Plant Alkaloid Research Articles

Enhanced Co-culture System Using Escherichia coli and Pichia pastoris (Komagataella phaffii) for Improved Microbial Production of Valuable Plant Alkaloids.

Advancements in synthetic biology have facilitated the microbial production of valuable plant metabolites. However, constructing complete biosynthetic pathways within a single host organism remains challenging. To solve this problem, modular co-culture systems involving host organisms with partial pathways have been developed. We focused on Escherichia coli, a general host for metabolite production, and Pichia pastoris (Komagataella phaffii), a novel synthetic biology host due to its high expression of biosynthetic enzymes. Previously, we reported the co-culture of E. coli cells, which produce reticuline (an important intermediate for various alkaloids) from glycerol, with P. pastoris cells, which produce the valuable alkaloid stylopine from reticuline. However, Pichia cells inhibited E. coli growth and reticuline production. Therefore, we aimed to improve this co-culture system. We investigated the pre-culture time before co-culture to enhance E. coli growth and reticuline production. Additionally, we examined the optimal concentration of Pichia cells inoculated for co-culture and methanol addition during co-culture for the continuous expression of biosynthetic enzymes in Pichia cells. We successfully established an improved co-culture system that exhibited an 80-fold increase in productivity compared to previous methods. This enhanced system holds great potential for the rapid and large-scale production of various valuable plant metabolites.

Exploring the Structural Importance of the C3=C4 Double Bond in Plant Alkaloids Harmine and Harmaline on Their Binding Interactions with Hemoglobin.

Harmine and harmaline are two structurally similar heterocyclic β-carboline plant alkaloids with various therapeutic properties, having a slight structural difference in the C3=C4 double bond. In the present study, we have reported the nature of the interaction between hemoglobin (Hb) with harmine and harmaline by employing several multispectroscopic, calorimetric, and molecular docking approaches. Fluorescence spectroscopic studies have shown stronger interaction of harmine with Hb compared to that of almost structurally similar harmaline. Steady-state anisotropy experiments further show that the motional restriction of harmine in the presence of Hb is substantially higher than that of the harmaline-Hb complex. Circular dichroism (CD) study demonstrates no conformational change of Hb in the presence of both alkaloids, but CD study in 1-cm cuvette path length also demonstrates stronger affinity of harmine toward Hb compared to harmaline. From the thermal melting study, it has been found that both harmine and harmaline slightly affect the stability of Hb. From isothermal titration calorimetry (ITC), we have found that the binding process is exothermic and enthalpy driven. Molecular docking studies indicated that both harmine and harmaline prefer identical binding sites in Hb. This study helps us to understand that slight structural differences in harmine and harmaline can alter the interaction properties significantly, and this key information may help in the drug discovery processes.

Benzoindolizidine Alkaloids Tylophorine and Lycorine and Their Analogues with Antiviral, Anti-Inflammatory, and Anticancer Properties: Promises and Challenges.

Ongoing viral research, essential for public health due to evolving viruses, gains significance owing to emerging viral infections such as the SARS-CoV-2 pandemic. Marine and plant alkaloids show promise as novel potential pharmacological strategies. In this narrative review, we elucidated the potential of tylophorine and lycorine, two naturally occurring plant-derived alkaloids with a shared benzoindolizidine scaffold, as antiviral agents to be potentially harnessed against respiratory viral infections. Possible structure-activity relationships have also been highlighted. The substances and their derivatives were found to be endowed with powerful and broad-spectrum antiviral properties; moreover, they were able to counteract inflammation, which often underpins the complications of viral diseases. At last, their anticancer properties hold promise not only for advancing cancer research but also for mitigating the oncogenic effects of viruses. This evidence suggests that tylophorine and lycorine could effectively counteract the pathogenesis of respiratory viral disease and its harmful effects. Although common issues about the pharmacologic development of natural substances remain to be addressed, the collected evidence highlights a possible interest in tylophorine and lycorine as antiviral and/or adjuvant strategies and encourages future more in-depth pre-clinical and clinical investigations to overcome their drawbacks and harness their power for therapeutic purposes.

Suspect screening for chemical residues in aquacultured shrimp and fish using liquid chromatography-high resolution mass spectrometry: comparison of data evaluation approaches.

