Antibacterial activity of Myrciaria dubia (Camu camu) against Streptococcus mutans and Streptococcus sanguinis

Emerging berries from the Brazilian Amazon and Atlantic Forest biomes: new sources of bioactive compounds with potential health benefits

Brazil has a broad geographic biodiversity spread across its six different biomes. However, it has been suffering from the abusive exploitation of its resources, which poses a threat to the local fauna and flora. The Amazon and Atlantic Forest, for example, are birthplaces to rare and edible native species, such as bacaba (Oenocarpus bacaba, Arecaceae) and camu-camu (Myrciaria dubia, Myrtaceae), and cereja-do-Rio Grande (Eugenia involucrata, Myrtaceae) and grumixama (Eugenia brasiliensis, Myrtaceae), respectively. These plants produce fruits which are sources of macro and micronutrients, including sugars, dietary fibers, vitamins, minerals, and/or lipids. Nutritionally, their consumption have the ability to reach partially or totally the daily recommendations for adults of some nutrients. More recently, these fruits have also been exposed as interesting sources of minor bioactive compounds, such as carotenoids, terpenes, and/or polyphenols, the latter which include anthocyanins, phenolic acids, and tannins. Particularly, bacaba stands out for being a rich source of polyunsaturated fatty acids (around 22%, dry weight) and dietary fibers (6.5-21%, dry weight); camu-camu has very high contents of vitamin C (up to 5000 mg per 100 g of pulp, dry basis); and cereja-do-Rio-Grande and grumixama are abundant sources of anthocyanins. Although they are still underexplored, several in vitro and in vivo studies with different parts of the fruits, including the peel, seed, and pulp, indicate their health potential through anti-oxidative, anti-obesity, antihyperglycemic, antidyslipidemic, antimicrobial, and/or anticancer effects. All things considered, the focus of this research was to highlight the bioactive potential and health impact of native fruits from the Amazon and Atlantic Forest biomes.

Camu-camu [Myrciaria dubia (HBK) McVaugh]: A review of properties and proposals of products for integral valorization of raw material

This review aims to evaluate the production and processing chain of camu-camu (Myrciaria dubia), giving suggestions to maximize the valorization of raw materials, demonstrating new product possibilities from processing to distribution and highlighting the suggested contributions. It is clear that despite the camu-camu pulp has important properties, a large part of its raw material, considered waste (around 50%) and formed by important bioactive compounds, can give rise to new products, such as bioactive extracts to be used by pharmaceutical, chemical and food industries, ingredients for bakery products, dairy and several others sectors, which constitutes opportunities, in addition to contributing to the reduction of agro-industrial waste and the preservation of the environment.

Bio-Mechanism of Catechin as Pheromone Signal Inhibitor: Prediction of Antibacterial Agent Action Mode by In Vitro and In Silico Study

The utilization of medicinal plants has long been explored for the discovery of antibacterial agents and the most effective mechanisms or new targets that can prevent and control the spread of antibiotic resistance. One kind of bacterial cell wall inhibition is the inactivation of the MurA enzyme that contributes to the formation of peptidoglycan. Another approach is to interfere with the cell–cell communication of bacteria called the Quorum sensing (QS) system. The blocking of auto-inducer such as gelatinase biosynthesis-activating pheromone (GBAP) can also suppress the virulence factors of gelatinase and serine protease. This research, in particular, aims to analyze lead compounds as antibacterial and anti-QS agents from Gambir (Uncaria gambir Roxburgh) through protein inhibition by in silico study. Antibacterial agents were isolated by bioactivity-guided isolation using a combination of chromatographic methods, and their chemical structures were determined by spectroscopic analysis methods. The in vitro antibacterial activity was evaluated by disc diffusion methods to determine inhibitory values. Meanwhile, in the in silico analysis, the compound of Uncaria gambir was used as ligand and compared with fosfomycin, ambuic acid, quercetin, and taxifolin as the standard ligand. These ligands were attached to MurA, GBAP, gelatinase, and serine proteases using Autodock Vina in PyRx 0.8 followed by PYMOL for combining the ligand conformation and proteins. plus programs to explore the complex, and visualized by Discovery Studio 2020 Client program. The antibacterial agent was identified as catechin that showed inhibitory activity against Enterococcus faecalis ATCC 29212 with inhibition zones of 11.70 mm at 10%, together with MIC and MBC values of 0.63 and 1.25 μg/mL, respectively. In the in silico study, the molecular interaction of catechin with MurA, GBAP, and gelatinase proteins showed good binding energy compared with two positive controls, namely fosfomycin and ambuic acid. It is better to use catechin–MurA (−8.5 Kcal/mol) and catechin–gelatinase (−7.8 Kcal/mol), as they have binding energies which are not marginally different from quercetin and taxifolin. On the other hand, the binding energy of serine protease is lower than quercetin, taxifolin, and ambuic acid. Based on the data, catechin has potency as an antibacterial through the inhibition of GBAP proteins, gelatinase, and serine protease that play a role in the QS system. This is the first discovery of the potential of catechin as an alternative antibacterial agent with an effective mechanism to prevent and control oral disease affected by antibiotic resistance.

