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

Navigating the redox landscape: reactive oxygen species in regulation of cell cycle

Objectives: To advance our knowledge of disease mechanisms and therapeutic options, understanding cell cycle regulation is critical. Recent research has highlighted the importance of reactive oxygen species (ROS) in cell cycle regulation. Although excessive ROS levels can lead to age-related pathologies, ROS also play an essential role in normal cellular functions. Many cell cycle regulatory proteins are affected by their redox status, but the precise mechanisms and conditions under which ROS promote or inhibit cell proliferation are not fully understood.Methods: This review presents data from the scientific literature and publicly available databases on changes in redox state during the cell cycle and their effects on key regulatory proteins.Results: We identified redox-sensitive targets within the cell cycle machinery and analysed different effects of ROS (type, concentration, duration of exposure) on cell cycle phases. For example, moderate levels of ROS can promote cell proliferation by activating signalling pathways involved in cell cycle progression, whereas excessive ROS levels can induce DNA damage and trigger cell cycle arrest or cell death.Discussion: Our findings encourage future research focused on identifying redox-sensitive targets in the cell cycle machinery, potentially leading to new treatments for diseases with dysregulated cell proliferation.

Synthesis and biological evaluation of novel isoxazoloquinone derivatives as potent STAT3-targeting antipsoriasis agents

Psoriasis is a troublesome scaling skin disease with no high-effective medication available by far. Signal transducer and activator of transcription 3 (STAT3) has recently been revealed as a crucial player in the pathogenesis and progression of psoriasis and emerged as an intriguing antipsoriatic drug target. Naturally occurring lapachol and its quinone analogs had been discovered as effective STAT3 inhibitors, however, their antipsoriatic effects are not well investigated. Previously, we have reported a series of isothiazoloquinone lapachol derivatives. Here, the antipsoriastic potentials of these isothiazoloquinones were investigated and, in addition, 35 novel isoxazoloquinone derivatives were prepared and studied for their anti-psoriasis properties. Among them, the most potent antipsoriatic compound B20 determined by in vitro test on HaCaT cells could directly bind to STAT3, reduce STAT3 level and inhibit STAT3 nuclear translocation. In vivo studies showed that topical application of B20 could effectively alleviate IMQ-induced psoriasis in mice with no obvious side effects. In addition, B20 inhibited the production of interleukin 17 (IL-17A), a STAT3-downstream cytokine essential for the progression of psoriasis, both in vitro and in vivo. Thus, isoxazoloquinone B20 is a potent STAT3-targeting antipsoriatic agent worth of further investigation.

A dual responsive nitric oxide / β-lapachone co-delivery platform for redox imbalance-enhanced tumor therapy

Nitric oxide (NO) / β-Lapachone (Lap) combined therapy by causing oxidative stress is an effective tumor therapy strategy. Herein, a dual-responsive lipid nanoparticles (LNPs) LSNO for NO / Lap co-delivery were constructed from the zinc-coordinated lipid (DSNO(Zn)) and the hydrophobic drug Lap in the presence of helper lipids (DOPE and DSPE-PEG2000). The zinc-coordinated structure in LSNO might elevate the Zn2+ content in tumor cells, contributing to antioxidant imbalance. The fluorescent assays proved the light-triggered NO release and fluorescent self-reporting abilities of LSNO. In addition, the LNPs had good drug release behavior under high concentration of GSH, indicating the NO / drug co-delivery capacity. In vitro antitumor assays showed that the NO / Lap combination treatment group could induce more significant tumor cell growth inhibition and cell apoptosis than individual NO or Lap treatment. The following mechanism studies revealed that NO / Lap combination treatment led to distinct oxidative stress by producing reactive oxygen species (ROS) and peroxynitrite anion (ONOO-). On the other hand, the intracellular redox balance could be further disrupted by Lap-induced NADPH consumption and Zn2+ / NO-induced reductase activities downregulation, thus promoting the degree of cell damage. Besides, it was also found that NO and Lap could directly damage nuclear DNA and induce mitochondrial dysfunction, thereby leading to caspase-3 activation and tumor cell death. These results proved that LSNO could serve as a promising multifunctional tumor therapy platform.

