Discovery of Anti-NRLP3 Inflammasome, Immunomodulatory Phytochemicals from the Extract of Habenaria intermediaD. Don: An Unexplored Plant Species.

The present study describes the isolation, identification, and quantification of biomarker compounds in plant extracts of Habenaria intermedia D. Don (Orchidaceae). The isolation of the compounds was carried out from H. intermedia D. Don by repeated column chromatography of petroleum ether and ethanol fractions of extract of tubers. These compounds were characterized by 1H and 13C NMR and mass spectral data. A new quantitative method was established by using high-performance liquid chromatography (HPLC)-PDA. As a result, seven compounds were isolated and characterized. This is the first report of isolation of these compounds from this plant species H. intermedia D.Don. Out of seven isolated compounds, five were used for the quantitative study. A reliable and suitable HPLC method was developed for the well-resolved chromatogram of compounds. The proposed method was applied successfully to the detection and quantification of compounds. This study also represents the immunomodulatory and anti-inflammasome biological studies of isolated natural products. Loroglossol (HBR-4) has been reported to possess immunomodulatory activity. The immunostimulating assay indicated that HBR-4 could significantly promote the cell proliferation, especially via IL-2, TNF-α, and IFN-γ secretion from spleen cells. These results suggested the potential utilization of HBR-4 as an attractive functional health supplement candidate for hypoimmunity population. Additionally, cyclophosphamide-induced immunosuppression was counteracted by treatment with HBR-4, revealing significant increase in hemagglutinating antibody responses and hemolytic antibody responses. The current work revealed the potential anti-inflammasome and immunomodulatory activities of H. intermedia D. Don compounds and validates the usage of this prominent Rasayna plant.

Scoparone chemical modification into semi-synthetic analogues featuring 3-substitution for their anti-inflammatory activity.

Natural products (NPs) continue to serve as a structural model for the development of new bioactive molecules and improve the process of identifying novel medicines. The biological effects of coumarins, one of the most researched compounds among NPs, are currently being thoroughly investigated. In the present investigation, we reported the synthesis of nineteen semi-synthetic 3-substituted scoparone analogues, followed by their characterization using analytical methods such as NMR, HPLC, and HRMS. All compounds screened for in vitro and in vivo study for their ability to reduce inflammation. The SAR study worked effectively for this particular scoparone 3-substitution, as compounds 3, 4, 9, 16, 18, and 20 displayed improved in vitro results for TNF-α than the parent molecule. Similarly, compounds 3, and 17 showed a higher percentage of IL-6 inhibition. Compounds 3, 4, and 12 have also been identified by in vivo studies as promising candidates with higher percent inhibition than the parent scoparone molecule. As evident from all in vitro and in vivo studies, compound 3 showed the most potent anti-inflammatory activity among all.

Correction to "LC-PDA-MS/MS-Based Dereplication Guided Isolation of a New Optical Isomer of 19,20-Epoxycytochalasin-N and Its Cytotoxic Activity".

[This corrects the article DOI: 10.1021/acsomega.2c03037.].

Correction: Chrysomycins A-C, antileukemic naphthocoumarins from Streptomyces sporoverrucosus.

[This corrects the article DOI: 10.1039/C3RA42884B.].

Exploring the Potential of Chemical Inhibitors for Targeting Post-translational Glycosylation of Coronavirus (SARS-CoV-2).

