Simultaneous extraction, identification and quantification of phenolic compounds in Eclipta prostrata using microwave-assisted extraction combined with HPLC–DAD–ESI–MS/MS

Assessment of the Chemical Profile and Potential Medical Effects of a Flavonoid-Rich Extract of Eclipta prostrata L. Collected in the Central Highlands of Vietnam

Eclipta prostrata L. (EPL), a medicinal plant, is widely utilized in the central highlands of Vietnam. This study aims to assess the chemical profile and potential medical effects of an EPL extract rich in flavonoids. A total of 36 secondary metabolites were identified from the EPL extract through GC-MS and UHPLC-UV analysis. Among them, 15 volatile compounds and several phenolic and flavonoid chemicals, including salicylic acid, epicatechin gallate, isovitexin, and apigetrin, were reported in EPL extract for the first time. This herbal extract demonstrated moderate inhibition against α-amylase and α-glucosidase, and high anti-oxidant and anti-acetylcholinesterase activities (IC50 = 76.8 ± 0.8 μg/mL). These promising attributes can be likely attributed to the high levels of major compounds, including wedelolactone (1), chlorogenic acid (3), epicatechin gallate (6), salicylic acid (8), isovitexin (9), apigetrin (11), and myricetin (12). These findings align with the traditional use of EPL for enhancing memory and cognitive function, as well as its potential benefits in diabetes management. The results of the molecular docking study reveal that the major identified compounds (1, 6, 9, and 11) showed a more effective acetylcholinesterase inhibitory effect than berberine chloride, with good binding energy (DS values, -12.3 to -14.3 kcal/mol) and acceptable values of RMSD (1.02-1.67 Å). Additionally, almost all the identified major compounds exhibited good ADMET properties within the required limits.

Wedelolactone induces natural killer cell activity and the improvement to bioavailability using polysaccharides from Ligustri Lucidi Fructus

Wedelolactone (WDL) is the major bioactive component in Ecliptae Herba. This present study investigated the effects of WDL on natural killer cell functions and possible underlying mechanisms. It was proved that wedelolactone enhanced the killing ability of NK92-MI by upregulating the expression of perforin and granzyme B through the JAK/STAT signaling pathway. Additionally, wedelolactone could induce the migration of NK-92MI cells by promoting CCR7 and CXCR4 expressions. However, the application of WDL is limited due to poor solubility and bioavailability. Accordingly, this study investigated the impact of polysaccharides from Ligustri Lucidi Fructus (LLFPs) on WDL. The biopharmaceutical properties and pharmacokinetic characteristics were determined to compare WDL individually and in combination with LLFPs. The results showed that LLFPs could benefit the biopharmaceutical properties of WDL. Specifically, stability, solubility, and permeability were increased by 1.19-1.82-fold, 3.22-fold, and 1.08-fold higher than those of WDL alone, respectively. Furthermore, the pharmacokinetic study revealed that LLFPs could remarkably improve AUC_(0-t) (150.34 vs. 50.47 ng/mL ∗ h), t_1/2 (40.78 vs. 2.81 h), and MRT_(0-∞) (46.64 vs. 5.05 h) for WDL. In conclusion, WDL would be considered a potential immunopotentiator, and LLFPs could overcome the instability and insolubility, ultimately improving the bioavailability of this plant-derived phenolic coumestan.

Bioactive (Poly)phenols, Volatile Compounds from Vegetables, Medicinal and Aromatic Plants

Polyphenols, as well as volatile compounds responsible for aromatic features, play a critical role in the quality of vegetables and medicinal, and aromatic plants (MAPs). The research conducted in recent years has shown that these plants contain biologically active compounds, mainly polyphenols, that relate to the prevention of inflammatory processes, neurodegenerative diseases, cancers, and cardiovascular disorders as well as to antimicrobial, antioxidant, and antiparasitic properties. Throughout the years, many researchers have deeply studied polyphenols and volatile compounds in medicinal and aromatic plants, particularly those associated with consumer's choices or with their beneficial properties. In this context, the purpose of this review is to provide an overview of the presence of volatile and nonvolatile compounds in some of the most economically relevant and consumed vegetables and medicinal and aromatic plants, with an emphasis on bioactive polyphenols, polyphenols as prebiotics, and, also, the most important factors that affect the contents and profiles of the volatile and nonvolatile compounds responsible for the aromatic features of vegetables and MAPs. Additionally, the new challenges for science in terms of improving polyphenol composition and intensifying volatile compounds responsible for the positive characteristics of vegetables and medicinal and aromatic plants are reported.

