Identification of trans-2-cis-8-Matricaria-ester from the Essential Oil of Erigeron multiradiatus and Evaluation of Its Antileishmanial Potential by in Vitro and in Silico Approaches

Chemical Constituents, Biological Activities and Molecular Docking Studies of Root and Aerial Part Essential Oils from Erigeron sublyratus Roxb. ex DC. (Asteraceae)

In this work, the volatile components of Erigeron sublyratus essential oils and their anti-inflammatory and cytotoxic activities were investigated for the first time. Gas chromatography-mass spectrometry (GC-MS) analysis identified 28 components in the root and aerial part essential oils. The main components included cis-lachnophyllum ester (53.4-64.2 %), germacrene D (5.6-8.6 %), trans-β-ocimene (2.6-7.5 %), β-caryophyllene (4.7-6.8 %), β-myrcene (2.0-6.3 %), and (E)-β-farnesene (4.8-5.0 %). The aerial part essential oil inhibited nitric oxide (NO) production on LPS-induced RAW 264.7 cells, with an IC50 value of 1.41±0.10 μg/mL. In addition, both root and aerial part essential oils exhibited cytotoxic activity against MCF-7, SK-LU-1, and HepG2. Molecular docking simulation results revealed that (E)-β-farnesene strongly binds to the VEGFR-2 enzyme, while δ-cadinene has a high affinity to the COX-2 enzyme via hydrophobic interactions. These findings proposed that E. sublyratus essential oils can be exploited for their anti-inflammatory and anti-cytotoxicity potential.

Synthesis and biological evaluation of natural Lachnophyllum methyl ester, Lachnophyllum lactone and their synthetic analogs

(2Z)-Lachnophyllum methyl ester and (4Z)-Lachnophyllum lactone were recently identified as major components in essential oils and extracts of Conyza bonariensis from Togo. Extended biological evaluation of these acetylenic compounds was however hampered by the reduced amounts isolated. A synthetic route was designed providing access to larger quantities of these two natural products as well as to original non-natural analogs with the prospect of exploring for the first time the structure-activity relationships in this series. Using LC/MS analysis, synthetic samples allowed confirming the presence of the two previously isolated natural products in plant extracts obtained by the accelerated solvent extraction technique. The nematocidal activity of the synthesized compounds confirmed the potency of the natural products, which remain the most active among all analogs tested. The synthesized compounds were also assessed against Leishmania infantum axenic amastigotes and the Mycobacterium tuberculosis H37Rv pathogenic strain. (2Z)-Lachnophyllum methyl ester, (4Z)-Lachnophyllum lactone and lactone analogs exhibited the strongest antileishmanial potency. As expected, a longer alkyl chain was necessary to observe significant antimycobacterial activity. The lactone analog bearing a C10 lipophilic appendage displayed the highest antimycobacterial potency. The notable activities of lactones, naturally occurring or analogs, either nematicidal, antileishmanial or antimycobacterial, were compared to their cytotoxicity for mammalian cells and revealed moderate selectivity index values. In this regard, the innocuous (2Z)-Lachnophyllum methyl ester and its analogs open up more promising perspectives for the discovery of bioactive agents to protect both agricultural crops and human health.

Conyza canadensis from Jordan: Phytochemical Profiling, Antioxidant, and Antimicrobial Activity Evaluation

