Anticancer Potential of Resveratrol, β-Lapachone and Their Analogues

Antifungal activity of β-lapachone against a fluconazole-resistant Candida auris strain

Candida spp. can be found in the human microbiome. However, immunocompromised patients are likely to develop invasive Candida infections, with mortality rates higher than 50%. The discovery of C. auris, a species that rapidly acquire antifungal resistance, increased the concern about Candida infections. The limited number of antifungal agents and the high incidence of resistance to them make imperative the development of new antifungal drugs. β-lapachone is a biological active naphthoquinone that displays antifungal activity against C. albicans and C. glabrata. The aim of this study was to evaluate if this substance affects C. auris growth and elucidate its mechanism of action. A fluconazole-resistant C. auris isolate was used in this study. The antifungal activity of β-lapachone was determined through microbroth dilution assays, and its mechanism of action was evaluated using fluorescent probes. Interaction with fluconazole and amphotericin B was assessed by disk diffusion assay and checkerboard. β-lapachone inhibited planktonic C. auris cell growth by 92.7%, biofilm formation by 84.9%, and decrease the metabolism of preformed biofilms by 87.1% at 100 µg/ml. At 100 µg/ml, reductions of 30% and 59% of Calcofluor White and Nile red fluorescences were observed, indicating that β-lapachone affects cell wall chitin and neutral lipids content, respectively. Also, the ratio 590 nm/529 nm of JC-1 decreased 52%, showing that the compound affects mitochondria. No synergism was observed between β-lapachone and fluconazole or amphotericin B. Data show that β-lapachone may be a promising candidate to be used as monotherapy to treat C. auris resistant infections.

Increasing the polarity of β-lapachone does not affect its binding capacity with bovine plasma protein

Despite ortho-quinones showing several biological and pharmacological activities, there is still a lack of biophysical characterization of their interaction with albumin - the main carrier of different endogenous and exogenous compounds in the bloodstream. Thus, the interactive profile between bovine serum albumin (BSA) with β-lapachone (1) and its corresponding synthetic 3-sulfonic acid (2, under physiological pH in the sulphonate form) was performed. There is one main binding site of albumin for both β-lapachones (n ≈ 1) and a static fluorescence quenching mechanism was proposed. The Stern-Volmer constant (KSV) values are 104 M-1, indicating a moderate binding affinity. The enthalpy (-3.41 ± 0.45 and - 8.47 ± 0.37 kJ mol-1, for BSA:1 and BSA:2, respectively) and the corresponding entropy (0.0707 ± 0.0015 and 0.0542 ± 0.0012 kJ mol-1 K-1) values indicate an enthalpically and entropically binding driven. Hydrophobic interactions and hydrogen bonding are the main binding forces. The differences in the polarity of 1 and 2 did not change significantly the affinity to albumin. In addition, the 1,2-naphthoquinones showed a similar binding trend compared with 1,4-naphthoquinones.

Unlocking the power of nanomedicine: the future of nutraceuticals in oncology treatment

Cancer, an intricate and multifaceted disease, is characterized by the uncontrolled proliferation of cells that can lead to serious health complications and ultimately death. Conventional therapeutic strategies mainly target rapidly dividing cancer cells, but often indiscriminately harm healthy cells in the process. As a result, there is a growing interest in exploring novel therapies that are both effective and less toxic to normal cells. Herbs have long been used as natural remedies for various diseases and conditions. Some herbal compounds exhibit potent anti-cancer properties, making them potential candidates for nutraceutical-based treatments. However, despite their promising efficacy, there are considerable limitations in utilizing herbal preparations due to their poor solubility, low bioavailability, rapid metabolism and excretion, as well as potential interference with other medications. Nanotechnology offers a unique platform to overcome these challenges by encapsulating herbal compounds within nanoparticles. This approach not only increases solubility and stability but also enhances the cellular uptake of nutraceuticals, allowing for controlled and targeted delivery of therapeutic agents directly at tumor sites. By harnessing the power of nanotechnology-enabled therapy, this new frontier in cancer treatment presents an opportunity to minimize toxicity while maximizing efficacy. In conclusion, this manuscript provides compelling evidence for integrating nanotechnology with nutraceuticals derived from herbal sources to optimize cancer therapy outcomes. We explore the roadblocks associated with traditional herbal treatments and demonstrate how nanotechnology can help circumvent these issues, paving the way for safer and more effective cancer interventions in future oncological practice.

Molecular mechanisms of resveratrol as chemo and radiosensitizer in cancer

One of the primary diseases that cause death worldwide is cancer. Cancer cells can be intrinsically resistant or acquire resistance to therapies and drugs used for cancer treatment through multiple mechanisms of action that favor cell survival and proliferation, becoming one of the leading causes of treatment failure against cancer. A promising strategy to overcome chemoresistance and radioresistance is the co-administration of anticancer agents and natural compounds with anticancer properties, such as the polyphenolic compound resveratrol (RSV). RSV has been reported to be able to sensitize cancer cells to chemotherapeutic agents and radiotherapy, promoting cancer cell death. This review describes the reported molecular mechanisms by which RSV sensitizes tumor cells to radiotherapy and chemotherapy treatment.