Evaluation of doxorubicin and β-lapachone analogs as anticancer agents, a biological and computational study

We have conducted an experimental and computational evaluation of new doxorubicin (4a-c) and β-lapachone (5a-c) analogs. These novel anticancer analogs were previously synthesized, but had not been tested or characterized until now. We have evaluated their antiproliferative and DNA cleavage inhibition properties using breast (MCF-7 and MDA-MB-231) and prostate (PC3) cancer cell lines. Additionally, cell cycle analysis was performed using flow cytometry. Computational studies, including molecular docking, pharmacokinetic properties, and an analysis of DFT and QTAIM chemical descriptors, were performed to gain insights into the electronic structure and elucidate the molecular binding of the new β-lapachone and doxorubicin analogs with a DNA sequence and Topoisomerase II (Topo II)α. Our results show that 4a analog displays the highest antiproliferative activity in cancer cell lines by inducing cell death. We observed that stacking interactions and hydrogen bonding are essential to stabilize the molecule-DNA-Topo IIα complex. Moreover, 4a and 5a analogs inhibited Topo's DNA cleavage activity. Pharmacodynamic results indicated that studied molecules have favorable adsorption and permeability properties. The calculated chemical descriptors indicate that electron accumulation in quinone rings is relevant to the reactivity and biological activity. Based on our results, 4a is a strong candidate for becoming an anticancer drug.

Structural variety and pharmacological potential of naphthylisoquinoline alkaloids

Naphthylisoquinoline alkaloids are a fascinating class of natural biaryl compounds. They show characteristic mono- and dimeric scaffolds, with chiral axes and stereogenic centers. Since the appearance of the last comprehensive overview on these secondary plant metabolites in this series in 1995, the number of discovered representatives has tremendously increased to more than 280 examples known today. Many novel-type compounds have meanwhile been discovered, among them naphthylisoquinoline-related follow-up products like e.g., the first seco-type (i.e., ring-opened) and ring-contracted analogues. As highlighted in this review, the knowledge on the broad structural chemodiversity of naphthylisoquinoline alkaloids has been decisively driven forward by extensive phytochemical studies on the metabolite pattern of Ancistrocladus abbreviatus from Coastal West Africa, which is a particularly "creative" plant. These investigations furnished a considerable number of more than 80-mostly new-natural products from this single species, with promising antiplasmodial activities and with pronounced cytotoxic effects against human leukemia, pancreatic, cervical, and breast cancer cells. Another unique feature of naphthylisoquinoline alkaloids is their unprecedented biosynthetic origin from polyketidic precursors and not, as usual for isoquinoline alkaloids, from aromatic amino acids-a striking example of biosynthetic convergence in nature. Furthermore, remarkable botanical results are presented on the natural producers of naphthylisoquinoline alkaloids, the paleotropical Dioncophyllaceae and Ancistrocladaceae lianas, including first investigations on the chemoecological role of these plant metabolites and their storage and accumulation in particular plant organs.

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.

Telomerase Inhibition in the Treatment of Leukemia: A Comprehensive Review

Leukemia, characterized by the uncontrolled proliferation and differentiation blockage of myeloid or lymphoid precursor cells, presents significant therapeutic challenges despite current treatment modalities like chemotherapy and stem cell transplantation. Pursuing novel therapeutic strategies that selectively target leukemic cells is critical for improving patient outcomes. Natural products offer a promising avenue for developing effective chemotherapy and preventive measures against leukemia, providing a rich source of biologically active compounds. Telomerase, a key enzyme involved in chromosome stabilization and mainly active in cancer cells, presents an attractive target for intervention. In this review article, we focus on the anti-leukemic potential of natural substances, emphasizing vitamins (such as A, D, and E) and polyphenols (including curcumin and indole-3-carbinol), which, in combination with telomerase inhibition, demonstrate reduced cytotoxicity compared to conventional chemotherapies. We discuss the role of human telomerase reverse transcriptase (hTERT), particularly its mRNA expression, as a potential therapeutic target, highlighting the promise of natural compounds in leukemia treatment and prevention.

