Antimicrobial and wound healing potential of naphthoquinones encapsulated in nanochitosan

Introduction: The use of chitosan in pharmaceutical formulations is an advantageous approach due to this compound intrinsic biodegradability and biocompatibility, as well as ready availability and low polymer cost. Methods: Herein, the naphthoquinones 3- chloromethylene-menadione (NQ1) and 2,3-dichloro-1,4-naphthoquinone (NQ2) were nanoencapsulated into chitosan (CNP) by the ionotropic gelatinization technique and characterized by DLS, FTIR, SEM, TGA and DSC, and their release profiles evaluated. The antimicrobial and wound healing activities were investigated. Results and Discussion: Homogeneous chitosan nanocapsulses of about 193 nm and Z potential ranging from +30.6 to +33.1 mV loaded with NQ1 (CNP-NQ1) or NQ2 (CNPQNQ2). With nanoencapsulation efficiencies of ≥ 96%, the solubility of naphthoquinones in aqueous environments was improved, making them suitable for biological system applications. The encapsulated naphthoquinones displayed a controlled release of approximately 80% for CNP-NQ1 and 90% for CNP-NQ2 over an 8 h period at 36°C. Both CNP-NQ1 and CNP-NQ2 retained the already established free naphthoquinone antimicrobial activity against two Staphylococcus aureus strains, Staphylococcus epidermidis, Streptococcus pyogenes and Pseudomonas aeruginosa. Although presenting low toxicity to healthy human cells, only CNP-NQ1 displayed therapeutic indices above 100 for S. aureus and S. epidermidis and above 27 for S. pyogenes and P. aeruginosa, allowing for safe use in human tissues. Furthermore, CNP-NQ1 did not impair the migration of human fibroblast cells in scratch assays, adding promising wound healing properties to this formulation. These findings emphasize that CNP-NQ1 may be useful in protecting injured skin tissue from bacterial contamination, avoiding skin infections not only by reducing bacterial loads but also by accelerating the healing process until complete dermal tissue recovery.

Tarin-Loaded Nanoliposomes Activate Apoptosis and Autophagy and Inhibit the Migration of Human Mammary Adenocarcinoma Cells

Background

Tarin, a lectin purified from Colocasia esculenta, promotes in vitro and in vivo immunomodulatory effects allied to promising anticancer and antimetastatic effects against human adenocarcinoma mammary cells. This makes this 47 kDa-protein a natural candidate against human breast cancer, a leading cause of death among women. Tarin encapsulated in pegylated nanoliposomes displays increased effectiveness in controlling the proliferation of a mammary adenocarcinoma lineage comprising MDA-MB-231 cells.

Methods

The mechanisms enrolled in anticancer and antimetastatic responses were investigated by treating MDA-MB-231 cells with nano-encapsulated tarin at 72 μg/mL for up to 48h through flow cytometry and transmission electron microscopy (TEM). The safety of nano-encapsulated tarin towards healthy tissue was also assessed by the resazurin viability assay, and the effect of nanoencapsulated tarin on cell migration was evaluated by scratch assays.

Results

Ultrastructural analyses of MDA-MB-231 cells exposed to nanoencapsulated tarin revealed the accumulation of autophagosomes and damaged organelles, compatible with autophagy-dependent cell death. On the other hand, the flow cytometry investigation detected the increased occurrence of acidic vacuolar organelles, a late autophagosome trait, along with the enhanced presence of apoptotic cells, activated caspase-3/7, and cell cycle arrest at G0/G1. No deleterious effects were observed in healthy fibroblast cells following tarin nanoencapsulated exposition, in contrast to reduced viability in cells exposed to free tarin. The migration of MDA-MB-231 cells was inhibited by nano-encapsulated tarin, with delayed movement by 24 h compared to free tarin.

Conclusion

The nanoliposome formulation delivers tarin in a delayed and sustained manner, as evidenced by the belated and potent antitumoral and anti-migration effects on adenocarcinoma cells, with no toxicity to healthy cells. Although further investigations are required to fully understand antitumorigenic tarin mechanisms, the activation of both apoptotic and autophagic machineries along with the caspase-3/7 pathway, and cell cycle arrest may comprise a part of these mechanisms.

