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The Inga genus comprises approximately 300 species that can be found from Mexico to northern Argentina. In folk medicine, Inga species are used to treat various diseases. The species Inga laurina is widely found in the Brazilian flora; however, there are few studies about its biological activity and chemical composition. The main purpose of this study was to identify and isolate the chemical constituents of Inga laurina barks and to evaluate the antifungal and cytotoxic activities. The total content of phenolics, proanthocyanidins, and flavonoids from the barks of Inga laurina were performed by spectrophotometric methods and the ethyl acetate (EAF) and n-butanol (BF) fractions showed the best results. Eleven compounds were identified in EAF by HPLC-ESI(−)-MS/MS, which showed good antifungal activity with MIC values of 23.4 and 46.8 μg mL−1, evaluated by broth microdilution method. Five new compounds of the genus Inga were isolated for the first time. Three of these compounds were isolated and reported on the literature for the first time: a proanthocyanidin B-type, gallocatechin-(4α→8)-4’-O-methylgallocatechin (XI) and two proanthocyanidins A-type, gallocatechin-(2→O→7,4→8)-4’-O-methylgallocatechin (XII) and gallocatechin-3-O-galloyl-(2→O→7,4→8)-4’-O-methylgallocatechin (XIII). The chemical study of the plant bark showed that this species is rich in phenolic compounds and it has great potential for the discovery of new bioactive compounds.

Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize substances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octadecanoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol.

This updated review article covers the literature between 2011 and 2021 on the antibacterial activity of EOs against the main bacteria that cause caries and periodontal diseases. The criteria to classify the in vitro antibacterial activity of EOs is updated and the most promising results are addressed.

Araticum is an edible and appreciable fruit of

Interest in researches into medicinal plants and therapeutic effects of essential oils (EOs) on humans has increased over the last few years. Eremanthus erythropappus, known as candeia, is a Brazilian aromatic herbaceous plant whose α-bisabolol-rich oil has been used in several cosmetic preparations. This paper reports in vitro anticaries, antimycobacterial, antileishmanial and cytotoxic activities of EOs from E. erythropappus leaves (EL-EO) and stalks (ES-EO), besides α-bisabolol, their main sesquiterpene. EL-EO and ES-EO were extracted by hydrodistillation and analyzed by GC-FID and GC-MS. α-Bisabolol, cis-α-bisabolene and β-bisabolene were identified as their major constituents. Antibacterial activity of EOs was evaluated against eight standard strains of pathogens from the American Type Culture Collection (ATCC) by determining minimum inhibitory concentrations (MICs) with the use of the microdilution method. Antibacterial activity was evaluated against Streptococcus mutans, S. mitis, S. sanguinis, S. sobrinus, S. salivarius, Mycobacterium tuberculosis, M. avium and M. kansasii. EL-EO, ES-EO and α-bisabolol exhibited high leishmanicidal activity against promastigote forms of Leishmania amazonensis; IC50 values were 9.22 µg/mL, 6.00 µg/mL and 3.12 µg/mL, respectively. The 50% cytotoxic concentrations (CC50) of EL-EO, ES-EO and α-bisabolol against mouse peritoneal macrophages were 24.65 µg/mL, 8.87 µg/mL and 1021.00 µg/mL, respectively. These results suggest that EOs from E. erythropappus seem to be very promising for the development of new bactericidal and leishmanicidal agents.

This study aims to investigate chemical composition of essential oils from Murraya paniculata (L.) Jack (Rutaceae) ripe and unripe fruits and determine their in vitro antibacterial activity. Essential oils were extracted by hydrodistillation from Murraya paniculata (L.) Jack ripe and unripe fruits collected in the Cerrado, in Rio Verde, southwestern Goiás, Brazil. They were analyzed by gas chromatography with flame ionization detector (GC-FID) and by gas chromatography-mass spectrometry (GC-MS). Sesquiterpenes, which represent the most abundant class of compounds in oils, predominated in both ripe and unripe fruits. Major constituents of essential oils extracted from ripe fruits (RF-EO) were (-caryophyllene (21.3%), (-ylangene (13.3%), germacrene-D (10.9%) and (-zingiberene (9.7%) whereas the ones of unripe fruits (UF-EO) were sesquithujene (25.0%), (-zingiberene (18.2%), germacrene-D (13.1%) and (-copaene (12.7%). In vitro antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both essential oils under investigation showed moderate anti-streptococcal activity against the following bacteria: Streptococcus mutans, S. mitis, S. sanguinis, S. sobrinus and S. salivarius. MIC values ranged between 100 and 400 µg/mL. Regarding the antimycobacterial activity, essential oils from M. paniculata (L.) Jack unripe and ripe fruits were active against Mycobacterium kansasii (MIC = 250 µg/mL), moderately active against M. tuberculosis (MIC = 500 µg/mL) and inactive against M. avium (MIC = 2000 µg/mL). This study was pioneer in revealing similar chemical profiles of both essential oils extracted from Murraya paniculata (L.) Jack unripe and ripe fruits, besides describing their in vitro anti-streptococcal and antimycobacterial activities.

