LC-MS–MS characterisation of curry leaf flavonols and antioxidant activity

Chemopreventive potential of hydroethanolic Murraya koenigii leaves extract against DMBA induced breast carcinogenesis: In-silico and in-vivo study

ETHNOPHARMACOLOGICAL RELEVANCE

Murraya koenigii (MK), a member of the Rutaceae family and widely known as the curry-leaf tree, is indigenous to India, Sri Lanka, and other south Asian nations. It is a renowned medicinal herb because of the wide range of bioactive components found in its leaves, such as girinimbine, koenimbine, mahanimbine and mahanine among others. All these bioactive components make this plant beneficial for treating a variety of ailments and diseases. Biological and pharmacological activities of MK include anti-oxidant, anti-microbial, anti-ulcer, anti-helminthic, anti-malarial, anti-trichomonal, hepatoprotective, anti-diabetic, etc. AIM OF THE STUDY: The present study aimed to evaluate the possible protective effect of hydroethanolic Murraya koenigii leaves extract (HEMKLE) against 7,12-Dimethylbenz[a]anthracene (DMBA)-induced breast cancer in rats, which further paves the way for future breast cancer treatment.

MATERIALS AND METHODS

For the preparation of hydroethanolic Murraya koenigii leaves extract (HEMKLE), Murraya koenigii (MK) leaves were taken from the botanical garden of the Panjab University campus, Chandigarh, and authenticated from the Department of Botany, Panjab University (accession number 22417). The phytochemical characterization of HEMKLE was performed using liquid chromatography-mass spectrometry (LC-MS). Following this, an in-silico molecular docking analysis was performed using Maestro Schrodinger software, and an in-vivo study was conducted. For the in-vivo study, female SD rats were divided into four different groups. Group I (C), Group II (DMBA), Group III (HEMKLE), and Group IV (HEMKLE + DMBA). Histopathogy, oxidative and antioxidant status, immunohistochemistry of estrogen receptor-α, TUNEL assays, mRNA and protein expression of apoptotic pathway genes were conducted in in-vivo study.

RESULTS

In LC-MS, major phytochemical constituents including flavonoids and carbazole alkaloids were identified. In-silico docking study revealed the strong binding affinity between the identified compounds with caspase-3. Additionally, koenine displayed the highest binding affinity/minimum energy of -9.21 kcal/mol with 6BDV as compared to other phytochemicals. Furthermore, in-vivo experimentation revealed that HEMKLE administration in Group IV(HEMKLE + DMBA) significantly inhibits the tumor incidence and volume as compared to alone DMBA treated group. The antioxidant action of HEMKLE was proven from the in-vivo analysis of antioxidant marker enzymes, histopathology, immunohistochemistry of ER-α studies. Further, increase number of TUNEL positive cells was observed in co-treated animals as compared to alone DMBA treated animals. In Group IV (HEMKLE + DMBA), upregulated expression of pro-apoptotic genes and downregulated expression of anti-apoptotic gene were observed when compared to Group II(DMBA) suggested the apoptotic effect of HEMKLE.

CONCLUSION

The results of the present study provide clear evidence of the chemopreventive capabilities of HEMKLE in rats with DMBA-induced breast cancer. The observed outcomes could potentially be attributed to the existence of diverse phytochemicals within the HEMKLE.

Unveiling the Potent Antiviral and Antioxidant Activities of an Aqueous Extract from Caesalpinia mimosoides Lamk: Cheminformatics and Molecular Docking Approaches

Our group previously demonstrated that Caesalpinia mimosoides Lamk exhibits many profound biological properties, including anticancer, antibacterial, and antioxidant activities. However, its antiviral activity has not yet been investigated. Here, the aqueous extract of C. mimosoides was prepared from the aerial parts (leaves, stalks, and trunks) to see whether it exerts anti-influenza (H1N1) effects and to reduce the organic solvents consumed during extraction, making it a desirable approach for the large-scale production for medical uses. Our plant extract was quantified to contain 7 g of gallic acid (GA) per 100 g of a dry sample, as determined using HPLC analysis. It also exerts potent antioxidant activities comparable to those of authentic GA. According to untargeted metabolomics (UPLC-ESI(-)-QTOF-MS/MS) with the aid of cheminformatics tools (MetFrag (version 2.1), SIRIUS (version 5.8.3), CSI:FingerID (version 4.8), and CANOPUS), the major metabolite was best annotated as "gallic acid", phenolics (e.g., quinic acid, shikimic acid, and protocatechuic acid), sugar derivatives, and dicarboxylic acids were deduced from this plant species for the first time. The aqueous plant extract efficiently inhibited an influenza A (H1N1) virus infection of MDCK cells with an IC50 of 5.14 µg/mL. Of equal importance, hemolytic activity was absent for this plant extract, signifying its applicability as a safe antiviral agent. Molecular docking suggested that GA interacts with conserved residues (e.g., Arg152 and Asp151) located in the catalytic inner shell of the viral neuraminidase (NA), sharing the same pocket as those of anti-neuraminidase drugs, such as laninamivir and oseltamivir. Additionally, other metabolites were also found to potentially interact with the active site and the hydrophobic 430-cavity of the viral surface protein, suggesting a possibly synergistic effect of various phytochemicals. Therefore, the C. mimosoides aqueous extract may be a good candidate for coping with increasing influenza virus resistance to existing antivirals.