Exploring the Antimicrobial and Antitumoral Activities of Naphthoquinone-Grafted Chitosans

Biopolymers obtained from natural macromolecules are noteworthy among materials presenting high biocompatibility and adequate biodegradability, as is the case of chitosan (CS), making this biopolymeric compound a suitable drug delivery system. Herein, chemically-modified CS were synthetized using 2,3-dichloro-1,4-naphthoquinone (1,4-NQ) and the sodium salt of 1,2-naphthoquinone-4-sulfonic acid (1,2-NQ), producing 1,4-NQ-CS and 1,2-NQ-CS by three different methods, employing an ethanol and water mixture (EtOH:H2O), EtOH:H2O plus triethylamine and dimethylformamide. The highest substitution degree (SD) of 0.12 was achieved using water/ethanol and triethylamine as the base for 1,4-NQ-CS and 0.54 for 1,2-NQ-CS. All synthesized products were characterized by FTIR, elemental analysis, SEM, TGA, DSC, Raman, and solid-state NMR, confirming the CS modification with 1,4-NQ and 1,2-NQ. Chitosan grafting to 1,4-NQ displayed superior antimicrobial activities against Staphylococcus aureus and Staphylococcus epidermidis associated with improved cytotoxicity and efficacy, indicated by high therapeutic indices, ensuring safe application to human tissue. Although 1,4-NQ-CS inhibited the growth of human mammary adenocarcinoma cells (MDA-MB-231), it is accompanied by cytotoxicity and should be considered with caution. The findings reported herein emphasize that 1,4-NQ-grafted CS may be useful in protecting injured tissue against bacteria, commonly found in skin infections, until complete tissue recovery.

Trends in Drug Delivery Systems for Natural Bioactive Molecules to Treat Health Disorders: The Importance of Nano-Liposomes

Drug delivery systems are believed to increase pharmaceutical efficacy and the therapeutic index by protecting and stabilizing bioactive molecules, such as protein and peptides, against body fluids' enzymes and/or unsuitable physicochemical conditions while preserving the surrounding healthy tissues from toxicity. Liposomes are biocompatible and biodegradable and do not cause immunogenicity following intravenous or topical administration. Still, their most important characteristic is the ability to load any drug or complex molecule uncommitted to its hydrophobic or hydrophilic character. Selecting lipid components, ratios and thermo-sensitivity is critical to achieve a suitable nano-liposomal formulation. Nano-liposomal surfaces can be tailored to interact successfully with target cells, avoiding undesirable associations with plasma proteins and enhancing their half-life in the bloodstream. Macropinocytosis-dynamin-independent, cell-membrane-cholesterol-dependent processes, clathrin, and caveolae-independent mechanisms are involved in liposome internalization and trafficking within target cells to deliver the loaded drugs to modulate cell function. A successful translation from animal studies to clinical trials is still an important challenge surrounding the approval of new nano-liposomal drugs that have been the focus of investigations. Precision medicine based on the design of functionalized nano-delivery systems bearing highly specific molecules to drive therapies is a promising strategy to treat degenerative diseases.

Aldehyde Accumulation in Aged Alcoholic Beer: Addressing Acetaldehyde Impacts on Upper Aerodigestive Tract Cancer Risks

Aldehydes, particularly acetaldehyde, are carcinogenic molecules and their concentrations in foodstuffs should be controlled to avoid upper aerodigestive tract (UADT) and liver cancers. Highly reactive, acetaldehyde forms DNA and protein adducts, impairing physiological functions and leading to the development of pathological conditions. The consumption of aged beer, outside of the ethanol metabolism, exposes habitual drinkers to this carcinogen, whose concentrations can be over-increased due to post-brewing chemical and biochemical reactions. Storage-related changes are a challenge faced by the brewing industry, impacting volatile compound formation and triggering flavor instability. Aldehydes are among the volatile compounds formed during beer aging, recognized as off-flavor compounds. To track and understand aldehyde formation through multiple pathways during beer storage, consequent changes in flavor but particularly quality losses and harmful compound formation, this systematic review reunited data on volatile compound profiles through gas chromatography analyses from 2011 to 2021. Conditions to avoid flavor instability and successful methods for reducing beer staling, and consequent acetaldehyde accumulation, were raised by exploring the dynamic conversion between free and bound-state aldehydes. Future research should focus on implementing sensory analyses to investigate whether adding aldehyde-binding agents, e.g., cysteine and bisulfite, would contribute to consumer acceptance, restore beer flavor, and minimize acetaldehyde-related health damage.