High-resolution mass spectrometry (HRMS) has become an important tool for monitoring chemical residues in food, but the time and effort required to evaluate the large amount of data generated by HRMS can be a limiting factor in the widespread application of this tool. Suspect screening, i.e., searching HRMS data against large compound databases or mass lists, represents a practical compromise between using HRMS data to only look for target compounds and performing full non-target analysis. Several different approaches for suspect screening using HRMS data were tested using data from shrimp and eel spiked with veterinary drugs and pesticides as well as from imported aquaculture samples. Most of the analytes (>70%) in the spiked samples were detected and identified by searching against compound databases. To query larger databases and on-line resources such as mzCloud, it was necessary to use software capable of differential analysis and selective filtering, such as Compound Discoverer. Using selective filtering, the number of compounds detected in fish sample extracts could be reduced from tens of thousands to a few hundred by subtracting method blanks and comparing to matrix blank extracts. This smaller list of potential compounds could be further evaluated and compared to available databases and libraries. Analysis of imported aquaculture samples resulted in detection of unexpected contaminants including the dewormer levamisole, the insecticide buprofezin, and potentially the plant alkaloid ricinine.

Transcriptomics and biochemical evidence of trigonelline ameliorating learning and memory decline in the senescence-accelerated mouse prone 8 (SAMP8) model by suppressing proinflammatory cytokines and elevating neurotransmitter release

In recent years, exploring natural compounds with functional properties to ameliorate aging-associated cognitive decline has become a research priority to ensure healthy aging. In the present study, we investigated the effects of Trigonelline (TG), a plant alkaloid, on memory and spatial learning in 16-week-old senescence-accelerated mouse model SAMP8 using an integrated approach for cognitive and molecular biology aspects. After 30 days of oral administration of TG at the dose of 5 mg/kg/day, the mice were trained in Morris Water Maze task. TG-treated SAMP8 mice exhibited significant improvement in the parameters of escape latency, distance moved, and annulus crossing index. Next, we performed a whole-genome transcriptome profiling of the mouse hippocampus using microarrays. Gene ontology analyses showed that a wide range of biological processes, including nervous system development, mitochondrial function, ATP synthesis, and several signaling pathways related to inflammation, autophagy, and neurotransmitter release, were significantly enriched in TG-treated SAMP8 compared to nontreated. Further, a nonlinear dimensionality reduction technique, Uniform Manifold Approximation and Projection (UMAP), was applied to identify clusters of functions that revealed TG primarily regulated pathways related to inflammation, followed by those involved in neurotransmitter release. In addition, a protein–protein interaction network analysis indicated that TG may exert its biological effects through negatively modulating Traf6-mediated NF-κB activation. Finally, ELISA test showed that TG treatment significantly decreased proinflammatory cytokines- TNFα and IL6 and increased neurotransmitters- dopamine, noradrenaline, and serotonin in mouse hippocampus. Altogether, our integrated bio-cognitive approach highlights the potential of TG in alleviating age-related memory and spatial impairment.

Noscapine alleviates unilateral ureteral obstruction-induced inflammation and fibrosis by regulating the TGFβ1/Smads signaling pathways

Renal fibrosis is a common pathway leading to progressive renal function loss in various forms of chronic kidney disease. Many fibrogenic factors regulate renal fibrosis; two key players are post-injury inflammation and transforming growth factor-β1 (TGF-β1)-induced myofibroblast differentiation. Myofibroblast differentiation is tightly regulated by the microtubule polymerization. Noscapine, an antitussive plant alkaloid, is a potent microtubule-interfering agent previously identified as a potential anticancer compound. Here, we examined how noscapine affects renal fibrogenesis in an in vitro renal fibroblast model and an in vivo unilateral ureteral obstruction (UUO) model. UUO mice were intraperitoneally treated with noscapine at 1 day before UUO surgery and daily thereafter. At 7 days post-surgery, kidneys were collected for further analysis. To analyze whether noscapine inhibits downstream TGF-β1-related signaling, we pre-incubated NRK-49F fibroblasts with noscapine and then performed TGF-β1 stimulation. In UUO mice, noscapine attenuated extracellular matrix protein deposition and the expression levels of type I collagen, type IV collagen, α-smooth muscle actin, and fibronectin. In addition, noscapine decreased tubulointerstitial inflammation in UUO kidneys by reducing TLR2 expression, modulating NLRP3 inflammasome activation, reducing macrophage infiltration, and antagonizing the M2 macrophage phenotype. Furthermore, noscapine pre-incubation suppressed the TGF-β1-induced fibroblast-myofibroblast transformation by downregulating the TGF-β/Smads signaling pathways in NRK-49F cells. These results suggest that noscapine reduces tubulointerstitial inflammation and fibrosis in the kidneys of UUO mice and inhibits the fibroblast-myofibroblast transformation induced by TGF-β1. Noscapine is an over-the-counter antitussive that has been used safely for several decades. Therefore, noscapine is an attractive therapeutic agent for inhibiting renal tubulointerstitial fibrosis.