Analytical Methods for the Determination of Quercetin and Quercetin Glycosides in Pharmaceuticals and Biological Samples

Flavonoids are plant-derived compounds that have several health benefits, including antioxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. Quercetin is a flavonoid that is widely present in various fruits, vegetables, and drinks. Accurate determination of quercetin in different samples is of great importance for its potential health benefits. This review, is an overview of sample preparation and determination methods for quercetin in diverse matrices. Previous research on sample preparation and determination methods for quercetin are summarized, highlighting the advantages and disadvantages of each method and providing insights into recent developments in quercetin sample treatment. Various analytical techniques are discussed including spectroscopic, chromatographic, electrophoretic, and electrochemical methods for the determination of quercetin and its derivatives in different samples. UV-Vis (Ultraviolet-visible) spectrophotometry is simple and inexpensive but lacks selectivity. Chromatographic techniques (HPLC, GC) offer selectivity and sensitivity, while electrophoretic and electrochemical methods provide high resolution and low detection limits, respectively. The aim of this review is to comprehensively explore the determination methods for quercetin and quercetin glycosides in diverse matrices, with emphasis on pharmaceutical and biological samples. The review also provides a theoretical basis for method development and application for the analysis of quercetin and quercetin glycosides in real samples.

Phytochemical Constituents and Biological Activities of Jasonia glutinosa L.: The First Report for the Plant Growing in North Africa

Jasonia glutinosa (rock tea), also known as Chiliadenus glutinosa Cass., is a medicinal plant growing in the Mediterranean Basin. It is used for the treatment of depression, gastrointestinal complaints, inflammations, appendicitis, colds, and respiratory disorders. The current study is the first report for the plant species growing in Libya and aims to investigate the phytochemical constituents, antioxidant, cytotoxic, and antimicrobial activities of the plant’s aqueous ethanolic extract. The phytochemical investigation was conducted by the spectrophotometric quantitative assay and the LC-MS analysis. The analysis revealed the presence of 14.67 and 46.72 mg/g of the total phenolics and flavonoids equivalent to gallic acid and rutin, respectively. A total of thirty compounds of phenolic acids and flavonoids were identified by the LC-MS analysis, with a total relative percentage of 18.69%. The analysis revealed the dominance of methoxylated flavonoids and cinnamic acid derivatives, including caffeoylquinic acids. The in vitro antioxidant assays showed 265.55, 513.32, and 27.10 μM Trolox eq/mg of extract in the ABTS, ORAC, and FRAP assays, respectively. Cancer cell growth inhibitions of 9.23, 11.42, and 34.01% at a concentration of 100 μg/mL against MCF-7, HepG2, and PANC-1 cell lines were obtained, which is considered a weak cytotoxic effect when compared to the standard anticancer agent, doxorubicin (DOX). No antimicrobial activity was noticed for the plant extract against all tested microorganisms, i.e., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium, Candida albicans, and Saccharomyces cerevisiae. The weak antimicrobial effect of the plant did not support the claim of traditional use of the plant as an antimicrobial agent.

Optimization of a Green Extraction of Polyphenols from Sweet Cherry (Prunus avium L.) Pulp

This work focused on the optimization of the ultrasound (US) extraction of polyphenols from sweet cherry pulp by monitoring cyanidin-3O-rutinoside, quercetin-3O-rutinoside, and trans-3-O-coumaroylquinic acid, representing the main anthocyanin, flavonol, and hydroxycinnamate, respectively, identified in the extracts through chromatographic analyses (HPLC-DAD), as output variables. The optimization was performed following a two-level central composite design and the influence of the selected independent variables (i.e., extraction time and solid to solvent ratio) was checked through the response surface methodology. The maximum recovery of the phenolic compounds was obtained at 3 min and 0.25 g/mL in water/ethanol (1:1, v/v) at a set temperature (25 °C), sonication power (100 W), and sonication frequency (37 kHz). Subsequent validation experiments proved the effectiveness and reliability of the gathered mathematical models in defining the best ultrasound-assisted extraction conditions.