The Spike (S) protein of SARS-CoV-2 expressed on the viral cell surface is of particular importance as it facilitates viral entry into the host cells. The S protein is heavily glycosylated with 22 N-glycosylation sites and a few N-glycosylation sites. During the viral surface protein synthesis via the host ribosomal machinery, glycosylation is an essential step in post-translational modifications (PTMs) and consequently vital for its life cycle, structure, immune evasion, and cell infection. Interestingly, the S protein of SARS-CoV-2 and the host receptor protein, ACE2, are also extensively glycosylated and these surface glycans are critical for the viral-host cell interaction for viral entry. The glycosylation pathway of both virus (hijacked from the host biosynthetic machinery) and target cells crucially affect SARS-CoV-2 infection at different levels. For example, the glycosaminoglycans (GAGs) of host cells serve as a cofactor as they interact with the receptor-binding domain (RBD) of S-glycoprotein and play a protective role in host immune evasion via masking the viral peptide epitopes. Hence, the post-translational glycan biosynthesis, processing, and transport events could be potential targets for developing therapeutic drugs and vaccines. Especially, inhibition of the N-glycan biosynthesis pathway amplifies S protein proteolysis and, thus, blocks viral entry. The chemical inhibitors of SARS-CoV-2 glycosylation could be evaluated for Covid-19. In this review, we discuss the current status of the chemical inhibitors (both natural and synthetically designed inhibitors) of viral glycosylation for Covid-19 and provide a future perspective. It could be an important strategy in targeting the various emerging SARS-CoV-2 variants of concern (VOCs), as these inhibitors are postulated to aid in reducing the viral load as well as infectivity.

LC-PDA-MS/MS-Based Dereplication Guided Isolation of a New Optical Isomer of 19,20-Epoxycytochalasin-N and Its Cytotoxic Activity.

The Rosellinia sanctae-cruciana extract was subjected to detailed liquid chromatography tandem mass spectrometry studies. A total of 38 peaks were annotated to m/z 508.26, m/z 510.28, m/z 524.26, m/z 526.28, m/z 540.26, m/z 542.27, and m/z 584.28 [M + H]+. The accurate mass, mutually supported UV/vis spectra, and database search identified these compounds as cytochalasins. Systematic dereplication helped identify a peak at m/z 540.26 [M + H]+ as the new compound. Further, the identified compound was purified by high-performance liquid chromatography and characterized by 2D NMR to be 19,20-epoxycytochalasin N1, a new optical isomer of 19,20-epoxycytochalasin-N. It exhibited substantial cytotoxicity with IC50 values ranging from 1.34 to 19.02 µM. This study shows a fast approach for dereplicating and identifying novel cytochalasin metabolites in crude extracts.

Functionalized Nitroimidazole Scaffold Construction and Their Pharmaceutical Applications: A 1950-2021 Comprehensive Overview.

Nitroimidazole represents one of the most essential and unique scaffolds in drug discovery since its discovery in the 1950s. It was K. Maeda in Japan who reported in 1953 the first nitroimidazole as a natural product from Nocardia mesenterica with antibacterial activity, which was later identified as Azomycin 1 (2-nitroimidazole) and remained in focus until now. This natural antibiotic was the starting point for synthesizing numerous analogs and regio-isomers, leading to several life-saving drugs and clinical candidates against a number of diseases, including infections (bacterial, viral, parasitic) and cancers, as well as imaging agents in medicine/diagnosis. In the present decade, the nitroimidazole scaffold has again been given two life-saving drugs (Delamanid and Pretomanid) used to treat MDR (multi-drug resistant) tuberculosis. Keeping in view the highly successful track-record of the nitroimidazole scaffold in providing breakthrough therapeutic drugs, this comprehensive review focuses explicitly on presenting the activity profile and synthetic chemistry of functionalized nitroimidazole (2-, 4- and 5-nitroimidazoles as well as the fused nitroimidazoles) based drugs and leads published from 1950 to 2021. The present review also presents the miscellaneous examples in each class. In addition, the mutagenic profile of nitroimidazole-based drugs and leads and derivatives is also discussed.

Stereoselective Synthesis of Nonpsychotic Natural Cannabidiol and Its Unnatural/Terpenyl/Tail-Modified Analogues.

Here, we report a three-step concise and stereoselective synthesis route to one of the most important phytocannabinoids, namely, (-)-cannabidiol (-CBD), from inexpensive and readily available starting material R-(+)-limonene. The synthesis involved the diastereoselective bifunctionalization of limonene, followed by effective elimination leading to the generation of key chiral p-mentha-2,8-dien-1-ol. The chiral p-mentha-2,8-dien-1-ol on coupling with olivetol under silver catalysis provided regiospecific (-)-CBD, contrary to reported ones which gave a mixture. The newly developed approach was further extended to its structural analogues cannabidiorcin and other tail/terpenyl-modified analogues. Moreover, its opposite isomer (+)-cannabidiol was also successfully synthesized from S-(-)-limonene.

