3D7 Strain Research Articles

In vitro Antiplasmodial Activities of Crude Extracts and Compounds Derived from Selected Indigenous Medicinal Plants used Traditionally to Treat Malaria in Kenya

Aims: To identify viable phytomedicines traditionally employed for the treatment of malaria in Kenya that could be developed into antimalarial agents.
 Study Design: Quantitative analysis of antiplasmodial activities and brine shrimp bioassays were carried out using standard procedures. The experiment was set in duplicate for each concentration of the drug and average IC50 determined.
 Place and Duration of Study: Seven indigenous plants: Achyranthesaspera, Heinsiacrinita, Brideliacathartica, Citrus limon, Microglossapyrifolia, Vernoniaglabra and Carissa edulis obtained from Kilifi and Homa-Bay counties in Kenya were evaluated for their anti-Plasmodium falciparumpotential.Collection of samples and analysis took about three months.
 Methodology: Both Chemical and aqueous crude extraction methods were carried out to identify the most active extracts against P. Falciparum and thenisolatepureactive phytochemicals. Pure compounds were subjected to Nuclear Magnetic Resonance (NMR), Infra-Red (IR) and Mass Spectroscopy (MS) analyses for structure elucidation.
 Results: Four extracts of hexane, dichloromethane (DCM), methanol and water of seven different species of plants were analyzed for their anti-plasmodial activities.W2 and D6 strains of Falciparum were tested. However, the three most active extracts were from Citrus lemon roots (DCM) with IC50 value of 7.017 µg/mL, C. edulis root (aqueous) with IC50 value of 8.054 µg/Ml and B. Cathertica leaves (methanol) with IC50 value of 15.647 µg/Ml. However, three pure compounds were obtained; suberosinIC5026.7 (Strain W2), 53.1 (Strain D6) and xanthyletin IC501580 (Strain W2) from C. Limon (DCM) and spinasterolIC5043.2 (Strain W2) fromM. pyrifolia (hexane).
 Conclusion: The three different species of plants with most active compounds have demonstrated their potentiality in treatment for falciparum malaria. Structures of the isolated three compounds can be modelled to synthesise anti- plasmodial drugs as they are active in vitro.

Constituents from ripe figs of Ficus vallis-choudae Delile (Moraceae) with antiplasmodial activity.

Ripe figs, barks, and wood of Ficus vallis-choudae are used in traditional medicine against several conditions including nausea and malaria. However, its use is still to be scientifically documented and validated. Hence, the aim of the present work was to evaluate the antiplasmodial activity of the dichloromethane-methanol (DCM-MeOH (1:1)) crude extract, their hexane, dichloromethane, ethyl acetate, and methanoli fractions, as well as the isolated chemical constituents. The chemical study of the DCM-MeOH (1:1) crude extract of F. vallis-choudae figs led to the isolation of fifteen (15) known compounds identified based on their spectroscopic data [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR), mass spectrometry] and by comparison of these data with those reported in the literature. Some of the isolated compounds were assessed in vitro for their antiplasmodial activity against Plasmodium falciparum chloroquine-sensitive 3D7 (Pf3D7) and multidrug-resistant Dd2 strains. The dichloromethane fraction exhibited very good antiplasmodial activity against both strains with IC50 values of 13.86 μg/mL and 8.18 μg/mL, respectively. Among the tested compounds, wighteone (2) was the most active against P. falciparum 3D7 (IC50 = 24.6 ± 1.5 μM) and Dd2 (IC50 = 11.9 ± 2.4 μM) strains. The obtained results could justify the traditional uses of F. vallis-choudae against malaria. Wighteone appears to be the most active ingredient. However, further consideration of this compound as starting point for antimalarial drug discovery will depend upon its selectivity of action towards Plasmodium parasites.Highlights• 15 (fifteen) compounds were isolated from the dichloromethane-methanol extract of Ficus vallis-choudae.• Their structures were determined on the basis of their spectroscopic data.• The dichloromethane fraction showed promising activities on the Pf3D7 and PfDd2 strains with IC50 values of 13.86 and 8.18 µg/mL, respectively.• Wighteone was the most active compound against PfDd2 (IC50 = 11.9 ± 2.4 μM).Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s00436-022-07540-5.