Synthesis of bile acid-thiadiazole conjugates as antibacterial and antioxidant agents

The synthesis, characterization, and antibacterial and antioxidant activity of thiadiazole-deoxycholic/lithocholic acid conjugates are described in this communication. The structures of the synthesised bile acid-thiadiazole conjugates were studied using 1H NMR, 13C NMR and FTIR. Compounds 4c (IC50; 15.34 ± 0.07 μM) and 5c (IC50; 13.45 ± 0.25 μM) demonstrated greater antioxidant activity than the reference compound ascorbic acid (IC50; 20.72 ± 1.02 μM) in DPPH assay. The most effective conjugates against P. vulgarise were 4c (IC50; 24 ± 2.3 μM), 4 g (IC50; 29 ± 2.5 μM), and 5c (IC50; 93 ± 3.6 μM), whereas the most effective conjugates against E. coli were 4e (IC50; 55 ± 2.1 μM) and 4f (IC50; 52 ± 3.5 μM). Conjugates 4c and 5c were the most effective against B. megaterium of all the synthesised conjugates, with IC50 values of 15 ± 1.08 and 20 ± 1.1 μM, respectively. Thus, a large library of compounds derived from bile acid can be easily synthesised for extensive structure-activity relationship studies in order to identify the most appropriate antibacterial agents and antioxidant activity.

Green tea extract and hydroxyl-chloroquine combination enhances apoptosis in A549 non-small cell lung cancer cells

Polyphenols, including catechins from green tea extract, have long been known for their potential anti-tumour activities. However, the precise mechanisms underlying their actions remain unclear. This study aimed to investigate the effects of green tea extract on A549 cells, a type of non-small lung cancer cells. A549 cells treated with green tea extract (GTE) were examined using an inverted light microscope and a fluorescence microscope. Cell sensitivity was evaluated using the MTT assay, while cell death was assessed using the Tali image-based cytometer. Ultra structural changes were observed using a transmission electron microscope. The findings suggested that even at the highest dose tested (150 µM), GTE did not exhibit toxic effects on A549 cells. Likewise, treatment with GTE resulted in a minimal, dose-dependent increase in the population of apoptotic cells. However, the analysis of cell structures using light and electron microscopy revealed an enhanced accumulation of vacuole-like structures in response to GTE. Moreover, under the fluorescence microscope, an increase in acidic vesicular organelles and the formation of LC3-II puncta were observed following GTE treatment. Assessment of autophagy function indicated that GTE-induced autophagy may serve as a self-protective mechanism against cytotoxicity, as blocking autophagy with bafilomycin A1 reduced cell viability and enhanced necrotic cell death in response to GTE treatment. In summary, our results demonstrate that A549 cells are insensitive to both low and high concentrations of green tea extract, likely due to the induction of cytoprotective autophagy. These findings suggest that the potential utility of GTE in lung cancer therapy may lie in its synergistic combinations with drugs or small molecules that target autophagy, rather than as a standalone therapy.

Signaling pathways driving ocular malignancies and their targeting by bioactive phytochemicals

Ocular cancers represent a rare pathology. The American Cancer Society estimates that 3,360 cases of ocular cancer occur annually in the United States. The major types of cancers of the eye include ocular melanoma (also known as uveal melanoma), ocular lymphoma, retinoblastoma, and squamous cell carcinoma. While uveal melanoma is one of the primary intraocular cancers with the highest occurrence in adults, retinoblastoma remains the most common primary intraocular cancer in children, and squamous cell carcinoma presents as the most common conjunctival cancer. The pathophysiology of these diseases involves specific cell signaling pathways. Oncogene mutations, tumor suppressor mutations, chromosome deletions/translocations and altered proteins are all described as causal events in developing ocular cancer. Without proper identification and treatment of these cancers, vision loss, cancer spread, and even death can occur. The current treatments for these cancers involve enucleation, radiation, excision, laser treatment, cryotherapy, immunotherapy, and chemotherapy. These treatments present a significant burden to the patient that includes a possible loss of vision and a myriad of side effects. Therefore, alternatives to traditional therapy are urgently needed. Intercepting the signaling pathways for these cancers with the use of naturally occurring phytochemicals could be a way to relieve both cancer burden and perhaps even prevent cancer occurrence. This research aims to present a comprehensive review of the signaling pathways involved in various ocular cancers, discuss current therapeutic options, and examine the potential of bioactive phytocompounds in the prevention and targeted treatment of ocular neoplasms. The current limitations, challenges, pitfalls, and future research directions are also discussed.

