Anti-trypanosomal Lignans Isolated from Salvadoran Peperomia pseudopereskiifolia.

A search for anti-trypanosomal natural compounds from plants collected in El Salvador, a country particularly endemic for Chagas disease, resulted in the isolation of five lignan-type compounds (1-5) from Peperomia pseudopereskiifolia. The lignan derivatives 1, 2, and 4 are new. Their absolute configuration was determined by chemical derivatization. Compounds 1, 5, 6, and 8 exhibited anti-trypanosomal activity against the amastigote form of T. cruzi comparable to that of the existing drug benznidazole.

Salvadoran Celastraceae Species as a Source of Antikinetoplastid Quinonemethide Triterpenoids.

Chagas disease and leishmaniasis are among the most widespread neglected tropical diseases, and their current therapies have limited efficacy and several toxic side effects. The present study reports the chemical and antikinetoplastid profiles of extracts from five Salvadoran Celastraceae species against the Trypanosoma cruzi epimastigotes stage and Leishmania amazonensis and Leishmania donovani promastigote forms. The phytochemical profile evinced the presence of flavonoids, tannins, sterols, and triterpenes as the main components in all plant species, whereas quinonemethide triterpenoids (QMTs) were restricted to the root bark of the studied species. Antikinetoplastid evaluation highlights the root bark extracts from Zinowewia integerrima, Maytenus segoviarum, and Quetzalia ilicina as the most promising ones, exhibiting higher potency against T. cruzi (IC50 0.71-1.58 µg/mL) and L. amazonensis (IC50 0.38-2.05 µg/mL) than the reference drugs, benznidazole (IC50 1.81 µg/mL) and miltefosine (IC50 2.64 µg/mL), respectively. This potent activity was connected with an excellent selectivity index on the murine macrophage J774A.1 cell line. These findings reinforce the potential of QMTs as antikinetoplastid agents for the development of innovative phytopharmaceuticals and the plant species under study as a source of these promising lead compounds.

Navigating the Chemical Space and Chemical Multiverse of a Unified Latin American Natural Product Database: LANaPDB.

The number of databases of natural products (NPs) has increased substantially. Latin America is extraordinarily rich in biodiversity, enabling the identification of novel NPs, which has encouraged both the development of databases and the implementation of those that are being created or are under development. In a collective effort from several Latin American countries, herein we introduce the first version of the Latin American Natural Products Database (LANaPDB), a public compound collection that gathers the chemical information of NPs contained in diverse databases from this geographical region. The current version of LANaPDB unifies the information from six countries and contains 12,959 chemical structures. The structural classification showed that the most abundant compounds are the terpenoids (63.2%), phenylpropanoids (18%) and alkaloids (11.8%). From the analysis of the distribution of properties of pharmaceutical interest, it was observed that many LANaPDB compounds satisfy some drug-like rules of thumb for physicochemical properties. The concept of the chemical multiverse was employed to generate multiple chemical spaces from two different fingerprints and two dimensionality reduction techniques. Comparing LANaPDB with FDA-approved drugs and the major open-access repository of NPs, COCONUT, it was concluded that the chemical space covered by LANaPDB completely overlaps with COCONUT and, in some regions, with FDA-approved drugs. LANaPDB will be updated, adding more compounds from each database, plus the addition of databases from other Latin American countries.

Multistage Detection of Tetrodotoxin Traces in Diodon hystrix Collected in El Salvador.

This study describes a multistage methodology to detect minute amounts of tetrodotoxin in fishes, a plan that may be broadened to include other marine organisms. This methodology was applied to porcupinefish (Diodon hystrix) collected in Punta Chiquirín, El Salvador. A three-stage approach along with post-acquisition processing was employed, to wit: (a) Sample screening by selected reaction monitoring (HPLC-MS/MS-SRM) analyses to quickly identify possible toxin presence via a LC/MS/MS API 3200 system with a triple quadrupole; (b) HPLC-HRFTMS-full scan analyses using an ion trap-Orbitrap spectrometer combined with an MZmine 2-enhanced dereplication-like workflow to collect high-resolution mass spectra; and (c) HPLC-HRMS2 analyses. This is the first time tetrodotoxin has been reported in D. hystrix specimens collected in El Salvador.