Design, synthesis and bioactivity investigation of peptide-camptothecin conjugates as anticancer agents with a potential to overcome drug resistance

Camptothecin (CPT) is a natural plant alkaloid from Camptotheca that exhibits a potent anticancer activity. However, its continued utilization is hindered by drawbacks such as low water solubility and restricted tumor selectivity. Cationic anticancer peptides (CAPs) are generally soluble in water, and exhibit favorable selectivity against malignant cells. In previous study, we have reported a CAP termed KM8-Aib present conspicuous selective anticancer effect. Thus, it is postulated conjugating KM8-Aib with CPT might be a plausible approach to improve the defects of CPT. A series of peptide-CPT conjugates were synthesized and subjected to biological evaluation. Among these compounds, Kb-CC07 displayed the highest selective activity against a set of cancer cell lines including drug-resistant cells, showing the IC50 values in the 0.11–1.01 μM range which is 1.9–22.6 times better than that of CPT, and a wide therapeutic index of 124.5 (vs 5.3 for CPT). The water solubility of Kb-CC07 was also improved by ∼ 100 fold compared with CPT. Further investigation unraveled that Kb-CC07 could effectively penetrate across plasma membranes and delivered more CPT molecules into cancer cells, overcoming the drug-resistance result from efflux drug transporters on tumor surface. In vivo experiments supported that Kb-CC07 has excellent in vivo antiproliferative activity against drug-resistant tumors over CPT (tumor growth inhibition of 98.2% and 37.5% for Kb-CC07 and CPT, respectively, at 5 μmol·kg−1), and prompts CPT accumulation in tumor tissue rather than normal organs, thus producing limited toxicities. To sum up, coupling therapeutic agents to CAPs would be a potential strategy to conquer the shortcomings of anticancer drugs. Additionally, Kb-CC07 is suggested to be a promising anticancer candidate deserving further investigation.

Do Naturally Modified Nucleotides Contribute to Stabilizing Complexes between Ribosomes and Small Molecules? A Case Study with the Antitumor Drug Homoharringtonine.

Modified nucleotides are ubiquitous with RNAs, also in contact with drugs that target the ribosome. Whether this represents a stabilization of the drug-ribosome complex, thus affecting the drug's affinity and possibly also intrinsic efficacy, remains an open question, however. The challenge of answering this question has been taken here with the only human-ribosome-targeting small-molecule currently in clinical use, the antitumor plant alkaloid homoharringtonine (HHT). The approach consisted in dissecting HHT-nucleotide interaction energies from QM-MM simulations in explicit water. What emerged is a network of mostly weak interactions of the large, branched HHT with standard nucleotides and a single modified nucleotide, out of the four ones present at PCT's A site. This is unlike the case of the small, compact marine antitumor alkaloid agelastatin A, which displays only a few, albeit strong, interactions with site-A ribosome nucleotides. This should aid tailoring drugs targeting the ribosome.

Nicotine-mediated effects in neuronal and mouse models of synucleinopathy.

