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.

Modelling the current and future distribution potential areas of Peperomia abyssinica Miq., and Helichrysum citrispinum Steud. ex A. Rich. in Ethiopia.

BACKGROUND: The aim of this study is to investigate how climate change influences the distribution of economically and environmentally important species of P. abyssinica and H. citrispinum in Ethiopia. The species distribution modeling intends to forecast species' ecological niche ranges and habitat suitability by employing a variety of environmental parameters as predictors, which is vital for conservation planning and restoration success. Six representative concentration pathways (RCP 2.6, 4.5, and 8.5 for the years 2050 and 2070) with the same resolution of 2.5 min that shows the emission scenarios were used for the prediction. To predict the current and future distributions of H. citrispinum and P. abyssinica 56 and 45 occurrence records from National Herbarium, Addis Ababa University, GBIF, and available literatures were used respectively. RESULTS: The MaxEnt model predicted habitat suitability for H. citrispinum species with an Area Under Curve (AUC) value of 0.961 ± 0.027, and 0.809 ± 0.045 for P. abyssinica, indicating excellent discriminatory ability or accuracy under the current climate scenario. The Future distribution of suitable habitat for both H. citrispinum and P. abyssinica plant species was accurately predicted with AUC values of 0.960 ± 0.017 and 0.780 ± 0.35, respectively under future climatic scenarios. The jackknife test result indicates that environmental variables such as topographic position index (92.5%), precipitation of the driest quarter (3%) and precipitation in the coldest quarter (1.8%) are associated with the distributions of H. citrispinum, while topographic position index (36.6%), precipitation of driest quarter (21.4%), precipitation of warmest quarter (16.2%) and precipitation seasonality (13.9%) were found to be limiting environmental variables for P. abyssinica under current and future climatic conditions in Ethiopia. The prediction map and interception calculation for both present and projected (in the 2050s and again in the 2070s) climate change scenarios indicate significant habitat loss, decreased, and fragmentation under all RCPs (2.6, 4.5, and 8.5) scenarios for P. abyssinica while habitat gain, and increasing for H. citrispinum in Ethiopia. CONCLUSIONS: Topographic position index (TPI) is the most impactful predictor variable on the distribution of the two species. Consequently, potentially habitable areas (with diverse aspects and slopes) are increasing for H. citrispinum while decreasing for P. abyssinica.

Cannabinoid-like meroterpenoids from Peperomia incana.

Ten previously undescribed metabolites were isolated from Peperomia incana (Haw.) A. Dietr. (Piperaceae), among which four contained a chromene moiety, two were identified as meroterpene lactones, and four were cannabinoid-like compounds. While the chemical structures of the compounds were assigned based on HRESIMS and 1D and 2D-NMR spectra analyses, the relative and absolute configurations were assigned from NOE correlations and a combination of ECD data and X-ray single crystal analyses, respectively. In a cytotoxic assay against a panel of seven human cancer cell lines (A549, MDA-MB-231, HeLa, DU 145, 5637, Hep G2, and MIA PaCa-2, which represent non-small cell lung cancer, as well as breast, cervical, prostate, bladder, liver, and pancreas carcinomas, respectively) most of the isolated compounds showed promising cytotoxic activities. The incanachromenes B, and incanabinoids A and C exhibited the highest cytotoxicity toward all tested cancer cell lines with IC50 values in the range of 5.0-10.0 µM, whereas incanolides A, B, and incanabinoid B showed the lowest cytotoxic activity. In addition, incanachromene C and incanabinoid C produced a significant antibacterial effect toward planktonic cells and biofilms of multidrug-resistant Staphylococcus aureus strains.

Three new secolignans from Peperomia blanda (Jacq.) Kunth.

Three new secolignans were found in the detailed chemical study of Peperomia blanda (Jacq.) Kunth collected from China. Detailed NMR data analysis, especially 1H NMR, 13C NMR and 2 D NMR, elucidates the structures of the three new secolignans.

New peperomin and polyketides from dichloromethane extract of Peperomia blanda Jack. (Kunth).

