Bioactives of Melipona rufiventris Propolis: Exploring its Antimicrobial, Anti-Inflammatory, and Antioxidant Activities.

This study explores the potential of propolis, a resinous substance produced by bees, from Melipona rufiventris species. With its composition encompassing resin, wax, pollen, and soil, propolis holds historical significance in traditional medicine within tropical regions. This research is driven by the scarcity of information surrounding M. rufiventris propolis, prompting an investigation into its chemical constituents, in vivo toxicity, and antimicrobial, antioxidant, and anti-inflammatory properties. This exploration could potentially uncover novel applications for this natural product, bolstering both meliponiculture practices and the preservation of native bee populations. The propolis was sampled in Cabo Verde-MG and underwent ethanolic extraction to yield an extract (EEP) for analysis. Chemical assessments (Folin-Ciocalteau, and UHPLC-HRMS) revealed the presence of polyphenols, including flavonoids. The EEP demonstrated higher antimicrobial activity against Gram-positive bacteria and exhibited efficacy against multiresistant strains isolated from complex wounds. Synergistic interactions with commercial antibiotics were also observed. Furthermore, anti-inflammatory evaluations showcased the EEP's potential in reducing NF-kB activation and TNF-α release at non-toxic concentrations. Despite these promising biological activities, the EEP exhibited no antiproliferative effects and demonstrated safety in both the MTS assay and the G. mellonella model. Collectively, these findings highlight the M. rufiventris propolis extract as a valuable reservoir of bioactive compounds with multifaceted potential.

PI3Kγ controls IL-17A expression and attenuates alveolar bone loss in an experimental periodontitis model.

OBJECTIVE: In this study, we investigated the modulatory effects of PI3Kγ on IL-17A expression and the progression of experimental periodontitis in vivo. METHODS: Ligature-induced periodontitis was developed around the first molar of mice. Animals were treated with anti-mouse IL-17A or IPI-549 (PI3Kγ inhibitor). In addition, PI3Kγ-deficient mice (PI3Kγ-/-) were used in the study. Alveolar bone loss was measured and real-time PCR of Il17a and Rankl genes was performed. A bioinformatics analysis was carried out using the Gene Set Enrichment Analysis computational tool. RESULTS: Nine days after ligature placement, alveolar bone loss scores were significantly increased, with upregulation of Il17a and Rankl genes in the gingival tissues. Treatment with anti-mouse IL-17A (100 µg/mice) significantly attenuated alveolar bone loss. Mice with ligature-induced periodontitis treated with IPI-549 (3 mg/kg) or PI3Kγ-/- mice showed reduced alveolar bone loss and downregulation of Il17a and Rankl gene expression in the gingival tissues. Consistent with this, the bioinformatics analysis showed upregulation of IL17F, IL17A, IL17D, and STAT3 genes, as well as greater activation of IL-17 and PI3KCI pathways (upregulation of PIK3CG gene) in the gingival tissue of patients with periodontitis. CONCLUSION: PI3Kγ plays an important role in modulating IL-17A expression and alveolar bone loss in vivo and can be considered a promising pathway for the management of periodontal disease and the development of new therapies.

Progress and promise of alternative animal and non-animal methods in biomedical research.

Cell culture and invertebrate animal models reflect a significant evolution in scientific research by providing reliable evidence on the physiopathology of diseases, screening for new drugs, and toxicological tests while reducing the need for mammals. In this review, we discuss the progress and promise of alternative animal and non-animal methods in biomedical research, with a special focus on drug toxicity.

A Systematic Review of the Potential Effects of Propolis Extracts on Experimentally-induced Diabetes.

Oxidative stress (OS) is involved in the development of diabetes mellitus (DM) and its complications. Thus, OS reduction may be an important strategy for DM therapy. Propolis is bee resins with high antioxidant activity and is used in the treatment of different diseases, including DM. Therefore, in this systematic review, we evaluated the impact of propolis administration in diabetic animals. We used the PRISMA strategy to collect preclinical studies published in English up to November 2021 in three databases (PubMed/Medline, Scopus, and Web of Science). We used the SYRCLE tool to analyze the risk of methodological bias. Our primary search returned 198 studies, of which 14 were considered eligible to be included in this review. The administration of propolis induced a hypoglycemic effect in the treated animals, which is probably due to the reduction of OS. The animals showed restoration of endogenous antioxidant defenses and reduced levels of markers for OS. The administration of propolis resulted in improvement in the lipid profile of treated animals. Our risk of bias assessment showed a methodological quality score of less than 30% due to a lack of randomization, blinding, and proper allocation of animals. Heterogeneity in treatments, lack of results, and use of non-standard extracts are limitations in our data analysis. Despite these limitations, propolis induced a significant hypoglycemic effect in diabetic animals when compared to untreated controls. This effect was associated with a reduction in OS, a process mediated by ROS neutralization and restoration of endogenous antioxidant defenses.