In this investigation, the chemical composition of the hydro-distilled essential oil (HD-EO), obtained from the fresh aerial parts (inflorescence heads (Inf), leaves (L), and stems (St)) of Conyza canadensis growing wild in Jordan was determined by GC/MS. Additionally, the methanolic extract obtained from the whole aerial parts of C. canadensis (CCM) was examined for its total phenolic content (TPC), total flavonoids content (TFC), DPPH radical scavenging activity, iron chelating activity and was then analyzed with LC-MS/MS for the presence of certain selected phenolic compounds and flavonoids. The GC/MS analysis of CCHD-EOs obtained from the different aerial parts revealed the presence of (2E, 8Z)-matricaria ester as the main component, amounting to 15.4% (Inf), 60.7% (L), and 31.6% (St) of the total content. Oxygenated monoterpenes were the main class of volatile compounds detected in the Inf-CCHD-EO. However, oils obtained from the leaves and stems were rich in polyacetylene derivatives. The evaluation of the CCM extract showed a richness in phenolic content (95.59 ± 0.40 mg GAE/g extract), flavonoids contents (467.0 ± 10.5 mg QE/ g extract), moderate DPPH radical scavenging power (IC50 of 23.75 ± 0.86 µg/mL) and low iron chelating activity (IC50 = 5396.07 ± 15.05 µg/mL). The LC-MS/MS profiling of the CCM extract allowed for the detection of twenty-five phenolic compounds and flavonoids. Results revealed that the CCM extract contained high concentration levels of rosmarinic acid (1441.1 mg/kg plant), in addition to caffeic acid phenethyl ester (231.8 mg/kg plant). An antimicrobial activity assessment of the CCM extract against a set of Gram-positive and Gram-negative bacteria, in addition to two other fungal species including Candida and Cryptococcus, showed significant antibacterial activity of the extract against S. aureus with MIC value of 3.125 µg/mL. The current study is the first phytochemical screening for the essential oil and methanolic extract composition of C. canadensis growing in Jordan, its antioxidant and antimicrobial activity.

Identification of novel inhibitors from Urtica spp against TNBC targeting JAK2 receptor for breast cancer therapy

Breast cancer is the most prevalent form of cancer in women globally, and TNBC (triple-negative breast cancer) is its aggressive type since it lacks the usual targets. JAK2/STAT3 pathway can be an important lead in anticancer drug discovery, as restraining the downstream signalling of this pathway results in the induction of cell apoptosis. Moreover, various limitations associated with chemotherapy are the reason to find an alternative herbal-based therapy. For this study, we collected Urtica dioica and U. parviflora from different regions of Uttarakhand, followed by preparation of their leaf and stem extracts in different solvents. The GC-MS analysis of these extracts revealed a total of 175 compounds to be present in them. Further, by molecular docking approach, we studied the interaction between these compounds and JAK2, and 12 major compounds with better binding energy than the control Paclitaxel were identified. In addition, the selected hits were also reported to display better pharmacokinetic properties. Moreover, extracts from both the Urtica spp. displayed significant anticancer activity against MDA-MB-231(TNBC cell line) and exhibited lower cytotoxicity in healthy cell lines, i.e. HEK293T, indicating that these extracts were safer to use. Hence, the findings in our study can be crucial in the area of herbal-based target-specific drug development against breast cancer.

Demystifying the potential of inhibitors targeting DNA topoisomerases in unicellular protozoan parasites

DNA topoisomerases are a group of enzymes omnipresent in all organisms. They maintain the DNA topology during replication, repair, recombination, and transcription. However, the structure of topoisomerase in protozoan parasites differs significantly from that of human topoisomerases; thus, this enzyme acts as a crucial target in drug development against parasitic diseases. Although the therapeutic potential of drugs targeting the parasitic topoisomerase is well known, to manage the shortcomings of currently available therapeutics and the emergence of drug resistance, the discovery of novel antiparasitic molecules is an urgent need. In this review, we describe various investigational and repurposed topoisomerase inhibitors developed against protozoan parasites over the past few years. Teaser: Fatal parasitic diseases are an increasing cause for concern; here, we provide a compilation of different inhibitors targeting DNA topoisomerases, enzymes that are essential for, and unique to, protozoan parasites; therefore, inhibitors are efficient and have few adverse effects.

