Modest Antimicrobial Activity Research Articles

Conventional and microwave-assisted synthesis, antimicrobial and antioxidant activity evaluation with in silico studies of carbazole-thiazole-Schiff base hybrids

Conventional and microwave irradiation (MWI) methods were applied to synthesize a series of thirteen carbazole-thiazole-Schiff base hybrids (2a-2m). MWI assisted synthesis was a benign approach to green synthesis on account of its miniscule reaction time and use of solvent. The structures of the synthesized derivatives were confirmed by means of spectral analytical data. All the compounds were evaluated for dual biological potency i.e., antimicrobial and antioxidant activity. The tested analogues had shown some modest antimicrobial activity and compounds 2f and 2i exhibited higher antioxidant activity compared to standard ascorbic acid. Oral bioavailability and adverse effects of the new entities were considered from druglikeness descriptors, having no violation of Lipinski's rule of five and Veber's rule for the synthesized compounds except for 2i, 2l, and 2m. The compounds which exhibited relatively high activity were explored further for molecular docking studies to understand the mode of binding interactions with the receptor protein. Molecular dynamics (MD) simulation was further studied to predict the stability of selective compounds inside the receptors which was well agreed with in vitro results and antioxidant value.

Total Synthesis and Microbiological Evaluation of Leopolic Acid A and Analogues.

New antimicrobial scaffolds are scarce, and there is a great need for the development of novel therapeutics. In this study, we report a convergent 9-step synthesis of leopolic acid A and a series of targeted analogues. The designed compounds allowed for incorporation of non-natural ureido dipeptide moieties and 4- and 5-position substituents around the 2,3-pyrrolidinedione of leopolic acid A. Leopolic acid A displayed modest antimicrobial activity (32 μg/mL) against MRSA, while the most active analogues displayed slightly improved activity (8-16 μg/mL). Additionally, several of the leopolic acid A analogues displayed promising antibiofilm activity, most notably having an MBEC:MIC ratio of ∼1. Overall, this work represents an initial SAR of the natural product and a framework for further optimization of these bioactive scaffolds within the context of bioactive pyrrolidinediones.

Synthesis, spectroscopic characterization, antibacterial activity and antiproliferative profile of a new silver(I) complex of 5-fluorocytosine

In this paper, we report the synthesis, structural characterization, and explore the potential antibacterial and antiproliferative activities of a new silver(I) complex of the nucleotide analogue 5-fluorocytosine, Ag-5FC. Elemental and thermogravimetric (TGA) analyses led to the minimal formula AgC4H4FN3O·H2O. Infrared (FT-IR) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopic analyses indicate that the ligand coordinates to the metal ion by its nitrogen and oxygen atoms. High resolution mass spectrometric (HRMS) data confirmed the proposed composition of the complex as well as the presence of recombination species in solution. Molecular modeling reinforces the proposed N,O-coordination of 5FC to silver as indicated by IR data with a possible structure of the complex in a dimeric form, of coordination formula [Ag(C4H4FN3O)(OH2)]2. The complex showed a modest antimicrobial activity (MIC = 4.3 mmol⋅L−1) against Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Staphylococcus aureus and Bacillus cereus) strains. Despite the low solubility, the Ag-5FC complex totally inhibited the proliferation of colon (HT-29), multidrug resistant ovarian (NCI/ADR-RES), prostate (PC-3), and renal (786–0) tumor cell lines in a concentration range of 6.2 to 9.3 µmol L−1. Further studies are necessary to confirm efficiency and safety for continuing the pre-clinical evaluation of the Ag-5FC complex.

In vitro antimikrobna aktivnost različitih ekstrakata Verbascum niveum

Introduction. Medicinal plants are the main ingredient of numerous medicines and pharmaceutical products, and antimicrobial activity has been demonstrated in a large number of medicinal plant extracts and essential oils. Considering that Verbascum L. species (mullein), officially approved by the European Medicines Agency, show antimicrobial properties, but also that there are species of this genus that have not been sufficiently studied, the aim of this study was to evaluate the antimicrobial activity of six different extracts of Verbascum niveum Ten. Material and methods. Antimicrobial bioassays were performed with one fungus (Candida albicans) and four bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis) by broth microdilution method according to the recommendations of the European Committee on Antimicrobial Susceptibility Testing. The results were expressed as the minimal inhibitory concentration (MIC) of an extract (mg/ml) that prevents the visible growth of bacteria/fungi. Results. The MIC values ranged from 0.39 to 1.25 mg/ml. The strongest effect was obtained with the ethanolic extract of leaves against Staphylococcus aureus (0.39 mg/ml). Conclusion. Although Verbascum species are considered to be an excellent antimicrobial agent, according to our result, the tested extracts had modest antimicrobial activity.