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Optimization of Total Phenol and Tannin Content and Biological Activity of Dittrichia graveolens (L.) GREUTER

Background:

Dittrichia graveolens (L.) is a strongly aromatic plant distributed in Mediterranean regions. This research concerns the optimization of the Total Phenolic Content (TPC) and the Total Tannin Content (TTC) of Dittrichia graveolens (L.) extracts using Response Surface Methodology for Ultrasound Assisted Extraction (UAE) and Microwave Assisted Extraction (MAE). Central Composite Design (CCD) was used to evaluate the effect of the solvent concentration and the extraction time, in different methods on TTC and TPC. The antioxidant activities and antibacterial activities were evaluated.

Methods:

The plant extracts were prepared using maceration, microwave and ultrasound assisted extraction. TPC and TTC were measured using Folin-Ciocalteu method. The antioxidant activities were studied using DPPH reagent and disc diffusion method was used to study the antibacterial activities.

Results:

This study showed the optimum condition for UAE was 49.96% methanol concentration and 11.2 min sonication, while for MAE was 55.44% methanol concentration and 2.26 min microwave extraction. It also indicated that MAE was the most effective method in comparison to UAE and maceration. The antioxidant activities of MAE extract (IC50=7.7mg/mL) were more than UAE extract (IC50=21.5mg/mL) and maceration (IC50=32.3mg/mL).

Conclusion:

As a conclusion, it was indicated that MAE was the most effective method. The higher total phenolic content caused higher antioxidant activities as MAE extract had the highest antioxidant activities. The antibacterial test showed the great potential of this plant as an antibacterial compound resource against different bacteria.

Bioactive terpenoid constituents from Eclipta prostrata

Chemical fractionation of the ethanolic extract of Eclipta prostrata yielded a series of unreported terpenoid constituents, including a rare 6/6/6/6-fused tetracyclic triterpenoid, a pentacyclic triterpenoid, two pentacyclic triterpenoid saponins, a diterpenoid and a sesquiterpenoid. Structures were assigned to these compounds on the basis of comprehensive spectroscopic analyses, with the absolute configurations of the tetracyclic triterpenoid, the diterpenoid and the sesquiterpenoid being determined via explanation of electronic circular dichroism data. Screening of these isolates in an array of bioassays revealed antibacterial, cytotoxic and α-glucosidase inhibitory activities for selective compounds. Of particular interest, the tetracyclic triterpenoid showed very strong inhibition against α-glucosidase with an IC₅₀ of 0.82 ± 0.18 μM, being 10³-fold as active as the positive control acarbose.

Innovative Approaches for Recovery of Phytoconstituents from Medicinal/Aromatic Plants and Biotechnological Production

Continuously growing demand for plant derived therapeutic molecules obtained in a sustainable and eco-friendly manner favors biotechnological production and development of innovative extraction techniques to obtain phytoconstituents. What is more, improving and optimization of alternative techniques for the isolation of high value natural compounds are issues having both social and economic importance. In this critical review, the aspects regarding plant biotechnology and green downstream processing, leading to the production and extraction of increased levels of fine chemicals from both plant cell, tissue, and organ culture or fresh plant materials and the remaining by-products, are discussed.

Release and metabolism of bound polyphenols from carrot dietary fiber and their potential activity in in vitro digestion and colonic fermentation

Dietary fiber is a carrier of abundant polyphenols and the potential benefits have attracted increasing attention.

Phytochemistry and neuroprotective effects of Eclipta alba (L.) Hassk

Eclipta alba (L.) Hassk. or Eclipta prostrata (Linn.) or Eclipta erecta (Linn.) is an herbaceous plant well known in Asian as African traditional medicines. These extracts are used in traditional medicine for treatment of microbial diseases and certain metabolic disorders. This review aimed to investigate phytochemical profile and neuroprotective effects of E. alba (L.) Hassk. Several compounds belonging to the families of phenolics, alkaloids, terpenoids and polysaccharides have been isolated, identified or characterized from E. alba extracts. This plant has a diverse neuropharmacological profile. Thus, its extract improves cognitive deficits and also attenuated epileptic seizures. Phytomolecules implicated in these potentials are Eclalbasaponin II and luteolin, respectively. This document updates isolated and identified organic compounds from the extracts of E. alba and reviews their neuropharmacological activities.