Alpha-synuclein (α-Syn) aggregation, transmission, and contribution to neurotoxicity represent central mechanisms underlying Parkinson's disease. The plant alkaloid "nicotine" was reported to attenuate α-Syn aggregation in different models, but its precise mode of action remains unclear. In this study, we investigated the effect of 2-week chronic nicotine treatment on α-Syn aggregation, neuroinflammation, neurodegeneration, and motor deficits in D-line α-Syn transgenic mice. We also established a novel humanized neuronal model of α-Syn aggregation and toxicity based on treatment of dopaminergic neurons derived from human induced pluripotent stem cells (iPSC) with α-Syn preformed fibrils (PFF) and applied this model to investigate the effects of nicotine and other compounds and their modes of action. Overall, our results showed that nicotine attenuated α-Syn-provoked neuropathology in both models. Moreover, when investigating the role of nicotinic acetylcholine receptor (nAChR) signaling in nicotine's neuroprotective effects in iPSC-derived dopaminergic neurons, we observed that while α4-specific antagonists reduced the nicotine-induced calcium response, α4 agonists (e.g., AZD1446 and anatabine) mediated similar neuroprotective responses against α-Syn PFF-provoked neurodegeneration. Our results show that nicotine attenuates α-Syn-provoked neuropathology in vivo and in a humanized neuronal model of synucleinopathy and that activation of α4β2 nicotinic receptors might mediate these neuroprotective effects.

Melatonin supplementation combats nickel-induced phytotoxicity in Trigonella foenum-graecum L. plants through metal accumulation reduction, upregulation of NO generation, antioxidant defence machinery and secondary metabolites

Nickel (Ni) at a toxic level (80 mg kg−1 of soil) adversely affects the crop performance of fenugreek (Trigonella foenum-graecum L.). Melatonin (MEL), a potent plant growth regulator, is ascribed to offer promising roles in heavy metal stress alleviation. In this study, different doses viz. 0, 25, 50, 75 and 100 μM of MEL were administered to plants through foliage under normal and Ni-stress conditions. The experiment unveiled positive roles of MEL in enhancing root-shoot lengths, fresh-dry weights, seed yield and restoring photosynthetic efficiency assessed in terms of higher Fv/Fm, YII, qP, and lower NPQ values in plants exposed to Ni (80 mg kg−1). MEL supplementation (at 75 μM) effectively restricted Ni accumulation and regulated oxidative stress via modulation of MDA, O2−, H2O2 and NO generation, most prominently. Besides, MEL at 75 μM more conspicuously perked up the activities of antioxidant enzymes like SOD, POX, CAT and APX by 15.7, 20.0, 14.5 and 16.5% higher than the Ni-exposed plants for effective ROS scavenging. Likewise, MEL at 75 μM also efficiently counteracted Ni-generated osmotic stress, through an upscaled accumulation of proline (19.6%) along with the enhancement in the concentration of total phenols (13.6%), total tannins (11.2%), total flavonoids (25.5%) and total alkaloids (19.2%) in plant's leaves. Furthermore, under 80 mg kg−1 Ni stress, MEL at 75 μM improved the seed's trigonelline content by 40.1% higher compared to Ni-disturbed plants, upgrading the pharmacological actions of the plant. Thus, the present study deciphers the envisaged roles of MEL in the alleviation of Ni stress in plants to enhance overall crop productivity.

QuEChERS method combined to liquid chromatography high-resolution mass spectrometry for the accurate and sensitive simultaneous determination of pyrrolizidine and tropane alkaloids in cereals and spices.

Within the last decades, in the EU, there has been an increasing interest in toxic plant alkaloids as food contaminants, especially after the continuous and growing consumption of plant-based foods compared with food of animal origin. In this regard, the once neglected presence of these tropane alkaloids (TAs) and pyrrolizidine alkaloids (PAs) has recently been reconsidered by the European Food Safety Authority, highlighting the lack of data and the need to develop risk assessment strategies. For this reason, the emphasis has been placed on detecting their occurrence in food through the development of accurate and sensitive analytical methods to achieve the determination of these compounds. The present study aims to elaborate and validate an analytical method based on QuEChERS sample preparation approach, exploiting the UHPLC coupled to the HRMS to simultaneously identify and quantify 21 PAs and two TAs in cereals and spices. For TAs, the obtained limit of detection (LOD) is 0.1μg·kg-1 and the limit of quantification (LOQ) is 0.4μg·kg-1 , while for PAs, the LODs values ranging between 0.2 to 0.3μg·kg-1 and the LOQ, between 0.4 and 0.8μg·kg-1 , ensuring compliance with the recently established European Regulations. Several commercial samples were analysed to further verify the applicability of this comprehensive analytical approach.

Drastic alterations in the loop structure around colchicine upon complex formation with an engineered lipocalin indicate a conformational selection mechanism.