A ferroptosis-reinforced nanocatalyst enhances chemodynamic therapy through dual H2O2 production and oxidative stress amplification

The existence of a delicate redox balance in tumors usually leads to cancer treatment failure. Breaking redox homeostasis by amplifying oxidative stress and reducing glutathione (GSH) can accelerate cancer cell death. Herein, we construct a ferroptosis-reinforced nanocatalyst (denoted as HBGL) to amplify intracellular oxidative stress via dual H2O2 production-assisted chemodynamic therapy (CDT). Specifically, a long-circulating liposome is employed to deliver hemin (a natural iron-containing substrate for Fenton reaction and ferroptosis), β-lapachone (a DNA topoisomerase inhibitor with H2O2 generation capacity for chemotherapy), and glucose oxidase (which can consume glucose for starvation therapy and generate H2O2). HBGL can achieve rapid, continuous, and massive H2O2 and •OH production and GSH depletion in cancer cells, resulting in increased intracellular oxidative stress. Additionally, hemin can reinforce the ferroptosis-inducing ability of HBGL, which is reflected in the downregulation of glutathione peroxidase-4 and the accumulation of lipid peroxide. Notably, HBGL can disrupt endo/lysosomes and impair mitochondrial function in cancer cells. HBGL exhibits effective tumor-killing ability without eliciting obvious side effects, indicating its clinical translation potential for synergistic starvation therapy, chemotherapy, ferroptosis therapy, and CDT. Overall, this nanocatalytic liposome may be a promising candidate for achieving potentiated cancer treatment.

The Role of mTOR in Doxorubicin-Altered Cardiac Metabolism: A Promising Therapeutic Target of Natural Compounds

Doxorubicin (DOX) is commonly used for the treatment of various types of cancer, however can cause serious side effects, including cardiotoxicity. The mechanisms involved in DOX-induced cardiac damage are complex and not yet fully understood. One mechanism is the disruption of cardiac metabolism, which can impair cardiac function. The mammalian target of rapamycin (mTOR) is a key regulator of cardiac energy metabolism, and dysregulation of mTOR signaling has been implicated in DOX-induced cardiac dysfunction. Natural compounds (NCs) have been shown to improve cardiac function in vivo and in vitro models of DOX-induced cardiotoxicity. This review article explores the protective effects of NCs against DOX-induced cardiac injury, with a focus on their regulation of mTOR signaling pathways. Generally, the modulation of mTOR signaling by NCs represents a promising strategy for decreasing the cardiotoxic effects of DOX.

β-Lapachone induces ferroptosis of colorectal cancer cells via NCOA4-mediated ferritinophagy by activating JNK pathway

β-Lapachone is a natural product that can promote ROS generation and ultimately triggers tumor cells death by inducing DNA damage. Recent studies have indicated that the targeting of ferroptosis or iron metabolism is a feasible strategy for treating cancer. In this study, bulk RNA-seq analysis suggested that β-Lapachone might induce ferroptosis in CRC cells. We further tested this hypothesis using a xenograft model of human colorectal cancer as an animal model and in SW620 and DLD-1 of CRC cell lines. Western blot was used to determine the key proteins of ferroptosis (SLC7A11, GPX4), autophagy (LC3B, P62, ATG7), ferritinophagy (NCOA4, FTH1, TFRC), and JNK pathway (p-JNK, JNK, p-c-Jun, c-Jun). The levels of MDA, GSH/GSSG, lipid ROS, and intracellular ferrous iron were determined after β-Lapachone treatment, and inhibitors of various pathways, including NAC, Ferrostatin-1, DFO, 3-MA, and SP600125 were utilized to explore the molecular mechanism underlying β-Lapachone-mediated ferroptosis. As the result, we identified that β-Lapachone inhibited cell proliferation and induced apoptosis, autophagy, and ROS generation. In addition, β-Lapachone induced ferroptosis as demonstrated by intra-cellular iron overload, increased levels of lipid ROS and MDA. Mechanistically, JNK signaling pathway was involved in β-Lapachone-induced xCT/GPX4-mediated ferroptosis and NCOA4-mediated ferritinophagy in CRC cells. In vivo experiments in nude mice demonstrated that β-Lapachone significantly inhibited CRC growth and induced ferroptosis and NCOA4-mediated ferritinophagy. These findings not only identify a novel role for β-Lapachone in ferroptosis but also indicate that β-Lapachone may be a valuable candidate for the research and development of anti-cancer therapeutic agents.

