ppm was well separated from other resonances in deuterated chloroform. The quantity of the compound was calculated from the relative ratio of the integral value of the target peak to that of a known amount of dimethylformamide as internal standard. In comparison with traditional Soxhlet extraction, the proposed method is less labour-intensive and provides a drastic reduction of extraction time and solvent consumption. In addition, MAE showed higher extraction yield and selectivity, with comparable reproducibility and recovery, relative to both conventional Soxhlet and sonication methods.

Analysis of Piperaceae germplasm by HPLC and LCMS: a method for isolating and identifying unsaturated amides from Piper spp extracts

A method for extraction and high performance liquid chromatography-mass spectrometer (HPLC-MS) analysis of the medicinally important genus Piper (Piperaceae) was developed. This allows for a rapid and accurate measure of unsaturated amides, or piperamides, in black pepper, Piper nigrum L., and in wild species from Central America. Reflux extraction provided the highest recovery of piperine (>80%) from leaf and peppercorn material. HPLC analysis using a binary gradient of acetonitrile and water separated the major amide peaks between 5 and 12 min. Atmospheric pressure chemical ionization (APCI)-MS improved the detection limit to 0.2 ng, 10-fold below the 2 ng limit of the HPLC-diode array detector (DAD) based on linear standard curves between 0.1 and 250 microg/mL (R2 = 0.999). The HPLC-MS method identified pellitorine, piperylin, 4,5-dihydropiperlonguminine, piperlonguminine, 4,5-dihydropiperine, piperine, and pipercide. The biological activity of six Costa Rican Piper species assessed by mosquito larval bioassays correlated well with piperamide content.

Quantitative 1H NMR: development and potential of a method for natural products analysis

Based on a brief revision of what constitutes state-of-the-art "quantitative experimental conditions" for (1)H quantitative NMR (qHNMR), this comprehensive review contains almost 200 references and covers the literature since 1982 with emphasis on natural products. It provides an overview of the background and applications of qHNMR in natural products research, new methods such as decoupling and hyphenation, and analytical potential and limitations, and compiles information on reference materials used for and studied by qHNMR. The dual status of natural products, being single chemical entities and valuable biologically active agents that need to be purified from complex matrixes, results in an increased analytical demand when testing their deviation from the singleton composition ideal. The outcome and versatility of reported applications lead to the conclusion that qHNMR is currently the principal analytical method to meet this demand. Considering both 1D and 2D (1)H NMR experiments, qHNMR has proved to be highly suitable for the simultaneous selective recognition and quantitative determination of metabolites in complex biological matrixes. This is manifested by the prior publication of over 80 reports on applications involving the quantitation of single natural products in plant extracts, dietary materials, and materials representing different metabolic stages of (micro)organisms. In summary, qHNMR has great potential as an analytical tool in both the discovery of new bioactive natural products and the field of metabolome analysis.

Characterization of gingerol-related compounds in ginger rhizome (Zingiber officinale Rosc.) by high-performance liquid chromatography/electrospray ionization mass spectrometry

This study sought to determine the utility of liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) coupled with diode array detection in identifying gingerol-related compounds from crude extracts of ginger rhizome. The fragmentation behaviors of compounds in both (-)- and (+)ESI-MS/MS were used to infer and confirm the chemical structures of several groups of compounds, including the gingerols, methylgingerols, gingerol acetates, shogaols, paradols, gingerdiols, mono- and diacetyl gingerdiols, and dehydrogingerdiones. Diode array detection at different wavelengths was used to confirm MS/MS-based identification. In total, 31 gingerol-related compounds were identified from the methanolic crude extracts of fresh ginger rhizome in this study. Three of these compounds were found to be new compounds. This study demonstrated that LC/ESI-MS/MS is a powerful on-line tool for identification of gingerol-related compounds, especially for thermally labile compounds that cannot be readily detected by GC/MS analysis.