Dereplication Analysis Research Articles

1H-NMR-Based Chemometrics and 13C-NMR Dereplication Analysis Applied to the Bioprospecting of the Yucatecan Flora: Identification of 3-O-Acetyl-Ceanotic Acid as an Inhibitor of Bacterial Virulence Factors from Colubrina yucatanensis

1H-NMR-Based Chemometrics and 13C-NMR Dereplication Analysis Applied to the Bioprospecting of the Yucatecan Flora: Identification of 3-O-Acetyl-Ceanotic Acid as an Inhibitor of Bacterial Virulence Factors from Colubrina yucatanensis

Exploring AI-enhanced NMR dereplication analysis for complex mixtures and its potential use in adulterant detection

Exploring AI-enhanced NMR dereplication analysis for complex mixtures and its potential use in adulterant detection

Dereplication of 4-Quinolone Alkaloids from Waltheria Indica (Malvaceae) Tissues Using Molecular Network Tools.

Waltheria indica (Malvaceae) is a plant popularly used in folk medicine by traditional African and indigenous communities, and in various countries worldwide, to treat general inflammation. Several biological activities of this plant have been reported, including acetylcholinesterase inhibition and potential anti-human immunodeficiency virus (HIV), antinociceptive, analgesic, antifungal, anticancer, anti-inflammatory, leishmanicidal, trypanocidal, antioxidant, and antibacterial activities. The chemical profile of Waltheria indica was assessed by dereplication analysis using UPLC-MS/MS, and data acquisition was performed using chemoinformatics tools, such as Mass Spectrometry-Data Independent AnaLysis (MS-DIAL) and MS-FINDER softwares. The preprocessed data were sent to the GNPS to build a feature-based molecular network (FBMN). Thirty-three 4-quinolone alkaloids were annotated in the extracts and fractions of stems and roots, whereas 12 were annotated in the extracts and fractions of flowers and leaves. This represents an inaugural chemical investigation study employing UPLC-Q-TOF-MS/MS analysis, along with a molecular network approach, within this species and genus.

Diversity and bioactive potential of Actinomycetia from the rhizosphere soil of Juniperus excelsa.

Microbial natural products are among the main sources of compounds used in the medical biotechnology field for the purpose of drug development. However, as antibiotic resistance in pathogenic microorganisms is known to be increasing dramatically, there exists a need to develop new antibiotics. Actinomycetia have proven to be a good source of biologically active compounds, although the rediscovery of previously known compounds significantly slows down the introduction of new antibiotics. As a consequence, increasing attention is being paid to the isolation of actinomycete strains from previously unexplored sources, which can significantly increase the likelihood of discovering new biologically active compounds. This study investigated the diversity and bioactive potential of 372 actinomycete strains isolated from the rhizosphere soil of Juniperus excelsa M. Bieb. The examined actinomycete strains belonged to 11 genera, namely, Actinoplanes, Actinorectispora, Amycolatopsis, Kribbella, Micrococcus, Micromonospora, Nocardia, Promicromonospora, Rhodococcus, Saccharopolyspora and Streptomyces. The bioactive potential of each isolated actinomycete strain was determined on the basis of its ability to produce antimicrobial metabolites against Gram-positive and Gram-negative bacteria and yeast. Some 159 strains (42.74%) exhibited antimicrobial activity against at least one of the tested microbial strains. The dereplication analysis of the extract of the Streptomyces sp. Je 1-651 strain, which exhibited strong antimicrobial activity, led to the annotation of spiramycins and stambomycins. Moreover, the phylogenetic analysis based on the 16S rRNA gene sequence of the Je 1-651 strain revealed it to be close to the S. ambofaciens.