β-Lapachone Exerts Anticancer Effects by Downregulating p53, Lys-Acetylated Proteins, TrkA, p38 MAPK, SOD1, Caspase-2, CD44 and NPM in Oxaliplatin-Resistant HCT116 Colorectal Cancer Cells

β-lapachone (β-Lap), a topoisomerase inhibitor, is a naturally occurring ortho-naphthoquinone phytochemical and is involved in drug resistance mechanisms. Oxaliplatin (OxPt) is a commonly used chemotherapeutic drug for metastatic colorectal cancer, and OxPt-induced drug resistance remains to be solved to increase chances of successful therapy. To reveal the novel role of β-Lap associated with OxPt resistance, 5 μM OxPt-resistant HCT116 cells (HCT116-OxPt-R) were generated and characterized via hematoxylin staining, a CCK-8 assay and Western blot analysis. HCT116-OxPt-R cells were shown to have OxPt-specific resistance, increased aggresomes, upregulated p53 and downregulated caspase-9 and XIAP. Through signaling explorer antibody array, nucleophosmin (NPM), CD37, Nkx-2.5, SOD1, H2B, calreticulin, p38 MAPK, caspase-2, cadherin-9, MMP23B, ACOT2, Lys-acetylated proteins, COL3A1, TrkA, MPS-1, CD44, ITGA5, claudin-3, parkin and ACTG2 were identified as OxPt-R-related proteins due to a more than two-fold alteration in protein status. Gene ontology analysis suggested that TrkA, Nkx-2.5 and SOD1 were related to certain aggresomes produced in HCT116-OxPt-R cells. Moreover, β-Lap exerted more cytotoxicity and morphological changes in HCT116-OxPt-R cells than in HCT116 cells through the downregulation of p53, Lys-acetylated proteins, TrkA, p38 MAPK, SOD1, caspase-2, CD44 and NPM. Our results indicate that β-Lap could be used as an alternative drug to overcome the upregulated p53-containing OxPt-R caused by various OxPt-containing chemotherapies.

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

Theranostics combines therapeutic and imaging diagnostic techniques that are extremely dependent on the action of imaging agent, transporter of therapeutic molecules, and specific target ligand, in which fluorescent probes can act as diagnostic agents. In particular, naphthoimidazoles are potential bioactive heterocycle compounds to be used in several biomedical applications. With this aim, a group of seven naphth[1,2-d]imidazole compounds were synthesized from β-lapachone. Their optical properties and their cytotoxic activity against cancer cells and their compounds were evaluated and confirmed promising values for molar absorptivity coefficients (on the order of 103 to 104), intense fluorescence emissions in the blue region, and large Stokes shifts (20–103 nm). Furthermore, the probes were also selective for analyzed cancer cells (leukemic cells (HL-60). The naphth[1,2-d]imidazoles showed IC50 between 8.71 and 29.92 μM against HL-60 cells. For HCT-116 cells, values for IC50 between 21.12 and 62.11 μM were observed. The selective cytotoxicity towards cancer cells and the fluorescence of the synthesized naphth[1,2-d]imidazoles are promising responses that make possible the application of these components in antitumor theranostic systems.

Antibacterial and Antibiofilm Activities of β-Lapachone by Modulating the Catalase Enzyme

Background: Bacterial infections constantly have a large impact on public health, because of increased rates of resistance and reduced frequency of development of novel antibiotics. The utility of conventional antibiotics for treating bacterial infections has become increasingly challenging. The aim of the study was to assess the antibacterial effect of β-Lapachone (β-Lap), a novel synthetic compound. Methods: The antibacterial activity of the β-Lap compound was examined against laboratory strains by agar well diffusion method and broth dilution assay. Growth kinetics in presence of β-Lap on Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa (ATCC 27853) were assessed by microplate alamarBlue assay. Crystal violet blue assay was used for biofilm inhibition and biofilm eradication. P. aeruginosa catalase (KatA) complexed with β-Lap was modeled using molecular docking approach. Results: β-Lap exhibited potent antimicrobial activity against laboratory strains of bacteria with MIC of 0.2 mM for S. saprophyticus and Staphylococcus aureus, and 0.04 mM for Staphylococcus epidermidis and Pseudomonas aeruginosa ATCC 27853. The inhibition of catalase enzyme was found to be the cause for its antibacterial activity. Bioinformatics analysis suggests that β-Lap can inhibit KatA activity by interacting with catalase proximal active site and heme binding site. The activity of some commercial antibiotics was enhanced in association with β-Lap. In addition, β-Lap inhibited the biofilm formation and eradicated the already formed and ultra-mature biofilms of aforesaid bacterial strains. Conclusion: These observations indicated that β-Lap could be a promising antibacterial agent for the treatment and prevention of infectious diseases.

Resveratrol and Its Role in the Management of B-Cell Malignancies-A Recent Update

The growing incidence of B cell malignancies globally has prompted research on the pharmacological properties of phytoconstituents in cancer management. Resveratrol, a polyphenolic stilbenoid widely found in nature, has been explored for its anti-inflammatory and antioxidant properties, and promising results from different pre-clinical studies have indicated its potential for management of B cell malignancies. However, these claims must be substantiated by a greater number of clinical trials in diverse populations, in order to establish its safety and efficacy profile. In addition to this, there is a need to explore nanodelivery of this agent, owing to its poor solubility, which in turn may impact its bioavailability. This review aims to offer an overview of the occurrence and pathogenesis of B cell malignancies with a special focus on the inflammatory pathways involved, the mechanism of actions of resveratrol and its pharmacokinetic profile, results from pre-clinical and clinical studies, as well as an overview of the marketed formulations. The authors have also presented their opinion on the various challenges associated with the clinical development of resveratrol and future perspectives regarding therapeutic applications of this agent.