Jinmaitong, a Traditional Chinese Compound Prescription, Ameliorates the Streptozocin-Induced Diabetic Peripheral Neuropathy Rats by Increasing Sciatic Nerve IGF-1 and IGF-1R Expression

Jinmaitong (JMT) is a Traditional Chinese Compound Prescription for the treatment of diabetic peripheral neuropathy (DPN). This study aims to investigate the effect of JMT on the insulin-like growth factor 1 (IGF-1) and the insulin like growth factor 1 receptor (IGF-1R) expression in sciatic nerves of diabetic rats. Firstly, the chemical profile of JMT was characterized by UPLC/Q-TOF-MS analysis. A total of 72 compounds were putatively identified. Secondly, streptozotocin (STZ)-induced diabetic rats were treated with neurotropin (NTP, 2.67 NU/kg/day) or JMT at low-dosage (0.4375 g/kg/day), medium-dosage (0.875 g/kg/day), and high-dosage (1.75 g/kg/day) for continuous 16 weeks. Blood glucose and body weight were detected every 4 weeks during the experiment. The mechanical pain and morphological change on sciatic nerves were detected by pain measurement instrument and microscopy. The IGF-1 level in serum and tissues were measured though ELISA and immunohistochemistry. The mRNA and protein expressions of IGF-1, IGF-1R, peripheral myelin protein zero (P0), and peripheral myelin protein 22 (PMP22) in the tissues were measured by qRT-PCR and western blot. As a result, JMT had no significant effect on body weight, but reduced the fasting blood glucose levels of diabetic rats. Besides, the pathological morphology, mechanical pain thresholds, serum level and tissue expression of IGF-1, mRNA, and protein levels of IGF-1R, P0, and PMP22 were significantly improved in JMT group at middle dosage. In conclusion, JMT could ameliorate the behavioristics and morphology changes in DPN rats by promoting IGF-1 and IGF-1R gene and protein expressions in sciatic nerves, as well as regulating the peripheral nerve remyelination genes P0 and PMP22 expressions, which provides scientific evidence for the clinical application of JMT in DPN patients.

Sample Preparation Focusing on Plant Omics

Because of strong impact of omics in many fields, and the complexity of the samples when focusing on areas such as genomics, (metallo)proteomics, metabolomics, among others, it is easy to rationalize the great importance that sample preparation has for achieving reliable results, mainly considering plant science. Then, this chapter points out applications of the sample preparation focusing on such areas, and a diversity of strategies, techniques, and procedures is highlighted and commented.

Microwave-Assisted Extraction of Phenolic Compounds from Melastoma sanguineum Fruit: Optimization and Identification

A microwave-assisted extraction (MAE) technology optimized by response surface methodology (RSM) was established to extract phenolic compounds from the fruit of Melastoma sanguineum. The effects of solvent composition, ratio of solvent to material, temperature, time and microwave power on phenol yield were evaluated in single-factor tests. The three parameters exerting main impacts on phenol yield were further optimized by RSM. Under optimal extraction conditions (31.33% ethanol, solvent/material ratio of 32.21 mL/g, 52.24 °C, 45 min and 500 W), the total phenolic content was 39.02 ± 0.73 mg gallic acid equivalent (GAE)/g dry weight (DW). This MAE method performed better in comparison with two conventional methods, those being maceration (25.79 ± 1.03 mg GAE/g DW) and Soxhlet extraction (18.40 ± 1.34 mg GAE/g DW), using lower process temperature, shorter irradiation time, and lower organic solvent consumption. In addition, five flavonoids (epicatechin gallate, epicatechin, rutin, pigallocatechin and quercetin) and two phenolic acids (protocatechuic acid and chlorogenic acid) in the extract were identified and quantified using UPLC-MS/MS.