Using Anticalin technology, a lipocalin protein dubbed Colchicalin, with the ability to bind the toxic plant alkaloid colchicine with picomolar affinity, has previously been engineered, thus offering a potential antidote in vivo and also allowing its sensitive detection in biological samples. To further analyze the mode of ligand recognition, the crystal structure of Colchicalin is now reported in its unliganded form and is compared with the colchicine complex. A superposition of the protein structures revealed major rearrangements in the four structurally variable loops of the engineered lipocalin. Notably, the binding pocket in the unbound protein is largely occupied by the inward-bent loop #3, in particular Ile97, as well as by the phenylalanine side chain at position 71 in loop #2. Upon binding of colchicine, a dramatic shift of loop #3 by up to 11.1 Å occurs, in combination with a side-chain flip of Phe71, thus liberating the necessary space within the ligand pocket. Interestingly, the proline residue at the neighboring position 72, which arose during the combinatorial engineering of Colchicalin, remained in a cis configuration in both structures. These findings provide a striking example of a conformational adaptation mechanism, which is a long-known phenomenon for antibodies in immunochemistry, during the recognition of a small ligand by an engineered lipocalin, thus illustrating the general similarity between the mode of antigen/ligand binding by immunoglobulins and lipocalins.

Biofilm stimulating activity of solanidine and Solasodine in Pseudomonas aeruginosa

BackgroundBiofilm formation has reported as an important virulence associated properties of Pseudomonas aeruginosa that is regulated by quorum-sensing associated genes. Biofilm and quorum-sensing interfering properties of steroidal alkaloids, Solanidine and Solasodine were investigated in the present study.ResultsBiofilm formation capacity and relative expression level of five studied genes(lasI, lasR, rhlI, rhlR and algD) were significantly increased dose-dependently after treatment with sub-inhibitory concentrations (32 and 512 µg/ml) of the both Solanidine and Solasodine. Biofilm formation capacity was more stimulated in weak biofilm formers(9 iaolates) in comparison to the strong biofilm producers(11 isolates). The lasI gene was the most induced QS-associated gene among five investigated genes.ConclusionBiofilm inducing properties of the plants alkaloids and probably medicines derived from them has to be considered for revision of therapeutic guidelines. Investigating the biofilm stimulating properties of corticosteroids and other medicines that comes from plant alkaloids also strongly proposed.

Sanguinarine exposure induces immunotoxicity and abnormal locomotor behavior in zebrafish.

Sanguinarine (C20H14NO4+), a plant alkaloid and pesticide, works well a fungicidal and insecticidal applications. The prospect that sanguinarine may have potentially toxic effects on aquatic organisms has been brought to light by its use in agriculture. The first evaluation of the immunotoxic and behavioral effects of sanguinarine exposure on larval zebrafish was done in this work. Firstly, zebrafish embryos exposed to sanguinarine had shorter body length, larger yolk sacs, and slower heart rates. Secondly, the number of innate immune cells was significantly reduced. Thirdly, alterations in locomotor behavior were observed as exposure concentrations increased. Total distance travelled, travel time, and mean speed were all reduced. We also found significant changes in oxidative stress-related indicators and a significant increase in apoptosis in the embryos. Further studies revealed aberrant expression of some key genes in the TLR immune signaling pathway including CXCL-c1c, IL8, MYD88, and TLR4. At the same time, the expression of the pro-inflammatory cytokine IFN-γ was upregulated. To sum up, our results suggest that sanguinarine exposure may cause immunotoxicity and aberrant behavior in larval zebrafish.

Exploring Anti-osteoporosis Medicinal Herbs using Cheminformatics and Deep Learning Approaches.