Штам актиноміцетів Streptomyces sp. Je 1-93, продуцент антифунгальних антибіотиків

Screening new naturally occurring biologically active compounds is an effective strategy for creating a portfolio of platforms for developing new chemical agents against multidrug-resistant microbial strains. Actinomycetes are an extremely prolific source of structurally diverse secondary metabolites, most of which have pharmaceutical or biotechnological significance. Among them, the genus Streptomyces stands out, producing about 55 % of all known naturally occurring antibiotics. However, due to the significant redisco­very of already known compounds, especially among actinomycetes, the rate of discovery of new antibiotics has slowed considerably. Today, there is growing interest in screening biologically active compounds from poorly studied and extreme habitats. In this study, we demonstrated the phylogeny, bioactivity and dereplication of secondary metabolites of the Je 1-93 strain isolated from the rhizosphere soil of juniper (Juniperus excelsa Bieb.). Phylogenetic analysis of the Je 1-93 strain based on the nucleotide sequence of the 16S rRNA gene allowed its identification in the Streptomyces genus and showed the greatest similarity with the S. hydrogenans CA04 strain (100 % identity). Analysis of the antimicrobial activity of this strain showed its strong antifungal activity against the reference Candida albicans ATCC 885-653 strain as well as the multi-resistant C. albicans №12 strain, which is resistant to nystatin, amphotericin B, clotrimazole, itraconazole, ketoconazole and fluconazole. To identify compounds that probably provide antifungal activity, we analysed secondary metabolites produced by Streptomyces sp. Je 1-93. To facilitate dereplication, the obtained extracts of secondary metabolites were separated by size-exclusion chromatography on a column filled with Sephadex LH-20. Methanol was used as the mobile phase. As a result of the dereplication analysis in the database of natural compounds (Dictionary of Natural Products), antibiotic antimycins were found among the secondary metabolites in the extract of the Je 1-93 strain, and they have a high probability of providing the antifungal activity of this strain.

Supplementation of syringic acid-rich Phrynium pubinerve leaves imparts protection against allergic inflammatory responses by downregulating iNOS, COX-2, and NF-κB expressions

BackgroundThe present study was designed to characterize the role of ethanolic leaf extract of Phrynium pubinerve Blume (EPP) supplement in attenuating allergic inflammation, encouraged by the presence of syringic acid in it, as this phenolic acid is reportedly promising in suppressing serum immunoglobulin E (IgE) and inflammatory cytokine levels. Materials and methodsHPLC-DAD dereplication analysis was performed to determine the presence of the vital polyphenolic metabolites. The efficacy of EPP against lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 cells was evaluated by measuring its inhibitory effects on NO and ROS/RNS production. The expressions of major inflammation-associated molecules (iNOS, COX-2, NF-κB, IL-6, and TNF-α) in RAW 264.7 cells were assessed through Western blot. Physiological and behavioral changes, BMI, and different biochemical parameters in mice blood serum were investigated in the toxicological assays. Formaldehyde-induced paw edema test in mice was conducted using established animal model. TDI-induced allergic model in mice was carried out to determine different allergy-like symptoms, and differential white blood cell (WBC) counts in blood and bronchoalveolar lavage (BAL) fluid. The intermolecular interaction analysis of the identified major metabolite of EPP with H1R and iNOS was studied by molecular docking. ResultsHPLC-DAD analysis showed the presence of syringic acid (89.19 mg/100 g EPP) and a few other compounds. LPS-induced NO generation was reduced by EPP in a concentration-dependent manner, showing IC50 of 28.20 ± 0.27 μg/mL. EPP exhibited a similar inhibitory effect on ROS/RNS production with IC50 of 29.47 ± 2.19 μg/mL. Western blotting revealed that EPP significantly downregulated the expressions of iNOS, COX-2, NF-κB, IL-6, and TNF-α in RAW 264.7 cells when challenged with LPS. The toxicological assays confirmed the dosage and organ-specific safety of EPP. In the formaldehyde-induced paw edema test, EPP caused a 66.41% reduction in mice paw volume at 500 mg/kg dose. It ameliorated TDI-induced allergy-like symptoms and decreased different inflammatory WBCs in mice's blood and BAL fluid in a dose-dependent manner. Finally, syringic acid demonstrated mentionable intermolecular binding affinity towards H1R (−6.6 Kcal/moL) and iNOS (−6.7 Kcal/moL). ConclusionsCollectively, considerable scientific reasoning was obtained in favor of the suppressive potential of EPP against allergic inflammatory responses that are proposed to be exerted via the downregulation of iNOS, COX-2, and NF-κB expressions, H1R antagonism and suppression of cytokines, such as IL-6, and TNF-α.