Much of the new research and investigation in pharmacy sciences are concerned with developing therapeutic agents, and identifying and finding new drugs with their chemical structure to treat different human diseases such as infectious diseases from natural products. Therefore, the present findings relate to isolating five new compounds the dichloromethane extract of Peperomia blanda (Jacq.) Kunth grown on Socotra Island, Yemen. two new secolignans; which have been proposed as peperomin I & J. These compounds were isolated together with the other two polyketides presented as surinone D and dindygulerione F. The chemical structures were elucidated and confirmed with nuclear magnetic resonance (NMR) and liquid chromatography-mass spectroscopy (LCMS) analysis. These compounds were first isolated and reported from this plant. These new compounds' antimicrobial activity has been evaluated, and minimum inhibitory concentration has been recorded in the range of 125-250 µg/mL. The pharmacotherapeutic spectrum of compounds was predicated using PASS software which showed potential activity.

Bioactive Phenolic Compounds from Peperomia obtusifolia.

Peperomia obtusifolia (L.) A. Dietr., native to Middle America, is an ornamental plant also traditionally used for its mild antimicrobial properties. Chemical investigation on the leaves of P. obtusifolia resulted in the isolation of two previously undescribed compounds, named peperomic ester (1) and peperoside (2), together with five known compounds, viz. N-[2-(3,4-dihydroxyphenyl)ethyl]-3,4-dihydroxybenzamide (3), becatamide (4), peperobtusin A (5), peperomin B (6), and arabinothalictoside (7). The structures of these compounds were elucidated by 1D and 2D NMR techniques and HREIMS analyses. Compounds 1-7 were evaluated for their anthelmintic (against Caenorhabditis elegans), antifungal (against Botrytis cinerea, Septoria tritici and Phytophthora infestans), antibacterial (against Bacillus subtilis and Aliivibrio fischeri), and antiproliferative (against PC-3 and HT-29 human cancer cell lines) activities. The known peperobtusin A (5) was the most active compound against the PC-3 cancer cell line with IC50 values of 25.6 µM and 36.0 µM in MTT and CV assays, respectively. This compound also induced 90% inhibition of bacterial growth of the Gram-positive B. subtilis at a concentration of 100 µM. In addition, compound 3 showed anti-oomycotic activity against P. infestans with an inhibition value of 56% by using a concentration of 125 µM. However, no anthelmintic activity was observed.

Hepatotoxicity and Mutagenicity assessment during chronic in vivo exposure to aqueous extracts from Peperomia pellucida.

Studies on herbal medicine have exposed some toxic effects on humans. Peperomia pellucida (L.) HBK (P. pellucida) is one of the herbal medicines recommended as an alternative to synthetic medicine for diseases. Studies exist on the pharmacological activities of P. pellucida extracts, but studies on the potential hepatotoxic and mutagenic effects of subchronic administration of P. pellucida aqueous extracts, which is very important knowledge when we venture into alternative medicine, are lacking. In this study, two concentrations (60 mg/kg and 30 mg/kg) of P. pellucida aqueous extracts - decoction and freeze-dried extracts -were administered in vivo to BALB/c mice for nine (9) weeks. Significant differences were observed between the 60 mg/kg freeze-dried extract and the control in terms of mice weight and micronucleus frequency at 7-8 weeks of treatment. Also, no significant differences were found between groups in serum transaminases levels. Generally, there is no sufficient evidence to show that subchronic exposure to P. pellucida aqueous extracts is hepatotoxic though 60 mg/kg concentration may be mutagenic. This study suggests that although the herbal medicine is safe for prolonged consumption, users are advised to take precautions and moderations of its use due to the possibility of potential mutagenic effects.

Gastroprotective activities of Peperomia pellucida L. and Pachyrhizus erosus L. extracts combination on ethanol-induced rats.