Cocculus hirsutus-Derived Phytopharmaceutical Drug Has Potent Anti-dengue Activity.

Dengue is a serious public health concern worldwide, with ∼3 billion people at risk of contracting dengue virus (DENV) infections, with some suffering severe consequences of disease and leading to death. Currently, there is no broad use vaccine or drug available for the prevention or treatment of dengue, which leaves only anti-mosquito strategies to combat the dengue menace. The present study is an extension of our earlier study aimed at determining the in vitro and in vivo protective effects of a plant-derived phytopharmaceutical drug for the treatment of dengue. In our previous report, we had identified a methanolic extract of aerial parts of Cissampelos pareira to exhibit in vitro and in vivo anti-dengue activity against all the four DENV serotypes. The dried aerial parts of C. pareira supplied by local vendors were often found to be mixed with aerial parts of another plant of the same Menispermaceae family, Cocculus hirsutus, which shares common homology with C. pareira. In the current study, we have found C. hirsutus to have more potent anti-dengue activity as compared with C. pareira. The stem part of C. hirsutus was found to be more potent (∼25 times) than the aerial part (stem and leaf) irrespective of the extraction solvent used, viz., denatured spirit, hydro-alcohol (50:50), and aqueous. Moreover, the anti-dengue activity of stem extract in all the solvents was comparable. Hence, an aqueous extract of the stem of C. hirsutus (AQCH) was selected due to greater regulatory compliance. Five chemical markers, viz., Sinococuline, 20-Hydroxyecdysone, Makisterone-A, Magnoflorine, and Coniferyl alcohol, were identified in fingerprinting analysis. In a test of primary dengue infection in the AG129 mice model, AQCH extract at 25 mg/kg body weight exhibited protection when administered four and three times a day. The AQCH was also protective in the secondary DENV-infected AG129 mice model at 25 mg/kg/dose when administered four and three times a day. Additionally, the AQCH extract reduced serum viremia and small intestinal pathologies, viz., viral load, pro-inflammatory cytokines, and vascular leakage. Based on these findings, we have undertaken the potential preclinical development of C. hirsutus-based phytopharmaceutical, which could be studied further for its clinical development for treating dengue.

Quantitative Determination and Characterization of a Kashmir Saffron (Crocus sativus L.)-Based Botanical Supplement Using Single-Laboratory Validation Study by HPLC-PDA with LC-MS/MS and HPTLC Investigations.

Food ingredients hold a higher nutritional value as a botanical supplement playing a vital role in modifying and maintaining the physiological conditions that improve human health benefits. The Kashmir saffron (Crocus sativus L; KCS) obtained from dried stigmas is known for its aroma precursors and apocarotenoid derivatives, imparting a wide range of medicinal values and therapeutic benefits. In the present study, a simultaneous determination of apocarotenoids and flavonoids in stigma-based botanical supplements was carried out using analytical investigations. The high-performance thin-layer chromatography-based qualitative analysis of the raw material (stigmas, stamens, and tepals) and stigma extract has been carried out to identify apocarotenoids and flavonoids. The rapid HPLC-PDA method for the simultaneous quantification of KCS apocarotenoids was robust, precise (<5.0%), linear (R 2 > 0.99), and accurate (80-110%) as per the single-laboratory validation data. Furthermore, the combined-expanded uncertainty (95%; K = 2) was calculated and found as 0.0035-0.007% (<5.0%) as per the EURACHEM guide for this HPLC analysis. Additionally, an untargeted identification of 36 compounds in the botanical supplement was based on the elution order, UV-vis spectra, mass fragmentation pattern, and standards by ESI-MS/MS analysis with comprehensive chromatographic fingerprinting. Thus, these analytical approaches enable a composite profile of the stigma-based extract as a potential supplement for human health benefits.

