Antimycobacterial activity of aqueous and methanol extracts of nine plants against Mycobacterium bacteria

Purpose: The present study was done to evaluate the antimycobacterial activity of aqueous and methanol extracts of nine plants viz., Buddleja saligna, Carpobrotus dimidiatus, Capparis tomentosa, Dichrostachys cinerea, Ekebergia capensis, Ficus sur, Gunnera perpensa, Leonotis leonurus and Tetradenia riparia in South Africa. Methods: Aqueous and methanol extracts of the leaves the plants were tested in vitro for their activity against Mycobacterium smegmatis, Mycobacterium tuberculosis H37Rv (ATCC 25177) and three well-characterized clinical isolates of MDR and XDR-TB isolates using the agar incorporation method. The minimum inhibitory concentration (MIC) of each of the active plant extract was determined using the broth microdilution method. Cytotoxic effect was evaluated against the mouse BALB/C monocyte macrophage (J774.2) and peripheral blood mononuclear cells (PBMCs) whole the toxicity screening was done using the brine shrimp lethality assay. Composition of each of the plants was determined using thin layer chromatography while qualitative analysis of antimycobacterial compounds was done using TLC-Bioautography Results: The methanol extracts of B. saligna, C. tormentosa and C. dimidiatus; and aqueous extracts of G. perpensa and T. riparia possessed significant activity against M. smegmatis, M. tuberculosis H37Rv (ATCC 25177) and the three well-characterized clinical isolates of MDR and XDR-TB. Except for a high concentration of G. perpensa none of the other plants which possessed antimycobacterial activity showed any toxic or cytotoxic activity. Conclusion: Our findings show that B. saligna, C. tormentosa, C. dimidiatus, G. perpensa, and T. riparia have antimycobacterial activity. Further studies would aim at isolation and identification of the active compounds from the plants extracts which had positive antimycobacterial activity.

In silico Design and Synthesis of Tetrahydropyrimidinones and Tetrahydropyrimidinethiones as Potential Thymidylate Kinase Inhibitors Exerting Anti-TB Activity Against Mycobacterium tuberculosis

Background and Purpose

Tuberculosis has been reported to be the worldwide leading cause of death resulting from a sole infectious agent. The emergence of multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis has made the battle against the infection more difficult since most currently available therapeutic options are ineffective against these resistant strains. Therefore, novel molecules need to be developed to effectively treat tuberculosis disease. Preliminary docking studies revealed that tetrahydropyrimidinone derivatives have favorable interactions with the thymidylate kinase receptor. In the present investigation, we report the synthesis and the mycobacterial activity of several pyrimidinones and pyrimidinethiones as potential thymidylate kinase inhibitors.

Methods

The title compounds (1a-d) and (2a-b) were synthesized by a one-pot three-component Biginelli reaction. They were subsequently characterized and used for whole-cell anti-TB screening against H37Rv and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis (MTB) by the resazurin microplate assay (REMA) plate method. Molecular modeling was conducted using the Accelry's Discovery Studio 4.0 client program to explain the observed bioactivity of the compounds. The pharmacokinetic properties of the synthesized compounds were predicted and analyzed.

Results

Of the compounds tested for anti-TB activity, pyrimidinone 1a and pyrimidinethione 2a displayed moderate activity against susceptible MTB H37Rv strains at 16 and 32 µg/mL, respectively. Only compound 2a was observed to exert modest activity at 128 µg/mL against MTB strains with cross-resistance to rifampicin and isoniazid. The presence of the trifluoromethyl group was essential to retain the inhibitory activity of compounds 1a and 2a. Molecular modeling studies of these compounds against thymidylate kinase targets demonstrated a positive correlation between the bioactivity and structure of the compounds. The in-silico ADME (absorption, distribution, metabolism, and excretion) prediction indicated favorable pharmacokinetic and drug-like properties for most compounds.

Conclusion

Pyrimidinone 1a and pyrimidinethione 2a were identified as the leading compounds and can serve as a starting point to develop novel anti-TB therapeutic agents.

Novel Series of Methyl 3-(Substituted Benzoyl)-7-Substituted-2-Phenylindolizine-1-Carboxylates as Promising Anti-Inflammatory Agents: Molecular Modeling Studies

The cyclooxygenase-2 (COX-2) enzyme is considered to be an important target for developing novel anti-inflammatory agents. Selective COX-2 inhibitors offer the advantage of lower adverse effects that are commonly associated with non-selective COX inhibitors. In this work, a novel series of methyl 3-(substituted benzoyl)-7-substituted-2-phenylindolizine-1-carboxylates was synthesized and evaluated for COX-2 inhibitory activity. Compound 4e was identified as the most active compound of the series with an IC50 of 6.71 M, which is comparable to the IC50 of indomethacin, a marketed non-steroidal anti-inflammatory drug (NSAID). Molecular modeling and crystallographic studies were conducted to further characterize the compounds and gain better understanding of the binding interactions between the compounds and the residues at the active site of the COX-2 enzyme. The pharmacokinetic properties and potential toxic effects were predicted for all the synthesized compounds, which indicated good drug-like properties. Thus, these synthesized compounds can be considered as potential lead compounds for developing effective anti-inflammatory therapeutic agents.

Synthesis and Structural Elucidation of Novel Benzothiazole Derivatives as Anti-tubercular Agents: In-silico Screening for Possible Target Identification

BACKGROUND

Benzothiazole derivatives are known for anti-TB properties. Based on the known anti-TB benzothiazole pharmacophore, in the present study, we described the synthesis, structural elucidation, and anti-tubercular screening of a series of novel benzothiazole (BNTZ) derivatives (BNTZ 1-7 and BNTZ 8-13).

OBJECTIVE

The study aims to carry out the development of benzothiazole based anti-TB compounds.

METHODS

Title compounds are synthesized by microwave method and purified by column chromatography. Characterization of the compounds is achieved by FT-IR, NMR (1H and 13C), LCMS and elemental analysis. Screening of test compounds for anti-TB activity is achieved by Resazurin Microplate Assay (REMA) Plate method.