β-lapachone protects against doxorubicin-induced hepatotoxicity through modulation of NAD+ /SIRT-1/FXR/p-AMPK/NF-kB and Nrf2 signaling axis

Doxorubicin (DOX) is a widely used antineoplastic drug, but its clinical use is limited by significant toxicities, such as hepatotoxicity. In this study, we evaluated the effects of β-lapachone (β-LAP), a natural quinone-containing compound, in a mouse model of DOX-induced hepatotoxicity. β-LAP was orally administered at 1.25, 2.5, and 5 mg/kg for 4 days, and a single dose of DOX (20 mg/kg) was injected intraperitoneally on the second day. Histopathological changes, liver function markers, antioxidant and inflammatory markers were assessed. β-LAP ameliorated liver injury and liver function markers evoked by DOX. β-LAP also downregulated the mRNA expression of nuclear factor-kB-corresponding genes including interleukin-6, interleukin-1β, and tumor necrosis factor-α. Moreover, β-LAP increased the nuclear factor erythroid 2-related factor 2 target genes heme oxygenase-1 and NAD(P)H: quinone oxidoreductase 1, along with antioxidant enzymes including reduced glutathione, catalase, and superoxide dismutase with simultaneous reduction in the lipid peroxidation product malondialdehyde. Meanwhile, it recovered NAD+ /NADH ratios and subsequently elevated the protein levels of sirtuin-1 (SIRT-1), farnesoid X receptor (FXR), and phosphorylated AMP-activated protein kinase (p-AMPK). Collectively, these findings suggest a protective role of β-LAP against DOX-induced hepatotoxicity by partly regulating the NAD+ /SIRT-1/FXR/p-AMPK axis.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Artemisia annua L. Polyphenols Enhance the Anticancer Effect of β-Lapachone in Oxaliplatin-Resistant HCT116 Colorectal Cancer Cells

Recent studies suggest that the anticancer activity of β-lapachone (β-Lap) could be improved by different types of bioactive phytochemicals. The aim of this study was to elucidate how the anticancer effect of β-Lap is regulated by polyphenols extracted from Korean Artemisia annua L. (pKAL) in parental HCT116 and oxaliplatin-resistant (OxPt-R) HCT116 colorectal cancer cells. Here, we show that the anticancer effect of β-Lap is more enhanced by pKAL in HCT116-OxPt-R cells than in HCT116 cells via a CCK-8 assay, Western blot, and phase-contrast microscopy analysis of hematoxylin-stained cells. This phenomenon was associated with the suppression of OxPt-R-related upregulated proteins including p53 and β-catenin, the downregulation of cell survival proteins including TERT, CD44, and EGFR, and the upregulation of cleaved HSP90, γ-H2AX, and LC3B-I/II. A bioinformatics analysis of 21 proteins regulated by combined treatment of pKAL and β-Lap in HCT116-OxPt-R cells showed that the enhanced anticancer effect of β-Lap by pKAL was related to the inhibition of negative regulation of apoptotic process and the induction of DNA damage through TERT, CD44, and EGFR-mediated multiple signaling networks. Our results suggest that the combination of pKAL and β-Lap could be used as a new therapy with low toxicity to overcome the OxPt-R that occurred in various OxPt-containing cancer treatments.

Tailored Beta-Lapachone Nanomedicines for Cancer-Specific Therapy

Nanotechnology shows the power to improve efficacy and reduce the adverse effects of anticancer agents. As a quinone-containing compound, beta-lapachone (LAP) is widely employed for targeted anticancer therapy under hypoxia. The principal mechanism of LAP-mediated cytotoxicity is believed due to the continuous generation of reactive oxygen species with the aid of NAD(P)H: quinone oxidoreductase 1 (NQO1). The cancer selectivity of LAP relies on the difference between NQO1 expression in tumors and that in healthy organs. Despite this, the clinical translation of LAP faces the problem of narrow therapeutic window that is challenging for dose regimen design. Herein, the multifaceted anticancer mechanism of LAP is briefly introduced, the advance of nanocarriers for LAP delivery is reviewed, and the combinational delivery approaches to enhance LAP potency in recent years are summarized. The mechanisms by which nanosystems boost LAP efficacy, including tumor targeting, cellular uptake enhancement, controlled cargo release, enhanced Fenton or Fenton-like reaction, and multidrug synergism, are also presented. The problems of LAP anticancer nanomedicines and the prospective solutions are discussed. The current review may help to unlock the potential of cancer-specific LAP therapy and speed up its clinical translation.

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.

Evaluation of β-lapachone-methyl-β-cyclodextrin inclusion complex prepared by spray drying and its application against different developmental stages of Schistosoma mansoni in murine model

BACKGROUND

β-lapachone (β-lap) is a naphthoquinone widely found in species of vegetables. However, its poor aqueous solubility limits its systemic administration and clinical applications in vivo. To overcome this limitation, several studies have been carried out in order to investigate techniques that can enhance the solubility and dissolution rate of β-lap, such as the use of inclusion complexes with cyclodextrin.