Curry Leaf Triggers Cell Death of P. gingivalis with Membrane Blebbing

Periodontal disease has become a serious public health problem, as indicated by accumulating evidence that periodontal disease is not only a major cause of tooth loss but is also associated with various systemic diseases. The present study assessed the anti-bacterial activities of three herbal products (curry leaf, clove, and cinnamon) against Porphyomonas gingivalis, a keystone pathogen for periodontal diseases. The curry leaf extract (CLE) showed the strongest growth inhibitory activity among them, and the activity was maintained even after extensive heat treatment. Of note, while clove and cinnamon extracts at sub-minimum inhibitory concentrations (sub-MICs) significantly enhanced the biofilm formation of P. gingivalis, CLE at sub-MIC did not have any effect on the biofilm formation. The MIC of CLE against P. gingivalis was higher than those against a wide range of other oral bacterial species. P. gingivalis cells were completely killed within 30 min after treatment with CLE. Spatiotemporal analysis using high-speed atomic force microscopy revealed that CLE immediately triggered aberrant membrane vesicle formation on the bacterial surface. Bacterial membrane potential assay revealed that CLE induced depolarization of the bacterial membrane. Taken together, these findings suggest the mechanism behind early bactericidal activity of CLE and its therapeutic applicability in patients with periodontal diseases.

The physicochemical, microbiological, and organoleptic properties and antioxidant activities of cream cheeses fortified with dried curry leaves (Murraya koenigii L.) powder

We aimed to investigate the effects of dried curry leaves powder (CLP) incorporation on physicochemical, microbiological, antioxidant, and sensory properties of cream cheeses. Varying levels of CLP infusions (i.e., T1: 0% [control], T2: 0.15%, T3: 0.2%, and T4: 0.25%; w/w%) were stored for 10 days at 4°C. Antioxidant properties were evaluated using total phenolic content, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging ability, and ferric reducing antioxidant power using in vitro assays. Total antioxidant capacity significantly (p < .05) increased with the increasing levels of CLP. Physicochemical and microbiological qualities were not significantly affected by the addition of CLP, indicating the suitability of using CLP without compromising the quality of cream cheese. Organoleptic properties were affected with CLP addition, where T3 had the highest scores for color, aroma, flavor, texture, and overall acceptability. The principal component analysis provides the holistic approach of studying the variation associated with cream cheeses and the overall relationship among studied parameters. This provides strong references for novel dairy products added with antioxidant-rich Murraya koenigii L. powder. The study also has merits to promote scientific knowledge concerning, and how the incorporation would influence the physicochemical, organoleptic, and microbiological properties of cream cheese to deliver the value-added or diversified product to emerging consumers.

Laguncularia racemosa Phenolics Profiling by Three-Phase Solvent System Step-Gradient Using High-Performance Countercurrent Chromatography with Off-Line Electrospray Mass-Spectrometry Detection

The detailed metabolite profiling of Laguncularia racemosa was accomplished by high-performance countercurrent chromatography (HPCCC) using the three-phase system n-hexane–tert-butyl methyl ether–acetonitrile–water 2:3:3:2 (v/v/v/v) in step-gradient elution mode. The gradient elution was adjusted to the chemical complexity of the L. racemosa ethyl acetate partition and strongly improved the polarity range of chromatography. The three-phase solvent system was chosen for the gradient to avoid equilibrium problems when changing mobile phase compositions encountered between the gradient steps. The tentative recognition of metabolites including the identification of novel ones was possible due to the off-line injection of fractions to electrospray ionization mass spectrometry (ESI-MS/MS) in the sequence of recovery. The off-line hyphenation profiling experiment of HPCCC and ESI-MS projected the preparative elution by selected single ion traces in the negative ionization mode. Co-elution effects were monitored and MS/MS fragmentation data of more than 100 substances were used for structural characterization and identification. The metabolite profile in the L. racemosa extract comprised flavonoids, hydrolysable tannins, condensed tannins and low molecular weight polyphenols.