Screening of medicinal plants from El Salvador for anti-viral activity against Herpes simplex 1.

Herpes simplex virus 1 is one of the most prevalent pathogens worldwide. Resistant strains to current anti-viral treatment have been reported, requiring the search for novel anti-virals. Using a qPCR method to assess anti-herpetic activity from natural products, we analyzed 72 plant extracts from El Salvador and identified eighteen methanolic extracts with anti-viral activity of ≥ 75%. Anti-herpetic activity has not been previously reported in fourteen of the plants (Euphorbia lancifolia, Piper tuberculatum, Cordia alliodora, Tecoma stans, Taraxacum officinale, Hamelia patens, Witheringia solanacea, Emilia fosbergii, Gnaphalium viscosum, Citrus aurantium, Ambrosia peruviana, Carica papaya, Solanum hazenii and Melothria pendula). Four extracts were from species with previously reported anti-herpetic activity (Plantago major, Psidium guajava, Sida acuta and Bursera simaruba). These extracts effective anti-viral concentrations (EC50) were between 203 and 6.31 µg/mL, while the selectivity indexes (SI) were between 55.91 and 2.57. Euphorbia lancifolia showed the most effective anti-viral activity (EC50 = 6.31 µg/mL, SI = 51.82).

Anti-trypanosomal screening of Salvadoran flora.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and in Central America, it is considered one of the four most infectious diseases. This study aimed to screen the anti-trypanosomal activity of plant species from Salvadoran flora. Plants were selected through literature search for plants ethnobotanically used for antiparasitic and Chagas disease symptomatology, and reported in Museo de Historia Natural de El Salvador (MUHNES) database. T. cruzi was incubated for 72 h with 2 different concentrations of methanolic extracts of 38 species, among which four species, Piper jacquemontianum, Piper lacunosum, Trichilia havanensis, and Peperomia pseudopereskiifolia, showed the activity (≤ 52.0% viability) at 100 µg/mL. Separation of the methanolic extract of aerial parts from Piper jacquemontianum afforded a new flavanone (4) and four known compounds, 2,2-dimethyl-6-carboxymethoxychroman-4-one (1), 2,2-dimethyl-6-carboxychroman-4-one (2), cardamomin (3), and pinocembrin (5), among which cardamomin exhibited the highest anti-trypanosomal activity (IC50 = 66 µM). Detailed analyses of the spectral data revealed that the new compound 4, named as jaqueflavanone A, was a derivative of pinocembrin having a prenylated benzoate moiety at the 8-position of the A ring.

Withanolide-Type Steroids from Physalis nicandroides Inhibit HIV Transcription.

The aim of the present study is to report the isolation, structural elucidation, and antiviral evaluation of four new withanolide-type steroids, named nicansteroidins A-D (1-4), together with nine related known compounds (5-13) isolated from the aerial parts of Physalis nicandroides. Their structures were established based on an extensive spectroscopic analysis, including 1D and 2D NMR techniques. Outstandingly, nicansteroidins A and B possess an unusual side chain with an exocyclic double bond on the δ-lactone system, whereas nicansteroidins C and D have an uncommon cycloperoxide functionality in ring A as distinct structural motifs. Their biological evaluation as inhibitors of human immunodeficiency virus type 1 replication revealed that two compounds from this series, 7 and 13, displayed strong inhibition of HIV-1 replication with IC50 values lower than 2 µM. Moreover, cellular mechanism experiments showed that the main target of these compounds in the HIV replication cycle is viral transcription. This study is the first report of withanolide-type steroids as HIV inhibitors and provides insight into their potential as candidates for further preclinical studies.

In Vitro Susceptibility of Kinetoplastids to Celastroloids from Maytenus chiapensis.