Antibacterial Effectiveness of Four Concentrations of the Hydroalcoholic Extract of Solanum tuberosum (Tocosh) against Streptococcus mutans ATCC 25175TM: A Comparative In Vitro Study

Objective. To determine the in vitro antibacterial effect of four concentrations of the hydroalcoholic extract of Solanum tuberosum “tocosh” (HET) against Streptococcus mutans ATCC 25175TM. Methods. This was a prospective, experimental, comparative study. Fermented tocosh was subjected to hydric stress to obtain a hydroalcoholic extract at four different concentrations: 100%, 50%, 75%, and 25%. S. mutans strains were cultured in brain heart infusion agar using the swab technique. The antibacterial effectiveness of HET was evaluated following the Kirby–Bauer disk diffusion method and compared with 0.12% chlorhexidine (positive control group). Results. The highest mean inhibitory effect was achieved with HET at 100% (33.1 ± 2.2 mm, showing a gradual reduction in the other HET groups at 75%, 50%, and 25% (29.7 ± 1.3 mm, 26.6 ± 2.0, and 20.1 ± 1.8 mm, respectively)). Inferential analysis found statistically significant differences among all the experimental groups (p=0.001). The post hoc analysis also showed significant differences among all the experimental groups evaluated; however, there were no significant differences between HET 50% and chlorhexidine 0.12% (p>0.05). Conclusions. It was found that the highest antibacterial effectiveness was obtained by HET 100%, being even higher than the 0.12% chlorhexidine positive control, and was statistically significant. Post hoc analysis showed that almost all the concentrations showed optimal efficacy against S. mutans.

Ethanol extract of Schinus molle L. (Molle) and Erythroxylum coca Lam (Coca): Antibacterial Properties at Different Concentrations against Streptococcus mutans: An In Vitro Study

OBJECTIVE

The aim of this study was to compare in vitro the antibacterial activity of an ethanol extract of Erythroxylum coca Lam (EEE) and Schinus molle L. (EES) at 50% and 75% versus Streptococcus mutans ATCC 25175.

MATERIALS AND METHODS

This was a prospective, comparative, longitudinal experimental study. The ethanol extract of coca and molle leaves was obtained by the vacuum filtration method at concentrations of 50% and 75% and was compared with a positive control (0.12% chlorhexidine). Streptococcus mutans strains were isolated in a culture medium (Mitis Salivarius Agar) ideal for the growth of bacterial colonies. The antibacterial activity of the ethanol extract was carried out following the Kirby-Bauer disk-diffusion method in Mueller-Hinton agar to measure bacterial sensitivity. A value of P < 0.05 was considered statistically significant.

RESULTS

Evaluation of the antibacterial effect of EEE and EES at 24 and 48 h showed that a concentration of 75% for both groups had the highest antimicrobial activity against S. mutans (11.2 ± 0.7 mm; 11.6 ± 0.5 mm and 11.3 ± 0.7 mm; 11.8 ± 0.5 mm, respectively). So, the results have shown that the concentration of EEE and EES of 75% has a greater efficacy than the concentration of 50%, but both concentrations are not as effective as chlorhexidine.

CONCLUSION

EEE and EES at concentrations of 50% and 75% present antibacterial activity against S. mutans ATCC 25175.