Phenolic Fingerprinting, Antioxidant, and Deterrent Potentials of Persicaria maculosa Extracts

Persicaria maculosa (Polygonaceae) (known as lady’s thumb) is an annual morphologically variable weed that is widely distributed in Chile. The purpose of this study was to investigate the antifeedant potential of methanolic (MeOH), ethanolic (EtOH), and dichloromethane (DCM) extracts from the aerial parts of this plant collected in the Valparaíso and Curicó provinces (Chile) and relate this activity to the antioxidant capacity and the presence of phenolic compounds in the extracts. A phenolic profile based on HPLC-ESI-MS/MS allowed the identification of 26 phenolic compounds, most of them glycosyl derivatives of isorhamnetin, quercetin, and kaempferol. In addition, the total phenolic content (TP), total flavonoids (TF), and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion scavenging (O₂⁻), ferric-reducing antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) of the extracts are reported. The antifeedant potentials of the plant extracts were tested against Epilachna paenulata, Pseudaletia adultera, Macrosiphum euphorbiae, and Diaphorina citri insects for the first time. The activity against the aphid M. euphorbiae was significant for the DCM extracts of plants from Valparaíso and Curicó (settling % = 23% ± 4% and 23% ± 5%, respectively). The antifeedant activities against the beetle E. paenulata and the lepidoptera P. adultera were significant for Valparaíso extracts, especially when tested against E. Paenulata (IFP = 1.0 ± 0.0). Finally, the MeOH and EtOH extracts from Valparaíso plants reduced the diet consumption of the psilid D. citri (p < 0.05). The results showed that P. maculosa is a good source of flavonoids with some antioxidant capacities and has potential interest as botanical eco-friendly alternative with deterrent activity.

Protection of natural antioxidants against low-density lipoprotein oxidation

This chapter reports essential information about the protective action of antioxidants against LDL oxidation. The activity of individual compounds (tocopherols, vitamin C, phenolic compounds) as well as extracts obtained from plant material (cereals, fruits, legumes, nuts, mushrooms, by-products of food industry) is reported. The structure-antioxidant activity relationship of phenolic compounds is discussed. This article summarizes the findings to date of both in vitro and in vivo studies using foods or phenolic extracts isolated from foodstuffs at inhibiting the incidence of LDL oxidation. This chapter summarizes also the reportings to date of in vivo studies using foods or beverages at inhibiting the incidence of LDL oxidation.

Phenolics, flavonoids and antioxidant capacities in Citrus species with different degree of tolerance to Huanglongbing

Huanglongbing (HLB) is a highly destructive disease to the citrus industry in Florida caused by the bacterium, Candidatus Liberibacter asiaticus(CLas) and is transmitted by Diaphorina citri. It is hypothesized that plants with high phenolic contents show higher tolerance to certain plant pathogens. In this regard, different citrus varieties and plants of genera related to Citrus were analyzed for their total phenolic and flavonoids contents, and their antioxidant capacities. In addition, the secondary metabolites in the leaves of seven citrus species were analyzed using high performance liquid chromatography-mass spectrometry (HPLC-MS). Colorimetric assays showed that curry leaf contained the highest total phenolic content and free radical scavenging activity (DPPH). Curry leaf also contained high concentrations of an unusual class of carbazole alkaloids. Tolerant Citrus species contained high levels of phenolics and flavonoids and showed high antioxidant capacities. Our results suggest that high phenolic and flavonoid leaf contents correlate with increased citrus tolerance to CLas bacterium. The results also suggest that the high level of carbazole alkaloids, known for their strong antimicrobial properties in curry leaf, could make it immune to the CLas bacteria. Understanding the mechanisms underpinning citrus tolerance to HLB will contribute to the development of commercially tolerant citrus cultivars.

Chemical profile and pancreatic lipase inhibitory activity of Sinobambusa tootsik (Sieb.) Makino leaves

Background

Sinobambusa tootsik (Sieb.) Makino (S. tootsik) is one species of bamboo distributed in China, Japan and Vietnam. The chemical profile of its leaves and its potential application was unknown yet.

Methods

The chemical profile of S. tootsik was studied by HPLC and UPLC-DAD-QTOF-MS. The S. tootsik extract was prepared by extraction with 50% aqueous ethanol, followed by H103 macroporous resins adsorption and desorption processes. Pancreatic lipase inhibitory activity was determined using p-nitrophenyl palmitate as the substance, which was hydrolyzed by lipase to form coloured p-nitrophenol.

Results

Eighteen compounds were identified in S. tootsik. Most of them were the C-glycosylated derivatives of luteolin and apigenin, such as isoorientin, isoorientin-2″-O-rhamnoside and isovitexin. Isoorientin-2″-O-rhamnoside was the most dominant flavonoid in the sample. S. tootsik extract was prepared through resin adsorption/desorption with yield of 1.12 ± 015% and total flavonoids content of 82 ± 2 mg/g (in term of isoorientin). The extract exhibited pancreatic lipase inhibitory activity with IC50 value of 0.93 mg/mL.