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1H-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities.

A series of 26 novel 1-(7-chloroquinolin-4-yl)-4-nitro-1H-pyrazoles bearing a dichloromethyl and an amino or thio moiety at C3 and C5 has been prepared in yields up to 72% from the reaction of 1,1-bisazolyl-, 1-azolyl-1-amino-, and 1-thioperchloro-2-nitrobuta-1,3-dienes with 7-chloro-4-hydrazinylquinoline. A new way for the formation of a pyrazole cycle from 3-methyl-2-(2,3,3-trichloro-1-nitroallylidene)oxazolidine (6) is also described. In addition, the antimalarial activity of the synthesized compounds has been evaluated in vitro against the protozoan malaria parasite Plasmodium falciparum. Notably, the 7-chloro-4-(5-(dichloromethyl)-4-nitro-3-(1H-1,2,4-triazol-1-yl)-1H-pyrazol-1-yl)quinoline (3b) and 7-chloro-4-(3-((4-chlorophenyl)thio)-5-(dichloromethyl)-4-nitro-1H-pyrazol-1-yl)quinoline (9e) inhibited the growth of the chloroquine-sensitive Plasmodium falciparum strain 3D7 with EC50 values of 0.2 ± 0.1 µM (85 ng/mL, 200 nM) and 0.2 ± 0.04 µM (100 ng/mL, 200 nM), respectively. Two compounds (3b and 10d) have also been tested for anti-SARS-CoV-2, antibacterial, and cytotoxic activity.

Chukranoids A-I, isopimarane diterpenoids from Chukrasia velutina.

Bioactivity guided separation of Chukrasia velutina root methanolic extract led to the isolation of nine new isopimarane diterpenoids, chukranoids A–I (1–9). The absolute configuration was then assigned by comparing the experimental CD spectra and the calculated CD spectra. Chukranoids A–I (1–9) showed moderate antimalarial activity against Plasmodium falciparum 3D7 strain. It seems that conjugate system in the isopimarane skeleton may influence their antimalarial activity.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11418-022-01623-4.

Fermentation optimization and amylase activity of endophytic Bacillus velezensis D1 isolated from corn seeds

To acquire quality amylase adopted in practical applications, endophytic bacteria were identified as Bacillus velezensis strain D1 which was isolated from corn seeds. The fermentation conditions and amylase properties of the strain were investigated. The strain D1 was identified via morphological, physiological and 16S rDNA phylogenetic analysis. The fermentation conditions of secreting amylase were optimized by single-factor and orthogonal experiments. The α-amylase gene was expressed in E. coli and purified by means of immobilized metal ion affinity chromatography (IMAC), upon which the enzyme activity of purified recombinant α-amylase was determined. The results outlined that (1) The strain D1 was identified as Bacillus velezensis. (2) The optimized fermentation conditions for maximum amylase yields included 44°C for 48h at pH 7.5. (3) The enzyme had an optimal reaction temperature of 60°C with the highest activity at 50°C and tolerance to 4-h incubation at 70°C. (4) The enzyme was strong acid resistant and tolerated at pH 5.0-6.0 while the optimal pH was 8.0. (5) Besides, the amylase activity was elevated by the presence of Ca2+ and Cu2+ . (6) The activity of purified recombinant amylase was 20.59U/ml under optimal conditions, nearly seven times that of crude amylase preparations. The amylase produced by Bacillus velezensis D1 is strongly tolerant towards acid and high temperatures. Amylases with thermophilic and acid-resistant characteristics are useful for a wide range of applications in food, brewing, textile, starch, paper and deterrent industries. The enzyme from Bacillus velezensis D1 can be effectively used in different areas of industries.