Optimization and validation of RT-LAMP assay for diagnosis of SARS-CoV2 including the globally dominant Delta variant.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19 pandemic, has infected more than 179 million people worldwide. Testing of infected individuals is crucial for identification and isolation, thereby preventing further spread of the disease. Presently, Taqman™ Reverse Transcription Real Time PCR is considered gold standard, and is the most common technique used for molecular testing of COVID-19, though it requires sophisticated equipments, expertise and is also relatively expensive. OBJECTIVE: Development and optimization of an alternate molecular testing method for the diagnosis of COVID-19, through a two step Reverse Transcription Loop-mediated isothermal AMPlification (RT-LAMP). RESULTS: Primers for LAMP were carefully designed for discrimination from other closely related human pathogenic coronaviruses. Care was also taken that primer binding sites are present in conserved regions of SARS-CoV2. Our analysis shows that the primer binding sites are well conserved in all the variants of concern (VOC) and variants of interest (VOI), notified by World Health Organization (WHO). These lineages include B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.427/B.1.429, P.2, B.1.525, P.3, B.1.526 and B.1.617.1. Various DNA polymerases with strand displacement activity were evaluated and conditions were optimized for LAMP amplification and visualization. Different LAMP primer sets were also evaluated using synthetic templates as well as patient samples. CONCLUSION: In a double blind study, the RT-LAMP assay was validated on more than 150 patient samples at two different sites. The RT-LAMP assay appeared to be 89.2% accurate when compared to the Taqman™ rt-RT-PCR assay.

Safranal inhibits NLRP3 inflammasome activation by preventing ASC oligomerization.

NLRP3 inflammasome is involved in several chronic inflammatory diseases. The inflammatory effect of the NLRP3 inflammasome is executed through IL-1ß and IL-18. Therefore, IL-1ß is one of the primary targets in chronic inflammatory conditions. However, current treatment regimens are dependent on anti- IL-1ß biologicals. The therapies targeting IL-1ß through inhibition of NLRP3 inflammasome are thus being actively explored. We identified safranal, a small molecule responsible for the essence of saffron as a potential inhibitor of the NLRP3 inflammasome. Safranal significantly suppressed the release of IL-1ß from ATP stimulated J774A.1 and bone marrow-derived macrophages (BMDMs) by regulating CASP1 and CASP8 dependent cleavage of pro-IL-1ß. Safranal markedly suppressed the expression of NLRP3 and its ATPase activity. Safranal treatment enhanced the expression of NRF2, whereas, si-RNA mediated silencing of Nrf2 abrogated the anti-NLRP3 effect of safranal. Furthermore, safranal inhibited ASC oligomerization and formation of ASC specks. Safranal also displayed anti-NLRP3 activity in multiple mice models. Treatment of animals with safranal reduced the production of IL-1ß in ATP elicited peritoneal inflammation, MSU induced air pouch inflammation, and MSU injected foot paw edema in mice. Thus, our data projects safranal as a potential preclinical drug candidate against NLRP3 inflammasome triggered chronic inflammation.

Screening of compound library identifies novel inhibitors against the MurA enzyme of Escherichia coli.

Bacterial cell has always been an attractive target for anti-infective drug discovery. MurA (UDP-N-acetylglucosamine enolpyruvyl transferase) enzyme of Escherichia coli (E.coli) is crucial for peptidoglycan biosynthetic pathway, as it is involved in the early stages of bacterial cell wall biosynthesis. In the present study we aim to identify novel chemical structures targeting the MurA enzyme. For screening purpose, we used in silico approach (pharmacophore based strategy) for 52,026 library compounds (Chembridge, Chemdiv and in house synthetics) which resulted in identification of 50 compounds. These compounds were screened in vitro against MurA enzyme and release of inorganic phosphate (Pi) was estimated. Two compounds (IN00152 and IN00156) were found to inhibit MurA enzyme > 70% in primary screening and IC50 of 14.03 to 32.30 µM respectively. These two hits were further evaluated for their mode of inhibition studies and whole-cell activity where we observed 2-4 folds increase in activity in presence of Permeabilizer EDTA (Ethylenediaminetetraacetic acid). Combination studies were also performed with known antibiotics in presence of EDTA. Hits are reported for the first time against this target and our report also support the use of OM permeabilizer in combination with antibacterial compounds to address the permeability and efficacy issue. These lead hits can be further optimized for drug discovery. KEY POINTS: • Emerging Gram negative resistant strains is a matter of concern. • Need for new screening strategies to cope with drying up antibiotics pipeline. • Outer membrane permeabilizers could be useful to improve potency of molecules to reach its target.