Pd(II) complex involving a new pyrole-based ligand: Synthesis, spectral analysis and antimicrobial activity

In the current study, firstly, a new pyrrole-based ligand (3,4-(ethylenedimercaptodiacetoxy)-N-(benzyl)-diethyl-2,5-pyrroledicarboxylate (L) was synthesized in the presence of diethyl-N-benzyl-3,4-dihydroxy-1H-pyrrole-2,5-dicarboxylate and 2,2'-(ethane-1,2-diylbis(sulfanediyl))diacetylchloride. Then, the palladium(II) complex of the synthesized ligand was obtained, and its structural features were examined by spectral (HRMS, ESI-MS, UV-Visible, FTIR, 1H NMR, 13C NMR, XRD-POWDER, SEM, EDX) and thermogravimetric (TG-DTA) techniques. The spectral and thermal measurements of the ligand and its Pd(II) complex show that the ligand is coordinated to the Pd2+ ion. Antimicrobial activities of both the ligand and its palladium complex were examined. It was determined that whereas the ligand indicated modest antimicrobial activity against Staphylococcus aureus and Candida albicans at a concentration of 6.25 µg/ml, the palladium complex was significantly effective against C. albicans at a concentration of 6.25 µg/ml.

Poloxamer and Chitosan-Based <i>In Situ</i> Gels Loaded with <i>Orthosiphon stamineus</i> Benth. Extracts Containing Rosmarinic Acid for the Treatment of Ocular Infections

Orthosiphon stamineus Benth. (OS) is a commonly used medicinal plant for curbing bacterial infections globally. This work aimed to fabricate poloxamer and chitosan-based in situ gels loaded with standardized aqueous-ethanolic OS leaf extracts and investigate their antimicrobial efficacy as a potential remedy against ocular infections. In situ gels containing 0.5% w/v OS extract prepared using cold dispersion method were subjected to physicochemical characterization, including in vitro-release studies. Antimicrobial efficacy was tested against Staphylococcus aureus, Micrococcus luteus, Escherichia coli, and Pseudomonas aeruginosa using agar diffusion method. Thin layer chromatography and high performance liquid chromatography chromatograms confirmed the presence of rosmarinic acid (RA) and sinensitin in OS extracts with same retention factor (0.26 and 0.49) and retention times (12.2 and 20.7 min) against reference standards. A homogenous brown coloured in situ gel exhibited low viscosity as a solution and increased viscosity in gel form at ocular temperature. The optimized formulations, P7 (21% P407/4% P188), P8 (21% P407/5% P188) and F5 (1.5% chitosan and 45% β-glycerophosphate) exhibited ideal ocular pH (7.27-7.46), phase transition at ocular temperature (33-37°C) and prolonged RA release up to 12 h. Formulation F5 showed an inhibition zone of 4.3 mm against M. luteus. Among all, formulation F5 alone exhibited modest antimicrobial activity against M. luteus. OS extracts at 5% and 10% were most active against tested bacteria however, loading them into in situ gels resulted in sedimentation. Hence, isolation of RA from OS extract is suggested before loading into formulations for a better antimicrobial activity.

Study on the Structure-Activity Relationship of an Antimicrobial Peptide, Brevinin-2GUb, from the Skin Secretion of Hylarana guentheri.