Crossing and selection of Chlamydomonas reinhardtii strains for biotechnological glycolate production

As an alternative to chemical building blocks derived from algal biomass, the excretion of glycolate has been proposed. This process has been observed in green algae such as Chlamydomonas reinhardtii as a product of the photorespiratory pathway. Photorespiration generally occurs at low CO2 and high O2 concentrations, through the key enzyme RubisCO initiating the pathway via oxygenation of 1.5-ribulose-bisphosphate. In wild-type strains, photorespiration is usually suppressed in favour of carboxylation due to the cellular carbon concentrating mechanisms (CCMs) controlling the internal CO2 concentration. Additionally, newly produced glycolate is directly metabolized in the C2 cycle. Therefore, both the CCMs and the C2 cycle are the key elements which limit the glycolate production in wild-type cells. Using conventional crossing techniques, we have developed Chlamydomonas reinhardtii double mutants deficient in these two key pathways to direct carbon flux to glycolate excretion. Under aeration with ambient air, the double mutant D6 showed a significant and stable glycolate production when compared to the non-producing wild type. Interestingly, this mutant can act as a carbon sink by fixing atmospheric CO2 into glycolate without requiring any additional CO2 supply. Thus, the double-mutant strain D6 can be used as a photocatalyst to produce chemical building blocks and as a future platform for algal-based biotechnology.Key Points• Chlamydomonas reinhardtii cia5 gyd double mutants were developed by sexual crossing• The double mutation eliminates the need for an inhibitor in glycolate production• The strain D6 produces significant amounts of glycolate with ambient air only

Semi-Synthesis of N-Aryl Amide Analogs of Piperine from Piper nigrum and Evaluation of Their Antitrypanosomal, Antimalarial, and Anti-SARS-CoV-2 Main Protease Activities.

Piper nigrum, or black pepper, produces piperine, an alkaloid that has diverse pharmacological activities. In this study, N-aryl amide piperine analogs were prepared by semi-synthesis involving the saponification of piperine (1) to yield piperic acid (2) followed by esterification to obtain compounds 3, 4, and 5. The compounds were examined for their antitrypanosomal, antimalarial, and anti-SARS-CoV-2 main protease activities. The new 2,5-dimethoxy-substituted phenyl piperamide 5 exhibited the most robust biological activities with no cytotoxicity against mammalian cell lines, Vero and Vero E6, as compared to the other compounds in this series. Its half-maximal inhibitory concentration (IC50) for antitrypanosomal activity against Trypanosoma brucei rhodesiense was 15.46 ± 3.09 μM, and its antimalarial activity against the 3D7 strain of Plasmodium falciparum was 24.55 ± 1.91 μM, which were fourfold and fivefold more potent, respectively, than the activities of piperine. Interestingly, compound 5 inhibited the activity of 3C-like main protease (3CLPro) toward anti-SARS-CoV-2 activity at the IC50 of 106.9 ± 1.2 μM, which was threefold more potent than the activity of rutin. Docking and molecular dynamic simulation indicated that the potential binding of 5 in the 3CLpro active site had the improved binding interaction and stability. Therefore, new aryl amide analogs of piperine 5 should be investigated further as a promising anti-infective agent against human African trypanosomiasis, malaria, and COVID-19.

Decoding the Role of Melatonin Structure on Plasmodium falciparum Human Malaria Parasites Synchronization Using 2-Sulfenylindoles Derivatives.

Melatonin acts to synchronize the parasite’s intraerythrocytic cycle by triggering the phospholipase C-inositol 1,4,5-trisphosphate (PLC-IP3) signaling cascade. Compounds with an indole scaffold impair in vitro proliferation of blood-stage malaria parasites, indicating that this class of compounds is potentially emerging antiplasmodial drugs. Therefore, we aimed to study the role of the alkyl and aryl thiol moieties of 14 synthetic indole compounds against chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) strains of Plasmodium falciparum. Four compounds (3, 26, 18, 21) inhibited the growth of P. falciparum (3D7) by 50% at concentrations below 20 µM. A set of 2-sulfenylindoles also showed activity against Dd2 parasites. Our data suggest that Dd2 parasites are more susceptible to compounds 20 and 28 than 3D7 parasites. These data show that 2-sulfenylindoles are promising antimalarials against chloroquine-resistant parasite strains. We also evaluated the effects of the 14 compounds on the parasitemia of the 3D7 strain and their ability to interfere with the effect of 100 nM melatonin on the parasitemia of the 3D7 strain. Our results showed that compounds 3, 7, 8, 10, 14, 16, 17, and 20 slightly increased the effect of melatonin by increasing parasitemia by 8–20% compared with that of melatonin-only-treated 3D7 parasites. Moreover, we found that melatonin modulates the expression of kinase-related signaling components giving additional evidence to investigate inhibitors that can block melatonin signaling.