Advances in extraction and analysis of phenolic compounds from plant materials

Phenolic compounds, the most abundant secondary metabolites in plants, have received more and more attention in recent years because of their distinct bioactivities. This review summarizes different types of phenolic compounds and their extraction and analytical methods used in the recent reports, involving 59 phenolic compounds from 52 kinds of plants. The extraction methods include solid-liquid extraction, ultrasound-assisted extractions, microwave-assisted extractions, supercritical fluid extraction, and other methods. The analysis methods include spectrophotometry, gas chromatography, liquid chromatography, thin-layer chromatography, capillary electrophoresis, and near-infrared spectroscopy. After illustrating the specific conditions of the analytical methods, the advantages and disadvantages of each method are also summarized, pointing out their respective suitability. This review provides valuable reference for identification and/or quantification of phenolic compounds from natural products.

Simultaneous HPLC determination of flavonoids and phenolic acids profile in Pêra-Rio orange juice

The aim of this study was to develop and validate an HPLC-DAD method to evaluate the phenolic compounds profile of organic and conventional Pêra-Rio orange juice. The proposed method was validated for 10 flavonoids and 6 phenolic acids. A wide linear range (0.01-223.4μg·g^-1), good accuracy (79.5-129.2%) and precision (CV≤3.8%), low limits of detection (1-22ng·g^-1) and quantification (0.7-7.4μg), and overall ruggedness were attained. Good recovery was achieved for all phenolic compounds after extraction and cleanup. The method was applied to organic and conventional Pêra-Rio orange juices from beginning, middle and end of the 2016 harvest. Flavones rutin, nobiletin and tangeretin, and flavanones hesperidin, narirutin and eriocitrin were identified and quantified in all organic and conventional juices. Identity was confirmed by mass spectrometry. Nineteen non-identified phenolic compounds were quantified based on DAD spectra characteristic of the chemical class: 7 cinnamic acid derivatives, 6 flavanones and 6 flavones. The phenolic compounds profile of Pêra-Rio orange juices changed during the harvest; levels increased in organic orange juices, and decreased or were about the same in conventional orange juices. Phenolic compounds levels were higher in organic (0.5-1143.7mg·100g^-1) than in conventional orange juices (0.5-689.7mg·100g^-1). PCA differentiated organic from conventional FS and NFC juices, and conventional FCOJ from conventional FS and NFC juices, thus differentiating cultivation and processing.

Metabolomics approach based on ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry to identify the chemical constituents of the Traditional Chinese Er-Zhi-Pill

Er-Zhi-Pill, which consists of Ligustri lucidi fructus and Ecliptae prostratae herba, is a classical traditional Chinese medicinal formulation widely used as a liver-nourishing and kidney-enriching tonic. To identify the bioactive ingredients of Er-Zhi-Pill and characterize the variation of chemical constituents between co-decoction and mix of individually decocted L. lucidi fructus and E. prostratae herba, a novel metabolomics approach based on ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in both positive and negative ion modes, was established to comprehensively analyze chemical constituents and probe distinguishable chemical markers. In total, 68 constituents were unambiguously or tentatively identified through alignment of accurate molecular weights within an error margin of 5 ppm, elemental composition and fragmentation characteristics, including eight constituents, which were confirmed by comparing to reference standards. Furthermore, principal component analysis and partial least squares discriminant analysis using Simca-p+ 12.0 software were applied to investigate chemical differences between formulations obtained by co-decoction and a mixture of individual decoctions. Global chemical differences were found in samples of two different decoction methods, and 16 components, including salidroside, specneuzhenide and wedelolactone, contributed most to the observed differences. This study provides a basic chemical profile for the quality control and further mechanism research of Er-Zhi-Pill.

A standardized methanol extract of Eclipta prostrata (L.) L. (Asteraceae) reduces bronchial hyperresponsiveness and production of Th2 cytokines in a murine model of asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Eclipta prostrata (L.) L. (Asteraceae) has been used in Brazilian traditional medicine to treat asthma and other respiratory illnesses.

AIMS OF THE STUDY

To investigate the effects of different doses of a standardized extract of E. prostrata using a murine model of allergen induced asthma.

MATERIALS AND METHODS

Balb/c mice were sensitized twice with ovalbumin (OVA) administered intraperitoneally and challenged over four alternate days with nasal instillations of OVA solution. The standardized methanol extract of E. prostrata was administered in doses of 100, 250 and 500mgkg^-1 concomitantly with nasal instillation over seven consecutive days. Control animals were treated with dexamethasone or saline solution. Bronchial hyperresponsiveness, production of Th1 and Th2 cytokines, allergen sensitization, airway and lung inflammation, mucous secretion and airway remodeling were assessed.