Mining Small Molecules from Teredinibacter turnerae Strains Isolated from Philippine Teredinidae.

Endosymbiotic relationship has played a significant role in the evolution of marine species, allowing for the development of biochemical machinery for the synthesis of diverse metabolites. In this work, we explore the chemical space of exogenous compounds from shipworm endosymbionts using LC-MS-based metabolomics. Priority T. turnerae strains (1022X.S.1B.7A, 991H.S.0A.06B, 1675L.S.0A.01) that displayed antimicrobial activity, isolated from shipworms collected from several sites in the Philippines were cultured, and fractionated extracts were subjected for profiling using ultrahigh-performance liquid chromatography with high-resolution mass spectrometry quadrupole time-of-flight mass analyzer (UHPLC-HRMS QTOF). T. turnerae T7901 was used as a reference microorganism for dereplication analysis. Tandem MS data were analyzed through the Global Natural Products Social (GNPS) molecular networking, which resulted to 93 clusters with more than two nodes, leading to four putatively annotated clusters: lipids, lysophosphatidylethanolamines, cyclic dipeptides, and rhamnolipids. Additional clusters were also annotated through molecular networking with cross-reference to previous publications. Tartrolon D cluster with analogues, turnercyclamycins A and B; teredinibactin A, dechloroteredinibactin, and two other possible teredinibactin analogues; and oxylipin (E)-11-oxooctadec-12-enoic acid were putatively identified as described. Molecular networking also revealed two additional metabolite clusters, annotated as lyso-ornithine lipids and polyethers. Manual fragmentation analysis corroborated the putative identification generated from GNPS. However, some of the clusters remained unclassified due to the limited structural information on marine natural products in the public database. The result of this study, nonetheless, showed the diversity in the chemical space occupied by shipworm endosymbionts. This study also affirms the use of bioinformatics, molecular networking, and fragmentation mechanisms analysis as tools for the dereplication of high-throughput data to aid the prioritization of strains for further analysis.

13C NMR dereplication-assisted isolation of bioactive polyphenolic metabolites from Clusia flava Jacq.

Presently it is estimated that many of the approximately 4000 new natural products isolated every year following complicated, long, and expensive isolation processes are already known; because of this, developing new strategies for locating secondary metabolites of interest in complex extracts or fractions is important. Currently, chromatographic and spectroscopic techniques are being used to optimize the isolation and identification of natural products. In this investigation we have used 13C NMR dereplication analyses for the quick identification of a number of triterpenes (friedelin, lupeol, betulinic acid), sterols (euphol, β-sitosterol) and fatty acids (palmitic acid) present in semipurified fractions obtained from the stem bark extract of Clusia flava and to assist in the isolation of the bioactive metabolites trapezifolixanthone and paralycolin A. The complete and correct assignment of the 1H and 13C NMR spectroscopic data for paralycolin A is reported for the first time and the antioxidant and antiAGEs activity of both metabolites is described.

Screening of Thiopeptide-Producing Streptomycetes Isolated From the Rhizosphere Soil of Juniperus excelsa.

The identification of an increasing number of drug-resistant pathogens has stimulated the development of new therapeutic agents to combat them. Microbial natural products are among the most important elements when it comes to drug discovery. Today, thiopeptide antibiotics are receiving increasing research attention due to their potent activity against Gram-positive bacteria. In this study, we demonstrated the successful use of a whole-cell microbial biosensor (Streptomyces lividans TK24 pMO16) for the specific detection of thiopeptide antibiotics among the native actinomycete strains isolated from the rhizosphere soil of Juniperus excelsa (Bieb.). Among the native strains, two strains of Streptomyces, namely sp. Je 1-79 and Je 1-613, were identified that were capable of producing thiopeptide antibiotics. A multilocus sequence analysis of five housekeeping genes (gyrB, atpD, recA, rpoB, and trpB) classified them as representatives of two different species of the genus Streptomyces. The thiopeptide antibiotics berninamycin A and B were identified in the extracts of the two strains by means of a dereplication analysis. The berninamycin biosynthetic gene cluster was also detected in the genome of the Streptomyces sp. Je 1-79 strain and showed a high level of similarity (93%) with the ber cluster from S. bernensis. Thus, the use of this whole-cell biosensor during the first stage of the screening process could serve to accelerate the specific detection of thiopeptide antibiotics.