Effect of Tarantula cubensis alcoholic extract on tumour pathways in azoxymethane-induced colorectal cancer in rats

The aim of this study was to determine the effects of Tarantula cubensis alcoholic extract (TCAE) on tumour development pathways in azoxymethane (AOM)-induced colorectal cancer in rats by molecular methods. Eighteen paraffin-embedded intestinal tissues, six from each group, were studied in the healthy control (C), cancer control (CC), cancer + TCAE (C-TCAE) groups. Sections of 5 µm thickness were taken from the paraffin blocks and submitted to staining with haematoxylin-eosin. In the histopathological examination, the number of crypts forming aberrant crypt foci (ACF) and the degree of dysplasia in the crypts were scored. Real-time PCR analysis was completed to determine β-catenin, KRAS (Kirsten rat sarcoma virus), APC (adenomatous polyposis coli) and P53 expressions on samples from each paraffin block. The grading scores of the number of crypts forming ACF and dysplasia in the crypts showed an evident decrease in the C-TCAE group in comparison to the CC group (P < 0.05). In real-time PCR analysis, mRNA expression levels of P53 (P > 0.05) and APC (P < 0.001) genes were found to be increased in the C-TCAE group according to the CC group. The expression levels of KRAS (P < 0.01) and β-catenin (P < 0.005) mRNA were found significantly decreased in the C-TCAE group. In conclusion, the effects of TCAE on AOM-induced colorectal cancer (CRC) in rats were evaluated molecularly; TCAE was found to modulate some changes in CRC developmental pathways, inhibiting tumour development and proliferation, and stimulating non-mutagenic tumour suppressor genes. Thus, it can be stated that TCAE is an effective chemopreventive agent.

In Vitro Cytotoxic Effects and Mechanisms of Action of Eleutherine Isolated from Eleutherine plicata Bulb in Rat Glioma C6 Cells

Gliomas are the most common primary malignant brain tumors in adults, and have a poor prognosis, despite the different types of treatment available. There is growing demand for new therapies to treat this life-threatening tumor. Quinone derivatives from plants have received increased interest as potential anti-glioma drugs, due to their diverse pharmacologic activities, such as inhibiting cell growth, inflammation, tumor invasion, and promoting tumor regression. Previous studies have demonstrated the anti-glioma activity of Eleutherine plicata, which is related to three main naphthoquinone compounds-eleutherine, isoeleutherine, and eleutherol-but their mechanism of action remains elusive. Thus, the aim of this study was to investigate the mechanism of action of eleutherine on rat C6 glioma. In vitro cytotoxicity was evaluated by MTT assay; morphological changes were evaluated by phase-contrast microscopy. Apoptosis was determined by annexin V-FITC-propidium iodide staining, and antiproliferative effects were assessed by wound migration and colony formation assays. Protein kinase B (AKT/pAKT) expression was measured by western blot, and telomerase reverse transcriptase mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Eleutherine reduced C6 cell proliferation in a dose-dependent manner, suppressed migration and invasion, induced apoptosis, and reduced AKT phosphorylation and telomerase expression. In summary, our results suggest that eleutherine has potential clinical use in treating glioma.

Plant-derived natural products for drug discovery: current approaches and prospects

Nature has abundant source of drugs that need to be identified/purified for use as essential biologics, either individually or in combination in the modern medical field. These drugs are divided into small bio-molecules, plant-made biologics, and a recently introduced third category known as phytopharmaceutical drugs. The development of phytopharmaceutical medicines is based on the ethnopharmacological approach, which relies on the traditional medicine system. The concept of ‘one-disease one-target drug’ is becoming less popular, and the use of plant extracts, fractions, and molecules is the new paradigm that holds promising scope to formulate appropriate drugs. This led to discovering a new concept known as polypharmacology, where natural products from varying sources can engage with multiple human physiology targets. This article summarizes different approaches for phytopharmaceutical drug development and discusses the progress in systems biology and computational tools for identifying drug targets. We review the existing drug delivery methods to facilitate the efficient delivery of drugs to the targets. In addition, we describe different analytical techniques for the authentication and fingerprinting of plant materials. Finally, we highlight the role of biopharming in developing plant-based biologics.