Bioassay-Guided Fractionation, ESI-MS Scan, Phytochemical Screening, and Antiplasmodial Activity of Afzelia africana.

Background Afzelia africana is a plant species with reported numerous medicinal potentials and secondary metabolites. Various parts of the plant have been applied for the treatment of hernia, rheumatism, pain, lumbago, malaria, etc. The study seeks to evaluate the phytochemical constituents, antiplasmodial, and ESI-MS scan of bioassay-guided fractions from the methanol extract of the bark of the plant. Aims The main aim of the study was to carry out bioassay-guided fractionation of the crude methanol extract of Afzelia africana in order to isolate fractions and to evaluate their antiplasmodial activities and ESI-MS fingerprints. Methods The methods employed include column chromatographic fractionation, phytochemical screening, antiplasmodial activity (malaria SYBER green assay (MSF)), and ESI-MS profile (full ESI-MS scan). Results The column chromatographic fractionation and phytochemical screening of the plant led to the separation of the following four fractions: 1 (flavonoids, phenolics, glycosides, terpenoids, and steroids), 2 (alkaloids, anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), 3 (anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), and 4 (alkaloids, flavonoids, phenolics, glycosides, terpenoids, and steroids). The antiplasmodial activities of the fractions were tested against the 3D7 strain of Plasmodium falciparum with reported stronger activities for 1 (IC50: 0.097 ± 0.034 μg/mL) and 3 (IC50: 1.43 ± 0.072 μg/mL), and weaker activities for 2 (IC50: >100 μg/mL) and 4 (IC50: 37.09 ± 6.14 μg/mL). The full ESI-MS fingerprint of fractions 1, 2, 3, and 4 revealed the presence of 14, 24, 34, and 37 major molecular ions or compounds in each fraction, respectively.

Investigation of an Allosteric Deoxyhypusine Synthase Inhibitor in P. falciparum.

The treatment of a variety of protozoal infections, in particular those causing disabling human diseases, is still hampered by a lack of drugs or increasing resistance to registered drugs. However, in recent years, remarkable progress has been achieved to combat neglected tropical diseases by sequencing the parasites’ genomes or the validation of new targets in the parasites by novel genetic manipulation techniques, leading to loss of function. The novel amino acid hypusine is a posttranslational modification (PTM) that occurs in eukaryotic initiation factor 5A (EIF5A) at a specific lysine residue. This modification occurs by two steps catalyzed by deoxyhypusine synthase (dhs) and deoxyhypusine hydroxylase (DOHH) enzymes. dhs from Plasmodium has been validated as a druggable target by small molecules and reverse genetics. Recently, the synthesis of a series of human dhs inhibitors led to 6-bromo-N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide, a potent allosteric inhibitor with an IC50 value of 0.062 µM. We investigated this allosteric dhs inhibitor in Plasmodium. In vitro P. falciparum growth assays showed weak inhibition activity, with IC50 values of 46.1 µM for the Dd2 strain and 51.5 µM for the 3D7 strain, respectively. The antimalarial activity could not be attributed to the targeting of the Pfdhs gene, as shown by chemogenomic profiling with transgenically modified P. falciparum lines. Moreover, in dose-dependent enzymatic assays with purified recombinant P. falciparum dhs protein, only 45% inhibition was observed at an inhibitor dose of 0.4 µM. These data are in agreement with a homology-modeled Pfdhs, suggesting significant structural differences in the allosteric site between the human and parasite enzymes. Virtual screening of the allosteric database identified candidate ligand binding to novel binding pockets identified in P. falciparum dhs, which might foster the development of parasite-specific inhibitors.