Jellyfish as an Alternative Source of Bioactive Antiproliferative Compounds.

Jellyfish are commonly considered a nuisance for their negative effects on human activities (e.g., fisheries, power plants and tourism) and human health. However, jellyfish provide several benefits to humans and are commonly eaten in eastern countries. Additionally, recent studies have suggested that jellyfish may become a source of high-value molecules. In this study, we tested the effects of the methanolic extracts and enriched fractions, obtained by solid-phase extraction fractionation, from the scyphomedusae Pelagia noctiluca, Rhizostoma pulmo, Cotylorhiza tuberculata and the cubomedusa Caryddea marsupialis on different human cancer cell lines in order to evaluate a potential antiproliferative activity. Our results indicated that fraction C from Caryddea marsupialis-(CM) and C. tuberculata oral arms (CTOA) were the most active to reduce cell viability in a dose-dependent manner. LC/MS based dereplication analyses highlighted that both bioactive fractions contained mainly fatty acids and derivatives, with CM additionally containing small peptides (0.7–0.8 kDa), which might contribute to its higher biological activity. The mechanism of action behind the most active fraction was investigated using PCR arrays. Results showed that the fraction C of CM can reduce the expression of genes involved in apoptosis inhibition in melanoma-treated cells, which makes jellyfish a potential new source of antiproliferative drugs to be exploited in the future.

Identification of Antimicrobial Compounds in Two Streptomyces sp. Strains Isolated From Beehives.

The World Health Organization warns that the alarming increase in antibiotic resistant bacteria will lead to 2.7 million deaths annually due to the lack of effective antibiotic therapies. Clearly, there is an urgent need for short-term alternatives that help to alleviate these alarming figures. In this respect, the scientific community is exploring neglected ecological niches from which the prototypical antibiotic-producing bacteria Streptomycetes are expected to be present. Recent studies have reported that honeybees and their products carry Streptomyces species that possess strong antibacterial activity. In this study, we have investigated the antibiotic profile of two Streptomycetes strains that were isolated from beehives. One of the isolates is the strain Streptomyces albus AN1, which derives from pollen, and shows potent antimicrobial activity against Candida albicans. The other isolate is the strain Streptomyces griseoaurantiacus AD2, which was isolated from honey, and displays a broad range of antimicrobial activity against different Gram-positive bacteria, including pathogens such as Staphylococcus aureus and Enterococus faecalis. Cultures of S. griseoaurantiacus AD2 have the capacity to produce the antibacterial compounds undecylprodigiosin and manumycin, while those of S. albus AN1 accumulate antifungal compounds such as candicidins and antimycins. Furthermore, genome and dereplication analyses suggest that the number of putative bioactive metabolites produced by AD2 and AN1 is considerably high, including compounds with anti-microbial and anti-cancer properties. Our results postulate that beehives are a promising source for the discovery of novel bioactive compounds that might be of interest to the agri-food sector and healthcare pharmaceuticals.

Anti-cancer and antimicrobial potential of five soil Streptomycetes: a metabolomics-based study.

Lack of new anti-cancer and anti-infective agents directed the pharmaceutical research to natural products' discovery especially from actinomycetes as one of the major sources of bioactive compounds. Metabolomics- and dereplication-guided approach has been used successfully in chemical profiling of bioactive actinomycetes. We aimed to study the metabolomic profile of five bioactive actinomycetes to investigate the interesting metabolites responsible for their antimicrobial and anti-cancer activities. Three actinomycetes, namely, Streptomyces sp. SH8, SH10 and SH13, were found to exhibit broad spectrum of antimicrobial activities, whereas isolate SH4 showed the broadest antimicrobial activity against all tested strains. In addition, isolates SH8, SH10 and SH12 displayed potent cytotoxicity against the breast cancer cell line Michigan Cancer Foundation-7 (MCF-7), whereas isolates SH4 and SH12 exhibited potent anti-cancer activity against the hepatoma cell line hepatoma G2 (HepG2) compared with their weak inhibitory properties on the normal breast cells MCF-10A and normal liver cells transformed human liver epithelial-2 (THLE2), respectively. All bioactive isolates were molecularly identified as Streptomyces sp. via 16S rRNA gene sequencing. Our actinobacterial dereplication analysis revealed putative identification of several bioactive metabolites including tetracycline, oxytetracycline and a macrolide antibiotic, novamethymycin. Together, chemical profiling of bioactive Streptomycetes via dereplication and metabolomics helped in assigning their unique metabolites and predicting the bioactive compounds instigating their diverse bioactivities.