[Studies on the Isolation and Molecular Mechanisms of Bioactive Phytochemicals]

Studies on the isolation and molecular mechanisms of phytochemicals with anti-tumor or anti-inflammatory properties are important to developing new drugs for cancer and neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. In the course of a study to screen bioactive isoflavones from Erythrina poeppigiana (Leguminosae), we isolated an isoflavone with potent apoptosis-inducing activity against human leukemia HL-60 cells. It was designated erypoegin K. The studies demonstrated an enantiomer, (S)-erypoegin K, displayed selective cytotoxic activity, was a novel inhibitor of topoisomerase II, and possessed anti-tumor activity both in vitro and in vivo. We identified other apoptosis-inducing isoflavones with the ability to inhibit glyoxalase I. Dimeric acridone alkaloids, carbazole alkaloids, and coumarin and quinoline derivatives-all obtained mainly from plants in the family Rutaceae-induced apoptosis of HL-60 cells via the production of reactive oxygen species and mitochondrial dysfunction. We also identified terpenoid coumarins, carbazole quinones, rotenoid derivatives, and quinolone alkaloids with anti-inflammatory activities. These compounds reduced nitric oxide (NO) production from RAW264.7 macrophage cells stimulated with lipopolysaccharides and interferon-γ. Some of the compounds displayed neuroprotective activity by reducing NO production. This review primarily describes our recent studies on erypoegin K, and other compounds with apoptosis-inducing and anti-inflammatory activities.

Anticancer activity of β-Lapachone derivatives on human leukemic cell lines

β-lapachone is a 1,2-naphthoquinone of great therapeutic interest that induces cell death by autophagy and apoptosis in tumor cells due to oxidative stress increasing. However, its high toxicity in healthy tissues limits its clinical use, which stimulates the planning and synthesis of more selective analogs. The aim of this study was to investigate the cytotoxic activity of three thiosemicarbazones derived from β-lapachone (BV2, BV3 and BV5) in leukemia cells. Cytotoxicity tests were performed on tumor cells (HL-60, K562, K562-Lucena and MOLT-4) and normal peripheral blood mononuclear cells (PBMCs). Subsequently, the mode of action of compounds was accessed by optical microscopy, transmission electron microscopy or fluorescence microscopy. Flow cytometry analysis was performed to investigate apoptosis induction, cell cycle, DNA fragmentation and mitochondrial depolarization. All derivatives inhibited tumor cell growth after 72 h (IC₅₀ < 10 μM to all cell lines, including the resistant K562-Lucena) with less toxic effects in PBMC cells, being BV3 the most selective compound with selective index (SI) of 275 for HL-60; SI of 40 to K562; SI of 10 for MOLT-4 and SI of 50 to K562-Lucena compared to β-lapachone with SI of 18 to HL-60, SI of 3.7 to K562; SI of 2.4 to MOLT-4 and SI of 0.9 to K562-Lucena. In addition, the K562 or MOLT-4 cells treated with BV3 showed characteristics of both apoptosis and autophagy cell death, mainly by autophagy. These results demonstrate the potent cytotoxic effect of thiosemicarbazones derived from β-lapachone as promising anticancer drugs candidates, encouraging the continuity of in vivo tests.

Chitosans and Nanochitosans: Recent Advances in Skin Protection, Regeneration, and Repair

Chitosan displays a dual function, acting as both an active ingredient and/or carrier for pharmaceutical bioactive molecules and metal ions. Its hydroxyl- and amino-reactive groups and acetylation degree can be used to adjust this biopolymer's physicochemical and pharmacological properties in different forms, including scaffolds, nanoparticles, fibers, sponges, films, and hydrogels, among others. In terms of pharmacological purposes, chitosan association with different polymers and the immobilization or entrapment of bioactive agents are effective strategies to achieve desired biological responses. Chitosan biocompatibility, water entrapment within nanofibrils, antioxidant character, and antimicrobial and anti-inflammatory properties, whether enhanced by other active components or not, ensure skin moisturization, as well as protection against bacteria colonization and oxidative imbalance. Chitosan-based nanomaterials can maintain or reconstruct skin architecture through topical or systemic delivery of hydrophilic or hydrophobic pharmaceuticals at controlled rates to treat skin affections, such as acne, inflammatory manifestations, wounds, or even tumorigenesis, by coating chemotherapy drugs. Herein, chitosan obtention, physicochemical characteristics, chemical modifications, and interactions with bioactive agents are presented and discussed. Molecular mechanisms involved in chitosan skin protection and recovery are highlighted by overlapping the events orchestrated by the signaling molecules secreted by different cell types to reconstitute healthy skin tissue structures and components.

Antitubercular activity assessment of fluorinated chalcones, 2-aminopyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives: In vitro, molecular docking and in-silico drug likeliness studies

A series of newer previously synthesized fluorinated chalcones and their 2-amino-pyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives were screened for their in vitro antitubercular activity and in silico methods. Compound 40 (MIC~ 8 μM) was the most potent among all 60 compounds, whose potency is comparable with broad spectrum antibiotics like ciprofloxacin and streptomycin and three times more potent than pyrazinamide. Additionally, compound 40 was also less selective and hence non-toxic towards the human live cell lines-LO2 in its MTT assay. Compounds 30, 27, 50, 41, 51, and 60 have exhibited streptomycin like activity (MIC~16–18 μM). Fluorinated chalcones, pyridine and pyran derivatives were found to occupy prime position in thymidylate kinase enzymatic pockets in molecular docking studies. The molecule 40 being most potent had shown a binding energy of -9.67 Kcal/mol, while docking against thymidylate kinase, which was compared with its in vitro MIC value (~8 μM). These findings suggest that 2-aminopyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives are prospective lead molecules for the development of novel antitubercular drugs.