RESULTS

It was noted that the BNTZ compound with an isoquinoline nucleus (BNTZ 9) exhibited remarkable anti-tubercular activity at 8 µg/mL against both the susceptible strain H37Rv and the multi-drug resistant tuberculosis strains of Mycobacterium tuberculosis. On the other hand, the BNTZ compound with a naphthalene nucleus (BNTZ 2) revealed anti-tubercular activity at 6 µg/mL and 11 µg/mL against both the susceptible strain H37Rv and the multi-drug resistant tuberculosis strains of M. tuberculosis, respectively. One of the selected BNTZ derivatives BNTZ 13 was used for single crystal X-ray studies.

CONCLUSION

To identify the appropriate target for potent BNTZ compounds from the series, molecular modeling studies revealed the multiple strong binding of several BNTZs with mycobacterium lysine-ɛ-aminotransferase and decaprenyl-phosphoryl-β-D-ribose 2'-oxidase. The interaction is derived by forming favorable hydrogen bonds and stacking interactions. This new class of BNTZ compounds gave promising anti-tubercular actions in the low micromolar range, and can be further optimized on a structural basis to develop promising, novel, BNTZ pharmacophore-based anti-tubercular drugs.

Computational, crystallographic studies, cytotoxicity and anti-tubercular activity of substituted 7-methoxy-indolizine analogues

Indolizines are heteroaromatic compounds, and their synthetic analogues have reportedly showed promising pharmacological properties. In this study, a series of synthetic 7-methoxy-indolizine derivatives were synthesised, characterised and evaluated for in vitro whole-cell anti-tuberculosis (TB) screening against susceptible (H37Rv) and multi-drug-resistant (MDR) strains of Mycobacterium tuberculosis (MTB) using the resazurin microplate assay method. The cytotoxicity was evaluated using the MTT assay. In silico molecular-docking study was conducted for compounds 5a-j against enoyl-[acyl-carrier] protein reductase, a key enzyme of the type II fatty acid synthesis that has attracted much interest for the development of novel anti-TB compounds. Thereafter, molecular dynamic (MD) simulation was undertaken for the most active inhibitors. Compounds 5i and 5j with the methoxy functional group at the meta position of the benzoyl group, which was at the third position of the indolizine nucleus, demonstrated encouraging anti-TB activity against MDR strains of MTB at 16 μg/mL. In silico studies showed binding affinity within the range of 7.07-8.57 kcal/mol, with 5i showing the highest binding affinity. Hydrogen bonding, π-π- interactions, and electrostatic interactions were common with the active site. Most of these interactions occurred with the catalytic amino acids (Pro193, Tyr158, Phe149, and Lys165). MD simulation showed that 5j possessed the highest binding affinity toward the enzyme, according to the two calculation methods (MM/PBSA and MM/GBSA). The single-crystal X-ray studies of compounds 5c and 5d revealed that the molecular arrangements in these two structures were mostly guided by C-H···O hydrogen-bonded dimeric motifs and C-H···N hydrogen bonds, while various secondary interactions (such as π···π and C-H···F) also contributed to crystal formation. Compounds 5a, 5c, 5i, and 5j exhibited no toxicity up to 500 μg/mL. In conclusion, 5i and 5j are promising anti-TB compounds that have shown high affinity based on docking and MD simulation results.

Larvicidal study of tetrahydropyrimidine scaffolds against Anopheles arabiensis and structural insight by single crystal X-ray studies

A series of methyl or ethyl 4-(substitutedphenyl/pyridyl)-6-methyl-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (HPM) analogues 4a-g were synthesized and evaluated for larvicidal activity against Anopheles arabiensis. These newly synthesized compounds were characterized by spectral studies such as FT-IR, NMR (¹ H and ¹³ C), LC-MS, and elemental analysis. The conformational features and supramolecular assembly of molecules 4a, 4b, and 4e were further analyzed from single crystal X-ray study. The larvicidal activity of these tetrahydropyrimidine pharmacophore series was analyzed based on their relative substituents. Among the synthesized HPM analogous from the series, compounds 4d and 4e both having electron withdrawing chlorine group on phenyl ring at the fourth position of the tetrahydropyrimidine pharmacophore exhibited the most promising larvicidal activity.

Benzothiazole analogs as potential anti-TB agents: computational input and molecular dynamics

Biotin is very important for the survival of Mycobacterium tuberculosis. 7,8-Diamino pelargonic acid aminotransaminase (DAPA) is a transaminase enzyme involved in the biosynthesis of biotin. The benzothiazole title compounds were investigated for their in vitro anti-tubercular activity against two tubercular strains: H37Rv (ATCC 25,177) and MDR-MTB (multidrug-resistant M. tuberculosis, resistant to isoniazid, rifampicin, and ethambutol) by an agar incorporation method. The possible binding mode and predicted affinity were computed using a molecular docking study. Among the synthesized compounds in the series, the title compound {2-(benzo[d]thiazol-2-yl-methoxy)-5-fluorophenyl}-(4-chlorophenyl)-methanone was found to exhibit significant activity with minimum inhibitory concentrations of 1 μg/mL and 2 μg/mL against H37Rv and MDR-MTB, respectively; this compound showed the highest binding affinity (-24.75 kcal/mol) as well.

Efficient Synthesis and Characterization of Novel Substituted 3-Benzoylindolizine Analogues via the Cyclization of Aromatic Cycloimmoniumylides with Electrondeficient Alkenes

Background:

Indolizine pharmacophore is known to exhibit various promising pharmacological properties such as analgesic, anticancer, antihistaminic, antidiabetic, anti-inflammatory, antileishmanic, antimicrobial, antimutagenic, antioxidant, antitubercular, antiviral, larvicidal and herbicidal activities.

Objective:

In the present investigation, it was envisaged to synthesize a series of novel ethyl-7-substituted-3-(4- substituted benzoyl)-2-substituted indolizine-1-carboxylates by employing chromium(IV)oxide as dehydrogenating agent with triethylamine combination.

Method:

Synthesis of a series of proposed polysubstituted indolizines by employing chromium(IV)oxide as dehydrogenating agent with triethylamine combination. Final compounds were characterized by spectroscopic techniques viz fourier-transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, liquid chromatography- mass spectrometry, elemental analysis and selected title compound diethyl-3-(4- cyanobenzoyl)indolizine-1,2-dicarboxylate by single crystal X-ray method.