Araticum is an edible and appreciable fruit of Annona coriacea, which is popularly known as a traditional herb in the Brazilian cerrado. A phytochemical study from the leaves of A. coriacea showed that HPLC-ESI-Q-Orbitrap® provided through PRM experiments (MS2) is an efficient method for the fast and accurate analysis of a complex mixture of annonaceous acetogenins, with the identification of sylvaticin and gigantetrocin-A type acetogenins for the first time. In addition, the crude leaf extract and acetogenin-rich fractions were assayed against Streptococcus mutans, S. mitis, S. sanguinis and S. salivarius strains, which are usually related to oral infections.

The 2-acetylpyridine-ethylcarbazate ligand (HL) formed four metal complexes, [Cu(HL)Cl2]⋅H2O (1), [Cu(HL)Br2]⋅H2O (2), [Zn(HL)Cl2] (3) and [Ni(L)2]⋅H2O (4). The carbazate and their metal complexes have been investigated by single crystal X-ray analysis, physicochemical, and spectroscopic methods. The Schiff base is coordinated to the metal ions as an anionic bi or tridentate ligand with the Z configuration about the imine C = N at the carbazate. Interactions in the crystal structures were analyzed using Hirshfeld surfaces and the 2D-fingerprint plots. Complexes 1, 2, and 3 present π⋅⋅⋅π stacking between the pyridyl rings with inter-centroid separations of 3.664(3)–3.887(2) Å. The water solvent molecules and the halogens allow the formation of intramolecular hydrogen bonds which close supramolecular structures in the molecular packing of the complexes. Free HL and 1–4 have been evaluated for antibacterial and antifungal activity against several multi-resistant bacteria and fungi. Significant antimicrobial activity of the complexes was observed; however, the free ligand and its complexes did not reveal any activity against some of the tested organisms.

In Brazilian folk medicine, Protium heptaphyllum is used to treat inflammatory conditions and to hasten wound repair. This paper aims to investigate the chemical composition and the in vitro antiba...

Two novel silver(I) complexes with the antibacterial sulfa drugs mafenide (Maf) and ethyl-mafenide (eMaf) are presented in this article. Elemental analysis indicated the 1:1 metal:ligand compositions AgC7H9N2O2S for Ag-Maf and AgC8H11N2O2S for Ag-eMaf. Infrared (IR), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopic analyses indicated coordination of the sulfa drugs to silver(I) by the nitrogen and oxygen atoms of the deprotonated sulfonamide (SO2NH) group in a bidentate chelate mode. The proposition of the coordination mode of the sulfa drugs to silver(I) was also supported by a combination of experimental and theoretical (DFT) data. The Ag-Maf and Ag-eMaf complexes exhibited antibacterial activity over Staphylococcus aureus, Burkholderia cepacia, Staphylococcus epidermidis, and Pseudomonas aeruginosa aerobic bacteria, with MIC (minimum inhibitory concentration) in the range 21.3–170 µmol L−1, being comparable to the commercial drug silver-sulfadiazine (SSD). Antiviral studies against Chikungunya virus (CHIKV) showed that the complexes exhibit anti-CHIKV activity at non-cytotoxic concentrations to the host cells. Biophysical studies based on gel electrophoresis indicated that the complexes do not interact with albumin and lysozyme, which suggests that proteins are not the main targets of the compounds.

In Mozambique, a large part of the population depends on plants for the treatment of various diseases. However, some of them have been little studied in relation to chemical and biological aspects. Among these species, Ozoroa obovata is widely used in traditional medicine in Mozambique. The factors that influence the use of medicinal plants in developing countries are mainly cultural habits, the inefficiency of the health system and the high cost of medicines. This work aimed to study the chemical composition and evaluate the antimicrobial activity of the twigs of O. obovata. Through the analysis by liquid chromatography coupled to mass spectrometry with electrospray ionization (HPLC-MS-ESI), it was possible to propose that in the ethanolic extract of the twigs, most of the constituents belong to the classes of phenolic acids and flavonoid. The phenolic compounds were represented by quinic, gallic and protocatechuic acids and five anacardic acids, whereas flavonoids were represented by mangiferin, taxifolin and quercetin mono and dihexoside. The extract was evaluated against bacteria in the oral cavity and showed moderate activity against Streptococcus mutans, S. mitis and Porphyromonas gingivalis (minimum inhibitory concentration - MIC 400 µg mL –1 ). In relation antifungal test, the extract showed activity against Candida albicans with MIC of 3000 µg mL –1 . The biological results indicated that the twigs of O. obovata have bioactive metabolites with antimicrobial potential.