A Multidisciplinary Approach to Unraveling the Natural Product Biosynthetic Potential of a Streptomyces Strain Collection Isolated from Leaf-Cutting Ants.

The rapid emergence of bacterial resistance to antibiotics has urged the need to find novel bioactive compounds against resistant microorganisms. For that purpose, different strategies are being followed, one of them being exploring secondary metabolite production in microorganisms from uncommon sources. In this work, we have analyzed the genome of 12 Streptomyces sp. strains of the CS collection isolated from the surface of leaf-cutting ants of the Attini tribe and compared them to four Streptomyces model species and Pseudonocardia sp. Ae150A_Ps1, which shares the ecological niche with those of the CS collection. We used a combination of phylogenetics, bioinformatics and dereplication analysis to study the biosynthetic potential of our strains. 51.5% of the biosynthetic gene clusters (BGCs) predicted by antiSMASH were unknown and over half of them were strain-specific, making this strain collection an interesting source of putative novel compounds.

Regulation of the redox signaling and inflammation by Terminalia myriocarpa leaves and the predictive interactions of it's major metabolites with iNOS and NF-ĸB

Ethnopharmacological relevanceThe present study was designed to investigate the regulation of the redox signaling and inflammation by ethanolic leaf extract of Terminalia myriocarpaVan Heurck & Müller (ETM), inspired by the reported antioxidant potential of the plant bark and the anti-edema effect of the same genus. Materials and methodsHPLC-DAD dereplication study was conducted to detect the major polyphenolic secondary metabolites. In-vitro DPPH free radical scavenging assay, nitric oxide (NO) scavenging assay, Fe2+ ion chelating ability assay and reducing power assay were conducted to evaluate the antioxidant capacity. The molecular mechanism of anti-inflammation was investigated via assessing the NO and NF-ĸB inhibiting properties in different cell lines. In-vivo carrageenan and histamine-induced edema tests were conducted using established animal models. Pro-inflammatory proteins iNOS and NF-κB were docked against the major metabolites of ETM in the in-silico study. ResultsHPLC dereplication analysis revealed the presence of considerable amount of ellagic acid, where methyl-(S)-flavogallonate was previously reported in T. myriocarpa. Significant antioxidant activity was found in every in- vitro redox assay conducted. NO was reduced in RAW 264.7 cells, showing 83.67 ± 4.18% inhibitory activity at the highest tested concentration. TNF-α induced NF-κB was also observed to be reduced in 293/NF-кB-luc cells with an inhibitory activity of 66.23 ± 0.81% at the highest dose tested. In-vivo carrageenan-induced edema test demonstrated significant anti-inflammatory activity (p < 0.05; p < 0.01) at both doses of 250 and 500 mg/kg with 60.10% highest reduction in rat paw volume. Using same doses, histamine-induced edema test exhibited mentionable anti-inflammatory potential (p < 0.05; p < 0.01) with 67.91% highest reduction in rat paw volume. Moreover, ellagic acid and methyl-(S)-flavogallonate showed significant binding affinity with iNOS (−8.5 and −8.7 Kcal/moL, respectively) and NF-κB (−7.3 and −7.3 Kcal/moL, respectively). ConclusionMentionable basis was found on behalf of the anti-inflammatory and antioxidant potentials of ETM which might be correlated with its NF-ĸB inhibiting properties.