Antimicrobial peptides (AMPs) are considered potential alternatives to antibiotics due to their advantages in solving antibiotic resistance. Brevinin-2GUb, which was extracted from the skin secretion of Hylarana guentheri, is a peptide with modest antimicrobial activity. Several analogues were designed to explore the structure–activity relationship and enhance its activity. In general, the Rana box is not an indispensable motif for the bioactivity of Brevinin-2GUb, and the first to the 19th amino acids at the N-terminal end are active fragments, such that shortening the peptide while maintaining its bioactivity is a promising strategy for the optimisation of peptides. Keeping a complete hydrophobic face and increasing the net charges are key factors for antimicrobial activity. With the increase of cationic charges, α-helical proportion, and amphipathicity, the activity of t-Brevinin-2GUb-6K (tB2U-6K), in combatting bacteria, drastically improved, especially against Gram-negative bacteria, and the peptide attained the capacity to kill clinical isolates and fungi as well, which made it possible to address some aspects of antibiotic resistance. Thus, peptide tB2U-6K, with potent antimicrobial activity against antibiotic-resistant bacteria, the capacity to inhibit the growth of biofilm, and low toxicity against normal cells, is of value to be further developed into an antimicrobial agent.

Impact of ciprofloxacin impurities on bacterial growth, antibiotic resistance development and content assays.

In addition to active pharmaceutical ingredient (API), antibiotics may contain small amounts of excipients and impurities and be prone to accumulation of degradation products. There has been limited work characterizing how these substances impact bacterial growth and antibiotic resistance development. We investigated how two ciprofloxacin (CIP) impurities, fluoroquinolonic acid (FQA) and ciprofloxacin ethylenediamine analogue (CEA), impact growth and antibiotic resistance in Escherichia coli. Additionally, we investigated how these impurities impact a frequently used API content assay. Both impurities displayed modest antimicrobial activity compared to the CIP API. The effective antimicrobial activity of a medicine containing increased impurity levels may permit bacterial growth and resistance development. Our results also suggest that increasing exposure concentration and duration to CEA and FQA, independent of CIP, can promote antibiotic resistance development. However, at concentrations of 100% and below the MIC of the API, impurities had limited contributions to resistance development compared to the CIP API. From a methodological standpoint, we found that UV spectrophotometry may be inadequate to account for antibiotic impurities or degradation products. This can lead to incorrect estimations of API content and we propose additional multi-wavelength measures when using UV spectrophotometry to help identify impurities or degradation.

Spermine Derivatives of Indole-3-carboxylic Acid, Indole-3-acetic Acid and Indole-3-acrylic Acid as Gram-Negative Antibiotic Adjuvants.

The discovery of new antibiotic adjuvants is an attractive option for overcoming antimicrobial resistance. We have previously reported the discovery of a bis-6-bromoindolglyoxylamide derivative of spermine as being able to enhance the action of antibiotics against Gram-negative bacteria but suffers from being cytotoxic and red-blood cell haemolytic. A series of analogues was prepared exploring variation of the indolglyoxylamide unit, to include indole-3-acrylic, indole-3-acetic and indole-3-carboxylate units, and evaluated for antibiotic enhancing properties against a range of Gram-negative bacteria, and for intrinsic antimicrobial, cytotoxic and haemolytic properties. Two spermine derivatives, bearing 5-bromo-indole-3-acetic acid (17) and 5-methoxy-indole-3-acrylic acid (14) end groups were found to exhibit good to moderate antibiotic adjuvant activities for doxycycline towards the Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae, but with more modest intrinsic antimicrobial activity and greatly reduced cytotoxic and haemolytic properties. The mechanism of action of the latter derivative identified its ability to disrupt the outer membranes of bacteria and to inhibit the AcrAB-TolC efflux pump directly or by inhibiting the proton gradient.

Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae)

Background/Aim. Plant essential oils (EOs) can have a significant antibacterial effect especially through additive or synergistic action as antibiotic adjuvants. We investigated the composition and activity of EOs of two species of genus Salvia (S) from Greece with the aim to determine their antimicrobial activity as well as the activity in combination with selected antibiotics. Methods. The aerial parts of wild-growing S. fruticosa and S. ringens were subjected to a steam distillation and the obtained EOs were analyzed by gas chromatography and gas chromatography/mass spectrometry. The broth-microdilution method was used in order to determine the minimum inhibitory concentrations (MICs) of EOs on seven strains of bacteria and one yeast. Antimicrobial activity of the combination of EO and antibiotics was investigated by checkerboard method and estimated by calculating fractional inhibitory concentration (FIC) of each component and fractional inhibitory concentration index (FICI). Results. Dominant component of S. fruticosa EO was transthujone (54.2%) and for S. ringens EO i t w as ?-pinene (28.1%). The MICs of EOs of both species were in the range from 200 ?g/mL to > 500 ?g/mL. The strongest antimicrobial effect was achieved against Bacillus subtilis and Candida albicans. According to FICI values, EO of S. fruticosa had additive effect with ciprofloxacin against most of bacterial strains but not with amikacin. Conclusion. The essential oils of S. ringens and S. fruticosa showed modest antimicrobial activity. However, the essential oil of S. fruticosa showed a promising additive effect in combination with ciprofloxacin.