PURPOSE

To evaluate the in vivo effect of β-lap complexed in methyl-β-cyclodextrin (MβCD) on the evolutionary stages of Schistosoma mansoni in a murine model.

METHODS

The development and characterization of the physicochemical properties of the inclusion complex of β-lap in β-lap:MβCD was prepared by solubility and dissolution tests, FTIR, DSC, X-RD and SEM. The mice were infected and subsequently treated with β-lap:MβCD orally with 50 mg/kg/day and 100 mg/kg/day for 5 consecutive days, starting therapy on the 1^st (skin schistosomula), 14^th (pulmonary schistosomula), 28^th (young worms) and 45^th (adult worms) days after infection. Control groups were also formed; one infected untreated, treated with MβCD, and the other treated with PZQ.

RESULTS

The loss of the crystalline form of β-lap in the β-lap:MβCD complex obtained by spray drying was proven through physical-chemical characterization analyses. β-lap:MβCD caused reduction in the number of worms of the 33.56%, 35.7%, 35.45% and 36.45%, when the dose was at 50 mg/kg, and 65.00%, 60.34%, 52.72% and 65.01%, in the dose 100 mg/kg; when treatment was started in the 1^st, 14^th, 28^th and 45^th days after infection, respectively. It was also possible to observe a significant reduction in the number of immature eggs and an increase in the number of ripe and dead eggs and, consequently, a reduction in the damage caused by the egg antigens to the host tissue, where we attributed the reduction in the average diameter of the granulomas to the β-lap.

CONCLUSION

The dissolved content of β-lap:MβCD by spray drying reached almost 100%, serving for future formulations and delineation of the mechanisms of action of β-lap against S. mansoni.

β-lapachone-mediated WST1 Reduction as Indicator for the Cytosolic Redox Metabolism of Cultured Primary Astrocytes

Electron cycler-mediated extracellular reduction of the water-soluble tetrazolium salt 1 (WST1) is frequently used as tool for the determination of cell viability. We have adapted this method to monitor by determining the extracellular WST1 formazan accumulation the cellular redox metabolism of cultured primary astrocytes via the NAD(P)H-dependent reduction of the electron cycler β-lapachone by cytosolic NAD(P)H:quinone oxidoreductase 1 (NQO1). Cultured astrocytes that had been exposed to β-lapachone in concentrations of up to 3 µM remained viable and showed an almost linear extracellular accumulation of WST1 formazan for the first 60 min, while higher concentrations of β-lapachone caused oxidative stress and impaired cell metabolism. β-lapachone-mediated WST1 reduction was inhibited by the NQO1 inhibitors ES936 and dicoumarol in a concentration-dependent manner, with half-maximal inhibition observed at inhibitor concentrations of about 0.3 µM. β-lapachone-mediated WST1 reduction depended strongly on glucose availability, while mitochondrial substrates such as lactate, pyruvate or ketone bodies allowed only residual β-lapachone-mediated WST1 reduction. Accordingly, the mitochondrial respiratory chain inhibitors antimycin A and rotenone hardly affected astrocytic WST1 reduction. Both NADH and NADPH are known to supply electrons for reactions catalysed by cytosolic NQO1. Around 60% of the glucose-dependent β-lapachone-mediated WST1 reduction was prevented by the presence of the glucose-6-phosphate dehydrogenase inhibitor G6PDi-1, while the glyceraldehyde-3-phosphate dehydrogenase inhibitor iodoacetate had only little inhibitory potential. These data suggest that pentose phosphate pathway-generated NADPH, and not glycolysis-derived NADH, is the preferred electron source for cytosolic NQO1-catalysed reductions in cultured astrocytes.

Drug discovery inspired by bioactive small molecules from nature

Natural products (NPs) have greatly contributed to the development of novel treatments for human diseases such as cancer, metabolic disorders, and infections. Compared to synthetic chemical compounds, primary and secondary metabolites from medicinal plants, fungi, microorganisms, and our bodies are promising resources with immense chemical diversity and favorable properties for drug development. In addition to the well-validated significance of secondary metabolites, endogenous small molecules derived from central metabolism and signaling events have shown great potential as drug candidates due to their unique metabolite-protein interactions. In this short review, we highlight the values of NPs, discuss recent scientific and technological advances including metabolomics tools, chemoproteomics approaches, and artificial intelligence-based computation platforms, and explore potential strategies to overcome the current challenges in NP-driven drug discovery.