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.

Taro Lectin Can Act as a Cytokine-Mimetic Compound, Stimulating Myeloid and T Lymphocyte Lineages and Protecting Progenitors in Murine Bone Marrow

Taro (Colocasia esculenta) corm is traditionally consumed as a medicinal plant to stimulate immune responses and restore a health status. Tarin, a taro lectin, is considered responsible for the immunomodulatory effects of taro. In the present study, in order to investigate the effects of tarin on bone marrow hematopoietic population, murine cells were stimulated with tarin combined with a highly enriched conditioned medium containing either IL-3 or GM-CSF. Cells challenged with tarin proliferated in a dose-dependent manner, evidenced by the increase in cell density and number of clusters and colonies. Tarin exhibited a cytokine-mimetic effect similar to IL-3 and GM-CSF, increasing granulocytic cell lineage percentages, demonstrated by an increase in the relative percentage of Gr-1+ cells. Tarin does not increase lymphocytic lineages, but phenotyping revealed that the relative percentage of CD3+ cells was increased with a concomitant decrease in CD19+ and IL-7Rα+ cells. Most bone marrow cells were stained with tarin-FITC, indicating non-selective tarin binding, a phenomenon that must still be elucidated. In conclusion, taro corms contain an immunomodulatory lectin able to boost the immune system by promoting myeloid and lymphoid hematopoietic progenitor cell proliferation and differentiation.

Tarin, a Potential Immunomodulator and COX-Inhibitor Lectin Found in Taro (Colocasia esculenta)

Taro (Colocasia esculenta) corm is a rustic staple food, rich in small starch granules, fibers, and bioactive phytoconstituents such as flavonoids, alkaloids, sterols, tannins, phytates, micronutrients, and proteins, including tarin, a GNA-related lectin. Tarin exhibits recognized biocide activities against viruses and insects, has antitumoral properties and is an immunomodulator molecule candidate. It has been isolated in highly purified form (>90%) from taro corms through low-cost and single-step affinity chromatography. It comprises 2-domain 27 to 28 kDa protomer, posttranslational cleaved into 2 nonidentical monomers, 11.9 and 12.6 kDa, held by noncovalent binding. At least 10 tarin isoforms sharing over 70% similarity have been described. The monomers assume the β-prism II fold, consisting of 3 antiparallel β-sheets formed by 4 β-strands each. Tarin exhibits an expanded-binding site for complex and high-mannose N-glycan chains 49, 212, 213, 358, 465, and 477 found on cell surface antigens of viruses, insects, cancer, and hematopoietic cells, explaining its broad biological activities. Tarin may stimulate innate and adaptive immune responses, enabling hosts to recover from infections or immunosuppressed status inherent to several pathological conditions. In a murine model, tarin stimulates the in vitro and in vivo proliferation of total spleen and bone marrow cells, especially B lymphocytes. Granulocyte repopulation has also been demonstrated in long-term mice bone marrow cell cultures. As a potential immunomodulator, tarin, administered to immunosuppressed mice, attenuated cyclophosphamide-induced leukopenia. We propose a molecular model that unites the potential prophylactic and therapeutic action of tarin on hematopoietic and cancer cells, as a potential immunomodulator.

Polyphenols from Root, Tubercles and Grains Cropped in Brazil: Chemical and Nutritional Characterization and Their Effects on Human Health and Diseases

Throughout evolution, plants have developed the ability to produce secondary phenolic metabolites, which are important for their interactions with the environment, reproductive strategies and defense mechanisms. These (poly)phenolic compounds are a heterogeneous group of natural antioxidants found in vegetables, cereals and leguminous that exert beneficial and protective actions on human health, playing roles such as enzymatic reaction inhibitors and cofactors, toxic chemicals scavengers and biochemical reaction substrates, increasing the absorption of essential nutrients and selectively inhibiting deleterious intestinal bacteria. Polyphenols present in some commodity grains, such as soy and cocoa beans, as well as in other vegetables considered security foods for developing countries, including cassava, taro and beetroot, all of them cropped in Brazil, have been identified and quantified in order to point out their bioavailability and the adequate dietary intake to promote health. The effects of the flavonoid and non-flavonoid compounds present in these vegetables, their metabolism and their effects on preventing chronic and degenerative disorders like cancers, diabetes, osteoporosis, cardiovascular and neurological diseases are herein discussed based on recent epidemiological studies.