By-Products of Camu-Camu [Myrciaria dubia (Kunth) McVaugh] as Promising Sources of Bioactive High Added-Value Food Ingredients: Functionalization of Yogurts

Camu-camu (Myrciaria dubia (Kunth) McVaugh) is a fruit economically relevant to the Amazon region, mostly consumed in the form of processed pulp. Our aim was to perform an unprecedented comparative study on the chemical composition and bioactivities of the camu-camu pulp and industrial bio-residues (peel and seed), and then the most promising fruit part was further explored as a functionalized ingredient in yogurt. A total of twenty-three phenolic compounds were identified, with myricetin-O-pentoside and cyanindin-3-O-glucoside being the main compounds in peels, followed by p-coumaroyl hexoside in the pulp, and ellagic acid in the seeds. The peel displayed the richest phenolic profile among samples, as well as the most significant antibacterial (MICs = 0.625–10 mg/mL) and anti-proliferative (GI₅₀ = 180 µg/mL against HeLa cells) activities. For this reason, it was selected to be introduced in a food system (yogurt). Taken together, our results suggest the possibility of using the camu-camu peel as a source of food additives.

Fruit Seeds as Sources of Bioactive Compounds: Sustainable Production of High Value-Added Ingredients from By-Products within Circular Economy

The circular economy is an umbrella concept that applies different mechanisms aiming to minimize waste generation, thus decoupling economic growth from natural resources. Each year, an estimated one-third of all food produced is wasted; this is equivalent to 1.3 billion tons of food, which is worth around US$1 trillion or even $2.6 trillion when social and economic costs are included. In the fruit and vegetable sector, 45% of the total produced amount is lost in the production (post-harvest, processing, and distribution) and consumption chains. Therefore, it is necessary to find new technological and environmentally friendly solutions to utilize fruit wastes as new raw materials to develop and scale up the production of high value-added products and ingredients. Considering that the production and consumption of fruits has increased in the last years and following the need to find the sustainable use of different fruit side streams, this work aimed to describe the chemical composition and bioactivity of different fruit seeds consumed worldwide. A comprehensive focus is given on the extraction techniques of water-soluble and lipophilic compounds and in vitro/in vivo functionalities, and the link between chemical composition and observed activity is holistically explained.

Development and Formulation of the Experimental Dentifrice Based on Passiflora mollissima (Tumbo) with and without Fluoride Anion: Antibacterial Activity on Seven Antimicrobial Strains

Objectives

To develop and formulate a new experimental dentifrice with and without fluoride based on the peel and the fruit of the Passiflora mollissima (tumbo) and also to evaluate its antimicrobial activity against seven bacterial strains.

Methods

The sample was calculated using the mean comparison formula, obtaining wells (n = 12) for each of the strains evaluated: S. mutans, E. faecalis, Actinomyces, Lactobacillus, C. albicans, S. sanguinis, and S. oralis. The antibacterial activity of the dentifrice was evaluated by the direct contact technique.

Results

It was found that the highest antimicrobial activity was only present in pulp-based dentifrices against strains of S. mutans 21.0 ± 1.8, E. faecalis 16.3 ± 3.9, Actinomyces 22.1 ± 1.3, and Lactobacillus 21.0 ± 1.3. However, in comparison with other strains such as C. albicans, S. sanguinis, and S. oralis, the peel-based dendrifrice of Passiflora mollissima obtained the highest antimicrobial activity.

Conclusion

The experimental dentifrice based on Passiflora mollissima had an antibacterial effect against the seven microbial strains during the first 24 and 48 hours.

Antibacterial Activity and Cytotoxic Effect of Pelargonium peltatum (Geranium) against Streptococcus mutans and Streptococcus sanguinis

OBJECTIVE

To evaluate the in vitro antibacterial and cytotoxic properties of the methanolic extract of Pelargonium peltatum (geranium) against Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556).

METHODS

Three extracts of P. peltatum were prepared using the leaf, stem, and root. Nine independent assays were prepared for each type of extract with chlorhexidine at 0.12% as the positive control. The agar diffusion method was performed to determine the antibacterial properties of each extract. The minimum inhibitory concentration (MIC) was determined using the microdilution method, and the cytotoxicity was analyzed by means of the MTT reduction test using a MDCK cell line.

RESULTS

The root extract had the highest antibacterial effect with a mean result of (27.68 ± 0.97) mm and (30.80 ± 0.55) mm against S. mutans and S. sanguinis, respectively. The minimum inhibitory concentration for the leaf and root extracts was 250 mg/mL for S. mutans and 125 mg/mL for S. sanguinis. Cytotoxicity assays showed that both extracts had a low cytotoxicity at high concentrations. The cellular viability was highest for the root extract at 95.3% followed by the stem extract at 80.8% and finally the leaf extract with 75.4%.

CONCLUSIONS

These findings show the antibacterial properties of the methanolic extracts of P. pelargonium against S. mutans and S. sanguinis. These extracts were not cytotoxic at high concentrations.