Whole-genome sequence of a putative pathogenic Bacillus sp. strain SD-4 isolated from cattle feed

ObjectivesThe present study describes the draft genome sequence of a novel Bacillus sp. strain SD-4 isolated from animal feed. The study aims to get a deeper insight into antimicrobial resistance and secondary metabolite biosynthetic gene clusters (BGCs) and the association between them. MethodsThe strain SD-4 was preliminarily evaluated for antibacterial activities, motility, biofilm formation, and enterotoxin production using in vitro assays. The genome of strain SD-4 was sequenced using the Illumina HiSeq 2500 platform with paired-end reads. The reads were assembled and annotated using SPAdes and PGAP, respectively. The genome was further analysed using several bioinformatics tools, including TYGS, AntiSMASH, RAST, PlasmidFinder, VFDB, VirulenceFinder, CARD, PathogenFinder, MobileElement finder, IslandViewer, and CRISPRFinder. ResultsIn vitro assays showed that the strain is motile, synthesises biofilm, and produces an enterotoxin and antibacterial metabolites. The genome analysis revealed that the strain SD-4 carries antimicrobial resistance genes (ARGs), virulence factors, and beneficial secondary metabolite BGCs. Further genome analysis showed interesting genome architectures containing several mobile genetic elements, including two plasmid replicons (repUS22 and rep20), five prophages, and at least four genomic islands (GIs), including one Listeria pathogenicity island LIPI-1. Moreover, the strain SD-4 is identified as a putative human pathogen. ConclusionThe genome of strain SD-4 harbours several BGCs coding for biologically active metabolites. It also contains antimicrobial resistance genes and is identified as a potential human pathogen. These results can be used to better comprehend antibiotic resistance in environmental bacteria that are not influenced by human intervention.

Effects of Single and Mixture Probiotic Supplements on Growth, Digestive Activity, Antioxidative Status, Immune and Growth-Related Genes, and Stress Response of Juvenile Red Sea Bream (Pagrus Major)

A 50-day feeding trial was conducted to evaluate the efficiency of single and mixed strains of probiotic bacteria supplements on juvenile red sea bream (Pagrus major). The study investigated the growth, digestibility, hemato-biochemistry, antioxidant, immune, immune, and growth gene expression and stress responses of P. major. Three hundred juvenile P. major ( 21.56 ± 0.09 g) were randomly distributed into fifteen 200-L polyethylene tanks (20 fish per tank) in triplicate of 5 treatments designated as D1 = the basal diet; Streptococcus faecalis (SF) T − 110 5 × 106 cfu/g diet and Bacillus amyloliquefaciens (BA) TOA 5001 5 × 105 cfu/g diet in the second group (D2) at 0.2%; mix SF T − 110 1 × 106 cfu/g diet, Lactobacillus plantarum (LP) TO − A 4 × 105 cfu/g diet, Bacillus mesentericus (BM) TO − A 1 × 102 cfu/g diet, BA TOA 5001 5 × 105 cfu/g diet in the third group (D3) at 1%; mix SF T − 110 1 × 106 cfu/g diet, LP TO − A 4 × 105 cfu/g diet, and BM TO − A 1 × 102 cfu/g diet in fourth group (D4) at 0.5%; and single strain BA TOA5001 5×105 cfu/g diet in the fifth group (D5) at 0.5% of dietary proportion. Results showed that D2 and D3 fish groups exhibit better performance, followed by D4, D5, and control group D1. This finding demonstrated that the use of BA in mix strain probiotic bacteria diet (D2, D3) had improved immune response, antioxidant enzymes, immunity (TNF-a, IL-1b), and growth-related (IGF-1, IGF-2) mRNA expression of juvenile P. major compared to the mix strain D4, single strain D5, and the control D1. Furthermore, single strain D5 and mix strain D4 also exhibit relatively better immune responses in P. major than in control D1. Considering the overall fish performances, mix strain SF+BA (D2) and mix strain SF+BM+LP+BA (D3) were the recommended potential mix strain probiotic bacteria supplement for P. major and may be useful also for other related aquatic species.