Neurotoxicosis in horses associated with consumption of Trema micrantha

BACKGROUND

Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed.

OBJECTIVES

This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions.

STUDY DESIGN

Retrospective case series.

METHODS

A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to necropsy and multiple samples were collected for histopathology. Details of clinical history and signs of the horses were obtained through inquiries to the owners and attending veterinarians.

RESULTS

All the 14 horses had neurological signs of ataxia, severe sialorrhoea, involuntary running movements, sternal and lateral recumbency, and death after a clinical course that lasted from 24 h to 9 days. For a few days prior to onset of clinical signs, all horses had spontaneously consumed, potentially toxic doses of T. micrantha leaves. All 14 brains had diffuse yellowish discoloration affecting the rhombencephalon, mesencephalon, diencephalon, telencephalon and corpus striatum. In all cases, the most severe lesions were observed in the pons. Spinal cord lesions were observed affecting the lumbar intumescence, which was swollen with darken and depressed areas at the dorsal and ventral horns, and at the sacral level, which on cut surface displayed a friable and yellowish grey matter. The lesions observed grossly in brain and spinal cord consisted microscopically of severe vasculitis and liquefactive necrosis of white and grey matter of the brainstem, cerebellum and spinal cord.

MAIN LIMITATIONS

This is a small retrospective series relying on clinical observations reported by owners and attending veterinarians. The mechanism of action of the plant toxin in the CNS is still unidentified.

CONCLUSION

T. micrantha poisoning in horses causes predominantly a neurological disease, with minimal to absent hepatic lesions.

Transabdominal or totally extraperitoneal laparoscopic hernia repair?

Laparoscopic repair of inguinal hernias follows some principles that have already proven its efficiency, as a posterior approach and the prosthetic repair that allows a "tension-free" repair with consequent early return to work and low recurrence rate. To determine the most appropriate laparoscopic repair, we compared the transabdominal preperitoneal (TAPP) and the totally extraperitoneal (TEP) approach. Patients undergoing TAPP and TEP were compared regarding technical feasibility and difficulties, time until return to work and follow-up, including intraoperative and postoperative complications. Seventy-eight patients (108 hernias) were submitted to TAPP and 67 (100 hernias) were repaired through TEP. All data were analyzed by Yates-corrected chi-square test to qualitative analysis of each group and p < or = 0.05 was considered significant. Both procedures were indicated mainly for bilateral and/or recurrent hernias (68%). The operative time was shorter in TAPP (not statistically significant). Surgeons complained of more technical difficulties while performing the TEP approach (70% complaints of difficulty in TEP--four conversions to TAPP). There was no difference in hospital stay (mean of 30 h) and return to work (TAPP 7 days and TEP 5.5 days). Regarding the complication rate (TAPP = 20.5% and TEP = 13.5%; not significant), none were related to the pneumoperitoneum technique or its systemic effects. In the TAPP approach, two trocar site hernias occurred, and in the TEP approach, one severe cellulitis occurred, which was managed without surgical intervention. The mean follow-up period for each procedure was not the same, so the recurrence rates are not comparable statistically (rate of 1.85% in TAPP and 0 in TEP). Both techniques are safe and have the same advantages, but TAPP is easier: a better view of the anatomy is achieved, shortening the learning curve. We suggest that TAPP can be an adequate laparoscopic approach to groin hernias. A longer follow-up period and more cases are needed to determine recurrence rates.

Laparoscopy-assisted colonoscopic polypectomy

One of the most feared complications in the removal of moderate-sized or large sessile polyps is colonic perforation. Complete colonoscopic total excision of these kinds of polyps can be safely undertaken using laparoscopic assistance, which enables prompt diagnosis and treatment of perforation. Laparoscopy-assisted endoscopic polyp excision can be safely performed, avoiding critical septic complications and can also help in the selection of patients to appropriate colonic resection without increasing morbidity or mortality.