Total Synthesis and Conformational Analysis of Naturally Occurring Lipovelutibols along with Lead Optimization of Lipovelutibol D.

Four lipopeptaibols, namely, lipovelutibols A-D, were recently isolated from psychrotrophic fungus Trichoderma velutinum and reported to have significant cytotoxic activity against HL-60, MDA-MD-231, A549, and LS180 cancer cell lines. In the present study, these peptides were synthesized in a solution using a segment condensation approach. The conformational analysis of these peptides carried out using CD spectrophotometry revealed the formation of 310-helix, and the NMR-VT experiments showed intramolecular hydrogen bonding for NH-5, NH-6, and NH-7. Lipovelutibol D showed potent cytotoxic activity and was chosen for lead optimization. It involved N- and C-terminal truncation, N- and C-terminal modification, random deletion, l/d configuration replacement, and other synthetic analogues. These were tested against various breast cancer cell lines. The C-terminal aldehyde analogue resulting from lead optimization of lipovelutibol D was found to have almost twofold enhanced cytotoxicity against MDA-MB-231 breast cancer cell lines.

Transcriptome-wide identification of squalene epoxidase genes from Glycyrrhiza glabra L.: expression analysis and heterologous expression of GgSQE1 suggest important role in terpenoid biosynthesis.

Squalene epoxidase (SQE) is a crucial regulatory enzyme for the biosynthesis of several important classes of compounds including sterols and triterpenoids. The present paper identified and characterised five SQE genes (GgSQE1 to GgSQE5) from Glycyrrhiza glabra through transcriptome data mining and homology-based cloning, for the first time. The phylogenetic analysis implied their functional divergence. The ORF corresponding to one of the five SQEs, namely, GgSQE1, was cloned and studied for its function in a heterologous system, following transient and stable expressions. The transient expression followed by GgSQE1 encoding protein purification suggested approximately 58.0-kDa protein following the predicted molecular mass of the deduced protein. The gene expression profiling based on qRT-PCR indicated its highest expression (6.4-folds) in the 10-month-old roots. Furthermore, ABA (12.4-folds) and GA3 (2.47) treatments upregulated the expression of GgSQE1 in the shoots after 10 and 12 hours, respectively, which was also reflected in glycyrrhizin accumulation. The inductive effects of ABA and GA3 over GgSQE1 expression were also confirmed through functional analysis of GgSQE1 promoters using GUS fusion construct. Stable constitutive expression of GgSQE1 in Nicotiana tabacum modulated the sterol contents. The study could pave the way for understanding the metabolic flux regulation concerning biosynthesis of related sterols and triterpenoids.

Tandem MS-Based Metabolite Profiling of 19,20-Epoxycytochalasin C Reveals the Importance of a Hydroxy Group at the C7 Position for Biological Activity.

Seven cytochalasins, 19,20-epoxycytochalasin N, cytochalasin P1, deacetyl 19,20-epoxycytochalasin C, 19,20-epoxycytochalasin D, 19,20-epoxycytochalasin C, cytochalasin D, and cytochalasin C, were isolated from a fungal (Rosellinia sanctae-cruciana) crude extract. A cytotoxicity assay (sulforhodamine B) was performed on a series of cancer cell lines: HT-29, A-549, PC-3, HCT-116, SW-620, and MCF-7. Simultaneously, the liquid chromatography-mass spectrometry (LC-MS)/MS profile of 19,20-epoxycytochalasin C-treated cell lines revealed that 19,20-epoxycytochalasin C (m/z 524.25) oxidized to a metabolite of m/z 522.25 Da (-2 Da (-2H) from 19,20-epoxycytochalasin C). Further chemical oxidation of 19,20-epoxycytochalasin C using the Dess-Martin reagent produced an identical metabolite. It has been noticed that the parent molecule (19,20-epoxycytochalasin C) showed an IC50 of 650 nM (on HT-29), whereas for the oxidized metabolite (m/z 522.24) of 19,20-epoxycytochalasin C, the IC50 was >10 µM. It is clear that the parent molecule had 16 times higher cytotoxic potential as compared to the oxidized metabolite. The spectroscopic investigation indicated that the oxidation of the hydroxyl (-OH) group occurred at the C7 position in 19,20-epoxycyctochalsin C and led to the inactivation of 19,20-epoxycytochalasin C. Further, cell cycle analysis and histopathological evidence support the findings, and CDK2 could be a possible target of 19,20-epoxycyctochalasin C.