Results:

Aromatic cycloimmoniumylides undergo smooth cyclization with electron-deficient alkenes in the presence of triethylamine and DMF at room temperature to afford intermediates ethyl 7-substituted-2- substituted-3-(4-substituted benzoyl)-1,2,3,8a-tetrahydroindolizine-1-carboxylates, which on dehydrogenation with chromium(IV)oxide to obtain the title compounds ethyl-7-substituted-3-(4-substituted benzoyl)-2- substituted indolizine-1-carboxylates.

Conclusion:

The research was focused on developing an efficient protocol for the synthesis of a novel series of ethyl 3-substituted benzoyl-7-substituted-2-substituted indolizine-1-carboxylates with suitable pharmacological properties in good to excellent yields.

Efficient synthesis and characterization of novel indolizines: exploration of in vitro COX-2 inhibitory activity and molecular modelling studies

Novel indolizine scaffolds as COX-2 inhibiting agents.

Antimycobacterial, docking and molecular dynamic studies of pentacyclic triterpenes from Buddleja saligna leaves

Buddleja saligna (family Buddlejaceae) is a medicinal plant endemic to South Africa. Two isomeric pentacyclic triterpenes, oleanolic acid and ursolic acid, were isolated from the leaves of B. saligna using silica gel column chromatography. Compounds oleanolic acid and ursolic acid were subjected to derivatization with acetic anhydride in the presence of pyridine to obtain oleanolic acid-3-acetate and ursolic acid-3-acetate, respectively. The structures of these compounds were fully characterized by detailed nuclear magnetic resonance (NMR) investigations, which included 1H and 13C NMR. Molecular docking studies predicted the free binding energy of the four triterpenes inside the steroid binding pocket of Mycobacterium tuberculosis fadA5 thiolase compared to a reported inhibitor. Thus, their ability to inhibit the growth of M. tuberculosis was predicted and was confirmed to possess significant antimycobacterial activity when tested against Mycobacterium smegmatis, M. tuberculosis H37Rv (ATCC 25177), clinical isolates of multi-drug-resistant M. tuberculosis (MDR-TB) and extensively drug-resistant M. tuberculosis (XDR-TB) using the Micro Alamar Blue Assay. Ursolic acid was isolated from this plant for the first time.

Molecular modeling studies and anti-TB activity of trisubstituted indolizine analogues; molecular docking and dynamic inputs

A series of trisubstituted indolizine analogues has been designed as a result of a fragment-based approach to target the inhibition of mycobacterial enoyl-acyl carrier protein reductase. Anti-tuberculosis (TB) screening of the characterized compounds by a resazurin microplate assay method revealed that ethyl group at second position of indolizine nucleus exhibited activity against susceptible and multidrug-resistant strains of Mycobacterium tuberculosis at concentration of 5.5 and 11.3 μg/mL, respectively. A molecular docking study was also conducted to evaluate the stability of the active compounds, and compound with ethyl substitution at second position of indolizine nucleus showed the highest free binding energy of ΔG -24.11 (kcal/mol), a low clash score of 3.04, and high lipo score of -13.33. Indolizine analog with ethyl substitution at second position demonstrated Molecular Mechanics/Generalized Born Surface Area (-23.85 kcal/mol). Two molecular dynamics studies were computed (100 ps and 50 ns) to calculate the relationship between the potential and kinetic energies of the active anti-TB compound with time and temperature. The discovery of this lead may have a positive impact on anti-TB drug discovery.

Synthetic Mono/di-halogenated Coumarin Derivatives and Their Anticancer Properties

BACKGROUND

Coumarins are naturally occurring plant metabolites and several synthetic coumarin analogues are known for their various pharmacological properties such as anticoagulant, antimicrobial, anticancer, antioxidant, anti-inflammatory and antiviral properties. Objective; Keeping this promising pharmacological properties in mind, in the present investigation, mono/dihalogenated coumarin analogues CMRN1-CMRN7 have been synthesized and evaluated for their anticancer activity.

METHOD

The cytotoxicity potential of the test compounds was evaluated against UACC-62, MCF-7 and PBM (Peripheral Blood Mononuclear) cell lines using MTT assay. The apoptotic potential of the coumarin compounds was evaluated against UACC-62 cell by assessing membrane change, mitochondria membrane potential, pro-apoptotic changes were investigated using the AnnexinV-PI staining, JC-1, caspase-3 enzyme kits respectively on flow cytometer.

RESULTS

The test compounds CMRN1, CMRN2, CMRN4 and CMRN5 have strongly suppressed the cell proliferation of UACC-62 and MCF-7 cancer cell lines. Furthermore the test compounds CMRN1, CMRN2, CMRN4 and CMRN5 exerted antiproliferative effects through apoptosis induction against UACC-62.

CONCLUSION

Compounds CMRN1, CMRN2, CMRN4 and CMRN5 can be considered as lead compounds to arrive at a promising anticancer agents.

Synthesis and characterization of a novel series of 1,4-dihydropyridine analogues for larvicidal activity against Anopheles arabiensis

The new-fangled bis(4-substituted benzyl) 4-(4-substitued phenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate derivatives were synthesized by the union of substituted aryl aldehyde, tert-butyl acetoacetate, ammonium carbonate with 4-substituted benzyl alcohol via Hantzsch ester synthesis in aqueous medium under catalyst-free conditions. The newly synthesized compounds were characterized by spectroscopic techniques such as IR, NMR (¹ H and ¹³ C), ESI mass, elemental analysis, and single-crystal X-ray diffraction. The characterized title compounds were evaluated for the larvicidal activity against Anopheles arabiensis by standard WHO larvicidal assay method using Temephos as standard at 4 μg/ml. The title compounds bis(4-methoxybenzyl) 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate and bis(4-chlorobenzyl) 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate exhibited promising larvicidal activity at 65.6% and 72.2%, respectively, when compared with the standard compound at 98.9%.

Greener synthesis of indolizine analogues using water as a base and solvent: study for larvicidal activity against Anopheles arabiensis

Greener synthesis of a series of novel indolizine analogues have been achieved by the cyclization of aromatic cycloimmonium ylides with electron-deficient alkynes in the presence of water as the base and solvent at 80 °C. Yield of the title compounds was good and reactions performed were eco-friendly. The structures of these newly synthesized compounds have been confirmed by spectroscopic techniques such as FTIR, NMR, LC-MS, and elemental analysis. Characterized title compounds were evaluated for larvicidal activity against Anopheles arabiensis by standard WHO larvicidal assay using Temefos as standard at 4 μg/mL. Title compounds 2e, 2f, and 2g emerged as promising larvicidal agents.