Evaluation of efficacy of new chalcone-based endodontic irrigant against dual biofilm Enterococcus faecalis and Candida albicans: a study in vitro.

The aim of this research was to develop a chalcone-based endodontic irrigant for cleaning and disinfecting the root canal. Minimal inhibitory concentration (MIC) experiments in C. albicans and E. faecalis strains with different aminochalcones (AM) were carried out, and the compound that presented the best activity against both pathogens was chosen. The formulation of an endodontic irrigant was elaborated, tested in mono and dual specie biofilms. Disks were sterilized and then incubated with E. faecalis, C. albicans and E. faecalis and C. albicans mixed for 72 h for biofilm maturation. After contamination, samples were divided in 4 experimental groups and 2 positive control group as follows: Group1: Irrigant; Group2: Irrigant + AM-38; Group3: Chlorhexidine 2% (positive control) and, Group 4: 1.0% sodium hypochlorite (positive control). The samples were analyzed by CFU/ml count. The sample was taken to sonicador to remove the cells and then plated. The toxicity was determined in vitro with human gingival fibroblast cells (HGF) and in vivo using the Galleria mellonella model. Formulation showed antimicrobial activity, with MIC on C. albicans 15.6 and E. faecalis 7.8 µg/ml. Treatment with formulation in concentration 156 µg/ml significantly reduced mono or dual species biofilm formation and viability (p < 0.05). The results were significant against C. albicans and E. faecalis and did not show toxicity in cells and G. mellonella. In general, the formulation showed effective antibiofilm activity, significantly reducing microorganisms, opening paths in search of new endodontic irrigants.

The effect of Brazilian propolis type-3 against oral microbiota and volatile sulfur compounds in subjects with morning breath malodor.

OBJECTIVES: To evaluate propolis type-3 mouthrinse effects on the concentration of volatile sulfur compounds (VSCs) and on tongue dorsum microbial profile. MATERIALS AND METHODS: A three-step double-blind, crossover, randomized study with 10 individuals divided into three groups: I-placebo (P); II-ethanolic extract of propolis type-3 3% (EEP); and III-chlorhexidine 0.12% (CHX) and instructed to rinse twice daily for 5 days. Each experimental period was followed by a 21-day washout interval. Morning mouth breath was assessed by VSC concentrations and microbiological samples were obtained from tongue dorsum at baseline and the end of period of rinses and analyzed using checkerboard DNA-DNA hybridization technique for 39 bacterial species. RESULTS: CHX and EEP presented the lowest VSC concentration when compared with placebo (p < 0.05). Even in the absence of mechanical plaque control, CHX and EEP treatments reduced VSC levels and there were no statistical differences for VSC measurement between CHX and EEP. There was a significant reduction in mean counts of 10 species including some VSC producers (Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) by EEP. Total counts of organisms, gram-negative and gram-positive bacterial species showed a decrease for EEP and CHX (p < 0.05). In addition, no statistical difference was observed between EEP and CHX (p > 0.05). A positive correlation was observed between decrease of bacterial counts and decrease of VCSs concentration for the EEP and CHX. CONCLUSIONS: The use of a 3% propolis type-3 mouthrinse is an effective way to prevent morning bad breath. Thus, propolis may be a promising agent for the treatment of halitosis. CLINICAL RELEVANCE: Propolis type-3 may be used as adjuvant treatment for morning breath malodor.

Isolation of diterpenes from Araucaria sp Brazilian brown propolis and development of a validated high-performance liquid chromatography method for its analysis.

Propolis comprises a complex resinous product composed of plant's parts or exudates, pollen, bee wax, and enzymes. Brazilian brown propolis from Araucaria sp displays several biological activities. Considering the lack of validated analytical methods for its analysis, we are reporting the development of a validated high-performance liquid chromatography with photodiode array detector method to analyze Araucaria brown propolis. The crude propolis were extracted and chromatographed, furnishing six main diterpenes. The isolated standards were used to draw the analytical curves, allowing the studies of selectivity, precision, accuracy, recovery, robustness, the determination of limits of detection and limits of quantification. The mobile phase consisted of 0.1% acetic acid in water and acetonitrile, using an octadecylsilane column, 1 mL/min flow rate and detection at 200 or 241 nm. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4% for all diterpenes. From the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.808 to 10.359 µg/mL and from 2.448 to 31.392 µg/mL, respectively. The recoveries were between 105.03 and 108.13%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analyzing Araucaria brown propolis.