The microorganisms that constitute the oral microbiome can cause oral diseases, including dental caries and endodontic infections. The use of natural products could help to overcome bacterial resistance to the antimicrobials that are currently employed in clinical therapy. This study assessed the antimicrobial activity of the Copaifera pubiflora oleoresin and of the compounds isolated from this resin against oral bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays provided values ranging from 6.25 to > 400 μg/mL for the C. pubiflora oleoresin and its isolated compounds. The fractional inhibitory concentration index (FICI) assay showed that the oleoresin and chlorhexidine did not act synergistically. All the tested bacterial strains formed biofilms. MICB50 determination revealed inhibitory action: values varied from 3.12–25 μg/mL for the oleoresin, and from 0.78 to 25 μg/mL for the ent-hardwickiic acid. Concerning biofilm eradication, the C. pubiflora oleoresin and hardwickiic acid eradicated 99.9 % of some bacterial biofilms. Acid resistance determination showed that S. mutans was resistant to acid in the presence of the oleoresin and ent-hardwickiic acid at pH 4.0, 4.5, and 5.0 at all the tested concentrations. Analysis of DNA/RNA and protein release by the cell membrane demonstrated that the oleoresin and hardwiickic acid damaged the bacterial membrane irreversibly, which affected membrane integrity. Therefore, the C. pubiflora oleoresin and ent-hardwickiic acid have potential antibacterial effect and can be used as new therapeutic alternatives to treat oral diseases such as dental caries and endodontic infections.

The present study reports the synthesis and characterization of six Cu(II) and Zn(II) complexes with 2-cetylpyridinenicotinichydrazone (HL). The characterization of the complexes were applied by conductivity measurements and spectroscopic techniques (FT-IR, UV–Vis, ESI(+)-MS and NMR 1H). Four complexes have been studied by single crystal X-ray diffraction, [Cu(L)2] (1), [Zn(L)2] (2), [CuCl2(HL)] (3) and [CuBr2(HL)] (4). Important interactions upon the molecular packing were also performed by the analysis of their Hirshfeld surfaces and compared to the 2D-fingerprint plots. The characterizations indicates the formation of mononuclear Cu(II) and Zn(II) complexes with the hydrazone ligand coordinated to the metal ions in tridentate mode through the NNO chelating system. The antibacterial activity of HL and its metal complexes was tested against cariogenic bacteria strains.

In Brazilian folk medicine

The oral cavity, which harbors more than 750 bacterial species, is one of the most diverse sites of the human body. Some of these bacteria have been associated with oral diseases, such as dental caries and endodontic infections. We report on the antimicrobial and cytotoxic activities of Copaifera oblongifolia oleoresin against bacteria that cause caries and endodontic infections. The aim of this study is to determine the minimum (MIC) and the bactericidal (MBC) inhibitory concentrations as well as the biofilm inhibition ability (through determination of MBIC 50 ) of the C. oblongifolia oleoresin. This study also investigated the bactericidal kinetics (time-kill curves) and the synergistic effect of the C. oblongifolia oleoresin. Additionally, this study evaluated the cytotoxic activity of the oleoresin toward V79 cells by means of the colony-forming assay. The C. oblongifolia oleoresin gave promising MIC and MBC values, which ranged from 25 to 200 μg/mL. Analysis of the MBIC 50 values of the oleoresin revealed it displayed biofilm inhibitory activity against all the assayed bacteria. Analysis of the bactericidal kinetics showed different behaviors of the oleoresin against the tested bacteria at the different time intervals and concentrations assayed in this study. An additive effect of the oleoresin with chlorhexidine dihydrochloride occurred only for S. mitis and A. actinomycetemcomitans. The C. oblongifolia oleoresin showed cytotoxic activity at concentrations ≥ 625 μg/mL.