Crystal structure of methyl 4-(4-hy-droxy-phen-yl)-6-methyl-2-oxo-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate monohydrate

The title hydrate, C₁₃H₁₄N₂O₄·H₂O, crystallizes with two formula units in the asymmetric unit (Z' = 2). The dihedral angles between the planes of the tetra-hydro-pyrimidine ring and the 4-hy-droxy-phenyl ring and ester group are 86.78 (4) and 6.81 (6)°, respectively, for one mol-ecule and 89.35 (4) and 3.02 (4)° for the other. In the crystal, the organic mol-ecules form a dimer, linked by a pair of N-H⋯O hydrogen bonds. The hydroxy groups of the organic mol-ecules donate O-H⋯O hydrogen bonds to water mol-ecules. Further, the hy-droxy group accepts N-H⋯O hydrogen bonds from amides whereas the water mol-ecules donate O-H⋯O hydrogen bonds to the both the amide and ester carbonyl groups. Other weak inter-actions, including C-H⋯O, C-H⋯π and π-π, further consolidate the packing, generating a three-dimensional network.

Synthesis, Polymorphism, and Insecticidal Activity of Methyl 4-(4-chlorophenyl)-8-iodo-2-methyl-6-oxo-1,6-dihydro-4H-pyrimido[2,1-b]quinazoline-3-Carboxylate Against Anopheles arabiensis Mosquito

Mosquitoes are the major vectors of pathogens and parasites including those causing malaria, the most deadly vector-borne disease. The negative environmental effects of most synthetic compounds combined with widespread development of insecticide resistance encourage an interest in finding and developing alternative products against mosquitoes. In this study, pyrimido[2,1-b]quinazoline derivative DHPM3 has been synthesized by three-step chemical reaction and screened for larvicide, adulticide, and repellent properties against Anopheles arabiensis, one of the dominant vectors of malaria in Africa. The title compound emerged as potential larvicide agent for further research and development, because it exerted 100% mortality, while adulticide activity was considered moderate.

Design, synthesis, and computational studies on dihydropyrimidine scaffolds as potential lipoxygenase inhibitors and cancer chemopreventive agents

Dihydropyrimidine scaffold has a wide range of potential pharmacological activities such as antiviral, antitubercular, antimalarial, anti-inflammatory, and anticancer properties. 5-Lipoxygenase enzyme is an enzyme responsible for the metabolism of arachidonic acid to leukotrienes. The elevated levels of this enzyme and its metabolites in cancer cells have a direct relation on the development of cancer when compared to normal cells. The development of novel lipoxygenase inhibitors can have a major role in cancer therapy. A series of substituted 1,4-dihydropyrimidine analogues were synthesized and characterized by (1)H-NMR, (13)C-NMR, and HRMS. Molecular docking against lipoxygenase enzyme (protein data bank code =3V99) was done using Molecular Operating Environment 2013.08 and Leadit 2.1.2 softwares and showed high affinities. The synthesized compounds were tested for their lipoxygenase inhibitory activity and showed inhibition ranging from 59.37%±0.66% to 81.19%±0.94%. The activity was explained by a molecular docking study. The title compounds were also tested for cytotoxic activity against two human cancer cell lines Michigan Cancer Foundation-7 and human melanoma cells and a normal peripheral blood mononuclear cell line.

Evaluation of halogenated coumarins for antimosquito properties

Mosquitoes are the major vectors of parasites and pathogens affecting humans and domestic animals. The widespread development of insecticide resistance and negative environmental effects of most synthetic compounds support an interest in finding and developing alternative products against mosquitoes. Natural coumarins and synthetic coumarin analogues are known for their several pharmacological properties, including being insecticidal. In the present study halogenated coumarins (3-mono/dibromo acetyl, 6-halogenated coumarin analogues) were screened for larvicidal, adulticidal, and repellent properties against Anopheles arabiensis, a zoophilic mosquito that is one of the dominant vectors of malaria in Africa. Five compounds exerted 100% larval mortality within 24 h of exposure. All coumarins and halogenated coumarins reversibly knocked down adult mosquitoes but did not kill them after 24 h of exposure. Repellent properties could not be evidenced. Five compounds were considered potential larvicidal agents for further research and development, while adulticidal activity was considered only mild to moderate.

Antimosquito properties of 2-substituted phenyl/benzylamino-6-(4-chlorophenyl)-5-methoxycarbonyl-4-methyl-3,6-dihydropyrimidin--ium chlorides against Anopheles arabiensis

Eight novel dihydropyrimidine analogs named DHPM1-DHPM8 was synthesized in their hydrochloride salt form using one pot synthesis between methyl 2-chloro-4-(4-chlorophenyl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate and substituted arylamines in isopropanol. The antimosquito effect of the test compounds were assessed against the adult mosquito Anopheles arabiensis. For adulticidal properties the test compounds were sprayed onto ceramic tiles and screened using the cone bio-assay method. The larvicidal activity was tested by monitoring larval mortality daily and up to 3 days of exposure. Repellency properties were tested in a feeding-probe assay using unfed female Anopheles arabiensis. Compounds DHPM1, DHPM4, DHPM5 and DHPM6 exerted larval mortality equivalent to temephos (trade name Abate, a commercial larvicidal compound). Compounds DHPM1 to DHPM5 repelled or knocked down 92 to 98% of mosquitoes exposed to rodent skin treated with the compounds. None of the compounds showed any significant activity against the adult mosquito Anopheles arabiensis.

Effect of traditional leafy vegetables on the growth of lactobacilli and bifidobacteria

Traditional leafy vegetables, apart from being a staple in the diet of most of sub-Saharan Africa, are an essential part of traditional medicine and are used daily by traditional healers in the region to treat a wide variety of ailments. In this study, a batch culture technique was used to investigate whether 25 infusions from 22 traditional leafy vegetables stimulated the growth of Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus reuteri and Bifidobacterium longum in pure culture. High performance liquid chromatography was used to determine the inulin content of the infusions. Sonchus oleraceus stimulated all four strains and Taraxacum officinale stimulated three strains. In total, 18 plants stimulated at least one of the four probiotic strains. The inulin content of the infusions varied between 2.5% and 3.6%, with Asparagus sprengeri containing the highest percentage. These results indicate that traditional leafy vegetables do stimulate the growth of the selected lactobacilli and bifidobacteria in pure culture and contain inulin. These infusions can now be tested for prebiotic potential using mixed culture systems or human hosts.

