Phytochemical analysis, toxicity and evaluation of antioxidant and antimicrobial activities of leaves of Dipteryx alata Vogel.

In this study, our objective was to conduct a comprehensive phytochemical analysis, determine toxicity levels, and assess the antioxidant and antimicrobial properties of extracts derived from the leaves of Dipteryx alata Vogel, a native species of the Brazilian cerrado flora. Three distinct extracts were prepared utilizing assisted ultrasound and the Soxhlet apparatus, namely, Ultrasound Crude Extract (UCE), Soxhlet Crude Extract (SCE), and the Soxhlet Ethanol Extract (SEE). The phytochemical analysis revealed the presence of flavonoids, tannins, phytosterols, and saponins in all extracts. Additionally, alkaloids were specifically identified in the SCE and SEE extracts. In the analysis using LC-DAD, the compounds gallic acid, rutin, quercetin, luteolin and kampefrol were determined in higher concentrations in the SCE, followed by the SEE and UCE, respectively. The GC-MS analysis revealed the presence of campesterol, stigmasterol and ß-sitosterol in all extracts, with UCE and SCE showing a higher concentration of ß-sitosterol. SCE showed the highest concentration of all identified compounds. In the analysis of antioxidant activity by DPPH• and ABTS•+, SEE showed greater efficiency (IC50 = 2.98 ± 2.92 and 6.57 ± 0.89 µg/mL, respectively). In the toxicity test with Allium cepa, all extracts stimulated root growth at 50 g/mL; UCE and SEE stimulated root growth at 250 g/mL; and SEE inhibited root growth at 750 g/mL. In the Artemia salina toxicity, all extracts were non-toxic. Antibacterial activity was identified in the microorganisms S. aureus and S. mutans; however, the extracts did not show antifungal action against the strain of C. albicans. The extracts of D. alata have therapeutic potential for applicability in dentistry.

Effect of cationic surfactant on the physicochemical and antibacterial properties of colloidal systems (emulsions and microemulsions).

Colloidal systems have been used to encapsulate, protect and release essential oils in mouthwashes. In this study, we investigated the effect of cetylpyridinium chloride (CPC) on the physicochemical properties and antimicrobial activity of oil-in-water colloidal systems containing tea tree oil (TTO) and the nonionic surfactant polysorbate 80. Our main aim was to evaluate whether CPC could improve the antimicrobial activity of TTO, since this activity is impaired when this essential oil is encapsulated with polysorbate 80. These systems were prepared with different amounts of TTO (0-0.5% w/w) and CPC (0-0.5% w/w), at a final concentration of 2% (w/w) polysorbate 80. Dynamic light scattering (DLS) results revealed the formation of oil-swollen micelles and oil droplets as a function of TTO concentration. Increases in CPC concentrations led to a reduction of around 88% in the mean diameter of oil-swollen micelles. Although this variation was of only 20% for the oil droplets, the samples appearance changed from turbid to transparent. The surface charge of colloidal structures was also markedly affected by the CPC as demonstrated by the transition in zeta potential from slightly negative to highly positive values. Electron paramagnetic resonance (EPR) studies showed that this transition is followed by significant increases in the fluidity of surfactant monolayer of both colloidal structures. The antimicrobial activity of colloidal systems was tested against a Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureaus) bacteria. Our results revealed that the inhibition of bacterial growth is observed for the same CPC concentration (0.05% w/w for E. coli and 0.3% w/w for S. aureus) regardless of TTO content. These findings suggest that TTO may not act as an active ingredient in polysorbate 80 containing mouthwashes.

New antioxidant lauryl-free herbal shampoo formulation with a Brazilian plant extract.