Lawsone (2-hydroxy-1,4-naphthaquinone) derived anticancer agents

2-Hydroxy-1,4-naphthaquinone, commonly known as lawsone, represents an extremely important biologically active naturally occurring compound. It can easily be isolated from Lawsonia inermis (henna) tree leaf extract. Last decade has seen tremendous applications of lawsone as a starting component for the preparation of various organic scaffolds. Many of these synthesized scaffolds showed a wide range of biological activities including potential activities towards several cancer cell lines. This review deals with diverse synthetic methods of lawsone derived scaffolds and their screening against different anti-cancer cell lines along with promising results.

Modern Approaches in the Discovery and Development of Plant-Based Natural Products and Their Analogues as Potential Therapeutic Agents

Natural products represents an important source of new lead compounds in drug discovery research. Several drugs currently used as therapeutic agents have been developed from natural sources; plant sources are specifically important. In the past few decades, pharmaceutical companies demonstrated insignificant attention towards natural product drug discovery, mainly due to its intrinsic complexity. Recently, technological advancements greatly helped to address the challenges and resulted in the revived scientific interest in drug discovery from natural sources. This review provides a comprehensive overview of various approaches used in the selection, authentication, extraction/isolation, biological screening, and analogue development through the application of modern drug-development principles of plant-based natural products. Main focus is given to the bioactivity-guided fractionation approach along with associated challenges and major advancements. A brief outline of historical development in natural product drug discovery and a snapshot of the prominent natural drugs developed in the last few decades are also presented. The researcher’s opinions indicated that an integrated interdisciplinary approach utilizing technological advances is necessary for the successful development of natural products. These involve the application of efficient selection method, well-designed extraction/isolation procedure, advanced structure elucidation techniques, and bioassays with a high-throughput capacity to establish druggability and patentability of phyto-compounds. A number of modern approaches including molecular modeling, virtual screening, natural product library, and database mining are being used for improving natural product drug discovery research. Renewed scientific interest and recent research trends in natural product drug discovery clearly indicated that natural products will play important role in the future development of new therapeutic drugs and it is also anticipated that efficient application of new approaches will further improve the drug discovery campaign.

Beta-lapachone: Natural occurrence, physicochemical properties, biological activities, toxicity and synthesis

β-Lapachone is an ortho-naphthoquinone originally isolated from the heartwood of Handroanthus impetiginosus and can be obtained through synthesis from lapachol, naphthoquinones, and other aromatic compounds. β-Lapachone is well known to inhibit topoisomerase I and to induce NAD(P)H: quinone oxidoreductase 1. Currently, phase II clinical trials are being conducted for the treatment of pancreatic cancer. In view of ever-increasing scientific interest in this naphthoquinone, herein, the authors present a review of the synthesis, physicochemical properties, biological activities, and toxicity of β-lapachone. This natural compound has shown activity against several types of malignant tumors, such as lung and pancreatic cancers and melanoma. Furthermore, this ortho-naphthoquinone has antifungal and antibacterial activities, underscoring its action against resistant microorganisms and providing anti-inflammatory, antiobesity, antioxidant, neuroprotective, nephroprotective, and wound-healing properties. β-Lapachone presents low toxicity, with no signs of toxicity against alveolar macrophages, dermal fibroblast cells, hepatocytes, or kidney cells.

Resveratrol and Its Analogs: Potent Agents to Reverse Epithelial-to-Mesenchymal Transition in Tumors

Epithelial-to-mesenchymal transition (EMT), a complicated program through which polarized epithelial cells acquire motile mesothelial traits, is regulated by tumor microenvironment. EMT is involved in tumor progression, invasion and metastasis via reconstructing the cytoskeleton and degrading the tumor basement membrane. Accumulating evidence shows that resveratrol, as a non-flavonoid polyphenol, can reverse EMT and inhibit invasion and migration of human tumors via diverse mechanisms and signaling pathways. In the present review, we will summarize the detailed mechanisms and pathways by which resveratrol and its analogs (e.g. Triacetyl resveratrol, 3,5,4'-Trimethoxystilbene) might regulate the EMT process in cancer cells to better understand their potential as novel anti-tumor agents. Resveratrol can also reverse chemoresistance via EMT inhibition and improvement of the antiproliferative effects of conventional treatments. Therefore, resveratrol and its analogs have the potential to become novel adjunctive agents to inhibit cancer metastasis, which might be partly related to their blocking of the EMT process.