Polymorphism in two biologically active dihydropyrimidinium hydrochloride derivatives: quantitative inputs towards the energetics associated with crystal packing

A new polymorph belonging to the tetrahydropyrimidinium class of compounds, namely 6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-2-(3-(trifluoromethylthio)phenylamino)-3,6-dihydropyrimidin-1-ium chloride, and a hydrate of 2-(3-bromophenylamino)-6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-3,6-dihydropyrimidin-1-ium chloride, have been isolated and characterized using single-crystal X-ray diffraction (XRD). A detailed comprehensive analysis of the crystal packing in terms of the associated intermolecular interactions and a quantification of their interaction energies have been performed for both forms of the two different organic salts (A and B) using X-ray crystallography and computational methods such as density functional theory (DFT) quantum mechanical calculations, PIXEL lattice-energy calculations (with decomposition of total lattice energy into the Coulombic, polarization, dispersion and repulsion contribution), the calculation of the Madelung constant (the EUGEN method), Hirshfeld and two-dimensional fingerprint plots. The presence of ionic [N-H](+)···Cl(-) and [C-H](+)···Cl(-) hydrogen bonds mainly stabilizes the crystal packing in both forms A and B, while in the case of B·H2O [N-H](+)···O(water) and O(water)-H···Cl(-) hydrogen bonds along with [N-H](+)···Cl(-) and [C-H](+)···Cl(-) provide stability to the crystal packing. The lattice-energy calculations from both PIXEL and EUGEN methods revealed that in the case of A, form (I) (monoclinic) is more stable whereas for B it is the anhydrous form that is more stable. The analysis of the `Madelung mode' of crystal packing of two forms of A and B and its hydrates suggest that differences exist in the position of the charged ions/atoms in the organic solid state. The R/E (distance-energy) plots for all the crystal structures show that the molecular pairs in their crystal packing are connected with either highly stabilizing (due to the presence of organic R(+) and Cl(-)) or highly destabilizing Coulombic contacts. The difference in crystal packing and associated intermolecular interactions between polymorphs (in the case of A) or the hydrates (in the case of B) have been clearly elucidated by the analysis of Hirshfeld surfaces and two-dimensional fingerprint plots. The relative contributions of the various interactions to the Hirshfeld surface for the cationic (dihydropyrimidinium) part and anionic (chloride ion) part for the two forms of A and B and its hydrate were observed to be different.

The antimosquito properties of extracts from flowering plants in South Africa

Extracts of selected flowering plants, which are considered eco-friendly, are used for the treatment of numerous ailments and vector control worldwide. This has resulted in approximately 25 per cent of currently used drugs being derived from herbal sources. The aqueous and methanolic extracts of twelve plant species, Psidium guajava (pink fruit), Psidium guajava (white fruit), Psidium cattleianum var. cattleianum, Psidium guineense and Psidium X durbanensis, Achyranthes aspera, Alternanthera sessilis, Guilleminea densa, Capparis tomentosa, Leonotis leonurus, Dichrostachys cinerea and Carpobrotus dimidiatus, were tested for insecticidal activity, including larvicidal, adulticidal and repellent activities against the adult female mosquito, Anopheles arabiensis. The extracts of P. guajava (white fruit), C. tomentosa, L. leonurus,D. cinerea, and C. dimidiatus exerted a pronounced inhibitory effect on adult insects, while those of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, A. aspera, A. sessilis, and G. densa were ineffective and failed to satisfy the criteria set by the World Health Organization. In the tests for repellency against An. arabiensis, all the tested aqueous and methanolic plant extracts except those of A. sessilis repelled 80-100% of mosquitoes. The most effective mosquito repellents were the methanol and aqueous extracts of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, G. densa,L. leonurus and D. cinerea, which are potential sources of cost effective mosquito repellents to be utilized in malarial endemic areas.

The in vitro photodynamic effect of laser activated gallium, indium and iron phthalocyanine chlorides on human lung adenocarcinoma cells

Metal-based phthalocyanines currently are utilized as a colorant for industrial applications but their unique properties also make them prospective photosensitizers. Photosensitizers are non-toxic drugs, which are commonly used in photodynamic therapy (PDT), for the treatment of various cancers. PDT is based on the principle that, exposure to light shortly after photosensitizer administration predominately leads to the production of reactive oxygen species for the eradication of cancerous cells and tissue. This in vitro study investigated the photodynamic effect of gallium (GaPcCl), indium (InPcCl) and iron (FePcCl) phthalocyanine chlorides on human lung adenocarcinoma cells (A549). Experimentally, 2 × 10(4)cells/ml were seeded in 24-well tissue culture plates and allowed to attach overnight, after which cells were treated with different concentrations of GaPcCl, InPcCl and FePcCl ranging from 2 μg/ml to 100 μg/ml. After 2h, cells were irradiated with constant light doses of 2.5 J/cm(2), 4.5 J/cm(2) and 8.5 J/cm(2) delivered from a diode laser (λ = 661 nm). Post-irradiated cells were incubated for 24h before cell viability was measured using the MTT Assay. At 24h after PDT, irradiation with a light dose of 2.5 J/cm(2) for each photosensitizing concentration of GaPcCl, InPcCl and FePcCl produced a significant decrease in cell viability, but when the treatment light dose was further increased to 4.5 J/cm(2) and 8.5 J/cm(2) the cell survival was less than 40%. Results also showed that photoactivated FePcCl decreased cell survival of A549 cells to 0% with photosensitizing concentrations of 40 μg/ml and treatment light dose of 2.5 J/cm(2). A 20 μg/ml photosensitizing concentration of FePcCl in combination with an increased treatment light dose of either 4.5 J/cm(2) or 8.5 J/cm(2) also resulted in 0% cell survival. This PDT study concludes that low concentrations on GaPcCl, InPcCl and FePcCl activated with low level light doses can be used for the effective in vitro killing of lung cancer cells.