Crocetin promotes clearance of amyloid-ß by inducing autophagy via the STK11/LKB1-mediated AMPK pathway.

Alzheimer disease (AD) is usually accompanied by two prominent pathological features, cerebral accumulation of amyloid-ß (Aß) plaques and presence of MAPT/tau neurofibrillary tangles. Dysregulated clearance of Aß largely contributes to its accumulation and plaque formation in the brain. Macroautophagy/autophagy is a lysosomal degradative process, which plays an important role in the clearance of Aß. Failure of autophagic clearance of Aß is currently acknowledged as a contributing factor to increased accumulation of Aß in AD brains. In this study, we have identified crocetin, a pharmacologically active constituent from the flower stigmas of Crocus sativus, as a potential inducer of autophagy in AD. In the cellular model, crocetin induced autophagy in N9 microglial and primary neuron cells through STK11/LKB1 (serine/threonine kinase 11)-mediated AMP-activated protein kinase (AMPK) pathway activation. Autophagy induction by crocetin significantly increased Aß clearance in N9 cells. Moreover, crocetin crossed the blood-brain barrier and induced autophagy in the brains' hippocampi of wild-type male C57BL/6 mice. Further studies in transgenic male 5XFAD mice, as a model of AD, revealed that one-month treatment with crocetin significantly reduced Aß levels and neuroinflammation in the mice brains and improved memory function by inducing autophagy that was mediated by AMPK pathway activation. Our findings support further development of crocetin as a pharmacological inducer of autophagy to prevent, slow down progression, and/or treat AD.Abbreviations: Aß: amyloid-ß; ABCB1/P-gp/P-glycoprotein: ATP-binding cassette, subfamily B (MDR/TAP), member 1; AD: Alzheimer disease; AMPK/PRKAA: AMP-activated protein kinase; APP: amyloid beta (A4) precursor protein; ATG: autophagy related; BBB: blood-brain barrier; BECN1: beclin 1, autophagy related; CAMKK2/CaMKKß: calcium/calmodulin-dependent protein kinase kinase 2, beta; CSE: Crocus sativus extract; CTSB: cathepsin B; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; GFAP: glial fibrillary acidic protein; GSK3B/GSK3ß: glycogen synthase kinase 3 beta; Kp: brain partition coefficient; LRP1: low density lipoprotein receptor-related protein 1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAP2: microtubule-associated protein 2; MAPK/ERK: mitogen-activated protein kinase; MAPT/tau: microtubule-associated protein tau; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; MTOR: mechanistic target of rapamycin kinase; MWM: Morris water maze; NFKB/NF-κB: nuclear factor of kappa light polypeptide gene enhancer in B cells; NMDA: N-methyl-d-aspartic acid; RPTOR: regulatory associated protein of MTOR; RPS6KB1/p70S6K: ribosomal protein S6 kinase 1; SQSTM1: sequestosome 1; SRB: sulforhodamine B; STK11/LKB1: serine/threonine kinase 11; TFEB: transcription factor EB; TSC2: TSC complex subunit 2; ULK1: unc-51 like kinase 1.

Membrane transporters: the key drivers of transport of secondary metabolites in plants.