Conclusion

The chemical profile of S. tootsik leaves was uncovered for the first time. C-glycosyl flavonoids were the main constituents in the plant. The extract exhibited pancreatic lipase inhibitory activity and may have potential for use as a food supplement for controlling obesity.

Identification of α-glucosidase inhibitors from cyclocarya paliurus tea leaves using UF-UPLC-Q/TOF-MS/MS and molecular docking

11 potential α-glucosidase inhibitors in leaves of Cyclocarya paliurus were quickly identified by UF-UPLC-Q/TOF-MS/MS, and their inhibitory activities were verified in vitro and in vivo, as well as docked with homology model.

The Potential Protective Effects of Phenolic Compounds against Low-density Lipoprotein Oxidation

BACKGROUND

The exact mechanism(s) of atherosclerosis in humans remains elusive, but one theory hypothesizes that this deleterious process results from the oxidative modification of low-density lipoprotein (LDL). Research suggests that foods rich in dietary phenolic compounds with antioxidant activity can mitigate the extent of LDL oxidation in vivo. With regard to the different classes of flavonoids, there appears to be a structurefunction relationship between the various moieties/constituents attached to the flavonoids' three ring system and their impact at retarding LDL oxidation.

METHODS

This article summarizes the findings to date of both in vitro and in vivo studies using foods or phenolic extracts isolated from foodstuffs at inhibiting the incidence of LDL oxidation. Three bases: SCOPUS, Web Science, and PubMed were used for search.

RESULTS

An often used method for the determination of antioxidant properties of natural phenolic compounds is the LDL oxidation assay. LDLs are isolated from human plasma and their oxidation is induced by Cu2+ ions or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The sample is incubated with a phenolic extract or individual/isolated phenolic compounds. LDL oxidation is then monitored by various chemical methods (e.g., measurement of the generation of conjugated dienes and trienes). This technique confirmed the antioxidant properties of several extracts as obtained from plant material (e.g., grapes, berries, orange, grapefruit, coffee, tea, chocolate, olives, nuts) as well as the individual phenolic compounds (e.g., luteolinidin, apigenidin, caffeic acid, chlorogenic acid, catechin, quercetin, rutin). Several studies in vivo confirmed protective effects of phenolic compounds against LDL oxidation. They covered the healthy subjects with hyperlipidaemia, overweight, obesity, metabolic syndrome, heavy smokers, patients receiving haemodialysis, patients with peripheral vascular disease, and subjects at high cardiovascular risk. The studies comprise individuals of all ages, and the number of participants in the different experiments varied widely.

CONCLUSION

Properly designed double-blind, placebo-controlled randomised clinical trials offer stronger evidence as to the impact of dietary phenolics consumption at retarding LDL oxidation. More such clinical trials are needed to strengthen the hypothesis that foods rich in dietary phenolic compounds with antioxidant activity can mitigate the extent of LDL oxidation in vivo.

Comparative Analysis of Chemical Composition, Antioxidant Activity and Quantitative Characterization of Some Phenolic Compounds in Selected Herbs and Spices in Different Solvent Extraction Systems

This study evaluated the efficacy of various organic solvents (80% acetone, 80% ethanol, 80% methanol) and distilled water for extracting antioxidant phenolic compounds from turmeric, curry leaf, torch ginger and lemon grass extracts. They were analyzed regarding the total phenol and flavonoid contents, antioxidant activity and concentration of some phenolic compounds. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and the ferric reducing antioxidant power (FRAP) assay. Quantification of phenolic compounds was carried out using high-performance liquid chromatography (HPLC). All the extracts possessed antioxidant activity, however, the different solvents showed different efficiencies in the extraction of phenolic compounds. Turmeric showed the highest DPPH values (67.83-13.78%) and FRAP (84.9-2.3 mg quercetin/g freeze-dried crude extract), followed by curry leaf, torch ginger and lemon grass. While 80% acetone was shown to be the most efficient solvent for the extraction of total phenolic compounds from turmeric, torch ginger and lemon grass (221.68, 98.10 and 28.19 mg GA/g freeze dried crude extract, respectively), for the recovery of phenolic compounds from curry leaf (92.23 mg GA/g freeze-dried crude extract), 80% ethanol was the most appropriate solvent. Results of HPLC revealed that the amount of phenolic compounds varied depending on the types of solvents used.