{2-[(1,3-Benzo-thia-zol-2-yl)meth-oxy]-5-chloro-phen-yl}(4-chloro-phen-yl)methan-one

In the title compound, C₂₁H₁₃Cl₂NO₂S, the benzo­thia­zole ring makes dihedral angles of 0.94 (1) and 70.65 (5)° with the 4-chloro­phenyl­methanone unit and the 5-chloro­phenyl ring, respectively. The dihedral angle between the 4-chloro­phenyl­methanone unit and the 5-chloro­phenyl ring is 66.20 (5)°. The crystal structure consists of dimeric units generated by C—H⋯N hydrogen bonds, further linked by C—H⋯O and C—H⋯π inter­actions, leading to a three-dimensional network.

{2-[(1,3-Benzo-thia-zol-2-yl)meth-oxy]-5-bromo-phen-yl}(phen-yl)methanone

In the title compound, C21H14BrNO2S, the dihedral angle between the planes of the benzo-thia-zole and phenyl-methanone groups is 63.4 (2)°. In the crystal, pairs of C-H⋯N hydrogen bonds link the mol-ecules to form inversion dimers, which are further linked by C-H⋯O inter-actions into chains along the c axis. C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.863 (1) Å] further stabilize the mol-ecular assembly.

2-(4-Bromoanilino)-6-(4-chlorophenyl)-5-methoxycarbonyl-4-methyl-3,6-dihydropyrimidin-1-ium chloride

In the title molecular salt, C₁₉H₁₈BrClN₃O₂⁺·Cl⁻, the dihedral angles between the pyrimidine ring and the chlorobenzene and bromobenzene rings are 72.4 (2) and 45.5 (2)°, respectively. The dihedral angle between the chlorobenzene and bromobenzene rings is 27.5 (2)°. The conformation of the mol­ecule is stabilized by an intra­molecular C—H⋯O inter­action. In the crystal, the anion and cation are linked by an N—H⋯Cl hydrogen bond. Pairs of weak C—H⋯O and C—H⋯Cl hydrogen bonds form inversion dimers. Further N—H⋯Cl hydrogen bonds form R₂¹(6) motifs and link the dimers into chains along [101]. Br⋯Cl short contacts [3.482 (2) Å] inter­link the hydrogen-bonded chains along the b-axis direction.

Review on natural coumarin lead compounds for their pharmacological activity

Coumarin (2H-1-benzopyran-2-one) is a plant-derived natural product known for its pharmacological properties such as anti-inflammatory, anticoagulant, antibacterial, antifungal, antiviral, anticancer, antihypertensive, antitubercular, anticonvulsant, antiadipogenic, antihyperglycemic, antioxidant, and neuroprotective properties. Dietary exposure to benzopyrones is significant as these compounds are found in vegetables, fruits, seeds, nuts, coffee, tea, and wine. In view of the established low toxicity, relative cheapness, presence in the diet, and occurrence in various herbal remedies of coumarins, it appears prudent to evaluate their properties and applications further.

Methyl 4-(4-chloro-phen-yl)-8-iodo-2-methyl-6-oxo-1,6-dihydro-4H-pyrimido[2,1-b]quinazoline-3-carboxyl-ate

In the title compound, C20H15ClIN3O3, the dihedral angle between the quinazolinone ring system [r.m.s. deviation = 0.047 (2) Å] and the pendant benzene ring is 82.63 (11)°. The mol-ecular conformation is stabilized by intra-molecular C-H⋯O inter-actions. In the crystal, the mol-ecules are linked by N-H⋯O hydrogen bonds into chains along the a-axis direction. Another set of chains propagating along [101] is formed due to inter-molecular I⋯Cl short contacts of 3.427 (1) Å, thus giving layers parallel to (010). The layers are connected by C-H⋯π and π-π inter-actions, the shortest distance between the centroids of aromatic rings being 3.8143 (16) Å.

Synthesis and antitubercular activity of 2-(substituted phenyl/benzyl-amino)-6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-3,6-dihydropyrimidin-1-ium chlorides

A series of 2-(substituted phenyl/benzyl-amino)-6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-3,6-dihydropyrimidin-1-ium chlorides 7-13 and 15 was synthesized in their hydrochloride salt form. The title compounds were characterized by FT-IR, NMR ((1)H and (13)C) and elemental analysis. They were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv, multidrug resistance tuberculosis and extensively drug resistance tuberculosis by agar diffusion method and tested for the cytotoxic action on peripheral blood mononuclear cells by MTT assay. Among all the tested compounds in the series, compounds 7 and 11 emerged as promising antitubercular agents at 16 μg/mL against multidrug resistance tuberculosis and over 64 μg/mL against extensively drug resistance tuberculosis. The conformational features and supramolecular assembly of the promising compounds 7 and 11 were determined by single crystal X-ray study.

Methyl (E)-2-[(3-chloro-4-cyano-phenyl)-imino]-4-(4-chloro-phen-yl)-6-methyl-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate

In the title compound, C₂₀H₁₆Cl₂N₄O₂, the dihedral angles between the planes of the chloro­phenyl, chloro­cyano­phenyl­imine and ester groups and the plane of the six-membered tetra­hydro­pyrimidine ring are 86.9 (2), 72.6 (2) and 7.9 (2)°, respectively. The Cl atom substituent on the cyano­phenyl ring is disordered over two rotationally related sites [occupancy factors 0.887 (2):0.113 (2)], while the mol­ecular conformation is stabilized by the presence of an intra­molecular aromatic C—H⋯π inter­action. Both N—H groups participate in separate inter­molecular hydrogen-bonding associations with centrosymmetric cyclic motifs [graph sets R₂²(8) and R₂²(12)], resulting in ribbons parallel to [010]. Further weak C—H⋯O hydrogen bonds link these ribbons into a two-dimensional mol­ecular assembly.

Methyl 2,6-diphenyl-1-p-tolyl-4-(p-tolylamino)-1,2,5,6-tetrahydropyridine-3-carboxylate

In the title compound, C₃₃H₃₂N₂O₂, the tetra­hydro­pyridine ring adopts a boat conformation with the carbonyl group in an s-cis conformation with respect to the C=C bond of the six-membered tetra­hydro­pyridine ring. The mol­ecular conformation is stabilized by intra­molecular N—H⋯O, C—H⋯O and C—H⋯π inter­actions. Formation of centrosymmetric head-to-head dimers is observed through pairwise inter­molecular N—H⋯O hydrogen bonds. Additional weak C—H⋯O and C—H⋯π inter­actions stabilize the three-dimensional mol­ecular assembly.