Reprogramming of erythrocyte lifespan by NFκB-TNFα naphthoquinone antagonist β-lapachone is regulated by calcium overload and CK1α

The pathophysiology of chemotherapy-associated anemia, prevalent in at least 75% of patients, remains difficult to establish. Chemotherapy-related anemia is attributed in part to eryptosis, and it is therefore of considerable interest to interrogate the toxicity of investigative anticancer compounds to red blood cells (RBCs). Beta-lapachone (LAP), an anthraquinone extracted from the bark of Lapacho tree (Tabebuia avellanedae), is effective against a myriad of cancer cells. However, the toxicity of LAP to RBCs remains unexplored. Hemoglobin leakage as a surrogate for hemolysis was photometrically measured, while flow cytometry was employed to capture phosphatidylserine (PS) exposure with Annexin-V-FITC, calcium levels with Fluo4/AM, cell size by forward scatter (FSC), and oxidative stress by H2DCFDA. Our results show that LAP, at antitumor levels (10-30 µM), induces dose-dependent hemolysis secondary to calcium influx from the extracellular space. Moreover, LAP stimulates eryptosis, as evident from PS exposure, which is associated with reduced cell volume and intracellular calcium overload. Importantly, it is also revealed that the cytotoxicity of LAP is mediated through casein kinase 1α. Altogether, this report shows, for the first time, that LAP possesses both hemolytic and eryptotic potential against RBCs that necessitates careful application in chemotherapy. PRACTICAL APPLICATIONS: Lapacho is a widely consumed herbal tea with origins in the Tabebuia avellanedae tree endogenous to South America. LAP is one of the active ingredients in lapacho with promising antitumor potential. We show that LAP is cytotoxic to human RBCs by virtue of eryptosis and hemolysis, and we identify associated molecular mechanisms. Given that these two manifestations are known to contribute to chemotherapy-induced anemia, our study provides invaluable insights into the suitability of LAP in cancer management and sheds some light on possible strategies to limit its undesirable side effects.

Characterization and trypanocidal activity of a β-lapachone-containing drug carrier

The treatment of Chagas disease (CD), a neglected parasitic condition caused by Trypanosoma cruzi, is still based on only two drugs, nifurtimox (Nif) and benznidazole (Bz), both of which have limited efficacy in the late chronic phase and induce severe side effects. This scenario justifies the continuous search for alternative drugs, and in this context, the natural naphthoquinone β-lapachone (β-Lap) and its derivatives have demonstrated important trypanocidal activities. Unfortunately, the decrease in trypanocidal activity in the blood, high toxicity to mammalian cells and low water solubility of β-Lap limit its systemic administration and, consequently, clinical applications. For this reason, carriers as drug delivery systems can strategically maximize the therapeutic effects of this drug, overcoming the above mentioned restrictions. Accordingly, the aim of this study is to investigate the in vitro anti-T. cruzi effects of β-Lap encapsulated in2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) and its potential toxicity to mammalian cells.

Normalization of Samples of Limited Amounts in Quantitative Metabolomics Using Liquid Chromatography Fluorescence Detection with Dansyl Labeling of Metabolites

Quantitative metabolomics requires the analysis of the same or a very similar amount of samples in order to accurately determine the concentration differences of individual metabolites in comparative samples. Ideally, the total amount or concentration of metabolites in each sample is measured to normalize all the analyzed samples. In this work, we describe a very sensitive method to measure a subclass of metabolites as a surrogate quantifier for normalization of samples with limited amounts. This method starts with low-volume dansyl labeling of all metabolites containing a primary/secondary amine or phenol group in a sample to produce a final solution of 21 μL. The dansyl-labeled metabolites generate fluorescence signals at 520 nm with photoexcitation at 250 nm. To remove the interference of dansyl hydroxyl products (Dns-OH) formed from the labeling reagents used, a fast-gradient liquid chromatography separation is used to elute Dns-OH using aqueous solution, followed by organic solvent elution to produce a chromatographic peak of labeled metabolites, giving a measurement throughput of 6 min per sample. The integrated fluorescence signals of the peak are found to be related to the injection amount of the dansyl-labeled metabolites. A calibration curve using mixtures of dansyl-labeled amino acids is used to determine the total concentration of labeled metabolites in a sample. This concentration is used for normalization of samples in the range from 2 to 120 μM in 21 μL with only 1 μL consumed for fluorescence quantification (i.e., 2-120 pmol). We demonstrate the application of this sensitive sample normalization method in comparative metabolome analysis of human cancer cells, MCF-7 cells, treated with and without resveratrol, using a starting material of as low as 500 cells.