Antimicrobial, anti-adherence and antibiofilm activity against Staphylococcus aureus of a 4-phenyl coumarin derivative isolated from Brazilian geopropolis.

The discovery of new drug candidates, especially from natural products, remains a promising approach to overcome the alarmingly high microbial resistance rates. A major 4-phenyl coumarin named cinnamoyloxy-mammeisin (CNM) isolated from stingless bee geopropolis showed interesting biological properties; however, its antimicrobial activity against Staphylococcus aureus has never been investigated. In order to clarify these properties, CNM isolated from geopropolis was initially tested against methicillin-susceptible and -resistant S. aureus strains. Further, the effects of CNM were assessed on the microbial adherence to human cells, biofilm formation and mature biofilm. Then, the acute toxicity of the compound was determined in Galleria mellonella. CNM showed bacteriostatic activity against methicillin-susceptible and -resistant S. aureus strains, with MIC of 11.3 µM. In addition, CNM at 5.7 µM reduced bacterial adherence to human keratinocytes from 1 to 3 h and disrupted biofilm formation by reducing cell viability and architecture, as evidenced by scanning electron microscopy. The acute toxicity assay indicated no significant harmful effects. Based on these findings, CNM can be considered a promising compound with anti-S. aureus properties and predicted low toxicity. Thus, it may be used as a drug candidate or lead compound for structure/activity optimization.

Effect of Cinnamomum verum leaf essential oil on virulence factors of Candida species and determination of the in-vivo toxicity with Galleria mellonella model.

BACKGROUND: Essential oils (EO) extracted from Cinnamomum verum has been used as an antimicrobial agents for centuries. The effects of C. verum leaf oil against virulence of microorganisms is not well studied yet. OBJECTIVES: This study evaluates the effect of C. verum leaf oil against three virulence factors of Candida albicans, C. tropicalis and C. dubliniensis and its in-vivo toxicity. METHODS: Chemical composition of EO was determined using gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentration (MIC) was determined using clinical and laboratory standards institute (CLSI) M27-A3 broth microdilution. Effect of EO on initial adhesion was quantified using XTT assay after allowing Candida cells to adhere to the polystyrene surface for 2 h. Biofilm formation of Candida in the presence of EO was quantified using XTT viability assay. Efficacy on reduction of germ tube formation was evaluated using standard protocol. Visualisation of biofilm formation and progression under the EO treatment were done using scanning electron microscope (SEM) and Time lapses microscope respectively. In-vivo toxicity of EO was determined using Galleria mellonella larvae. Chlorhexidine digluconate: positive control. RESULTS: Eugenol was the main compound of EO. MIC was 1.0 mg/mL. 50% reduction in initial adhesion was achieved by C. albicans, C. tropicalis and C. dubliniensis with 1.0, > 2.0 and 0.34 mg/mL respectively. 0.5 and 1.0 mg/mL significantly inhibit the germ tube formation. MBIC50 for forming biofilms were ≤ 0.35 mg/mL. 1.0 mg/mL prevent biofilm progression of Candida. SEM images exhibited cell wall damages, cellular shrinkages and decreased hyphal formation. No lethal effect was noted with in-vivo experiment model at any concentration tested. CONCLUSION: C. verum leaf oil acts against virulence factors of Candida and does not show any toxicity.

Docking Prediction, Antifungal Activity, Anti-Biofilm Effects on Candida spp., and Toxicity against Human Cells of Cinnamaldehyde.