Reversal of Pathogen-Induced Barrier Defects in Intestinal Epithelial Cells by Contra-pathogenicity Agents.

Environmental enteropathy (EE) is associated with stunting, impairment of responses to oral vaccines, and other adverse health consequences in young children throughout the developing world. EE is characterized by chronic low-grade intestinal inflammation and disrupted epithelial barrier integrity, partly resulting from dysregulation of tight junction proteins, observed in other enteropathies such as celiac disease. During EE, this dysregulation of tight junction expression amplifies translocation of pathogenic bacteria across the intestinal mucosa. The aim was to determine whether enteropathogen-mediated epithelial barrier failure can be ameliorated using contra-pathogenicity therapies. Intestinal epithelial barrier damage was assessed in Caco-2 cells incubated with three important enteropathogens identified in EE patients: Enteropathogenic Escherichia coli (EPEC), Citrobacter rodentium (C. rodentium), and Cryptosporidium parvum (C. parvum). Potential therapeutic molecules were tested to detect effects on transepithelial resistance (TER), bacterial translocation (BT), claudin-4 expression, and regulation of the inflammatory cytokine response. All three enteropathogens compared to uninfected cells, reduced TER (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0007), reduced claudin-4 expression, and permitted BT (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0003) through the monolayer. Zinc, colostrum, epidermal growth factor, trefoil factor 3, resistin-like molecule-β, hydrocortisone, and the myosin light chain kinase inhibitor ML7 (Hexahydro-1-[(5-iodo-1-naphthalenyl)sulfonyl]-1H-1,4-diazepine hydrochloride); ML7) improved TER (up to 70%) and decreased BT (as much as 96%). Only zinc demonstrated modest antimicrobial activity. The enteropathogens impaired intestinal-epithelial barrier integrity with dysregulation of claudin-4 and increased bacterial translocation. Enteropathogen-mediated damage was reduced using contra-pathogenicity agents which mitigated the effects of pathogens without direct antimicrobial activity.

Synthesis and Antimicrobial Assessment of Some New 2-(Thiazol-5-yl)-1,3,4-oxadiazoles

Considering the promising antimicrobial activity of compounds bearing the thiazole or the oxadiazole rings in their structures, we set out to obtain new antimicrobial molecules bearing the 2-(thiazol-5-yl)-1,3,4-oxadiazole schaffold. The structures of the 8 new compounds obtained was confirmed by physicochemical characterization including: 1H-NMR, MS and elemental analysis. Antimicrobial activity was investigated against 5 Gram-positive bacterial strains, 2 Gram-negative bacterial strains and 2 fungal strains. The newly synthesized compounds showed modest antimicrobial activity.

A CuAAC Click Approach for the Introduction of Bidentate Metal Complexes to a Sulfanilamide-Derived Antibiotic Fragment.

A simple "click-chemistry" approach was employed in order to functionalize the known antibiotic fragment sulfanilamide with a bidentate pyridyl-triazole pocket, which allowed for the synthesis of ruthenium(II) and rhenium(I) carbonyl chloride complexes. Six new complexes were prepared and comprehensively characterized, including five single crystal X-ray structures, photophysical characterization, and testing for antimicrobial activity. Interestingly, functionalization of the pyridine ring with an ortho-hydroxymethyl group resulted in a greater than 100-fold increase in the rate of ligand release in a dimethylsulfoxide solution. Subsequent studies indicated this process could be further accelerated by irradiation with 265 nm light. Structural characterization of four of the complexes indicates that this is the result of a lengthening and weakening of the Re-NPyridine bond (average (Ltri) = 2.19 Å vs LtriOH = 2.25 Å) due to the steric influence of the hydroxymethyl group. The organometallic rhenium(I) pyridyl-triazole functionality maintains its characteristic fluorescent properties despite the presence of the sulfonamide moiety. Two of the compounds showed modest antimicrobial activity against methicillin-resistant Staphylococcus aureus, whereas the structurally similar sulfamethoxazole alone showed no activity under the same conditions.