Osteoporosis is a prevalent disease for the aged population. Chinese herbderived natural compounds have anti-osteoporosis effects. Due to the complexity of chemical ingredients and natural products, it is necessary to develop a high-throughput approach with the integration of cheminformatics and deep-learning methods to explore their mechanistic action, especially herb/drug-gene interaction networks. Ten medicinal herbs for clinical osteoporosis treatment were selected. Chemical ingredients of the top 10 herbs were retrieved from the TCMIO database, and their predicted targets were obtained from the SEA server. Anti-osteoporosis clinical drugs and targets were collected from multidatabases. Chemical space, fingerprint similarity, and scaffold comparison of the compounds between herbs and clinical drugs were analyzed by RDKit and SKlearn. A network of herb-ingredient-target was constructed via Gephi, and GO and KEGG enrichment analyses were performed using clusterProfiler. Additionally, the bioactivity of compounds and targets was predicted by DeepScreening. Molecular docking of YYH flavonoids to HSD17B2 was accomplished by AutoDockTools. Cheminformatics result depicts a pharmacological network consisting of 89 active components and 30 potential genes. The chemical structures of plant steroids, flavonoids, and alkaloids are key components for anti-osteoporosis effects. Moreover, bioinformatics result demonstrates that the active components of herbs mainly participate in steroid hormone biosynthesis and the TNF signaling pathway. Finally, deep-learning-based regression models were constructed to evaluate 22 anti-osteoporosis-related protein targets and predict the activity of 1350 chemical ingredients of the 10 herbs. The combination of cheminformatics and deep-learning approaches sheds light on the exploration of medicinal herbs mechanisms, and the identification of novel and active compounds from medical herbs in complex molecular systems.

Nicotine and Cytisine Embryotoxicity in the Experimental Zebrafish Model.

Tobacco smoking is one of the most serious health problems. Potentially lethal effects of nicotine for adults can occur with as little as 30 to 60 mg, although severe symptoms can arise with lower doses. Furthermore, the route of administration also influences the toxicity. Cytisine is one of the most popular medications in nicotinism treatment. Like nicotine, cytisine is a plant alkaloid, signaling through nicotinic acetylcholine receptors. Our study evaluated the effects of cytisine in nicotine-induced embryotoxic effects using zebrafish larvae. We examined the teratogenicity of nicotine and cytisine alone or in combination. Nicotine increased mortality and delayed hatching of zebrafish larvae in a dose-dependent manner. Cytisine did not affect mortality in a wide range of concentrations, and hatching delay was observed only at the highest concentrations, above 2 mM. Administering compounds together partially reduced the adverse teratogenic effect induced by nicotine alone. The protective effect of cytisine against the nicotine effect, observed in zebrafish, will contribute to future studies or treatments related to nicotine addiction or prenatal nicotine exposure in humans.

Age-related decline in hippocampal tyrosine phosphatase PTPRO is a mechanistic factor in chemotherapy-related cognitive impairment.

Chemotherapy-related cognitive impairment (CRCI) or "chemo brain" is a devastating neurotoxic sequela of cancer-related treatments, especially for the elderly individuals. Here we show that PTPRO, a tyrosine phosphatase, is highly enriched in the hippocampus, and its level is tightly associated with neurocognitive function but declined significantly during aging. To understand the protective role of PTPRO in CRCI, a mouse model was generated by treating Ptpro-/- female mice with doxorubicin (DOX) because Ptpro-/- female mice are more vulnerable to DOX, showing cognitive impairments and neurodegeneration. By analyzing PTPRO substrates that are neurocognition-associated tyrosine kinases, we found that SRC and EPHA4 are highly phosphorylated/activated in the hippocampi of Ptpro-/- female mice, with increased sensitivity to DOX-induced CRCI. On the other hand, restoration of PTPRO in the hippocampal CA3 region significantly ameliorate CRCI in Ptpro-/- female mice. In addition, we found that the plant alkaloid berberine (BBR) is capable of ameliorating CRCI in aged female mice by upregulating hippocampal PTPRO. Mechanistically, BBR upregulates PTPRO by downregulating miR-25-3p, which directly targeted PTPRO. These findings collectively demonstrate the protective role of hippocampal PTPRO against CRCI.

Evaluation of berberine nanoparticles as a strategy to modulate acetylcholinesterase activity

Researchers have concentrated efforts in the search for natural-based reversible inhibitors for cholinesterase enzymes as they may play a key role in the treatment of degenerative diseases. Diverse plant alkaloids can inhibit the action of acetylcholinesterase and, among them, berberine is a promising bioactive. However, berberine has poor water solubility and low bioavailability, which makes it difficult to use in treatment. The solid dispersion technique can improve the water affinity of hydrophobic substances, but berberine solid dispersions have not been extensively studied. Safety testing is also essential to ensure that the berberine-loaded solid dispersions are safe for use. This study investigated the effectiveness of berberine-loaded solid dispersions (SD) as inhibitors of acetylcholinesterase enzyme (AChE). Docking simulation was used to investigate the influence of berberine on AChE, and in vitro assays were conducted to confirm the enzymatic kinetics of AChE in the presence of berberine. Berberine SD also showed improved cytotoxic effects on tumoral cells when dispersed in aqueous media. In vivo assays using Allium cepa were implemented, and no cytotoxicity/genotoxicity was found for the berberine solid dispersion. These results suggest that berberine SD could be a significant step towards safe nanostructures for use in the treatment of neurodegenerative diseases.