Two new chromanone acids from the stem bark of Calophyllum peekelii Lauterb

Three chromanone acids were isolated from the stem bark of Calophyllum peekelii Lauterb. Among them are two new chromanone acids, calopeekelioic acids A (1) and B (2), along with calolongic acid (3), Their structures were established by analyzing a combination of HRESIMS, 1 D, and 2 D NMR spectra. Chromanone acids 1-3 were evaluated for their antiplasmodial activity against Plasmodium falciparum strain 3D7. Compounds 1-2 showed high activity with an IC50 value of 1.70 and 1.01 µg/mL, respectively.

In-Silico Functional Annotation of Plasmodium falciparum Hypothetical Proteins to Identify Novel Drug Targets.

Plasmodium falciparum is one of the plasmodium species responsible for the majority of life-threatening malaria cases. The current antimalarial therapies are becoming less effective due to growing drug resistance, leading to the urgent requirement for alternative and more effective antimalarial drugs or vaccines. To facilitate the novel drug discovery or vaccine development efforts, recent advances in sequencing technologies provide valuable information about the whole genome of the parasite, yet a lot more needs to be deciphered due to its incomplete proteome annotation. Surprisingly, out of the 5,389 proteins currently annotated in the Plasmodium falciparum 3D7 strain, 1,626 proteins (∼30% data) are annotated as hypothetical proteins. In parasite genomic studies, the challenge to annotate hypothetical proteins is often ignored, which may obscure the crucial information related to the pathogenicity of the parasite. In this study, we attempt to characterize hypothetical proteins of the parasite to identify novel drug targets using a computational pipeline. The study reveals that out of the overall pool of the hypothetical proteins, 266 proteins have conserved functional signatures. Furthermore, the pathway analysis of these proteins revealed that 23 proteins have an essential role in various biochemical, signalling and metabolic pathways. Additionally, all the proteins (266) were subjected to computational structure analysis. We could successfully model 11 proteins. We validated and checked the structural stability of the models by performing molecular dynamics simulation. Interestingly, eight proteins show stable conformations, and seven proteins are specific for Plasmodium falciparum, based on homology analysis. Lastly, mapping the seven shortlisted hypothetical proteins on the Plasmodium falciparum protein-protein interaction network revealed 3,299 nodes and 2,750,692 edges. Our study revealed interesting functional details of seven hypothetical proteins of the parasite, which help learn more about the less-studied molecules and their interactions, providing valuable clues to unravel the role of these proteins via future experimental validation.

Plant community context controls short‐ versus medium‐term effects of pre‐emergent herbicides on target and non‐target species after fire

AbstractQuestionsSelective herbicide application is a common restoration strategy to control exotic invaders that interfere with native plant recovery after wildfire. Whether spraying with pre‐emergent or bio‐herbicides releases native plants from competition with exotics (“spray‐and‐release” strategy) and makes communities resistant to reinvasion by exotic annual grasses (e.g. cheatgrass, medusahead), without risks to non‐target native plants or secondary invasion, is a major question for land managers of semiarid plant communities.LocationSagebrush steppe of southwest Idaho, USA.MethodsWe applied chemical herbicides (imazapic, rimsulfuron) and weed‐suppressive bacteria (Pseudomonas fluorescens strains MB906 and D7) to three sagebrush steppe communities after fire. We measured plant cover prior to burning and for four years (five for exotic annual grasses) post treatment.ResultsBoth chemical herbicides significantly reduced exotic annual grass cover in all communities in the first post‐spraying year, but rimsulfuron plots were re‐invaded after 1–2 years, while imazapic plots continued to resist reinvasion four and even five years post spraying, well after the herbicide should have degraded. We did not detect any increase in native perennial grass cover with either herbicide, and herbicides had both positive and negative effects on individual bunchgrass basal diameter, depending on species and plant community. Rimsulfuron was more damaging than imazapic to shallow‐rooted perennial bunchgrasses. Moss and lichen cover, key components of soil integrity, increased with chemical herbicide treatments in some communities. Both herbicides increased secondary invaders (exotic forbs or grasses), which varied by plant community and herbicide. Weed‐suppressive bacteria treatments had no significant effects on cover of any functional group.ConclusionsWhile short‐term effects of chemical herbicides that target exotic annual grasses were relatively consistent and predictable, longer‐term effects were specific to the herbicide and plant community. The “spray‐and‐release” strategy may confer resistance to re‐invasion by exotic annual grasses if herbicides prevent re‐invasion for an extended period.