The modulation of sirtuins by natural compounds in the management of cisplatin-induced nephrotoxicity

Cisplatin is a highly effective antitumor agent. However, its use is limited due to severe adverse effects, particularly nephrotoxicity, which occurs in approximately 30% of patients. There is a need for novel renoprotective compounds. Sirtuins play a vital role in various physiological and pathological processes such as oxidative stress, apoptosis, inflammation, and mitochondrial bioenergetics. It has been shown that sirtuins can exert a protective effect on cisplatin-induced acute kidney injury by targeting multiple signaling pathways. Besides, sirtuins not only did not reduce the anticancer effect of cisplatin but also increased it. Several natural compounds have been reported to inhibit cisplatin-mediated nephrotoxicity through sirtuin stimulation. These compounds exert their therapeutic effects on cisplatin-induced renal injury by targeting various signaling pathways including Sirt1/p53, Sirt1/NF-κb/p56, AMPK/Sirt1, Sirt1/PGC-1α, and/or by enhancing mitochondrial function.

Antitumor Effect of Glandora rosmarinifolia (Boraginaceae) Essential Oil through Inhibition of the Activity of the Topo II Enzyme in Acute Myeloid Leukemia

It was previously shown that the antitumor and cytotoxic activity of the essential oil (EO) extracted from the aerial parts of Glandora rosmarinifolia appears to involve a pro-oxidant mechanism in hepatocellular carcinoma (HCC) and in triple-negative breast cancer (TNBC) cell lines. Its most abundant compound is a hydroxy-methyl-naphthoquinone isomer. Important pharmacological activities, such as antitumor, antibacterial, antifungal, antiviral and antiparasitic activities, are attributed to naphthoquinones, probably due to their pro-oxidant or electrophilic potential; for some naphthoquinones, a mechanism of action of topoisomerase inhibition has been reported, in which they appear to act both as catalytic inhibitors and as topoisomerase II poisons. Our aim was to evaluate the cytotoxic activity of the essential oil on an acute myeloid leukemia cell line HL-60 and on its multidrug-resistant (MDR) variant HL-60R and verify its ability to interfere with topoisomerase II activity. MTS assay showed that G. rosmarinifolia EO induced a decrease in tumor cell viability equivalent in the two cell lines; this antitumor effect could depend on the pro-oxidant activity of EO in both cell lines. Furthermore, G. rosmarinifolia EO reduced the activity of Topo II in the nuclear extracts of HL-60 and HL-60R cells, as inferred from the inability to convert the kinetoplast DNA into the decatenated form and then not inducing linear kDNA. Confirming this result, flow cytometric analysis proved that EO induced a G0-G1 phase arrest, with cell reduction in the S-phase. In addition, the combination of EO with etoposide showed a good potentiation effect in terms of cytotoxicity in both cell lines. Our results highlight the antitumor activity of EO in the HL-60 cell line and its MDR variant with a peculiar mechanism as a Topo II modulator. Unlike etoposide, EO does not cause stabilization of a covalent Topo II-DNA intermediate but acts as a catalytic inhibitor. These data make G. rosmarinifolia EO a potential anticancer drug candidate due to its cytotoxic action, which is not affected by multidrug resistance.

In Silico Antiprotozoal Evaluation of 1,4-Naphthoquinone Derivatives against Chagas and Leishmaniasis Diseases Using QSAR, Molecular Docking, and ADME Approaches

Chagas and leishmaniasis are two neglected diseases considered as public health problems worldwide, for which there is no effective, low-cost, and low-toxicity treatment for the host. Naphthoquinones are ligands with redox properties involved in oxidative biological processes with a wide variety of activities, including antiparasitic. In this work, in silico methods of quantitative structure-activity relationship (QSAR), molecular docking, and calculation of ADME (absorption, distribution, metabolism, and excretion) properties were used to evaluate naphthoquinone derivatives with unknown antiprotozoal activity. QSAR models were developed for predicting antiparasitic activity against Trypanosoma cruzi, Leishmania amazonensis, and Leishmania infatum, as well as the QSAR model for toxicity activity. Most of the evaluated ligands presented high antiparasitic activity. According to the docking results, the family of triazole derivatives presented the best affinity with the different macromolecular targets. The ADME results showed that most of the evaluated compounds present adequate conditions to be administered orally. Naphthoquinone derivatives show good biological activity results, depending on the substituents attached to the quinone ring, and perhaps the potential to be converted into drugs or starting molecules.