RESULTS

The concentrations of chemical markers in the standardized methanol extract were 0.02% oroboside, 1.69% demethylwedelolactone and 1.71% wedelolactone. Treatment with 250mgkg^-1 of extract, which provided 0.745, 4.22 and 4.30mgkg^-1day^-1 of oroboside, demethylwedelolactone and wedelolactone, respectively, significantly reduced (P<0.05) respiratory resistance and elastance. Such effects were comparable with those produced by dexamethasone. The total number of inflammatory cells and eosinophils in the bronchoalveolar lavage and the concentrations of interleukin (IL)-4, IL-5 and IL-13 in lung homogenate were significantly reduced (P<0.05) by the methanol extract of E. prostrata.

CONCLUSION

The results presented herein demonstrate for the first time the anti-inflammatory activity of E. prostrata in a murine model of asthma, thereby supporting the ethnopharmacological uses of the plant.

The Recent Developments in Sample Preparation for Mass Spectrometry-Based Metabolomics

Metabolomics is a critical member in systems biology. Although great progress has been achieved in metabolomics, there are still some problems in sample preparation, data processing and data interpretation. In this review, we intend to explore the roles, challenges and trends in sample preparation for mass spectrometry- (MS-) based metabolomics. The newly emerged sample preparation methods were also critically examined, including laser microdissection, in vivo sampling, dried blood spot, microwave, ultrasound and enzyme-assisted extraction, as well as microextraction techniques. Finally, we provide some conclusions and perspectives for sample preparation in MS-based metabolomics.

Simultaneous Extraction and Identification of Phenolic Compounds in Anoectochilus roxburghii Using Microwave-Assisted Extraction Combined with UPLC-Q-TOF-MS/MS and Their Antioxidant Activities

This study used MAE and RSM to extract phenolic compounds from Anoectochilus roxburghii, and the optimum conditions defined by the model to give an optimum yield of 1.31%. The antioxidant activity in vitro showed when the concentration of phenolic compounds was reached 1 mg mL^-1, the clearance rates were 82.58% for DPPH and 97.62% for ABTS⁺. In vivo antioxidant experiments used D-galactose to build oxidative damage in healthy Kunming mice. The result showed that the extractions of A. roxburghii can improve the antioxidant ability and the medium and low dose groups had better ability to scavenge free radicals. The UPLC-Q-TOF-MS/MS was developed to identify 21 kinds of phenolic compounds by molecular mass, ms/ms fragmentation, as well as retention time. The result showed that the phenolic compounds of A. roxburghii had significant potential as a natural antioxidant to promote health and to reduce the risk of disease.

Trace determination of antibacterial pharmaceuticals in fishes by microwave-assisted extraction and solid-phase purification combined with dispersive liquid-liquid microextraction followed by ultra-high performance liquid chromatography-tandem mass spectrometry

A novel pretreatment method involving microwave-assisted extraction and solid-phase purification combined with dispersive liquid-liquid microextraction (MAE-SPP-DLLME) followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was established for the simultaneous determination of six antibacterial pharmaceuticals including metronidazole, tinidazole, chloramphenicol, thiamphenicol, malachite green and crystal violet. The conditions of MAE were optimized using an orthogonal design and the optimal conditions were found to be 8mL for acetonitrile, 50°C for 5min. Then, neutral alumina column was employed in the solid-phase purification. Finally, the critical parameters affecting DLLME, including selection of extraction and dispersive solvent, adjustment of pH, salt concentration, extraction time, were investigated by single factor study. Under optimum conditions, good linearities (r>0.9991) and satisfied recoveries (Recoveries>87.0%, relative standard deviation (RSD)<6.3%) were observed for all of the target analytes. The limits of detection and quantification were 4.54-101.3pgkg(-1) and 18.02-349.1pgkg(-1), respectively. Intra-day and inter-day RSDs were all lower than 3.6%. An obvious reduction in matrix effect was observed by this method compared with microwave assisted extraction followed by purification. The established method was sensitive, rapid, accurate and employable to simultaneously determine target analytes in farmed fish, river fish and marine fish.