Leishmaniasis and Chagas are among the most significant neglected tropical diseases. Due to several drawbacks with the current chemotherapy, developing new antikinetoplastid drugs has become an urgent issue. In the present work, a bioassay-guided investigation of the root bark of Maytenus chiapensis on Leishmania amazonensis and Trypanosoma cruzi led to the identification of two D:A-friedo-nor-oleanane triterpenoids (celastroloids), 20ß-hydroxy-tingenone (celastroloid 5) and 3-O-methyl-6-oxo-tingenol (celastroloid 8), as promising antikinetoplastid leads. They displayed higher potency on L. amazonensis promastigotes (50% inhibitory concentrations [IC50s], 0.44 and 1.12 µM, respectively), intracellular amastigotes (IC50s, 0.83 and 1.91 µM, respectively), and T. cruzi epimastigote stage (IC50s, 2.61 and 3.41 µM, respectively) than reference drugs miltefosine and benznidazole. This potency was coupled with an excellent selectivity index on murine macrophages. Mechanism of action studies, including mitochondrial membrane potential (Δψm) and ATP-level analysis, revealed that celastroloids could induce apoptotic cell death in L. amazonensis triggered by the mitochondria. In addition, the structure-activity relationship is discussed. These findings strongly underline the potential of celastroloids as lead compounds to develop novel antikinetoplastid drugs.

Latin American databases of natural products: biodiversity and drug discovery against SARS-CoV-2.

In this study, we evaluated 3444 Latin American natural products using cheminformatic tools. We also characterized 196 compounds for the first time from the flora of El Salvador that were compared with the databases of secondary metabolites from Brazil, Mexico, and Panama, and 42 969 compounds (natural, semi-synthetic, synthetic) from different regions of the world. The overall analysis was performed using drug-likeness properties, molecular fingerprints of different designs, two parameters similarity, molecular scaffolds, and molecular complexity metrics. It was found that, in general, Salvadoran natural products have a large diversity based on fingerprints. Simultaneously, those belonging to Mexico and Panama present the greatest diversity of scaffolds compared to the other databases. This study provided evidence of the high structural complexity that Latin America's natural products have as a benchmark. The COVID-19 pandemic has had a negative effect on a global level. Thus, in the search for substances that may influence the coronavirus life cycle, the secondary metabolites from El Salvador and Panama were evaluated by docking against the endoribonuclease NSP-15, an enzyme involved in the SARS CoV-2 viral replication. We propose in this study three natural products as potential inhibitors of NSP-15.

Computationally aided stereochemical assignment of undescribed bisabolenes from Calea urticifolia.

Calea urticifolia (Mill.) DC. (Compositae) is a medicinal plant found in El Salvador. Calea is used in folkloric medicine as a psychoactive principle with calming effect, as well as in the treatment of diarrhea and fever. Three undescribed bisabolenes, named caleanolenes A-C, as well as, three known sesquiterpene lactones 2,3-epoxyjuanislamin, calealactone B, calein C, and the flavonoid acacetin, were isolated from the chloroform extract of the leaves of C. urticifolia. The chemical structures of the isolated compounds were determined on the basis of HRMS, IR, CD, and from 1D and 2D NMR spectroscopic studies. The absolute configurations of the caleanolenes have been partly established using GIAO NMR and ECD calculations. The isolated compounds were evaluated for cytotoxicity against the CA46 and Raji lymphoma, and the MCF7 breast cancer cell lines, with 2,3-epoxyjuanislamin showing the best activity in all cell lines (IC50 value range 2.9-12.3 µM).

Efecto analgésico, caracterización fitoquímica y análisis toxicológico del extracto etanólico de hojas de pereskia lychnidiflora / Analgesic effect, phytochemical characterization and toxicological analysis of ethanolic extract of pereskia lychnidiflora leaves