Tooth decay is a major public health problem which affects a large number of people in several countries. Even though more than 700 bacterial species have been detected in the oral cavity, Streptococcus and Lactobacillus stand out as the genera that cause tooth decay and other periodontal diseases. In this study, essential oils from Citrus aurantifolia leaves (CL-EO) and fruit peel (CP-EO) were obtained by hydrodistillation by a Clevenger-type apparatus whereas their chemical composition was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Limonene (77.5 %), linalool (20.1 %), citronellal (14.5 %) and citronellol (14.2 %) were the main constituents found in the essential oils from C. aurantifolia leaves and fruit peel. Antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both CL-EO and CP-EO displayed some activity against all oral pathogens under investigation; MIC values ranged from 20 to 200 µg/mL. CL-EO and CP-EO not only had promising activity against Streptococcus mutans (MIC = 20 µg/mL) and Lactobacillus casei (31.25 µg/mL), but also displayed antibacterial activity against all studied cariogenic bacteria. Efficacy of essential oils against S. mutans and L. casei is noteworthy and should be further investigated.

Xylella fastidiosa is a plant-pathogenic bacterium that lives inside host xylem vessels, where it forms biofilm which is believed to be responsible for disrupting the passage of water and nutrients. Pectobacterium carotovorum is a Gram-negative plant-specific bacterium that causes not only soft rot in various plant hosts, but also blackleg in potato by plant cell wall degradation. Chagas disease, which is caused by Trypanosoma cruzi, has been commonly treated with nifurtimox and benzonidazole, two drugs that cause several side effects. As a result, the use of natural products for treating bacterial and neglected diseases has increased in recent years and plants have become a promising alternative to developing new medicines. Therefore, this study aimed to determine, for the first time, the chemical composition of essential oil from Psidium guajava flowers (PG-EO) and to evaluate its in vitro anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi and cytotoxic activities. PG-EO was obtained by hydrodistillation in a Clevenger apparatus while its chemical composition was determined by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Major compounds identified in PG-EO were α-cadinol (37.8%), β-caryophyllene (12.2%), nerolidol (9.1%), α-selinene (8.8%), β-selinene (7.4%) and caryophyllene oxide (7.2%). Results showed that the PG-EO had strong trypanocidal activity against the trypomastigote forms of Trypanosoma cruzi (IC50 = 14.6 μg/mL), promising antibacterial activity against X. fastidiosa (MIC = 12.5 μg/mL) and P. carotovorum (MIC = 62.5 μg/mL), and moderate cytotoxicity against LLCMK2 adherent epithelial cells in the concentration range (CC50 = 250.5 μg/mL). In short, the PG-EO can be considered a new source of bioactive compounds for the development of pesticides and trypanocide drugs. Resumo Xylella fastidiosa é uma bactéria patogênica que vive dentro dos vasos do xilema hospedeiro, onde forma um biofilme responsável por interromper a passagem de água e nutrientes. Pectobacterium carotovorum é uma bactéria Gram-negativa que causa não só podridão macia em várias plantas hospedeiras, mas também canela-preta na batata por degradação da parede celular da planta. A doença de Chagas, causada pelo Trypanosoma cruzi, é comumente tratada com nifurtimox e benzonidazol, duas drogas que causam vários efeitos colaterais. Como resultado, o uso de produtos naturais para o tratamento de doenças bacterianas e negligenciadas aumentou nos últimos anos e as plantas continuam sendo uma alternativa promissora para o desenvolvimento de novos medicamentos. Portanto, este estudo teve como objetivo determinar, pela primeira vez, a composição química do óleo essencial de flores de Psidium guajava (PG-EO) e avaliar suas propriedades anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi e citotóxica in vitro. PG-EO foi obtido por hidrodestilação em um aparelho Clevenger, enquanto sua composição química foi determinada por cromatografia em fase gasosa com detecção por ionização por chama (CG-DIC) e por cromatografia em fase gasosa acoplada à espectrometria de massa (CG-EM). Os principais compostos identificados no PG-EO foram α-cadinol (37,8%), β-cariofileno (12,2%), nerolidol (9,1%), α-selineno (8,8%), β-selineno (7,4%) e óxido de cariofileno (7,2%). Os resultados mostraram que o PG-EO apresentou forte atividade tripanocida contra as formas tripomastigotas de T. cruzi (CI50 = 14,6 μg/mL), promissora atividade antibacteriana contra X. fastidiosa (MIC = 12,5 μg/mL) e P. carotovorum (MIC = 62,5 μg/mL) e citotoxicidade moderada contra células epiteliais aderentes (LLCMK2) na faixa de concentração (CC50 = 250,5 μg/mL). Em suma, o PG-EO pode ser considerado uma nova fonte de compostos bioativos para o desenvolvimento de pesticidas e drogas tripanocidas.