The efficacy of extracts and essential oils from Allium tuberosum, Coriandrum sativum, Cymbopogon martini, Cymbopogon winterianus, and Santolina chamaecyparissus was evaluated against Candida spp. isolates from the oral cavity of patients with periodontal disease. The most active oil was fractionated and tested against C. albicans biofilm formation. The oils were obtained by water‐distillation and the extracts were prepared with macerated dried plant material. The Minimal Inhibitory Concentration—MIC was determined by the microdilution method. Chemical characterization of oil constituents was performed using Gas Chromatography and Mass Spectrometry (GC‐MS). C. sativum activity oil upon cell and biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). The best activities against planktonic Candida spp. were observed for the essential oil and the grouped F_8–10 fractions from C. sativum. The crude oil also affected the biofilm formation in C. albicans causing a decrease in the biofilm growth. Chemical analysis of the F_8–10 fractions detected as major active compounds, 2‐hexen‐1‐ol, 3‐hexen‐1‐ol and cyclodecane. Standards of these compounds tested grouped provided a stronger activity than the oil suggesting a synergistic action from the major oil constituents. The activity of C. sativum oil demonstrates its potential for a new natural antifungal formulation.

PARP14 and PARP9 play a key role in macrophage immune regulation. SARS‐CoV‐2 is an emerging viral disease that triggers hyper‐inflammation known as cytokine storm. In this study, using in silico tools, we hypothesize about the immunological phenomena of molecular mimicry between SARS‐CoV‐2 Nsp3 and the human PARP14 and PARP9. The results showed an epitope of SARS‐CoV‐2 Nsp3 protein that contains consensus sequences for both human PARP14 and PARP9 that are antigens for MHC class 1 and 2, which can potentially induce an immune response against human PARP14 and PARP9; while its depletion causes a hyper‐inflammatory state in SARS‐CoV‐2 patients.

Periodontal disease afflicts 20% of world population. This process usually occurs in the form of being lethargic and chronic, and consequently this disease is known as chronic process. All chronic diseases constantly cause activation of the immune system, and therefore the presentation of microbial peptides which are presented to lymphocytes by professional antigen presenting cells can present microbial peptides very similar to important structures of human economy causing autoimmune diseases, process known as molecular mimicry. Thus, the aim of this study was to verify the presence of molecular mimicry phenomenon between periodontopathogens and human proteins. Blasting microbes of Socransky periodontal complexes against human collagen were performed and then the proteins with similarities were modelled and were screened in the MHI binding virtual methods. The epitopes selected were produced and plasma of chronic periodontal volunteers was obtained and a dot immunobinding assay was performed. Hypothetical protein ofPrevotellasp. and human collagen epitopes with high similarities were positive for dot immunobinding assay. With this result it can be suggested that the mimicry phenomena can occur on periodontal disease.

Oral microbiome possesses more than 1000 microbial species that co-exist with human oral cavity. However, when there is an imbalance in microbial ecosystem, infection and inflammation occurs. Chronic inflammation produces constant antigen-cell presentation and reactivity T and B cell results in an adaptive immune response with high specificity cell-cell and antibody response producing an autoimmune disease by molecular mimicry. In this chapter, using just BLAST, shows self-epitopes (autoantigens) from different autoimmune diseases such as Systemic lupus erythematosus, Sjögren’s syndrome, neuromyelitis optica, Stiff-Person syndrome, autoimmune diabetes, autoimmune thyroiditis, myasthenia gravis, autoimmune gastritis, autoimmune hepatitis, myositis and rheumatoid arthritis that possess similarities with microbial epitopes belonging to oral microbiome acting has a computer trojan occult in a software package.

In this work we describe the isolation of a new isoform L-amino acid oxidase (LAAO) referred to as Balt-LAAO-II fromBothrops alternatussnake venom, which was highly purified using a combination of molecular exclusion (Sephadex G-75) and RP-HPLC chromatographics steps. When analyzed by SDS-PAGE, the purified Balt-LAAO-II presented a molecular weight of ∼66 kDa. The N-terminal amino acid sequence and internal peptide sequences showed close structural homology to other snake venom L-amino acid oxidases.This enzyme inducesin vitrocytotoxicity on cultured human leukemic HL60 cells. Cells were grown in RPMI medium and were incubated with isoform Balt-LAAO-II (1, 10 and 100 μg/mL) for up to 72 h. All three concentrations of venom markedly decreased the cell viability from 6 h onwards based on the staining with propidium iodide, the reduction of 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and the uptake of neutral red.Flow cytometry showed that all isoform Balt-LAAO-II and whole venom concentrations induced apoptosis after 2-6 h of incubation. Morphological analysis of cells incubated with isoform Balt-LAAO-II and whole venom showed cell rounding and lysis that increased with the venom concentration and duration of incubation. These results show that isoform Balt-LAAO-II from venomBothrops alternatusis cytotoxic to cultured HL60 cells and suggest that this damage may involve apoptotic and oxidative stress pathways.