RESUMEN Objetivo Evaluar el efecto analgésico del extracto etanólico de las hojas de Pereskia lychnidiflora, la prospección de metabolitos secundarios y el análisis toxicológico. Materiales y métodos La actividad analgésica fue evaluada mediante la prueba del ácido acético y la formalina en ratones NIH a una concentración de 30, 50 y 100 mg/kg de peso corporal, utilizando como control Ibuprofeno a 200 mg/kg y agua destilada como blanco. La prospección de metabolitos secundarios se realizó por el método de cromatografía de capa fina y la toxicidad del extracto fue evaluada in vivo según la dosis máxima de 2000 mg/kg de peso corporal. Resultados La prospección fitoquímica determinó la presencia de alcaloides, taninos, triterpenos y esteroles como mayores constituyentes químicos. Se determinó que el extracto etanólico de Pereskia lychnidiflora posee una actividad analgésica similar al Ibuprofeno. No se observaron signos de toxicidad en los ratones de experimentación y se clasifica el extracto como no tóxico con una DL50 mayor de 2000 mg/kg. Conclusión El extracto etanólico de Pereskia lychnidiflora tiene un efecto analgésico antiinflamatorio que podría estar condicionado por la presencia de alcaloides, taninos y esteroles (terpenoides) presentes en esta especie vegetal y puede ser clasificado como no tóxico.

ABSTRACT Objective To evaluate the analgesic effect of the ethanolic extract of the leaves of Pereskia lychnidiflora, the prospection of secondary metabolites and the toxicologic analysis. Materials and Methods Analgesic activity was evaluated by testing acetic acid and formalin in NIH mice at a concentration of 30, 50 and 100 mg/kg body weight, using Ibuprofen control at 200 mg/kg and distilled water as the target. Secondary metabolites were prospected using the thin layer chromatography method and the toxicity of the extract was evaluated in vivo according to the maximum dose of 2,000 mg/kg body weight. Results Phytochemical prospecting determined the presence of alkaloids, tannins, triterpenes, and sterols as major chemical constituents. The ethanolic extract of Pereskia lychnidiflora was found to have an analgesic activity similar to ibuprofen. No signs of toxicity were observed in the experimental mice and the extract is classified as non-toxic with a DL50 greater than 2,000 mg/kg. Conclusions The ethanolic extract of Pereskia lychnidiflora has an anti- inflammatory analgesic effect that could be conditioned by the presence of alkaloids, tannins, and sterols (terpenoids) present in this species and can be classified as non-toxic.

[Analgesic effect, phytochemical characterization and toxicological analysis of ethanolic extract of pereskia lychnidiflora leaves]. / Efecto analgésico, caracterización fitoquímica y análisis toxicológico del extracto etanólico de hojas de pereskia lychnidiflora.

OBJECTIVE: To evaluate the analgesic effect of the ethanolic extract of the leaves of Pereskia lychnidiflora, the prospection of secondary metabolites and the toxicologic analysis. MATERIALS AND METHODS: Analgesic activity was evaluated by testing acetic acid and formalin in NIH mice at a concentration of 30, 50 and 100 mg/kg body weight, using Ibuprofen control at 200 mg/kg and distilled water as the target. Secondary metabolites were prospected using the thin layer chromatography method and the toxicity of the extract was evaluated in vivo according to the maximum dose of 2,000 mg/kg body weight. RESULTS: Phytochemical prospecting determined the presence of alkaloids, tannins, triterpenes, and sterols as major chemical constituents. The ethanolic extract of Pereskia lychnidiflora was found to have an analgesic activity similar to ibuprofen. No signs of toxicity were observed in the experimental mice and the extract is classified as non-toxic with a DL50 greater than 2,000 mg/kg. CONCLUSIONS: The ethanolic extract of Pereskia lychnidiflora has an anti- inflammatory analgesic effect that could be conditioned by the presence of alkaloids, tannins, and sterols (terpenoids) present in this species and can be classified as non-toxic.