Anti-malarial activity in a Chinese herbal supplement containing Inonotus obliquus and Panax notoginseng.

Plasmodium falciparum, the most virulent human malaria parasite, causes serious diseases among the infected patients in the world and is particularly important in African regions. Although artemisinin combination therapy is recommended by the WHO for treatment of P. falciparum-malaria, the emergence of artemisinin-resistant parasites has become a serious issue which underscores the importance of sustained efforts to obtain novel chemotherapeutic agents against malaria. As a part of such efforts, thirty-nine herbal extracts from traditional Chinese medicine (TCM) were assayed for their anti-malarial activity using 3D7 strain of P. falciparum. Three herbal supplements appeared to possess higher specific anti-malarial activity than the others. One of them (D3) was separated by two sequential fractionations with reverse-phase (the first step) and normal-phase (the second step) liquid chromatography, in which some fractions resulted in higher specific activities than those of D3 or the previous fractions. Cell toxicity assay was performed with the fractions of the first fractionation and demonstrated no obvious cell toxicity. These results suggest that structure determination of the major compound for the anti-malarial activity in D3 may help the development of more potent chemicals in the future.

Enhanced biodegradation of hexachlorocyclohexane (HCH) isomers by Sphingobium sp. strain D4 in the presence of root exudates or in co-culture with HCH-mobilizing strains

Lindane and other 1,2,3,4,5,6-hexachlorocyclohexane (HCH) isomers are persistent organic pollutants highly hydrophobic, which hampers their availability and biodegradation. This work aimed at (i) investigating genes encoding enzymes involved in HCH degradation in the bacterium Sphingobium sp. D4, (ii) selecting strains, from a collection of environmental isolates, able to mobilize HCHs from contaminated soil, and (iii) analysing the biodegradation of HCHs by strain D4 in co-culture with HCH-mobilizing strains or when cultivated with root exudates. Fragments of the same size and similar sequence to linA and linB genes were successfully amplified. Two isolates, Streptomyces sp. M7 and Rhodococcus erythropolis ET54b able to produce emulsifiers and to mobilize HCH isomers from soil were selected. Biodegradation of HCH isomers by strain D4 was enhanced when co-inoculated with HCH mobilizing strains or when cultivated with root exudates. The degrader strain D4 was able to decompose very efficiently HCHs isomers, reducing their concentration in soil slurries by more than 95% (from an average initial amount of 50 ± 8 mg HCH kg−1 soil) in 9 days. The combination of HCH-degrading and HCH-mobilizing strains can be considered a promising inoculum for future soil bioremediation studies using bioaugmentation techniques or in combination with plants in rhizodegradation assays.

Oral Administration of Piperine as Curative and Prophylaxis Reduces Parasitaemia in Plasmodium berghei ANKA-Infected Mice.

Malaria remains a public health problem and a leading cause of death worldwide. Consequently, the discovery of novel agents, including substances from medicinal plants, is urgently needed. Piper nigrum has long been used by the community in the treatment of the symptoms of malaria. In a previous study, Piper nigrum was demonstrated to exhibit promising antiplasmodial activity against Plasmodium falciparum 3D7 and INDO strains. The aim of this study was to further investigate the antimalarial activity (curative and prophylactic) of piperine (a major isolated constituent of Piper nigrum) in Plasmodium berghei ANKA-infected mice. Piperine 10, 20, and 40 mg/kg body weight (bw), artesunate 5 mg/kg bw, and DMSO were administered orally for four days to different groups of Swiss Webster mice. Then, mice were monitored for parasitaemia, body weight, rectal temperature, survival rate, and clinical parameters. Piperine 40 mg/kg bw in curative and prophylactic tests had the maximum parasitaemia chemosuppression of 79.21% and 58.8% (p < 0.05), respectively, with a significant effect on the survival rate compared with control animals. In the curative test, piperine 40 mg/kg bw reduced the mean clinical score compared with the control group. Additionally, piperine showed an ability to protect organs (lungs, liver, spleen, and kidneys) from some damage in a dose-dependent manner. This study can be used as a basis for further discovery of novel chemotherapeutic or chemoprophylactic compounds.