OBJECTIVE: This study evaluated the antifungal activity of cinnamaldehyde on Candida spp. In vitro and in situ assays were carried out to test cinnamaldehyde for its anti-Candida effects, antibiofilm activity, effects on fungal micromorphology, antioxidant activity, and toxicity on keratinocytes and human erythrocytes. Statistical analysis was performed considering α = 5%. RESULTS: The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of cinnamaldehyde ranged from 18.91 µM to 37.83 µM. MIC values did not change in the presence of 0.8 M sorbitol, whereas an 8-fold increase was observed in the presence of ergosterol, suggesting that cinnamaldehyde may act on the cell membrane, which was subsequently confirmed by docking analysis. The action of cinnamaldehyde likely includes binding to enzymes involved in the formation of the cytoplasmic membrane in yeast cells. Cinnamaldehyde-treated microcultures showed impaired cellular development, with an expression of rare pseudo-hyphae and absence of chlamydoconidia. Cinnamaldehyde reduced biofilm adherence by 64.52% to 33.75% (p < 0.0001) at low concentrations (378.3-151.3 µM). Cinnamaldehyde did not show antioxidant properties. CONCLUSIONS: Cinnamaldehyde showed fungicidal activity through a mechanism of action likely related to ergosterol complexation; it was non-cytotoxic to keratinocytes and human erythrocytes and showed no antioxidant activity.

Brazilian red propolis reduces orange-complex periodontopathogens growing in multispecies biofilms.

This study investigated the antimicrobial effects of the ethanolic extract of Brazilian red propolis (BRP) on multispecies biofilms. A seven-day-old subgingival biofilm with 32 species was grown in a Calgary device. Biofilms were treated with BRP (1,600, 800, 400 and 200 µg ml-1) twice a day for 1 min, starting from day 3. Chlorhexidine (0.12%) and dilution-vehicle were used as positive and negative controls, respectively. On day 7, metabolic activity and the microbial composition of the biofilms by DNA-DNA hybridization were determined. The viability data were analyzed by one-way ANOVA followed by Tukey's post hoc, whereas the microbial composition data were transformed via BOX-COX and analyzed using Dunnett's post hoc. BRP (1,600 µg ml-1) decreased biofilm metabolic activity by 45%, with no significant difference from chlorhexidine-treated samples. BRP (1,600 µg ml-1) and chlorhexidine significantly reduced levels of 14 bacterial species compared to the vehicle control. Taken together, BRP showed promising antimicrobial properties which may be useful in periodontal disease control.

Antimicrobial activity of nitrochalcone and pentyl caffeate against hospital pathogens results in decreased microbial adhesion and biofilm formation.

The present study investigated the antimicrobial, anti-adhesion and anti-biofilm activity of the modified synthetic molecules nitrochalcone (NC-E05) and pentyl caffeate (C5) against microorganisms which have a high incidence in hospital-acquired infections. The compounds were further tested for their preliminary systemic toxicity in vivo. NC-E05 and C5 showed antimicrobial activity, with minimum inhibitory concentrations (MICs) ranging between 15.62 and 31.25 µg ml-1. Treatment with NC-E05 and C5 at 1 × MIC and/or 10 × MIC significantly reduced mono or mixed-species biofilm formation and viability. At MIC/2, the compounds decreased microbial adhesion to HaCaT keratinocytes from 1 to 3 h (p < 0.0001). In addition, NC-E05 and C5 demonstrated low toxicity in vivo in the Galleria mellonella model at anti-biofilm concentrations. Thus, the chemical modification of these molecules proved to be effective in the proposed anti-biofilm activity, opening opportunities for the development of new antimicrobials.

Diacetylcurcumin: a new photosensitizer for antimicrobial photodynamic therapy in Streptococcus mutans biofilms.

This study evaluated the effect of antimicrobial photodynamic therapy (aPDT) on S. mutans using diacetylcurcumin (DAC) and verified DAC toxicity. In vitro, S. mutans biofilms were exposed to curcumin (CUR) and DAC and were light-irradiated. Biofilms were collected, plated and incubated for colony counts. DAC and CUR toxicity assays were conducted with Human Gingival Fibroblast cells (HGF). In vivo, G. mellonella larvae were injected with S. mutans and treated with DAC, CUR and aPDT. The hemolymph was plated and incubated for colony counts. Significant reductions were observed when DAC and CUR alone were used and when aPDT was applied. HGF assays demonstrated no differences in cell viability for most groups. DAC and CUR reduced the S. mutans load in G. mellonella larvae both alone and with aPDT. Systematic toxicity assays on G. mellonella demonstrated no effect of DAC and CUR or aPDT on the survival curve.

Effect of TiF4 varnish on microbiological changes and caries prevention: in situ and in vivo models.