Transferring near infrared spectral calibration models without standards via multistep wavelength selection

Two case studies were conducted to verify calibration model transfer methods without standards by multi-step wavelength selection, using 3–7 near infrared spectrometers to predict ingredients in corn and total plant alkaloids (TPA) in tobacco leaves. Based on the characteristic wavelengths of Uc, which are selected using the scale-invariant feature transform (SIFT), this study advances two multistep wavelength selection methods by selecting wavelengths with high independence and a high standard deviation of the sample spectra (SDSS). The first method, SIFT-SDSS-CORX, selects important characteristic wavelengths Uc-i from Uc whose SDSS is greater than a threshold SDSSacrit. Subsequently, rx, the correlation coefficient matrix between spectral signals of Uc-i, is calculated, and only one wavelength is retained from those whose correlation coefficients exceed a threshold, rxacrit. The wavelength set Uc-i-rx, which is finally screened, is important and independent. In the second method, SIFT-CORX-SDSS, Uc-rx is first selected from Uc by retaining only one wavelength from those whose correlation coefficients between spectral signals of Uc exceed a threshold, rxbcrit. Subsequently, the wavelengths Uc-rx-i with SDSS exceeding a threshold SDSSbcrit are selected from Uc-rx. Near infrared spectroscopy calibration models for predicting protein and oil in corn and TPA in tobacco leaves were built using partial least squares regression (PLS) based on different wavelength sets of Uc, Uc-i, Uc-i-rx, Uc-rx, and Uc-rx-i, respectively. The latent variables used in the PLS models were determined by an accumulative contribution ratio over 99.9%. The results indicate that the PLS models built on Uc-i-rx and Uc-rx-i are effective on both primary and secondary units for corn and tobacco samples. This study utilises a three-step wavelength selection method to select highly independent, important, and characteristic spectral variables, thereby enhancing the robustness, simplicity, and interpretability of NIR) calibration models and facilitating their transfer to secondary units without standards.

Triggering the Amphotericin B Pore-Forming Activity by Phytochemicals.

The macrolide polyene antibiotic amphotericin B (AmB), remains a valuable drug to treat systemic mycoses due to its wide antifungal activity and low probability of developing resistance. The high toxicity of AmB, expressed in nephropathy and hemolysis, could be partially resolved by lowering therapeutic AmB concentration while maintaining efficacy. This work discusses the possibility of using plant polyphenols and alkaloids to enhance the pore-forming and consequently antifungal activity of AmB. We demonstrated that phloretin, phlorizin, naringenin, taxifolin, quercetin, biochanin A, genistein, resveratrol, and quinine led to an increase in the integral AmB-induced transmembrane current in the bilayers composed of palmitoyloleoylphosphocholine and ergosterol, while catechin, colchicine, and dihydrocapsaicin did not practically change the AmB activity. Cardamonin, 4'-hydroxychalcone, licochalcone A, butein, curcumin, and piperine inhibited AmB-induced transmembrane current. Absorbance spectroscopy revealed no changes in AmB membrane concentration with phloretin addition. A possible explanation of the potentiation is related to the phytochemical-produced changes in the elastic membrane properties and the decrease in the energy of formation of the lipid mouth of AmB pores, which is partially confirmed by differential scanning microcalorimetry. The possibility of AmB interaction with cholesterol in the mammalian cell membranes instead of ergosterol in fungal membranes, determines its high toxicity. The replacement of ergosterol with cholesterol in the membrane lipid composition led to a complete loss or a significant decrease in the potentiating effects of tested phytochemicals, indicating low potential toxicity of these compounds and high therapeutic potential of their combinations with the antibiotic. The discovered combinations of AmB with plant molecules that enhance its pore-forming ability in ergosterol-enriched membranes, seem to be promising for further drug development in terms of the toxicity decrease and efficacy improvement.