Resistance-proof antimicrobial drug discovery to combat global antimicrobial resistance threat

Drug resistance is well-defined as a serious problem in our living world. To survive, microbes develop defense strategies against antimicrobial drugs. Drugs exhibit less or no effective results against microbes after the emergence of resistance because they are unable to cross the microbial membrane, in order to alter enzymatic systems, and/or upregulate efflux pumps, etc. Drug resistance issues can be addressed effectively if a "Resistance-Proof" or "Resistance-Resistant" antimicrobial agent is developed. This article discusses first the need for resistance-proof drugs, the imminent properties of resistance-proof drugs, current and future research progress in the discovery of resistance-proof antimicrobials, the inherent challenges, and opportunities. A molecule having imminent resistance-proof properties could target microbes efficiently, increase potency, and rule out the possibility of early resistance. This review triggers the scientific community to think about how an upsurge in drug resistance can be averted and emphasizes the discussion on the development of next-generation antimicrobials that will provide a novel effective solution to combat the global problem of drug resistance. Hence, resistance-proof drug development is not just a requirement but rather a compulsion in the drug discovery field so that resistance can be battled effectively. We discuss several properties of resistance-proof drugs which could initiate new ways of thinking about next-generation antimicrobials to resolve the drug resistance problem. This article sheds light on the issues of drug resistance and discusses solutions in terms of the resistance-proof properties of a molecule. In summary, the article is a foundation to break new ground in the development of resistance-proof therapeutics in the field of infection biology.

Molecular docking and molecular dynamics simulation approaches for evaluation of laccase-mediated biodegradation of various industrial dyes

Dyes are being increasingly utilized across the globe, but there is no appropriate method of bioremediation for their full mineralization from the environment. Laccases are key enzymes that help microbes to degrade dyes as well as their intermediate metabolites. Various dyes have been reported to be degraded by bacteria, but it is still unclear how these enzymes function during dye degradation. To effectively eradicate toxic dyes from the system, it is essential to understand the molecular function of enzymes. As a result, the interaction of laccase with different toxic dyes was investigated using molecular docking. Based on the highest binding energy we have screened ten dyes with positive interaction with laccase. Evaluating the MD simulation results, three out of ten dyes were more stable as potential targets for degradation by laccase of Bacillus subtilis. As a result, subsequent research focused solely on the results of three substrates: pigment red, fuchsin base, and Sudan IV. Analysis of MD simulation revealed that pigments red 23, fuchsin base, and Sudan IV form hydrogen and hydrophobic bond as well as Vander Waals interactions with the active site of laccase to keep it stable in aqueous solution. The conformation of laccase is greatly altered by the inclusion of all three substrates in the active site. The MD simulation findings show that laccase complexes remain stable throughout the catalytic reaction. Therefore, this research provides a molecular understanding of laccase expression and its role in the bioremediation of the pigments red 23, fuchsin base, and Sudan IV.Communicated by Ramaswamy H. Sarma.

Goldenrod Root Compounds Active against Crop Pathogenic Fungi

Root extracts of three goldenrods were screened for antimicrobial compounds. 2Z,8Z- and 2E,8Z-matricaria esters from European goldenrod (Solidago virgaurea) and E- and Z-dehydromatricaria esters from grass-leaved goldenrod (Solidago graminifolia) and first from showy goldenrod (Solidago speciosa) were identified by high-performance thin-layer chromatography combined with effect-directed analysis and high-resolution mass spectrometry or nuclear magnetic resonance spectroscopy after liquid chromatographic fractionation and isolation. Next to their antibacterial effects (against Bacillus subtilis, Aliivibrio fischeri, and Pseudomonas syringae pv. maculicola), they inhibited the crop pathogenic fungi Fusarium avenaceum and Bipolaris sorokiniana with half maximal inhibitory concentrations (IC₅₀) between 31 and 107 μg/mL. Benzyl 2-hydroxy-6-methoxybenzoate, for the first time found in showy goldenrod root, showed the strongest antifungal effect, with IC₅₀ of 25-26 μg/mL for both fungal strains.