Gastroprotective is an effect caused by the compounds that have the capability of protecting the gastric mucosa. Peperomia pellucida L. plants contain alkaloids, flavonoids, saponins, tannins, and terpenoids, while Pachyrhizus erosus L. contains flavonoids, alkaloids, tannins, and saponins. Peperomia pellucida L. reportedly contains dillapiole compounds with a gastroprotective effect. Moreover, its isolation result from Pachyrhizus erosus L. indicates the presence of dulcitol, gentisic acid, and formononetin, which has antioxidant activity. This study aims to determine the gastroprotective effect of the combination of Peperomia pellucida L. and Pachyrhizus erosus L. extract on rats with gastric ulcer models by looking at the ulcer index, percentage of inhibition, and histopathology. The research method used in this study was by making a combination of Peperomia pellucida L. and Pachyrhizus erosus L. extract. The combined extract was then given to five treatment groups. Group I as a negative control, group II as a positive control was given sucralfate, groups III, IV, and V were given a combination of Peperomia pellucida L. and Pachyrhizus erosus L. extract of 100, 200, and 400 mg/kg BW. The treatment was given orally for 14 days, after 1 h of treatment on the 14th day, 96% ethanol induction was given orally at a dose of 5 mg/kg BW. The animal dissection was performed 24 h after the induction. The results from observations showed an increase in body weight before and after the treatment. The ulcer index produced by negative control, positive control in the treatment with doses of 100, 200, and 400 were 4.18; 2.98; 2.42; 2.04; and 1.07. This study showed that the combination of Peperomia pellucida L. and Pachyrhizus erosus L. extract has a gastroprotective effect.

Chemical Composition of Leaves, Stem, and Roots of Peperomia pellucida (L.) Kunth.

Peperomia pellucida is a species known in the Amazon as "erva-de-jabuti" that has been used in several therapeutic applications based on folk medicine. Herein, we describe the classes, subclasses, and the main compounds of the leaves, stems, and roots from P. pellucida by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry associated with molecular networks, mirror plot on the GNPS library, and machine learning. These data show compounds that were annotated for the first time in the Peperomia genus, such as 2',4',5'-trihydroxybutyrophenonevelutin, dehydroretrofractamide C, and retrofractamide B.

Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology.

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, ß-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

Variation in Peperomia pellucida growth and secondary metabolism after rhizobacteria inoculation.

Peperomia pellucida L. Kunth is a herb well-known for its secondary metabolites (SM) with biological potential. In this study, the variations in the SM of P. pellucida during association with rhizobacteria were evaluated. Plants were inoculated with Enterobacter asburiae and Klebsiella variicola, which were identified by sequencing of the 16S rRNA gene. The data were evaluated at 7, 21, and 30-day post inoculation (dpi). Plant-bacteria symbiosis improved plant growth and weight. Total phenolic content and phenylalanine ammonia lyase enzyme activity had a significant increase mainly at 30 dpi. P. pellucida was mainly composed of phenylpropanoids (37.30-52.28%) and sesquiterpene hydrocarbons (39.28-49.42%). The phenylpropanoid derivative 2,4,5-trimethoxy-styrene (ArC2), the sesquiterpene hydrocarbon ishwarane, and the phenylpropanoid dillapiole were the major compounds. Principal component analysis (PCA) of the classes and compounds ≥ 2.0% indicated that plants colonized by E. asburiae had a reduction in the content of sesquiterpene hydrocarbons and an increase in phenylpropanoids and derivatives. Plants treated with this bacterium also had an increase in the content of 2,4,5-trimethoxystyrene at 30 dpi. Plants inoculated with K. variicola had significant increases only in the content of the classes monoterpene hydrocarbons and 'other compounds' (hydrocarbons, esters, ketones, etc.). These data suggest that the production of plant secondary metabolites can be modified depending on the type of rhizobacteria inoculated.

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.

Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology / 中西医结合学报

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, β-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

Chemical Composition and Preliminary Toxicity Evaluation of the Essential Oil from Peperomia circinnata Link var. circinnata. (Piperaceae) in Artemia salina Leach.

Peperomia Ruiz and Pav, the second largest genus of the Piperaceae, has over the years shown potential biological activities. In this sense, the present work aimed to carry out a seasonal and circadian study on the chemical composition of Peperomia circinata essential oils and aromas, as well as to evaluate the preliminary toxicity in Artemia salina Leach and carry out an in silico study on the interaction mechanism. The chemical composition was characterized by gas chromatography (GC/MS and GC-FID). In the seasonal study the essential oil yields had a variation of 1.2-7.9%, and in the circadian study the variation was 1.5-5.6%. The major compounds in the seasonal study were ß-phellandrene and elemicin, in the circadian they were ß-phellandrene and myrcene, and the aroma was characterized by the presence of ß-phellandrene. The multivariate analysis showed that the period and time of collection influenced the essential oil and aroma chemical composition. The highest toxicity value was observed for the essential oil obtained from the dry material, collected in July with a value of 14.45 ± 0.25 µg·mL-1, the in silico study showed that the major compounds may be related to potential biological activity demonstrated by the present study.