Wine Intake in the Framework of a Mediterranean Diet and Chronic Non-Communicable Diseases: A Short Literature Review of the Last 5 Years

Dietary habits are a determining factor of the higher incidence and prevalence of chronic non-communicable diseases (NCDs). In the aim to find a possible preventive and intervention strategy, the Mediterranean diet (MedDiet) has been proposed as an effective approach. Within the MedDiet, moderate wine consumption with meals is a positive item in the MedDiet score; however, recent studies have reported a dose-response association between alcohol consumption and higher risk of a large number of NCDs. This review aimed to evaluate the association between NCDs and wine consumption in the framework of the MedDiet, with a simple review of 22 studies of the highest-level literature published over the last five years. We found that the information regarding the effects of wine in different health outcomes has not varied widely over the past five years, finding inconclusive results among the studies evaluated. Most of the literature agrees that light to moderate wine intake seems to have beneficial effects to some extent in NCDs, such as hypertension, cancer, dyslipidemia and dementia, but no definitive recommendations can be made on a specific dose intake that can benefit most diseases.

A comprehensive review on β-lapachone: Mechanisms, structural modifications, and therapeutic potentials

β-Lapachone (β-lap, 1), an ortho-naphthoquinone natural product isolated from the lapacho tree (Tabebuia avellanedae) in many regions of South America, has received extensive attention due to various pharmacological activities, such as antitumor, anti-Trypanosoma cruzi, anti-Mycobacterium tuberculosis, antibacterial, and antimalarial activities. Related mechanisms of β-lap have been widely investigated for a full understanding of its therapeutic potentials. Numerous derivatives of β-lap have been reported with aims to generate new chemical entities, improve the corresponding biological potency, and overcome disadvantages of its physical and chemical properties and safety profiles. This review will give insight into the pharmacological mechanisms of β-lap and provide a comprehensive understanding of its structural modifications with regard to different therapeutic potentials. The available clinical trials related to β-lap and its derivatives are also summarized.

Thiadiazole derivatives as anticancer agents

In spite of substantial progress made toward understanding cancer pathogenesis, this disease remains one of the leading causes of mortality. Thus, there is an urgent need to develop novel, more effective anticancer therapeutics. Thiadiazole ring is a versatile scaffold widely studied in medicinal chemistry. Mesoionic character of this ring allows thiadiazole-containing compounds to cross cellular membrane and interact strongly with biological targets. Consequently, these compounds exert a broad spectrum of biological activities. This review presents the current state of knowledge on thiadiazole derivatives that demonstrate in vitro and/or in vivo efficacy across the cancer models with an emphasis on targets of action. The influence of the substituent on the compounds' activity is depicted. Furthermore, the results from clinical trials assessing thiadiazole-containing drugs in cancer patients are summarized.

The Potential of Phytochemicals in Oral Cancer Prevention and Therapy: A Review of the Evidence

The etiological factors of oral cancer are complex including drinking alcohol, smoking tobacco, betel quid chewing, human papillomavirus infection, and nutritional deficiencies. Understanding the molecular mechanism of oral cancer is vital. The traditional treatment for patients with oral squamous cell carcinoma (e.g., surgery, radiotherapy, and chemotherapy) and targeted molecular therapy still have numerous shortcomings. In recent years, the use of phytochemical factors to prevent or treat cancer has received increasing attention. These phytochemicals have little or no toxicity against healthy tissues and are thus ideal chemopreventive agents. However, phytochemicals usually have low water solubility, low bioavailability, and insufficient targeting which limit therapeutic use. Numerous studies have investigated the development of phytochemical delivery systems to address these problems. The present article provides an overview of oral cancer including the etiological factors, diagnosis, and traditional therapy. Furthermore, the classification, dietary sources, anticancer bioactivity, delivery system improvements, and molecular mechanisms against oral cancer of phytochemicals are also discussed in this review.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

The Effect of 4'-hydroxy-3,4,5-trimetoxystilbene, the Metabolite of Resveratrol Analogue DMU-212, on Growth, Cell Cycle and Apoptosis in DLD-1 and LOVO Colon Cancer Cell Lines

Resveratrol is a phytoalexin that naturally occurs in grapes, blueberries, cranberries, peanuts and many other plants. Although resveratrol inhibits carcinogenesis in all three stages, its clinical application is restricted due to poor pharmacokinetics. The methylated analogues of resveratrol have been found to have higher bioavailability and cytotoxic activity than that of the prototupe compound. Among the various methoxy derivatives of resveratrol, 3,4,5,4′-tetrametoxystilbene (DMU-212) is suggested to be one of the strongest activators of cytotoxicity and apoptosis. DMU-212 has been shown to exert anti-tumor activity in DLD-1 and LOVO colon cancer cells. Since colorectal cancer is the third most common cause of cancer-related deaths worldwide, the development of new anticancer agents is nowadays of high significance. The aim of the present study was to assess the anticancer activity of 4′-hydroxy-3,4,5-trimetoxystilbene (DMU-281), the metabolite of DMU-212, in DLD-1 and LOVO cell lines. We showed for the first time the cytotoxic activity of DMU-281 triggered via cell cycle arrest at G2/M phase and apoptosis induction accompanied by the activation of caspases-9, -8, -3/7. Furthermore, DMU-281 has been found to change the expression pattern of genes and proteins related to intrinsic as well as extrinsic apoptosis. Since the activation of these pathways of apoptosis is still the most desired strategy in anticancer research, DMU-281 seems to provide a promising approach to the treatment of colon cancer.