Evidences of Tenacibaculum maritimum evading strategies against Senegalese sole (Solea senegalensis) primary head-kidney leucocytes

Antimicrobial peptides (AMPs) are an essential component of innate immunity of invertebrates. Anti-lipopolysaccharide factor (ALF), as a main type of AMPs in crustaceans, attends in the disease prevention in general. In this research, a novel Group D ALF was identified and characterized from Penaeus monodon, named PenmonALF8. It was an anionic peptide, with both the full-length peptide and lipopolysaccharide binding domain (LBD) a low isoelectric point. PenmonALF8, composed of a signal peptide of 26 amino acids and a mature peptide of 98 amino acids, probably contained three alpha helixes and four beta sheets. Moreover, PenmonALF8 was detected in all tested tissues of P. monodon, and the expression level in hemocyte and intestine was relatively high. When challenged by Vibrio parahaemolyticus, PenmonALF8 showed 30–100 times higher expression level in all the tissues except in hemocyte and intestine, indicating that PenmonALF8 played a very important role in the immune response of P. monodon. By fusing to a SUMO protein, PenmonALF8 was successfully over-expressed in E. coli and purified by affinity chromatography. Additionally, the reconstituted PenmonALF8 and its LBD region displayed modest antimicrobial activity. This is the first research about the Group D ALF in P. monodon, which provides more information for humoral immunity study of shrimps.

De novo assembly, characterization of tissue-specific transcriptomes and identification of immune related genes from the scallop Argopecten purpuratus

Antimicrobial peptides (AMPs) are an essential component of innate immunity of invertebrates. Anti-lipopolysaccharide factor (ALF), as a main type of AMPs in crustaceans, attends in the disease prevention in general. In this research, a novel Group D ALF was identified and characterized from Penaeus monodon, named PenmonALF8. It was an anionic peptide, with both the full-length peptide and lipopolysaccharide binding domain (LBD) a low isoelectric point. PenmonALF8, composed of a signal peptide of 26 amino acids and a mature peptide of 98 amino acids, probably contained three alpha helixes and four beta sheets. Moreover, PenmonALF8 was detected in all tested tissues of P. monodon, and the expression level in hemocyte and intestine was relatively high. When challenged by Vibrio parahaemolyticus, PenmonALF8 showed 30–100 times higher expression level in all the tissues except in hemocyte and intestine, indicating that PenmonALF8 played a very important role in the immune response of P. monodon. By fusing to a SUMO protein, PenmonALF8 was successfully over-expressed in E. coli and purified by affinity chromatography. Additionally, the reconstituted PenmonALF8 and its LBD region displayed modest antimicrobial activity. This is the first research about the Group D ALF in P. monodon, which provides more information for humoral immunity study of shrimps.

Characterization of a group D anti-lipopolysaccharide factor (ALF) involved in anti-Vibrio response in Penaeus monodon

Antimicrobial peptides (AMPs) are an essential component of innate immunity of invertebrates. Anti-lipopolysaccharide factor (ALF), as a main type of AMPs in crustaceans, attends in the disease prevention in general. In this research, a novel Group D ALF was identified and characterized from Penaeus monodon, named PenmonALF8. It was an anionic peptide, with both the full-length peptide and lipopolysaccharide binding domain (LBD) a low isoelectric point. PenmonALF8, composed of a signal peptide of 26 amino acids and a mature peptide of 98 amino acids, probably contained three alpha helixes and four beta sheets. Moreover, PenmonALF8 was detected in all tested tissues of P. monodon, and the expression level in hemocyte and intestine was relatively high. When challenged by Vibrio parahaemolyticus, PenmonALF8 showed 30–100 times higher expression level in all the tissues except in hemocyte and intestine, indicating that PenmonALF8 played a very important role in the immune response of P. monodon. By fusing to a SUMO protein, PenmonALF8 was successfully over-expressed in E. coli and purified by affinity chromatography. Additionally, the reconstituted PenmonALF8 and its LBD region displayed modest antimicrobial activity. This is the first research about the Group D ALF in P. monodon, which provides more information for humoral immunity study of shrimps.