Enhanced effects and mechanisms of Syngonium podophyllum-Peperomia tetraphylla co-planting on phytoremediation of low concentration uranium-bearing wastewater.

To improve the remediation efficiency of plants on low concentration uranium-bearing wastewater and clarify its strengthening mechanism, Syngonium podophyllum-Peperomia tetraphylla co-planting system was established, the enhanced effects of plants interaction on uranium removal were investigated, the chemical forms, valence states, and subcellular distribution of uranium in plants were confirmed, and the mechanisms of alleviating uranium stress by plants interaction were revealed. In Syngonium podophyllum-Peperomia tetraphylla co-planting system, the total amount of ethanol-extracted uranium and deionized water-extracted uranium with higher toxicity in their roots were reduced by 10.30% and 7.17%, respectively, which reduced the toxicity of uranium to plants. Plants interaction can inhibit the reduction of U(VI) in the root of Peperomia tetraphylla, which is conducive to the transport of uranium from roots to shoots. In addition, uranium in plants mainly existed in the cell wall (54.44%-66.52%) and the soluble fraction (23.85%-32.89%). These results indicated that Syngonium podophyllum and Peperomia tetraphylla co-planting can enhance their effects of uranium removal by alleviating uranium stress with the cell wall immobilization and vacuole compartmentation, improving biomass of plants, increasing bioaccumulation factor and translocation factor of uranium.

Phylogenetics and comparative plastome genomics of two of the largest genera of angiosperms, Piper and Peperomia (Piperaceae).

Biological radiations provide unique opportunities to understand the evolution of biodiversity. One such radiation is the pepper plant family Piperaceae, an early-diverging and mega-diverse lineage that could serve as a model to study the diversification of angiosperms. However, traditional genetic markers lack sufficient variation for such studies, and testing hypotheses on poorly resolved phylogenetic frameworks becomes challenging. Limited genomic data is available for Piperaceae, which contains two of the largest genera of angiosperms, Piper (>2100 species) and Peperomia (>1300 species). To address this gap, we used genome skimming to assemble and annotate whole plastomes (152-161kbp) and >5kbp nuclear ribosomal DNA region from representatives of Piper and Peperomia. We conducted phylogenetic and comparative genomic analyses to study plastome evolution and investigate the role of hybridization in this group. Plastome phylogenetic trees were well resolved and highly supported, with a hard incongruence observed between plastome and nuclear phylogenetic trees suggesting hybridization in Piper. While all plastomes of Piper and Peperomia had the same gene content and order, there were informative structural differences between them. First, ycf1 was more variable and longer in Piper than Peperomia, extending well into the small single copy region by thousands of base pairs. We also discovered previously unknown structural variation in 14 out of 25 Piper taxa, tandem duplication of the trnH-GUG gene resulting in an expanded large single copy region. Other early-diverging angiosperms have a duplicated trnH-GUG, but the specific rearrangement we found is unique to Piper and serves to refine knowledge of relationships among early-diverging angiosperms. Our study demonstrates that genome skimming is an efficient approach to produce plastome assemblies for comparative genomics and robust phylogenies of species-rich plant genera.

Obtainment of the spray-dried extracts of Peperomia pellucida L. (H.B.K.) using different atomization temperatures: physicochemical characterization and technological development for pharmaceutical applications.

Spray-dried extracts are prepared as powders or granules after solvent removal, which can be obtained in the presence or absence of pharmaceutical adjuvants. This work aimed to optimize the process of obtaining dried extracts of Peperomia pellucida L. (HBK) by spray drying. The characterization of the extract was performed by thermal analysis, specific surface area, particle size and high performance liquid chromatography (HPLC); then, capsules were developed for antimicrobial treatment, evaluating four bench lots by the determination of the angle of repose and time of flow, scanning electron microscopy, porosity and physicochemical quality control. There were no significant differences between the extracts obtained by spray drying at atomization temperatures of 140 °C, 160 °C and 180 °C, which was confirmed by thermal analysis. Specific surface area varied inversely with the mean particle size. Regarding the marker content by HPLC, no significant differences were found between the samples, although the flavonoid fraction was more stable at 160 °C. Bench lots (I to IV) were developed using the diluents Flowlac®, Starch® 1500, microcrystalline cellulose 250 and Cellactose® 80. Based on the results, the bench lot I, containing Flowlac®, was selected. The results of physicochemical quality control demonstrated that the selected formulation meets the pre-established parameters, and proving to be economically viable.