UPLC-PDA-Q/TOF-MS Profile of Polyphenolic Compounds of Liqueurs from Rose Petals (Rosa rugosa)

Polyphenolic compounds, as a secondary metabolite of plants, possess great nutritional and pharmacological potential. Herein, we applied the green analytical method to study the nutrient profile of Rosa rugosa petals and liqueurs manufactured from them. Using the fast and validated ultra performance liquid chromatography-photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) method, we confirm the presence of the following compounds: phenolic acids, flavonols, flavan-3-ols and hydrolisable tannins (gallotannins and ellagitannins). R. rugosa petals contains up to 2175.43 mg polyphenols per 100 g fresh weight, therein 1517.01 mg ellagitannins per 100 g fresh weight. Liqueurs, traditionally manufactured from said petals using a conventional extraction method (maceration), also contain polyphenols in significant amounts (from 72% to 96% corresponding to percentage of theoretical polyphenol content in the used petals), therein ellagitannins amount to 69.7% on average. We confirmed that traditional maceration, most common for the isolation of polyphenols, is still suitable for the food industry due to its using aqueous ethanol, a common bio-solvent, easily available in high purity and completely biodegradable. Therefore R. rugosa used as a food may be considered as an ellagitannin-rich plant of economic importance. Manufactured rose liqueurs were stable and kept all their properties during the whole period of aging.

Cytotoxicity and Proteasome Inhibition by Alkaloid Extract from Murraya koenigii Leaves in Breast Cancer Cells-Molecular Docking Studies

Murraya koenigii (curry tree) leaves are rich in bioactive compounds such as flavonoids, alkaloids, and coumarins. Alkaloids from M. koenigii leaves have antianalgesic, antiulcerogenic, antiobesity, and antitumor activities. In this study, we tested the cytotoxic and proteasome-inhibitory potential of a total alkaloid extract (TAE) from M. koenigii leaves in the breast cancer cell line MDA-MB-231. The TAE decreased cell viability with an IC₅₀ of 14.4 μg/mL and altered growth kinetics of breast cancer cells. TAE (32 μg/mL) arrested cells (35%) in the "S" phase of the cell cycle and induced apoptosis. The 26S proteasome, a multicatalytic protease complex, promotes tumor cell proliferation and protects tumor cells from apoptosis. The TAE and mahanine, a carbazole alkaloid present in M. koenigii leaves, preferentially inhibited the trypsin-like, but not the chymotrypsin-like proteolytic activity of the proteasome with an IC₅₀ of 162 μg/mL and 287 μM, respectively. In silico analysis of 26 compounds from M. koenigii leaves revealed significant docking scores for mahanine and two other carbazole alkaloids with the β2 and β5 subunits of the catalytic 20S proteasome. Taken together, this study demonstrates that inhibition of the proteasome is an important biological activity of M. koenigii alkaloids, which may lead to cancer cell death.

The Methanolic Extract from Murraya koenigii L. Inhibits Glutamate-Induced Pain and Involves ATP-Sensitive K+ Channel as Antinociceptive Mechanism

Murraya koenigii L. is a perennial shrub, belonging to the family Rutaceae. Traditionally, the leaves of this plant are extensively used in treatment of a wide range of diseases and disorders including pain and inflammation. Although researchers have revealed the antinociceptive effects of this plant's leaves during past few years, the mechanisms underlying these effects are still unknown. Therefore, the present study evaluated some antinociceptive mechanisms of the methanolic extract of M. koenigii (MEMK) leaves along with its antinociceptive potential using several animal models. The antinociceptive effects of MEMK were evaluated using formalin-induced licking and acetic acid-induced writhing tests at the doses of 50, 100, and 200 mg/kg. In addition, we also justified the possible participations of glutamatergic system and ATP-sensitive potassium channels in the observed activities. Our results demonstrated that MEMK significantly (p < 0.01) inhibited the pain thresholds induced by formalin and acetic acid in a dose-dependent manner. MEMK also significantly (p < 0.01) suppressed glutamate-induced pain. Moreover, pretreatment with glibenclamide (an ATP-sensitive potassium channel blocker) at 10 mg/kg significantly (p < 0.05) reversed the MEMK-mediated antinociception. These revealed that MEMK might have the potential to interact with glutamatergic system and the ATP-sensitive potassium channels to exhibit its antinociceptive activities. Therefore, our results strongly support the antinociceptive effects of M. koenigii leaves and provide scientific basis of their analgesic uses in the traditional medicine.