DDX3 DEAD-box RNA helicase (Hel67) gene disruption impairs infectivity of Leishmania donovani and induces protective immunity against visceral leishmaniasis

Visceral leishmaniasis (VL) is a vector-borne disease caused by the digenetic protozoan parasite Leishmania donovani complex. So far there is no effective vaccine available against VL. The DDX3 DEAD-box RNA Helicase (Hel67) is 67 kDa protein which is quite essential for RNA metabolism, amastigote differentiation, and infectivity in L. major and L. infantum. To investigate the role of Hel67 in the L. donovani, we created L. donovani deficient in the Hel67. Helicase67 null mutants (LdHel67^-/-) were not able to differentiate as axenic amastigotes and were unable to infect the hamster. So, we have analyzed the prophylactic efficacy of the LdHel67^-/- null mutant in hamsters. The LdHel67^-/- null mutant based candidate vaccine exhibited immunogenic response and a higher degree of protection against L. donovani in comparison to the infected control group. Further, the candidate vaccine displayed antigen-specific delayed-type hypersensitivity (DTH) as well as strong antibody response and NO production which strongly correlates to long term protection of candidate vaccine against the infection. This study confirms the potential of LdHel67^-/- null mutant as a safe and protective live attenuated vaccine candidate against visceral leishmaniasis.

DNA-based microarray studies in visceral leishmaniasis: identification of biomarkers for diagnostic, prognostic and drug target for treatment

Visceral leishmaniasis (VL) is one of the major infectious diseases affecting the poorest regions of the world. Current therapy is not very much satisfactory. The alarming rise of drug resistance and the unavailability of an effective vaccine against VL urges research towards identifying new targets or biomarkers for its effective treatment. New technology developments offer some fresh hope in its diagnosis, treatment, and control. DNA microarray approach is now broadly used in parasitology research to facilitate the thoughtful of mechanisms of disease and identification of drug targets and biomarkers for diagnostic and therapeutic development. An electronic search on "VL" and "Microarray" was conducted in Medline and Scopus and papers published in the English mentioning use of DNA microarray on VL were selected and read to write this paper review. Functional analysis and interpretation of microarray results remain very challenging due to the inherent nature of experimental workflows, access, cost, and complexity of data obtained. We have explained and emphasized the use of curate knowledge of microarray in the case of VL for the identification of therapeutic target and biomarker and their selection/implementation in clinical use.

Genetically modified live attenuated vaccine: A potential strategy to combat visceral leishmaniasis

Visceral leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani mainly influencing the population of tropical and subtropical regions across the globe. The arsenal of drugs available is limited, and prolonged use of such drugs makes parasite to become resistant. Therefore, it is very imperative to develop a safe, cost-effective and inexpensive vaccine against VL. Although in recent years, many strategies have been pursued by researchers, so far only some of the vaccine candidates reached for clinical trial and more than half of them are still in pipeline. There is now a broad consent among Leishmania researchers that the perseverance of parasite is very essential for eliciting a protective immune response and may perhaps be attained by live attenuated parasite vaccination. For making a live attenuated parasite, it is very essential to ensure that the parasite is deficient of virulence and should further study genetically modified parasites to perceive the mechanism of pathogenesis. So it is believed that in the near future, a complete understanding of the Leishmania genome will explore clear strategies to discover a novel vaccine. This review describes the need for a genetically modified live attenuated vaccine against VL, and obstacles associated with its development.

A spotlight on the diagnostic methods of a fatal disease Visceral Leishmaniasis

Leishmania donovani (a causative agent of visceral leishmaniasis) poses a serious health threat to the human population which is fatal if left untreated. The life cycle of Leishmania alternates between vertebrate host and Phlebotomine fly as intermediate ones. Due to the difficulties linked to vector (sandfly) control and the lack of an effective vaccine, the control of leishmaniasis relies mostly on chemotherapy. Unfortunately, the prevalence of parasites becoming resistant to the first-line drug pentavalent antimonial (Sb^V )/sodium antimony gluconate (SAG) and some other anti-leishmanial drug is increasing in several parts of the world. With the alarming rise of drug resistance and other issues related to VL, there is an urgent need to focus on early detection and quick diagnosis of VL case. Therefore, we have reviewed most of the methods used in the diagnostic process of VL. Along with existing diagnostic methods, developing more effective and sensitive diagnostic methods and biomarkers is also vital for enhancing VL identification and control programs. This review gathers the comprehensive information on diagnostics methods of VL under a single umbrella that could be the prominent tools for the development of rapid, accurate and cost-effective diagnostic kits for VL which can be used in field conditions.