Using 13C‐NMR dereplication to aid in the identification of xanthones present in the stem bark extract of Calophyllum brasiliense

Xanthones are metabolites with a variety of biological properties. The Clusiaceae family, which until recently included the genus Calophyllum, is recognised for its production of monohydroxylated and polyhydroxylated xanthones. Presently, C. brasiliense is the only Calophyllum spp. known to occur in the Yucatan peninsula. To use a combination of traditional phytochemical methods and carbon-13 nuclear magnetic resonance (13 C-NMR) dereplication analysis to identify xanthones in the stem bark of C. brasiliense. Initial fractionation and purification of the stem bark extract of C. brasiliense produced macluraxanthone (1). Additional xanthones, together with chromanones and terpenoids, were identified using 13 C-NMR dereplication analysis in different semipurified fractions obtained from the low and medium polarity fractions of the stem bark extract of C. brasiliense. Initial identification of macluraxanthone (1) was confirmed by 13 C-NMR dereplication analysis; additionally, 13 C-NMR dereplication analysis allowed the identification of a number of monohydroxylated and polyhydroxylated xanthones, together with chromanones and terpenoids. This study confirms C. brasiliense as a rich source of xanthones and the 13 C-NMR dereplication analysis as a suitable method to quickly identify the presence of different families of secondary metabolites in semipurified fractions.

Actinomycetes strain Streptomyces sp. Je 1-42: phylogenetic analysis, biological activity and secondary metabolite profile

Aim. Screening of new natural bioactive molecules is one of the effective approach in combating multidrug-resistant pathogens and tumor cells. The aim of this work was to study the taxonomic characteristic, biological activity and secondary metabolites production of isolate Je 1-42 from the rhizosphere of Juniperus excelsa Bieb. Methods. Microbiological, molecular genetic, high performance liquid chromatography mass spectrometry and scanning electron microscopy methods were used in this work. Results. Based on a phylogenetic analysis of the 16S rRNA and gyrB gene sequences, microbiological and physiological characterization the isolate Je 1-42 has been affiliated to the genus Streptomyces. The isolate Je 1-42 showed a wide range of antibacterial activity. The antibiotics desertomycin A, kanchanamycin A, butylcycloheptylprodigiosine and spectinabilin were annotated in the Je 1-42 extract using dereplication analysis in the database DNP. Conclusions. Actinomycetes strain Streptomyces sp. Je 1-42 is an antagonist of gram-positive, gram-negative bacteria, fungi and produces antibiotics desertomycin A, canchanamycin A, butylcycloheptylprodigiozin, spectinabilin, which has a broad spectrum of antimicrobial activity. The production of these compounds obviously determines the ability of Je 1-42 to inhibit the growth of a wide range of bacteria and fungi. The strain of Streptomyces sp. Je 1-42 was deposited in the Microbial Culture Collection of Antibiotics Producers at Ivan Franko National University of Lviv (collection number Lv 1-042).&#x0D; Keywords: Streptomyces, secondary metabolites, antibacterial activity, phylogenetic analysis.

MixONat, a Software for the Dereplication of Mixtures Based on 13C NMR Spectroscopy.

Whether chemists or biologists, researchers dealing with metabolomics require tools to decipher complex mixtures. As a part of metabolomics and initially dedicated to identifying bioactive natural products, dereplication aims at reducing the usual time-consuming process of known compounds isolation. Mass spectrometry and nuclear magnetic resonance are the most commonly reported analytical tools during dereplication analysis. Though it has low sensitivity, 13C NMR has many advantages for such a study. Notably, it is nonspecific allowing simultaneous high-resolution analysis of any organic compounds including stereoisomers. Since NMR spectrometers nowadays provide useful data sets in a reasonable time frame, we have embarked upon writing software dedicated to 13C NMR dereplication. The present study describes the development of a freely distributed algorithm, namely MixONat and its ability to help researchers decipher complex mixtures. Based on Python 3.5, MixONat analyses a {1H}-13C NMR spectrum optionally combined with DEPT-135 and 90 data-to distinguish carbon types (i.e., CH3, CH2, CH, and C)-as well as a MW filtering. The software requires predicted or experimental carbon chemical shifts (δc) databases and displays results that can be refined based on user interactions. As a proof of concept, this 13C NMR dereplication strategy was evaluated on mixtures of increasing complexity and exhibiting pharmaceutical (poppy alkaloids), nutritional (rosemary extracts) or cosmetics (mangosteen peel extract) applications. Associated results were compared with other methods commonly used for dereplication. MixONat gave coherent results that rapidly oriented the user toward the correct structural types of secondary metabolites, allowing the user to distinguish between structurally close natural products, including stereoisomers.