OBJECTIVE: The aim of this study was to evaluate microbiological changes, oral soft tissue toxicity, and caries-preventive effect of an experimental titanium tetrafluoride (TiF4) varnish compared with a commercially available fluoride varnish (NaF), using in situ and in vivo models. MATERIALS AND METHODS: The treatment groups were the following: TiF4 varnish (experimental varnish), Duraphat® (fluoride positive control), placebo varnish (no fluoride), and no treatment (negative control). The varnishes were applied once over the enamel surface using a microbrush. For the in vivo study, 48 Wistar rats were infected with Streptococcus sobrinus 6715, received a treatment, and were submitted to a cariogenic challenge. After 4 weeks, S. sobrinus, oral soft tissue toxicity, presence, and severity of caries were evaluated. For the in situ study, 12 volunteers took part in this randomized crossover, double-blind study performed in four phases of 14 days each. They used intraoral appliances containing four enamel specimens that received the varnish according treatment group. After 24 h, the varnish was removed and plaque accumulation was allowed. A 20% sucrose solution was dripped over the enamel blocks (10×/day for 5 min each). Total streptococci, S. mutans, Lactobacillus, Candida spp. counts, and presence of white spot lesions were evaluated. Lesion depth was also quantified by micro-CT. RESULTS: For the in vivo study, the fluoride (F-varnishes) showed a statistically significant reduction in the percentage of S. sobrinus compared to the negative control (p < 0.05). Toxicological analysis revealed no abnormalities in oral tissues of rats from all groups, and both F-varnishes reduced the number and severity of caries lesions, without significant differences (p < 0.05). No statistical differences in microbiological counts were seen for the in situ experiment (p > 0.05). However, the specimens treated with TiF4 exhibited lower percentage of white spot lesions and the lesion depth was significantly reduced by F-varnishes (p < 0.05). CONCLUSIONS: F-varnishes showed reduction in the percentage of S. sobrinus in vivo, no oral soft tissue toxicity, and a caries-preventive effect in vivo and in situ. CLINICAL RELEVANCE: NaF varnish is largely used due its capacity to form CaF2-like layer on enamel. Therefore, development of studies focused on other fluoride compounds such as a TiF4 varnish, which may have greater efficacy than NaF against tooth demineralization, is important.

Candida auris: Epidemiology, risk factors, virulence, resistance, and therapeutic options.

Candida auris emerged as a pathogen resistant to multiple antifungal and has been associated with nosocomial outbreaks with high transmission capacity between hospitalized individuals. C. auris was first described in 2009, after being isolated from the external ear canal discharge of a patient in Japan. The difficulty in identification, incorrect use of antifungal drugs, and treatment failure are causes of high mortality. Since then, C. auris has been increasingly reported from East Asia to North America, with substantial fatalities and misidentification. This review aims at describing the epidemiology, virulence, risk factors, resistance, and therapeutic options in C. auris infections.

Isoflavonoids from Brazilian red propolis down-regulate the expression of cancer-related target proteins: A pharmacogenomic analysis.

Vestitol and neovestitol are bioactive isoflavonoids isolated from Brazilian red propolis, a unique Apis melifera type of propolis botanically originated from Dalbergia ecastophyllum. Although these molecules have relevant biological effects, including anticancer and immunomodulatory activities, their mechanism(s) of action and the affected pathways remain largely unknown. Here, we carried out a pharmacogenomic analysis to investigate the effects of vestitol and neovestitol on the whole-genome expression in human tumor cells, particularly cancer-related target proteins. HeLa cells were exposed to the compounds at IC20 and genomic information of treated cells was analyzed using the Illumina transcriptome system and GeneGo MetaCore software. Our results showed that vestitol (IC20  = 214.7 µM) reduced the expression of genes enrolled with the alpha tubulin (fold -3.7), tubulin in microtubules (fold -3.7), and histone h3 (fold = -3.03), and that treatment with neovestitol (IC20  = 102.91 µM) downregulated prostaglandin E synthase gene (fold = -3.12), which are considered ideal targets for anticancer therapy. These data open avenues for the study of vestitol and neovestitol as potential promising candidates for anticancer therapy. Toxicological, non-clinical, and clinical validation of the findings presented herein is needed.

Biological response to self-etch adhesive after partial caries removal in rats.