Antibacterial metabolites from an unexplored strain of marine fungi Emericellopsis minima and determination of the probable mode of action against Staphylococcus aureus and methicillin-resistant S. aureus.

Increasing prevalence of drug resistance has led researchers to focus on discovering new antibacterial agents derived from the marine biome. Although ample studies have investigated marine fungi for their bioactive metabolites with hopeful prospects in drug discovery. The present study was aimed to isolate/ identify potential antimethicillin-resistant Staphylococcus aureus compounds producing marine fungal strain from the Indian marine environment. The effective anti-MRSA compound was produced by a marine fungal strain designated as D6. The D6 strain exhibited 99% similarity to Emericellopsis minima based on 18S rRNA gene analysis. The culture conditions of E. minima D6 were optimized using nutritional and environmental parameters for enhanced anti-MRSA compound production. The agar well diffusion assay was used to determine the inhibition zone diameter of the crude extract against S. aureus and methicillin-resistant S. aureus, whereas the broth microdilution method was used to determine their minimum inhibitory concentration (MIC) active fraction. MIC values of the ethyl acetate fraction ranged from 0.8 to 1 mg/mL. SEM analysis revealed that the ethyl acetate fraction induces deep craters in methicillin-resistant S. aureus. Further, GC-MS analysis confirmed the occurrence of a total of 15 major compounds in active ethyl acetate fraction. Some of the major antibacterial compounds included cyclopentanol, isothiazole, benzoic acid, pyrrolo[1,2-a] pyrazine-1,4-dione, and hexahydro. These findings suggest that the marine fungi of E. minima can be a valuable candidate for prospecting antibiotics and an alternative complementary strategy for drug-resistant bacterial infections.

Cytotoxic and antimicrobial activities of new phytosteroids from the leaves of Anonidium mannii (Oliv.) Engl. & Diels (Annonaceae)

Phytochemical studies of the dichloromethane-methanol (1:1) extract of the leaves of Anonidium mannii (Oliv.) Engl. & Diels led to the isolation of two new phytosteroids named anonimadiol A (AM1C) and B (AM2C) together with the known stigmasterol (AM3C). The structures of compounds were established by means of spectroscopic methods covering NMR analysis (1H and 13C NMR, DEPT135, 1H–1H–COSY, HSQC and HMBC), FTIR and high-resolution mass spectrometry (HR-ESI-MS), and by comparison with data previously reported in the literature. Biological activities of the crude extract and the metabolites (AM1C, AM2C and AM3C) were evaluated, namely: cytotoxicity on adenocarcinoma of the cervix (Henrietta Lacks, HeLa) cells; antimalarial test using parasite lactate dehydrogenase (pLDH) from Plasmodium falciparum (3D7) strain; antibacterial test on Escherichia coli (8739), Salmonella typhi (1403), Staphylococcus aureus (25923) and Enterococcus faecalis (6230434); antifungal test using Candida albicans (10231) and anti-mycobacterial test using Mycobacterium tuberculosis (H3DTB). AM1C and AM2C at 20 µg/mL showed considerable cytotoxicity potential with percentage viability of 20.2 and 30.4, respectively, against HeLa cells. Furthermore, the crude extract and AM1C had 50% inhibition concentrations (IC50s) of 50 and 11.21 μg/mL, respectively, against Plasmodium falciparum. Regarding the antituberculosis effects, a notable 90% minimum inhibition concentration (MIC90) value of 39.4 µg/mL was obtained with AM1C. Moreover, AM1C and AM2C had notable activity against Salmonella typhi and Candida albicans delivering MICs of 60 and 250 μg/mL respectively compared to the positive control ciprofloxacin with MICs values of 39 and 1250 μg/mL. However, the crude extract and the three metabolites showed no activity against HIV protease and HIV integrase. These results suggest the possible potential effect of these isolates from Annonidium mannii against cancer of the cervix and many microbial infections.