Lysophosphatidylcholines and Chlorophyll-Derived Molecules from the Diatom Cylindrotheca closterium with Anti-Inflammatory Activity.

Microalgae have been shown to be excellent producers of lipids, pigments, carbohydrates, and a plethora of secondary metabolites with possible applications in the pharmacological, nutraceutical, and cosmeceutical sectors. Recently, various microalgal raw extracts have been found to have anti-inflammatory properties. In this study, we performed the fractionation of raw extracts of the diatom Cylindrotheca closterium, previously shown to have anti-inflammatory properties, obtaining five fractions. Fractions C and D were found to significantly inhibit tumor necrosis factor alpha (TNF-⍺) release in LPS-stimulated human monocyte THP-1 cells. A dereplication analysis of these two fractions allowed the identification of their main components. Our data suggest that lysophosphatidylcholines and a breakdown product of chlorophyll, pheophorbide a, were probably responsible for the observed anti-inflammatory activity. Pheophorbide a is known to have anti-inflammatory properties. We tested and confirmed the anti-inflammatory activity of 1-palmitoyl-sn-glycero-3-phosphocholine, the most abundant lysophosphatidylcholine found in fraction C. This study demonstrated the importance of proper dereplication of bioactive extracts and fractions before isolation of compounds is commenced.

Dereplication Analysis and Antitrypanosomal Potential of the Red Sea Sponge Amphimedon sp. Supported by Molecular Modelling

The present investigation was oriented to the discovery of chemical compounds from the Red Sea sponge Amphimedon sp., as a source of active agents against Trypanosoma brucei, the causal agent of human sleeping sickness. Dereplication analysis of the active fraction from Amphimedon sp. using liquid chromatography coupled with high-resolution mass spectrometry revealed the chemical richness of this sponge with diverse alkaloidal classes such as purine, manzamine, bis-piperidine, and pyridine. Activity-guided fractionation of the total extract showed the antitrypanosomal activity concentrated in the ethyl acetate fraction (IC50 = 3.8 μg/ml). In silico modelling was carried out on the dereplicated compounds to provide an insight into their antitrypanosomal mechanism of action with docking study on eight trypanosomal proteins. Molecular dynamics was run for the complex of zamamidine D and ornithine decarboxylase, which illustrated that zamamidine D has the highest affinity to the ornithine decarboxylase enzyme. These results highlight the valuable chemical profile of Amphimedon sp., as a lead source for antitrypanosomal natural products.

Sesbania grandiflora L. Poir leaves: A dietary supplement to alleviate type 2 diabetes through metabolic enzymes inhibition

Sesbania grandiflora L. Poir is an edible medicinal plant widely distributed in Asian countries. One of its folk medicinal uses is the alleviation or treatment of Type 2 Diabetes mellitus (T2DM). A number of animal studies confirmed its use in treating T2DM; however, none of them explored the chemistry or the possible mechanism. This study aims to unveil the chemical profile of S. grandiflora through LC-HRMS dereplication analysis, followed by isolation, identification and quantification of the major secondary metabolites with potential α-amylase and α glucosidase inhibitory effect as the potential anti-diabetic mechanism. LC-HRMS chemical profiling of its leaves and twigs identified 32 metabolites. Bio-guided fractionation and HPLC purification led to the isolation of 14 major metabolites that were screened for their α-amylase and α-glucosidase inhibitory activities. For the first time, two terpenoids; vomifoliol (11) and loliolide (14) showed inhibitory effect against α-glucosidase with IC50 values of 64.5 and 388.48 µM, respectively. Quercetin (10) exhibited the highest α-glucosidase inhibition with IC50 value of 17.45 µM. Further, predicated molecular modelling studies demonstrated strong binding interactions between active compounds and enzyme-substrate binding pockets supporting the observed enzyme inhibitory activity. Interestingly, the quantitative analysis of the most potent inhibitors indicated their existence at a high percentage within S. grandiflora extract. Our findings suggested S. grandiflora is a useful dietary supplement to control postprandial blood glucose.