Ailanthus altissima (Miller) Swingle seed oil: chromatographic characterization by GC-FID and HS-SPME-GC-MS, physicochemical parameters, and pharmacological bioactivities.

This study aimed to identify the physicochemical and the chemical properties of Ailanthus altissima (Miller) Swingle seed oil and to evaluate its in vitro antioxidant and antibacterial activities and in vivo analgesic and anti-inflammatory activities. The fatty acids' composition was determined using GC-FID. The oil was screened for antioxidant activity by DPPH test. The analgesic and anti-inflammatory activities were determined using the acetic acid writhing test in mice and the carrageenan-induced paw edema assay in rats, respectively. Volatile compounds were characterized by HS-SPME-GC-MS. A. altissima produces seeds which yielded 17.32% of oil. The seed oil was characterized by a saponification number of 192.6mg KOH∙g of oil, a peroxide value of 11.4meq O2∙kg of oil, a K232 of 4.04, a K270 of 1.24, and a phosphorus content of 126.2ppm. The main fatty acids identified were palmitic (3.06%), stearic (1.56%), oleic (38.35%), and linoleic acids ones (55.76%). The main aroma compounds sampled in the headspace were carbonyl derivatives. The oil presents an important antioxidant activity (IC50 = 24.57μg/mL) and a modest antimicrobial activity. The seed oil at 1g/kg showed high analgesic (91.31%) and anti-inflammatory effects (85.17%). The presence of high levels of unsaturated fatty acids and the noteworthy antioxidant capacity of the seed oil can hypothesize its use as an analgesic and anti-inflammatory agent.

Computational resources and tools for antimicrobial peptides.

Antimicrobial peptides (AMPs), as evolutionarily conserved components of innate immune system, protect against pathogens including bacteria, fungi, viruses, and parasites. In general, AMPs are relatively small peptides (<10 kDa) with cationic nature and amphipathic structure and have modes of action different from traditional antibiotics. Up to now, there are more than 19 000 AMPs that have been reported, including those isolated from nature sources or by synthesis. They have been considered to be promising substitutes of conventional antibiotics in the quest to address the increasing occurrence of antibiotic resistance. However, most AMPs have modest direct antimicrobial activity, and their mechanisms of action, as well as their structure-activity relationships, are still poorly understood. Computational strategies are invaluable assets to provide insight into the activity of AMPs and thus exploit their potential as a new generation of antimicrobials. This article reviews the advances of AMP databases and computational tools for the prediction and design of new active AMPs. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Penicilloitins A and B, new antimicrobial fatty acid esters from a marine endophytic Penicillium species

Two new antimicrobial fatty acid esters, penicilloitins A and B (1 and 2), along with α-cyclopiazonic acid (3), tryptamine (4) and indole-3-carbaldehyde (5), were isolated from mycelial extracts and the culture broth of a marine endophytic Penicillium species and their structures established by spectroscopic techniques including 1D (1H NMR and 13C NMR) and 2D NMR (COSY, multiplicity-edited HSQC, and HMBC) as well as HRESIMS. Of these compounds, 1, 3 and 4 displayed modest antimicrobial activity.

Four new tetramic acid and one new furanone derivatives from the plant endophytic fungus Neopestalotiopsis sp.

Four new tetramic acid analogues neopestalotins A–D (1–4), one new furanone derivative neopestalotin E (6), and the known compound hymenosetin have been isolated from the solid cultures of the plant endophytic fungus Neopestalotiopsis sp. The structures of the new compounds were determined mainly by nuclear magnetic resonance (NMR) experiments. The absolute configurations of 1 and 2 were assigned by circular dichroism (CD) data, whereas those of 3 and 4 were deduced by a combination of CD and heteronuclear long range coupling (HETLOC) data. Compound 2 showed modest antimicrobial activity against the Gram-positive bacteria, Bacillus subtilis, Staphylococcus aureus col, and Streptococcus pneumoniae.