Identification of Antimotilins, Novel Inhibitors of Helicobacter pylori Flagellar Motility That Inhibit Stomach Colonization in a Mouse Model

New treatment options against the widespread cancerogenic gastric pathogen Helicobacter pylori are urgently needed. We describe a novel screening procedure for inhibitors of H. pylori flagellar biosynthesis. The assay is based on a flaA flagellin gene-luciferase reporter fusion in H. pylori and was amenable to multi-well screening formats with an excellent Z factor. We screened various compound libraries to identify virulence blockers ("antimotilins") that inhibit H. pylori motility or the flagellar type III secretion apparatus. We identified compounds that either inhibit both motility and the bacterial viability, or the flagellar system only, without negatively affecting bacterial growth. Novel anti-virulence compounds which suppressed flagellar biosynthesis in H. pylori were active on pure H. pylori cultures in vitro and partially suppressed motility directly, reduced flagellin transcript and flagellin protein amounts. We performed a proof-of-principle treatment study in a mouse model of chronic H. pylori infection and demonstrated a significant effect on H. pylori colonization for one antimotilin termed Active2 even as a monotherapy. The diversity of the intestinal microbiota was not significantly affected by Active2. In conclusion, the novel antimotilins active against motility and flagellar assembly bear promise to complement commonly used antibiotic-based combination therapies for treating and eradicating H. pylori infections. IMPORTANCE Helicobacter pylori is one of the most prevalent bacterial pathogens, inflicting hundreds of thousands of peptic ulcers and gastric cancers to patients every year. Antibacterial treatment of H. pylori is complicated due to the need of combining multiple antibiotics, entailing serious side effects and increasing selection for antibiotic resistance. Here, we aimed to explore novel nonantibiotic approaches to H. pylori treatment. We selected an antimotility approach since flagellar motility is essential for H. pylori colonization. We developed a screening system for inhibitors of H. pylori motility and flagellar assembly, and identified numerous novel antibacterial and anti-motility compounds (antimotilins). Selected compounds were further characterized, and one was evaluated in a preclinical therapy study in mice. The antimotilin compound showed a good efficacy to reduce bacterial colonization in the model, such that the antimotilin approach bears promise to be further developed into a therapy against H. pylori infection in humans.

β-lapachone: A Promising Anticancer Agent with a Unique NQO1 Specific Apoptosis in Pancreatic Cancer

Cancer, one of the major health problems all over the world, requires more competent drugs for clinical use. One recent possible chemotherapeutic drug under research is β-lapachone. β- lapachone (1,2-naphthoquinone) has promising activity against those tumors showing raised levels of Nicotinamide di-phosphate Quinone Oxidoreductases-1 (NQO1). NQO1 is found to be up-regulated in pancreatic tumor cells, and thus β-lapachone could generate cytotoxicity in various cancers like pancreatic tumors. β-lapachone harborage independent growth and clonogenic cell survival in agar. The cell-killing effects of β-lapachone can be stopped by using dicumarol, an inhibitor of NAD(P)H Quinone Oxidoreductases-1. In previously established pancreatic cancer xenografts in mice, β- lapachone inhibited the tumor growth when given orally rather than when combined with cyclodextrin to improve its bioavailability.

Beta-Lapachone Attenuates BMSC-Mediated Neuroblastoma Malignant Transformation by Inhibiting Gal-3/Gal-3BP/IL6 Axis

The inflammatory factor IL6 secreted by bone marrow mesenchymal stem cells (BMSCs) in the tumor microenvironment (TME) facilitates the survival and therapeutic resistance of neuroblastoma (NB). Here, we found that IL6 expression in primary tumor tissues or bone marrow (BM) metastases was closely associated with the disease risk and prognosis of NB patients. IL6 secretion from immortalized BMSC (iBMSC) was directly regulated by NB cells and is involved in promoting the proliferation and metastasis of NB cells. Beta-Lapachone (ARQ-501, LPC), an ortho-naphthoquinone natural product, significantly prevented the iBMSC-induced malignant transformation effect on NB cells through suppressing the expression and secretion of IL6 from iBMSC in vitro and in vivo. Mechanistically, LPC disrupted the crosstalk between NB cells and iBMSC in an NQO1-dependent manner through blocking the Gal-3/Gal-3BP/IL6 axis. Our results reveal the effect of iBMSC-derived IL6 on TME-induced malignant transformation of NB cells, and provide theoretical basis for the clinical application of LPC as a potential IL6 inhibitor in high-risk refractory NB patients.