Fungal endophytes in Peperomia obtusifolia and their potential as inhibitors of chickpea fungal pathogens.

Chickpea (Cicer arietinum L., Fabaceae) is the second most important legume after common bean (Phaseolus vulgaris L., Fabaceae) and third in production among the legumes grains worldwide. Ascochyta blight and Fusarium wilt are among the main fungal infections which cause the major losses of chickpea crop. In this work we report the phyto-pathogen controlling properties of 24 endophyte Phomopsis/Diaporthe isolates on the chickpea fungal pathogens Ascochyta rabiei, Fusarium oxysporum and Fusarium solani. The Phomopsis/Diaporthe strains were isolated amongst a total of 62 endophytic fungi from the aerial parts of the herbaceous perennial American plant Peperomia obtusifolia (Piperaceae) along with Fusarium, Septoria, Colletotrichum, Alternaria and Roussoella genera among others. Phomopsis/Diaporthe isolates were identified as Diaporthe infecunda (12 isolates), Diaporthe sackstoni (1 isolate), Diaporthe cf. brasiliensis (4 isolates) and Phomopsis cf. tuberivora (7 isolates). All the Phomopsis/Diaporthe strains antagonized A. rabiei strain AR2 with a mean of inhibition (% I) of 86.59 ± 1.49% in dual cultures. The metabolic characterization of the Phomopsis/Diaporthe strains showed groups in three clusters which were in agreement with the taxonomic identification. Bioautographic evaluation of organic extracts showed that those of D. cf. brasiliensis and D. infecunda were better as inhibitors. Strain Po 45 was one of the most active (cluster 1, 96.87% I), and its ethyl acetate extract inhibited A. rabiei growth in a bioautographic assay until at least 10 µg/mm applied showing a specific chromatographic band as the responsible of the A. rabiei inhibition.

Anti-inflammatory and sedative activities of Peperomia galioides: in vivo studies in mice.

Aerial parts (leaves, flowers, stem) of Peperomia galioides extract administered to mice, was used to confirm its anti-inflammatory and sedative folk uses. The anti-inflammatory activity was assessed by croton oil-induced ear oedema and myeloperoxidase (acute inflammation); cotton pellet-induced granuloma (sub-acute inflammation) and Escherichia coli Lipopolysaccharide (LPS) induced inflammation (cellular mediators). The sedative activity was studied by the pentobarbital-induced sleeping time test. Single doses (300 and 600 mg/kg; i.p.) of the extract reduced croton oil-induced ear oedema and myeloperoxidase activity. Six days administration of the extract (300 mg/kg, i.p.) to mice implanted with cotton pellets diminished granuloma formation. LPS (20 mg/kg, i.p.) enhanced plasma nitrites and TNF-α levels that were inhibited by the extract. The duration but not the onset of sleeping time was enhanced by 300 and 600 mg/kg of the extract. Our results show that P. galioides has anti-inflammatory and sedative activities in mice, which validates its traditional use.

Antibacterial activity of prenylated benzopyrans from Peperomia obtusifolia (Piperaceae).

Peperomia obtusifolia is a herbaceous perennial plant native to the Americas reported as a traditional medicine to treat snake bites and as a skin cleanser. The bioassay-guided fractionation of crude extracts from aerial parts of P. obtusifolia against a panel of clinically important fungi and bacteria, showed that hexane and dichloromethane extracts demonstrated selective bacterial inhibition, allowing the isolation of the known compounds peperobtusin A (1), and 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3"-methyl-2"-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylic acid (2) from dichloromethane extract. Compound 2 was active against Gram-positive bacteria including community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates and an Enterococcus faecalis vancomycin-resistant strain, with minimal inhibitory concentration (MIC) values of 4 µg/mL (10.8 µM) and 8 µg/mL (21.6 µM) respectively. The interaction of compound 2 with the bacterial membrane was demonstrated by means of Zeta potential experiments on S. aureus, then confirming the membrane damage by fluorescent microscopy experiments.