Translocation and accumulation of Cr, Hg, As, Pb, Cu and Ni by Amaranthus dubius (Amaranthaceae) from contaminated sites

Phytoremediation is an emerging technology where specially selected and engineered metal-accumulating plants are used for bioremediation. This study was undertaken to evaluate the potential of Amaranthus dubius for phytoremediation of chromium (Cr), mercury (Hg), arsenic (As), lead (Pb), copper (Cu) and nickel (Ni). Locally gathered soil and plants of A. dubius were investigated for the metals from a regularly cultivated area, a landfill site and a waste water treatment site. Metals were extracted from the samples using microwave-digestion and analyzed using Inductively Coupled Plasma-Mass Spectroscopy. The mode of phytoremediation, effect of the metals on the plants, ability of the plant to extract metals from soil (Bioconcentration Factor) and the ability of the plants to move the metals to the aerial parts of the plants (Translocation Factor) were evaluated. The survey of the three sites showed that soils were heavily contaminated with Cr, Hg, Cu and Ni. These levels were far above acceptable standards set for soils and above the standards set for the Recommended Dietary Allowance. Specimens of A. dubius from the three sites showed that they could tolerate Hg, sequester it from the soil, and translocate it to the shoots. Cr could only be removed from the soil and stored in the roots, with limited amounts translocated to the aerial parts. Pb, As, Ni, and Cu have some degree of transportability from the soil to the roots but not to aerial parts. The ability of A. dubius to be considered for phytoremediation has to be viewed with caution because translocation of the metals to the aerial parts of the plant is limited.

Biocontrol of aflatoxins B1, B2, G1, G2, and fumonisin B1 with 6,7-dimethoxycoumarin, a phytoalexin from Citrus sinensis

Phytoalexins (stress-induced compounds) from Citrus sinensis cultivar Valencia were screened for antifungal and antimycotoxic activity against a test organism (Cladosporium cladosporoides) and mycotoxin-producing fungi Fusarium verticillioides and Aspergillus parasiticus. The active compound, a member of the coumarin family of compounds, has antifungal and antimycotoxic activities and was chemically identified. High-performance liquid chromatography results indicated that Valencia oranges contain a trace amount (0.36 microg/g) of scoparone in untreated fruit, but concentrations increased in UV-irradiated fruit (15.2 microg/g). Infection with Penicillium digitatum, a natural spoilage mold of citrus fruit, caused a 35.51-microg/g increase in the phytoalexin. UV absorption, infrared absorption, and 1H nuclear magnetic resonance spectroscopy revealed that this phytoalexin is identical to 6,7-dimethoxycoumarin. This is the first report indicating that the stress-induced compound, 6,7-dimethoxycoumarin, isolated from P. digitatum-infected Valencia fruit confers resistance against the mycotoxigenic fungi A. parasiticus and F. verticillioides and causes a reduction in production of fumonisin B1 and aflatoxins G1, G2, B1, and B2.

Aflatoxin B1-induced toxicity in HepG2 cells inhibited by carotenoids: morphology, apoptosis and DNA damage

Aflatoxin B1 (AFB1) is a fungal toxin that has been associated with primary hepatocellular carcinoma (HCC) in humans. This study was undertaken to determine the cellular and molecular mechanisms by which the antioxidants beta-carotene and lycopene inhibit AFB1-induced toxic changes in human hepatocytes (HepG2 cells). An in vitro system was optimized to test the chemoprotective effects of lycopene and beta-carotene on HepG2 cells exposed to different concentrations of AFB1. Ultrastructurally, HepG2 cells cultured in the presence of AFB1 showed mitochondrial damage, nuclear condensation and a loss of cell-to-cell contact; the latter was reflected in the observation of dysfunctional gap junctions, resulting in a loss of cell-to-cell communication. At the genomic level, AFB1 formed AFB1-N7-guanine adducts, caused apoptotic cell death and suppressed p53 protein expression. In the presence of the carotenoids, survival of cells exposed to AFB1 was increased, and there was also a significant increase in cellular mitochondrial activity. Our results demonstrate that HepG2 cells pretreated with lycopene and beta-carotene are protected from the toxic effects of AFB1 at both the cellular and molecular levels.

Visualisation of transforming growth factor-β1, tissue kallikrein, and kinin and transforming growth factor-β receptors on human clear-cell renal carcinoma cells

Transforming growth factor-beta1 (TGF-beta1) has a biphasic effect on the growth of renal epithelial cells. In transformed cells, TGF-beta1 appears to accelerate the proliferation of malignant cells. The diverse cellular functions of TGF-beta1 are regulated by three high-affinity serine/threonine kinase receptors, namely TbetaRI, TbetaRII and TbetaRIII. The renal serine protease tissue kallikrein acts on its endogenous protein substrate kininogen to form kinin peptides. The cellular actions of kinins are mediated through B1 and B2 G protein-coupled rhodopsin receptors. Both kinin peptides and TGF-beta1 are mitogenic, and therefore may play an important role in carcinogenesis. Experiments were designed to immunolabel tissue kallikrein, TGF-beta1, TbetaRII, TbetaRIII and kinin receptors using specific antibodies on serial sections of normal kidney and clear-cell renal carcinoma (CCRC) tissue, which included both the tumour and the adjacent renal parenchyma. The essential result was the localisation of tissue kallikrein, kinin B 1 and B 2 receptors and TGF-beta1 primarily on the cell membranes of CCRC cells. In the distal and proximal tubules of the renal parenchyma adjacent to the carcinoma (RPTAC), immunolabelling for tissue kallikrein was reduced, but the expression of kinin B1 and B2 receptors was enhanced. Immunolabelling for TbetaRII and TbetaRIII was more pronounced in the proximal tubules of the tissue adjacent to the carcinoma when compared to the normal kidney. The expression of tissue kallikrein, kinin receptors, and TbetaRII and TbetaRIII may be relevant to the parenchymal invasion and metastasis of clear-cell renal carcinoma.

