Anti-biofilm Effect of β-Lapachone and Lapachol Oxime Against Isolates of Staphylococcus aureus

Vanillic acid-based pro-coagulant hemostatic shape memory polymer foams with antimicrobial properties against drug-resistant bacteria

Uncontrolled bleeding is the primary cause of trauma-related death. For patients that are brought to the hospital in time to receive treatment, there is a great risk of contracting drug-resistant bacterial wound infections. Therefore, low-cost hemostatic agents with procoagulant and antibacterial properties are essential to reduce morbidity and mortality in patients with traumatic wounds. To that end, we introduced vanillic acid (VA) into shape memory polymer (SMP) foams through a dual incorporation mechanism to make dual vanillic acid (DVA) foams. The dual mechanism increases VA loading while allowing burst and sustained delivery of VA from foams. DVA foams exhibit antimicrobial and antibiofilm properties against native and drug-resistant Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis. Also, DVA foams inhibit the growth rate of both methicillin-sensitive and -resistant S. aureus colonies to limit their size and promote small colony variants. DVA SMP foams induced primary and secondary hemostasis in in vitro blood interaction studies. As a proof of concept, we demonstrated easy delivery and rapid clotting in a porcine liver injury model, indicating DVA foam feasibility for use as a hemostatic dressing. Thus, the inexpensive production of DVA SMP foams could enable a cost-effective procoagulant hemostatic dressing that is resistant to bacterial colonization to improve short- and long-term outcomes for hemorrhage control in traumatically injured patients. STATEMENT OF SIGNIFICANCE: Uncontrolled bleeding is the primary cause of preventable death on the battlefield. Of patients that survive, ∼40 % develop polymicrobial infections within 5 days of injury. Drug-resistant infections are anticipated to cause more deaths than all cancers combined by 2050. Therefore, novel non-drug-based biomaterials strategies for infection control in wound care are increasingly important. To that end, we developed hemostatic polyurethane foams that include antimicrobial and pro-coagulant vanillic acid, a plant-based antimicrobial species. These foams provide excellent protection against native and drug-resistant bacteria and enhanced coagulation while remaining cytocompatible. In a pilot porcine liver injury model, vanillic acid-containing foams stabilized a bleed within <5 min. These biomaterials provide a promising solution for both hemorrhage and infection control in wound care.

Unlocking the potential of 1,4-naphthoquinones: A comprehensive review of their anticancer properties

Cancer encompasses a group of pathologies with common characteristics, high incidence, and prevalence in all countries. Although there are treatments available for this disease, they are not always effective or safe, often failing to achieve the desired results. This is why it is necessary to continue the search for new therapies. One of the strategies for obtaining new antitumor drugs is the use of 1,4-naphthoquinone as a scaffold in synthetic or natural products with antitumor activity. This review focuses on compiling studies related to the antitumor activity of 1,4-naphthoquinone and its natural and synthetic derivatives over the last 10 years. The work describes the main natural naphthoquinones with antitumor activity and classifies the synthetic naphthoquinones based on the structural modifications made to the scaffold. Additionally, the formation of metal complexes using naphthoquinones as a ligand is considered. After a thorough review, 197 synthetic compounds with potent biological activity against cancer have been classified according to their chemical structures and their mechanisms of action have been described.

Natural cordiaquinones as strategies to inhibit the growth and biofilm formation of methicillin-sensitive and methicillin-resistant Staphylococcus spp

AIMS

The aim of this study was to investigate the antibacterial and antibiofilm potential of cordiaquinones B, E, L, N, and O against different Staphylococci strains, in addition to analyzing in silico the observed effect.

METHODS AND RESULTS

The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined according to CLSI guidelines. The inhibition of biofilm formation was investigated at sub-MICs. Atomic force microscopy (AFM) and density functional theory method were performed. The tested strains of Staphylococcus spp. were susceptible to cordiaquinones B, E, and L, among which cordiaquinone B exerted a bactericidal effect, confirmed by a bacterial growth curve study, against Staphylococcus saprophyticus. Cordiaquinones B and E showed lowest MBC values against S. saprophyticus. AFM revealed that cordiaquinone L reduced the mean cell size of S. saprophyticus. Cordiaquinones B and E inhibited the biofilm formation ability of S. aureus by ∼90%. The in silico analysis suggested that the antimicrobial activity of cordiaquinones is driven by their electron donation capability.

CONCLUSIONS

Cordiaquinones inhibit the growth and biofilm formation (virulence factor) of both methicillin-sensitive and methicillin-resistant Staphylococci strains, indicating their antimicrobial potential.

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.

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.

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.

Novel Approaches to Combat Medical Device-Associated BioFilms

Biofilms are aggregates formed as a protective survival state by microorganisms to adapt to the environment and can be resistant to antimicrobial agents and host immune responses due to chemical or physical diffusion barriers, modified nutrient environments, suppression of the growth rate within biofilms, and the genetic adaptation of cells within biofilms. With the widespread use of medical devices, medical device-associated biofilms continue to pose a serious threat to human health, and these biofilms have become the most important source of nosocomial infections. However, traditional antimicrobial agents cannot completely eliminate medical device-associated biofilms. New strategies for the treatment of these biofilms and targeting biofilm infections are urgently required. Several novel approaches have been developed and identified as effective and promising treatments. In this review, we briefly summarize the challenges associated with the treatment of medical device-associated biofilm infections and highlight the latest promising approaches aimed at preventing or eradicating these biofilms.