Rapid Identification of Flavonoid Constituents Directly from PTP1B Inhibitive Extract of Raspberry (Rubus idaeus L.) Leaves by HPLC-ESI-QTOF-MS-MS

Many potential health benefits of raspberry (Rubus idaeus L.) leaves were attributed to polyphenolic compounds, especially flavonoids. In this study, the methanol extract of R. idaeus leaves showed significant protein tyrosine phosphatase-1B (PTP1B) inhibitory activity with IC50 value of 3.41 ± 0.01 µg mL(-1) Meanwhile, a rapid and reliable method, employed high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry, was established for structure identification of flavonoids from PTP1B inhibitive extract of R. idaeus leaves using accurate mass measurement and characteristic fragmentation patterns. A total of 16 flavonoids, including 4 quercetin derivatives, 2 luteolin derivatives, 8 kaempferol derivatives and 2 isorhamnetin derivatives, were identified. Compounds 3: and 4: , Compounds 6: and 7: and Compounds 15: and 16: were isomers with different aglycones and different saccharides. Compounds 8: , 9: and 10: were isomers with the same aglycone and the same saccharide but different substituent positions. Compounds 11: and 12: were isomers with the same aglycone but different saccharides. Compounds 2: , 8: , 9: and 10: possessed the same substituent saccharide of glycuronic acid. Most of them were reported inR. idaeus for the first time.

Rapid screening and identification of phenolic antioxidants in Hydrocotyle sibthorpioides Lam. by UPLC-ESI-MS/MS

The aim of the study was to identify the phenolic compounds present in Hydrocotyle sibthorpioides (HS), Centella asiatica (CA) and Amaranthus viridis (AV) extracts and investigate their respective antioxidant activities. Herein, an ultra-high pressure liquid chromatography-mass spectrometer (UPLC-MS/MS) analytical method has been developed for the separation, and systematic characterization of the phenolic compounds in HS, CA and AV extracts and was compared along with ten standard phenolic compounds. Additionally, in vitro antioxidant activity of the phenolic compounds was also determined. The HS extract revealed excellent antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (IC50=19.7 ± 1.2 μg/mL), total reduction capability (0.169 ± 0.003 at 100 μg/mL), nitric oxide radical scavenging activity (IC50=39.33 ± 3.2 μg/mL), metal chelating activity (IC50=56.51 ± 3.6 μg/mL) and inhibition of lipid peroxidation (IC50=12.34 ± 2.3 μg/mL) as compared to CA and AV extracts. Furthermore, catechin, epicatechin, quercetin and chlorogenic acid were found to be the major components responsible for the antioxidant activity of the HS extract as evidenced from UPLC-MS/MS. Taken together, this study demonstrates the promising antioxidant properties of the HS extract, which can further be utilized in various pharmaceutical, food, and agricultural applications.

Systematic characterization and simultaneous quantification of the multiple components of Rhododendron dauricum based on high-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry

Rhododendron dauricum L. has been used as a traditional Chinese medicine to treat cough and asthma and relieve phlegm and bronchitis. In this study, a reliable method based on high-performance liquid chromatography with diode array detection and quadrupole time-of-flight tandem mass spectrometry was established to systematically identify and quantify the components in this herb for the first time. A total of 33 compounds were identified, including 24 flavonoids, six phenolic acids, two coumarins and one terpene. Among them, poriolin (17), farrerol-7-O-β-d-glucopyranoside (20), and syzalterin (30) were isolated from this plant for the first time, and quercetin-3-β-d-(6-p-hydroxy benzoyl) galactoside (19), quercetin-3-β-d-(6-p-coumaroyl) galactoside (21), and myrciacetin (23) were identified from this genus for the first time. Fragmentation pathways of flavonoids also have been investigated by electrospray ionization mass spectrometry. Moreover, seven bioactive constituents, namely, gallic acid (1), scopoletin (6), dihydroquercetin (7), quercetin (22), kaempferol (25), 8-desmethyl farrerol (27), and farrerol (28), were simultaneously quantified. The developed method has been validated and applied to analyze ten samples of R. dauricum from Hebei Province successfully. The contents of the seven compounds have been detected and compared.

Phytochemical analysis of Pfaffia glomerata inflorescences by LC-ESI-MS/MS

Pfaffia glomerata contains high levels of β-ecdysone, which has shown a range of beneficial pharmacological effects. The present study demonstrated that inflorescences of P. glomerata contain other important bioactive compounds in addition to β-ecdysone. The identification of compounds from inflorescences using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was performed for the first time. The eight compounds identified were β-ecdysone, flavonoid glycosides such as quercetin-3-O-glucoside, kaempferol-3-O-glucoside and kaempferol-3-O-(6-p-coumaroyl)-glucoside, oleanane-type triterpenoid saponins such as ginsenoside Ro and chikusetsusaponin IV, in addition to oleanonic acid and gluconic acid. This study provided information on the phytochemicals contained in P. glomerata inflorescences revealing the potential application of this plant part as raw material for the phytotherapeutic and cosmetic industries.