Mycotic keratitis: profile of Fusarium species and their mycotoxins. Mykotische Keratitis: Profil von Fusarium-Arten und ihren Mykotoxinen

In this study, Fusarium species isolated from 29 patients with mycotic keratitis were identified and tested for their ability to produce mycotoxins. Members of the F. solani species complex (Fs complex) were the predominant species isolated, followed by F. verticillioides, F. dimerum, members of the F. oxysporum species complex Fo complex), F. incarnatum, F. chlamydosporum and F. lateritium. Of these, 76% of the Fusarium isolates produced fusaric acid, moniliformin or fumonisin B1. Many of the fusaria isolated are common aetiological agents of mycotic keratitis infections. However, F. incarnatum, F. chlamydosporum and F. lateritium have previously not been found in this infection. These findings indicate that a greater variety of fusarial species are becoming associated with mycotic keratitis infections. This paper further demonstrates the mycotoxin-producing ability of these clinical isolates and assesses cellular cytotoxicity.

Immune responses in cancer

The complex of humoral factors and immune cells comprises two interleaved systems, innate and acquired. Immune cells scan the occurrence of any molecule that it considers to be nonself. Transformed cells acquire antigenicity that is recognized as nonself. A specific immune response is generated that results in the proliferation of antigen-specific lymphocytes. Immunity is acquired when antibodies and T-cell receptors are expressed and up-regulated through the formation and release of lymphokines, chemokines, and cytokines. Both innate and acquired immune systems interact to initiate antigenic responses against carcinomas. A new approach to the treatment of cancer has been immunotherapy, which aims to up-regulate the immune system in order that it may better control carcinogenesis. Currently, several forms of immunotherapy that use natural biological substances to activate the immune system are being explored therapeutically. The various forms of immunotherapy fall into three main categories: monoclonal antibodies, immune response modifiers, and vaccines. While these modalities have individually shown some promise, it is likely that the best strategy to combat cancer may require multiple immunotherapeutic strategies in order to demonstrate benefit in different patient populations. It may be that the best results are obtained with vaccines in combination with a variety of immunotherapy combinations. Another potent strategy may be in combining with more traditional cancer drugs as evidenced from the benefit derived from enhancing the efficacy of chemotherapy with cytokines. Through such concerted efforts, a durable, therapeutic antitumour immune response may be achieved and maintained over the course of a patient's lifespan.

Natural products for cancer prevention: a global perspective

The control of cancer, the second leading cause of death worldwide, may benefit from the potential that resides in alternative therapies. The primary carcinogens stem from a variety of agricultural, industrial, and dietary factors. Conventional therapies cause serious side effects and, at best, merely extend the patient's lifespan by a few years. There is thus the need to utilise alternative concepts or approaches to the prevention of cancer. This review focuses on the many natural products that have been implicated in cancer prevention and that promote human health without recognisable side effects. These molecules originate from vegetables, fruits, plant extracts, and herbs.

Immune responses in cancer

The complex of humoral factors and immune cells comprises two interleaved systems, innate and acquired. Immune cells scan the occurrence of any molecule that it considers to be nonself. Transformed cells acquire antigenicity that is recognized as nonself. A specific immune response is generated that results in the proliferation of antigen-specific lymphocytes. Immunity is acquired when antibodies and T-cell receptors are expressed and up-regulated through the formation and release of lymphokines, chemokines, and cytokines. Both innate and acquired immune systems interact to initiate antigenic responses against carcinomas. A new approach to the treatment of cancer has been immunotherapy, which aims to up-regulate the immune system in order that it may better control carcinogenesis. Currently, several forms of immunotherapy that use natural biological substances to activate the immune system are being explored therapeutically. The various forms of immunotherapy fall into three main categories: monoclonal antibodies, immune response modifiers, and vaccines. While these modalities have individually shown some promise, it is likely that the best strategy to combat cancer may require multiple immunotherapeutic strategies in order to demonstrate benefit in different patient populations. It may be that the best results are obtained with vaccines in combination with a variety of immunotherapy combinations. Another potent strategy may be in combining with more traditional cancer drugs as evidenced from the benefit derived from enhancing the efficacy of chemotherapy with cytokines. Through such concerted efforts, a durable, therapeutic antitumour immune response may be achieved and maintained over the course of a patient's lifespan.

Naturally occurring phenols: a detoxification strategy for fumonisin B1

Phenolic compounds from plants offer a means for both the prevention and detoxification of mycotoxins that affect human health. This research investigates the control of fungal growth and toxin production by Fusarium verticillioides with plant phenolic compounds, namely chlorophorin, iroko and maakianin, benzoic acid, caffeic acid, ferulic acid, and vanillic acid. Inhibition by these compounds of fungal growth was determined by the agar overlay method and their effect on fumonisin B(1) (FB(1)) production was determined by high-performance liquid chromatography. Chlorophorin was the most effective compound in inhibiting fungal growth, followed by iroko, maakianin, vanillic acid and caffeic acid. Chlorophorin also was the most effective compound in reducing toxin production (94% reduction), followed by caffeic acid, ferulic acid, vanillic acid and iroko, which reduced FB(1) levels by 90-91%. The widespread occurrence of fumonisins world-wide and the lack of adequate prevention of fumonisins require 'biologically safe' alternatives to prevent the transfer of fungi and their health hazardous toxins into our daily foods and environment.

The effect of modified atmospheres and packaging on patulin production in apples

This study was undertaken to determine the effectiveness of modified atmospheres and packaging materials on the growth of Penicillium expansum and patulin production in apples. Granny Smith apples were surface sterilized with 76% ethanol and inoculated with 0.1 ml of a 1.1 x 10(7) spore/ml P. expansum spore suspension. The apples were packaged either in polyethylene (PE) or polypropylene (PP) and treated with three different gas combinations, viz., 58% CO2/42% N2, 48% CO2/52% N2, and 88% CO2/12% N2, and were then incubated for 14 days at 25 degrees C. Fungal growth was monitored every 2 to 4 days by measuring radial growth from the point of inoculation. After the 14th day, apples were pulped, and patulin was extracted, purified, and quantified by high-performance liquid chromatography. PP did not inhibit fungal growth in any of the atmospheres tested, and it only inhibited patulin production in atmospheric gas and 58% CO2/42% N2. PE was very effective and inhibited fungal growth by four- or fivefold, depending on the modified atmosphere. Patulin production in PE-packaged apples was almost completely inhibited by all three gas combinations. Gas chromatographic analysis of the PE-packaged samples before and after the incubation period showed that CO2 levels dropped and N2 levels increased for all of the atmospheres tested. Our studies showed conclusively that PE is an excellent packaging material for the storage of apples since it inhibited the growth of P. expansum, thereby allowing <3.2 microg/ml of patulin to be produced, regardless of gaseous environment.