OBJECTIVES: The purposes of this study were to evaluate a model of slow caries progression and to investigate the performance of a self-etch adhesive system for partial caries removal. MATERIALS AND METHODS: Rat molars were infected with Streptococcus sobrinus 6715 culture. Different time points were analyzed: days 78, 85, and 95 (± 2). After this, the samples were processed for morphological analysis. Additionally, the first molars were restored with zinc oxide and eugenol (IRM™; Dentsply; Brazil) or adhesive system (Clearfil SE Bond™; Kuraray Medical; Japan) 78 days after caries induction. After, 3 or 15 days post-treatment, the animals were euthanized, and their mandibles were processed for morphological analysis, classified by means of scores, and submitted to statistical analysis. Subsequently, immunohistochemical analysis was performed for osteonectin (OSN) and transforming growth factor-ß1 (TGF-ß1) expression. RESULTS: According to the caries induction model used, on day 95 greater inflammatory infiltration (p < 0.001), and more extensive degradation of secondary/primary dentin were demonstrated than on day 78 (p < 0.05). Furthermore, the restorative materials presented similar performance (p > 0.05) and proved to be fundamental to control the carious lesion. The TGF-ß1 and OSN were shown to be active during the caries process. CONCLUSIONS: The slow caries lesion model was feasible for morphological analysis of the dentin-pulp complex. The self-etch adhesive system triggered no acute inflammatory infiltration or pulp necrosis, instead it seemed to stimulate early pulp repair. CLINICAL RELEVANCE: Clearfil SE Bond™ applied directly on caries-affected dentin did not predispose to pulp inflammation; instead, it appeared to provide early biological benefits.

Unexplored endemic fruit species from Brazil: Antibiofilm properties, insights into mode of action, and systemic toxicity of four Eugenia spp.

Brazilian endemic fruit species have aroused attention due to their highly valuable, yet unexplored, agro-industrial, food and therapeutic potential. Herein, we describe the antifungal activity of four Eugenia spp. against Candida albicans biofilms, and further demonstrate insights into their potential mode(s) of action and toxicity in vitro and in vivo. Extracts from different parts (seeds, pulps, leaves) of E. leitonii (EL), E. brasiliensis (EB), E. myrcianthes (EM) and E. involucrata (EI) were obtained (S23°23',W45°39') and chemically characterized by GC/MS. The active extracts were tested against C. albicans biofilm viability and architecture, as well as mode of action, and toxicology using RAW 264.7 macrophages and Galleria mellonella larvae. The MIC values ranged from 15.62 to >2000 µg/mL. The most active extracts were EL (seed, 15.62 µg/mL) and EB (leaf and seeds, 31.25 and 15.62 µg/mL, respectively). Treatment with these extracts at 10xMIC reduced biofilm viability by 54-55% (P < 0.0001) as compared to 42% by nystatin. At 10xMIC, all extracts caused damages to biofilm architecture and integrity, and fewer hyphae remained attached to treated biofilms. None of them was found to interfere with cell wall biosynthesis or complexation with ergosterol. The extracts had low toxicity against macrophages in vitro (P > 0.05) and G. mellonella larvae, with mean in vivo LD50 of 1500 mg/kg (EL, seeds); 2500 mg/kg (EB, seeds); and 1250 mg/kg (EB, leaf). The phenolic compounds epicatechin and gallic acid were the major constituents in the extracts. Our findings may open avenues for the application of these yet unexplored native fruits in the food and pharmaceutical industry.

Alternative Animal and Non-Animal Models for Drug Discovery and Development: Bonus or Burden?

Mammalian models have served as a basis for R&D over the past decades. Nevertheless, these models are expensive, laborious, may yield results that cannot always be translated into the human in vivo situation and, more recently, have reverberated great social and ethical dilemmas. Hence, the prospect of changes in the global scientific scenario and the Three Rs principle (Reduction, Replacement and Refinement) have encouraged the development of alternative methods to the use of mammals. Despite the efforts, suitable alternative tests are not available in all areas of biomedical research, as regulatory acceptance requires time, prior validation and robust financial and scientific investment. In this perspective, we aim to shed light on the concepts, challenges and perspectives for implementation of innovative alternative animal and non-animal methods in scientific research. The applicability and meaningfulness of invertebrate animal models, in silico analysis and reverse pharmacology are discussed, among other aspects of relevance in today's scenario. Overall, the use of alternative models, including Artemia salina (brine shrimp), Caenorhabditis elegans (roundworm), Danio rerio (zebra fish), Drosophila melanogaster (fruit fly), Galleria mellonella (greater waxmoth) and in silico modelling, increased 909% from 1990 to 2015, as compared to 154% of conventional mammals in the same period. Thus, technological and scientific advancements in the fields of toxicology and drug development seem to have diminished the need for mammalian models. Today, however, mammals still remain critically indispensable to provide - in most cases -reliable data subsidizing and validating translation into the clinical setting.