Protective effect of antioxidant rich aqueous curry leaf (Murraya koenigii) extract against gastro-toxic effects of piroxicam in male Wistar rats

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Piroxicam causes gastric ulceration through oxidative stress.

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Curry leaf extract protects against piroxicam induced gastric injury.

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Antioxidant mechanism(s) are involved in such protection.

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The extract may have future therapeutic potential.

Piroxicam (chemically 4-hydroxy-2-methyl-N-2-pyridinyl-2H-1,2-benzothiazine-3-carboxamide), a classical non-steroidal anti-inflammatory drug (NSAID) is orally administered to arthritic patients. Inhibition of prostaglandin E₂ (PGE₂) synthesis and subsequent free hydroxyl radical generation in vivo exert gastro-toxic side effects on piroxicam treatment. Leaves of curry plant are rich in antioxidants with prolific free radical scavenging activities. This led us to investigate the efficiency of the use of curry leaves in ameliorating piroxicam induced gastric damage. Piroxicam was orally (30 mg per kg body weight) administered in male albino Wistar rats to generate gastric ulcers. These rats were orally fed with graded doses of aqueous extract of curry or Murraya koenigii leaves (Cu LE) prior to piroxicam administration. Oxidative stress biomarkers, activities of antioxidant and pro-oxidant enzymes, mucin content and nature, PGE₂ level, activities of mitochondrial enzymes and histomorphology of gastric tissues were studied. Piroxicam treatment altered all the above mentioned parameters whereas, curry leaf extract pre-treated animals were protected against piroxicam induced alterations. Hence, the protective action of the antioxidant rich Cu LE was investigated to propose a new combination therapy or dietary management to arthritic patients using piroxicam.

Hydroxycinnamic acids and flavonols in native edible berries of South Patagonia

Diverse edible berries are native to the Patagonian region of Southern Chile. These berries are underused because their nutritional properties are relatively unknown. In this work, the profiles and concentrations of hydroxycinnamic acid derivatives and flavonols, and the antioxidant capacity of the berry extracts, were studied using HPLC-DAD-ESI-MS/MS and CUPRAC assays, respectively. In total, 46 compounds were identified, including 17 hydroxycinnamic acid derivatives and 26 flavonols. Caffeoylquinic acid isomers were the most abundant compounds, and quercetin and myricetin derivatives were the main flavonols found. The berries from Ribes genera showed a high diversity and concentration of these 2 families of compounds and contained 3-caffeoylquinic acid and quercetin-3-rutinoside at the highest concentrations. The Patagonian berries, especially the berries of Rubus and Ribes genera, had high cupric reducing antioxidant capacity, comparable with that described for berries from the Northern hemisphere. These results contribute to promote the nutritional study of these fruits.

Augmented primary humoral immune response and decreased cell-mediated immunity by Murraya koenigii in rats

BACKGROUND

Murraya koenigii (Rutaceae) (curry patta: Hindi) of the family Rutaceae is used in the traditional Indian system of medicine for its immunomodulatory properties. The essential oil of the leaves of M. koenigii possesses antimicrobial, antifungal, and pesticidal activities and is used for the treatment of amebiasis, diabetes, and hepatitis. The present study was performed to evaluate the effect of M. koenigii on humoral and cell-mediated immune responses in rats.

METHODS

Aqueous extract of M. koenigii leaves was administered orally in a dose of 350 mg/kg. Cell-mediated immunity was assessed by measuring foot pad thickness following sensitization by injection of keyhole limpet hemocyanin and subsequent challenge by the same. Humoral immunity was assessed by measurement of hemagglutination titer to sheep red blood cells (SRBCs).

RESULTS

In the humoral immune response, the administration of M. koenigii [350 mg/kg per os (p.o.)] from day 1 to day 7 after sensitization with SRBC on day 0 caused a significant increase in the primary anti-SRBC titer. However, the secondary immune response was decreased significantly (p<0.05) as shown by a decrease in secondary anti-SRBC titer measured on day 11 following a booster dose of antigen on day 8. In the delayed-type hypersensitivity test, M. koenigii (350 mg/kg, p.o.), when administered for 14 days, produced a significant (p<0.05) decrease in foot pad thickness when compared with the control group.

CONCLUSIONS

Thus, these results suggest that oral administration of M. koenigii augments primary humoral immune response and decreases cell-mediated immunity.