KEY MESSAGE: This review summarizes the recent updates in the area of transporters of plant secondary metabolites, including their applied aspects in metabolic engineering of economically important secondary metabolites. Plants have evolved biosynthetic pathways to produce structurally diverse secondary metabolites, which serve distinct functions, including defense against pathogens and herbivory, thereby playing a pivotal role in plant ecological interactions. These compounds often display interesting bioactivities and, therefore, have been used as repositories of natural drugs and phytoceuticals for humans. At an elevated level, plant secondary metabolites could be cytotoxic to the plant cell itself; therefore, plants have developed sophisticated mechanisms to sequester these compounds to prevent cytotoxicity. Many of these valuable natural compounds and their precursors are biosynthesized and accumulated at diverse subcellular locations, and few are even transported to sink organs via long-distance transport, implying the involvement of compartmentalization via intra- and intercellular transport mechanisms. The transporter proteins belonging to different families of transporters, especially ATP binding cassette (ABC) and multidrug and toxic compound extrusion (MATE) have been implicated in membrane-mediated transport of certain plant secondary metabolites. Despite increasing reports on the characterization of transporter proteins and their genes, our knowledge about the transporters of several medicinally and economically important plant secondary metabolites is still enigmatic. A comprehensive understanding of the molecular mechanisms underlying the whole route of secondary metabolite transportome, in addition to the biosynthetic pathways, will aid in systematic and targeted metabolic engineering of high-value secondary metabolites. The present review embodies a comprehensive update on the progress made in the elucidation of transporters of secondary metabolites in view of basic and applied aspects of their transport mechanism.

Investigating 11 Withanosides and Withanolides by UHPLC-PDA and Mass Fragmentation Studies from Ashwagandha (Withania somnifera).

Withania somnifera (WS), also known as ashwagandha or Indian ginseng, is known for its pharmacological significance in neurodegenerative diseases, stress, cancer, immunomodulatory, and antiviral activity. In this study, the WS extract (WSE) from the root was subjected to ultrahigh-performance liquid chromatography with photodiode array detection (UHPLC-PDA) analysis to separate 11 withanoside and withanolide compounds. The quantification validation was carried out as per ICHQ2R1 guidelines in a single methodology. The calibration curves were linear (r 2 > 0.99) for all 11 compounds within the tested concentration ranges. The limits of detection and quantification were in the range of 0.213-0.362 and 0.646-1.098 µg/mL, respectively. The results were precise (relative standard deviation, <5.0%) and accurate (relative error, 0.01-0.76). All compounds showed good recoveries of 84.77-100.11%. For the first time, withanoside VII, 27-hydroxywithanone, dihydrowithaferin A, and viscosalactone B were quantified and validated along with bioactive compounds withanoside IV, withanoside V, withaferin A, 12-deoxywithastramonolide, withanolide A, withanone, and withanolide B simultaneously in WS. This UHPLC-PDA method has practical adaptability for ashwagandha raw material, extract, and product manufacturers, along with basic and applied science researchers. The method has been developed on UHPLC for routine analysis. The 11 withanosides and withanolides were confirmed using the fragmentation pattern obtained by the combined use of electrospray ionization and collision-induced dissociation in triple-quadrupole tandem mass spectrometry (TQ-MS/MS) in the WSE.

High-throughput screening of compounds library to identify novel inhibitors against latent Mycobacterium tuberculosis using streptomycin-dependent Mycobacterium tuberculosis 18b strain as a model.

One of the significant challenges to treat tuberculosis is the phenotypic resistance adapted by the latent or dormant Mycobacterium tuberculosis (M. tuberculosis) cells against most of the available drugs. Different in-vitro assay such as oxygen depletion model and nutrient starvation models have contributed to unravelling the pathogen phenotypic resistance but are too cumbersome for application to high-throughput screening (HTS) assays. In this context, non-replicating streptomycin-starved 18b (SS18b) mutant strain of M. tuberculosis provided a simple and reproducible model. This model mimics latent tuberculosis and is best suited for screening medicinally appropriate libraries. Using SS18b strain in a resazurin reduction microplate assay (REMA), high-throughput screening of ChemDiv library constituting of 30,000 compounds resulted in the identification of 470 active compounds. Clustering and scaffolding based medicinal chemistry analysis characterized these hits into 15 scaffolds. Seven most potent compounds exhibiting an MIC ≤ 1 µg/ml against SS18b were non-toxic in HepG2 cell line (selective Index ≥ 160). Our screening revealed seven novel compounds exhibiting activity against the non-replicating form of M tuberculosis. 8002-7516 was the most promising compound showing intracellular killing and could be optimized to develop a lead drug candidate.