OBJETIVO: Evaluar el efecto analgésico del extracto etanólico de las hojas de Pereskia lychnidiflora, la prospección de metabolitos secundarios y el análisis toxicológico. MATERIALES Y MÉTODOS: La actividad analgésica fue evaluada mediante la prueba del ácido acético y la formalina en ratones NIH a una concentración de 30, 50 y 100 mg/kg de peso corporal, utilizando como control Ibuprofeno a 200 mg/kg y agua destilada como blanco. La prospección de metabolitos secundarios se realizó por el método de cromatografía de capa fina y la toxicidad del extracto fue evaluada in vivo según la dosis máxima de 2000 mg/kg de peso corporal. RESULTADOS: La prospección fitoquímica determinó la presencia de alcaloides, taninos, triterpenos y esteroles como mayores constituyentes químicos. Se determinó que el extracto etanólico de Pereskia lychnidiflora posee una actividad analgésica similar al Ibuprofeno. No se observaron signos de toxicidad en los ratones de experimentación y se clasifica el extracto como no tóxico con una DL50 mayor de 2000 mg/kg. CONCLUSIÓN: El extracto etanólico de Pereskia lychnidiflora tiene un efecto analgésico antiinflamatorio que podría estar condicionado por la presencia de alcaloides, taninos y esteroles (terpenoides) presentes en esta especie vegetal y puede ser clasificado como no tóxico.

Distinct sesquiterpene pyridine alkaloids from in Salvadoran and Peruvian Celastraceae species.

As part of a bioprospecting program aimed at the discovery of undescribed natural products from Salvadoran and Peruvian flora, the phytochemical investigations of four Celastraceae species, Celastrus vulcanicola, Maytenus segoviarum, Maytenus jeslkii, and Maytenus cuzcoina, were performed. The current study reports the isolation and structural characterization of five previously undescribed macrolide sesquiterpene pyridine alkaloids, named vulcanicoline-A, cuzcoinine, vulcanicoline-B, jelskiine, and vulcanicoline-C, along with sixteen known alkaloids. The structures of the alkaloids were established by spectrometric and extensive 1D and 2D NMR spectroscopic analysis, including COSY, HSQC, HMBC, and ROESY experiments. The absolute configurations of alkaloids were proposed based on optical rotation sign, and biogenetic considerations. This study represents the first phytochemical analysis of Maytenus segoviarum.

Isolation of Acacetin from Calea urticifolia with Inhibitory Properties against Human Monoamine Oxidase-A and -B.

Calea urticifolia (Asteraceae: Asteroideae) has long been used as a traditional medicine in El Salvador to treat arthritis and fever, among other illnesses. The chloroform extract of the leaves of C. urticifolia showed potent inhibition of recombinant human monoamine oxidases (MAO-A and -B). Further bioassay-guided fractionation led to the isolation of a flavonoid, acacetin, as the most prominent MAO inhibitory constituent, with IC50 values of 121 and 49 nM for MAO-A and -B, respectively. The potency of MAO inhibition by acacetin was >5-fold higher for MAO-A (0.121 µM vs 0.640 µM) and >22-fold higher for MAO-B (0.049 µM vs 1.12 µM) as compared to apigenin, the closest flavone structural analogue. Interaction and binding characteristics of acacetin with MAO-A and -B were determined by enzyme-kinetic assays, enzyme-inhibitor complex binding, equilibrium-dialysis dissociation analyses, and computation analysis. Follow-up studies showed reversible binding of acacetin with human MAO-A and -B, resulting in competitive inhibition. Acacetin showed more preference toward MAO-B than to MAO-A, suggesting its potential for eliciting selective pharmacological effects that might be useful in the treatment of neurological and psychiatric disorders. In addition, the binding modes of acacetin at the enzymatic site of MAO-A and -B were predicted through molecular modeling algorithms, illustrating the high importance of ligand interaction with negative and positive free energy regions of the enzyme active site.

Dihydro-ß-agarofuran sesquiterpenes from celastraceae species as anti-tumour-promoting agents: Structure-activity relationship.

Inhibition of tumour promotion in multistage chemical carcinogenesis is considered a promising strategy for cancer chemoprevention. In an ongoing investigation of bioactive secondary metabolites from Celastraceae species, five new dihydro-ß-agarofuran sesquiterpenes (1-5), named Chiapens A-E, and seventeen known ones, were isolated from Maytenus chiapensis. Their structures were elucidated by extensive NMR spectroscopic and mass spectrometric techniques, and their absolute configurations were determined by circular dichroism studies, chemical correlations and biogenic means. The isolated compounds, along with twenty known sesquiterpenes, previously isolated from Zinowiewia costaricensis, have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorpol-13-acetate (TPA). Thirty three compounds from this series showed stronger effects than that of ß-carotene, the reference inhibitor. The structure-activity relationship (SAR) analysis revealed that the type of substituent, in particular at the C-1 position of the sesquiterpene scaffold, was able to modulate the anti-tumour promoting activity. Compounds 3, 6, and 33 showed significant effects in an in vivo two-stage mouse-skin carcinogenesis model.