Promises of phytochemical based nano drug delivery systems in the management of cancer

Cancer is the leading cause of human disease and death worldwide, accounting for 7.6 million deaths per year and projected to reach 13.1 million by 2030. Many phytochemicals included in traditional medicine have been utilized in the management of cancer. Conventional chemotherapy is generally known to be the most effective treatment of metastatic cancer but these cancerous cells might grow resistant to numerous anticancer drugs over time that resulting in treatment failure. This review tried to portray the advancement in the anticancer and chemopreventive effects of several phytochemicals and some of its members encapsulated in the nano-based delivery system of the drug. It comprises the issue associated with limited use of each phytoconstituents in human cancer treatment are discussed, and the benefits of entrapment into nanocarriers are evaluated in terms of drug loading efficiency, nanocarrier size, release profile of the drug, and in vitro and/or in vivo research and treatment testing, such as cytotoxicity assays and cell inhibition/viability.

Redox ticklers and beyond: Naphthoquinone repository in the spotlight against inflammation and associated maladies

Cellular redox status has been considered as a focal point for the pathogenesis of multiple disorders. High and persistent levels of free radicals kick off inflammation and associated disorders. Though oxidative stress at high levels is harmful but at low levels it has been shown to exert cytoprotective effects. Therefore, cytoprotection by perturbation in cellular redox balance is a leading strategy for therapeutic interventions. Prooxidants are potent redox modifiers that generate mild oxidative stress leading to a spectrum of bioactivities. Naphthoquinones are a group of highly reactive organic chemical species that interact with biological systems owing to their prooxidants nature. Owing to the ability of naphthoquinones and its derivatives to perturb redox balance in a cell and modulate redox signaling, they have been in epicenter of drug development for plausible utilization in multiple clinical settings. The present review highlights the potential of 1,4-naphthoquinone and its natural derivatives (plumbagin, juglone, lawsone, menadione, lapachol and β-lapachone) as redox modifiers with anti-inflammatory, anti-cancer, anti-diabetic and anti-microbial activities for implication in therapeutic settings.

Bioactivity of Chitosan-Based Particles Loaded with Plant-Derived Extracts for Biomedical Applications: Emphasis on Antimicrobial Fiber-Based Systems

Marine-derived chitosan (CS) is a cationic polysaccharide widely studied for its bioactivity, which is mostly attached to its primary amine groups. CS is able to neutralize reactive oxygen species (ROS) from the microenvironments in which it is integrated, consequently reducing cell-induced oxidative stress. It also acts as a bacterial peripheral layer hindering nutrient intake and interacting with negatively charged outer cellular components, which lead to an increase in the cell permeability or to its lysis. Its biocompatibility, biodegradability, ease of processability (particularly in mild conditions), and chemical versatility has fueled CS study as a valuable matrix component of bioactive small-scaled organic drug-delivery systems, with current research also showcasing CS’s potential within tridimensional sponges, hydrogels and sutures, blended films, nanofiber sheets and fabric coatings. On the other hand, renewable plant-derived extracts are here emphasized, given their potential as eco-friendly radical scavengers, microbicidal agents, or alternatives to antibiotics, considering that most of the latter have induced bacterial resistance because of excessive and/or inappropriate use. Loading them into small-scaled particles potentiates a strong and sustained bioactivity, and a controlled release, using lower doses of bioactive compounds. A pH-triggered release, dependent on CS’s protonation/deprotonation of its amine groups, has been the most explored stimulus for that control. However, the use of CS derivatives, crosslinking agents, and/or additional stabilization processes is enabling slower release rates, following extract diffusion from the particle matrix, which can find major applicability in fiber-based systems within ROS-enriched microenvironments and/or spiked with microbes. Research on this is still in its infancy. Yet, the few published studies have already revealed that the composition, along with an adequate drug release rate, has an important role in controlling an existing infection, forming new tissue, and successfully closing a wound. A bioactive finishing of textiles has also been promoting high particle infiltration, superior washing durability, and biological response.