Studies of naturally occurring friedelane triterpenoids as insulin sensitizers in the treatment type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a rapidly expanding public epidemic and frequently results in severe vascular complications. In an attempt to find anti-diabetic agents, we report herein on the isolation, structural elucidation and bioactivity of nine friedelane-type triterpenes (1-9) and twenty two known ones (10-31) from the root barks of Celastrus vulcanicola and Maytenus jelskii. Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques. Two compounds from this series (1 and 3) exhibited increased insulin-mediated signalling, which suggests these friedelane triterpenes have potential therapeutic use in insulin resistant states.

ent-Rosane and abietane diterpenoids as cancer chemopreventive agents.

Two ent-rosane- (cuzcol, 1 and 6-dehydroxycuzcol, 2) and a abietatriene- (salvadoriol, 3) type diterpenoids have been isolated from Maytenus cuzcoina and Crossopetalum uragoga, respectively, along with five known diterpene compounds (4-8). Their stereostructures have been elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques, and computational data. The absolute configuration of cuzcol was determined by application of Riguera ester procedure. This is the first instance of isolation of ent-rosane diterpenoids from species of the Celastraceae. The isolated diterpenes were found to be potent anti-tumour-promoter agents, and carnosol (7) also showed a remarkable chemopreventive effect in an in vivo two-stage carcinogenesis model.

Biological evaluation, structure-activity relationships, and three-dimensional quantitative structure-activity relationship studies of dihydro-beta-agarofuran sesquiterpenes as modulators of P-glycoprotein-dependent multidrug resistance.

Multidrug resistance (MDR) is one of the main challenges in the chemotherapy of cancer, malaria, and other important diseases. Here, we report the inhibitory activity of a series of 76 dihydro-beta-agarofuran sesquiterpenes, tested on NIH-3T3 cells expressing the human P-glycoprotein (Pgp) multidrug transporter, to establish quantitative comparisons of their respective abilities to block the drug transport activity. The screening was performed on the basis of the ability of sesquiterpenes to modulate the intracellular accumulation of the classical Pgp substrate daunorubicin. To understand the structural basis for inhibitory activity and guide the design of more potent Pgp inhibitors, we have performed a three-dimensional quantitative structure-activity relationship model using the comparative molecular similarity indices analysis (CoMSIA). The most salient features of these requirements are in the region of the substituents at the C-2, C-3, and C-8 positions, which seem to be critical for determining the overall effectiveness of sesquiterpenes as Pgp inhibitors.

Activity of lupane triterpenoids from Maytenus species as inhibitors of nitric oxide and prostaglandin E2.

In the present study, we report that three new lupane triterpenes (1-3), in addition to 16 known ones (4-19), were isolated from the root bark of Maytenus cuzcoina and the leaves of Maytenus chiapensis. Their structures were elucidated by spectral analysis, including homonuclear and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC, and HMBC). The natural compounds and derivatives 6a, 6b, 9a, and 9b have been tested for potential anti-inflammatory activity, and several compounds including 3-epicalenduladiol (2), 11alpha-hydroxy-glochidone (3), rigidenol (6), acetoxy-rigidenol (6a), 11alpha-acetoxy-30-chloro-3-oxo-lup-20(29)-ene (6b), betulin (9), 28-acetoxy-betulin (9a), epibetulin (12), epibetulinic acid (13), and betulonic acid (16) exhibited potent inhibitory effects on NO and prostaglandin E(2) production in mouse macrophages (RAW 264.7) stimulated with bacterial endotoxin. The structure-activity relationship is discussed in detail.