Sodium lauryl sulfate is the main cleaning ingredient in shampoos, even though it may be potentially damaging to hair. The demand for antioxidant-rich cosmetics, on the other hand, has encouraged green cosmetics research. Brazil has vast biodiversity that can be exploited for the production of these cosmetics. This work aimed to develop a minimalist antioxidant lauryl-free shampoo formulation with leaf extracts from the Brazilian plant Hancornia speciosa Gomes. Two hydroethanolic extracts were prepared using different extraction methods, Soxhlet, and ultrasound. The extracts were characterized by the presence of saponins, polyphenol quantification, and HLPC chemical identification of the compounds. Antioxidant activity was determined using the DPPH method. The antioxidant lauryl-free shampoo was developed using hydroxyethyl cellulose with two concentrations of leaf extract obtained by Soxhlet, 0.125 mg/g (XP1) and 0.250 mg/g (XP2). Along with the antioxidant activity, the physical and chemical properties, cleaning potential, and foam quality were evaluated. The Soxhlet leaf extract revealed a more favorable chemical profile, including a positive result for saponins, as well as a larger quantity of polyphenols and increased antioxidant activity. The XP2 formulation showed better foam height, dirt dispersion, and antioxidant activity. Thus, the use of mangabeira leaf extract appears to be promising for the development of shampoos with antioxidant activity.

Analysis of the lignocellulosic components of biomass residues for biorefinery opportunities.

The present study aims to identify the renewable resources available in Brazil such as açai seed, coconut husks, coffee husks, rice husks, eucalyptus sawdust, grass, soy peel, bamboo, banana stems and banana stalks. To identify such renewable energy sources, samples were examined for their physical and chemical characteristics using X-ray diffraction (XRD), proximate and ultimate analyses, thermogravimetric analysis (TGA), calorific value determination, near-infrared (NIR) spectroscopy, UV spectroscopy, high-pH anion-exchange chromatography (HPAEC-PAD) and accelerated solvent extraction (ASE). Among the biomasses, açai and coffee exhibited higher total sugar content, 67.70% and 62.55%, respectively. Sawdust exhibited low ash, along with the highest calorific value and lignin content. The highest glucose contents were observed in bamboo (44.65%) and sawdust (38.80%). The maximum yield for the bioproducts levulinic acid (LA), formic acid (FA) and furfural were estimated; açai exhibited the highest yield of LA and FA, while coffee exhibited the best furfural yield. All of these properties indicate that the residues are potential candidates for bioenergy production.

Multivariate analysis of coconut residues by near infrared spectroscopy.

Near infrared (NIR) spectroscopy was used to determine the content of Klason lignin, acid-soluble lignin, total lignin, extractives, ash, acid-insoluble residue, glucose, xylose, rhamnose, galactose, arabinose, mannose and total sugars in coconut residues. The samples were analyzed at several processing stages: wet unground (WU), dried unground (DU) and dried and sieved (DS). Partial least squares models were built, and the models for the analytes exhibited R(2)>0.80, with the exceptions of rhamnose, arabinose, galactose, mannose and ash from all fractions, and the lignin content from the WU fraction, which were predicted poorly (R(2)<0.70). There were some significant differences between the models for the main lignocellulosic components at the various stages of biomass. These results proved that NIR spectroscopy is useful for analysis at biorefineries, and it can be used as a faster and more economical alternative to the standard methods.

Potential of visible-near infrared spectroscopy combined with chemometrics for analysis of some constituents of coffee and banana residues.

Banana (stalk, leaf, rhizome, rachis and stem) and coffee (leaf and husks) residues are promising feedstock for fuel and chemical production. In this work we show the potential of near-infrared spectroscopy (NIR) and multivariate analysis to replace reference methods in the characterization of some constituents of coffee and banana residues. The evaluated parameters were Klason lignin (KL), acid soluble lignin (ASL), total lignin (TL), extractives, moisture, ash and acid insoluble residue (AIR) contents of 104 banana residues (B) and 102 coffee (C) residues from Brazil. PLS models were built for banana (B), coffee (C) and pooled samples (B+C). The precision of NIR methodology was better (p<0.05) than the reference method for almost all the parameters, being worse for moisture. With the exception of ash (B and C) and ASL (C) content, which was predicted poorly (R(2)<0.80), the models for all the analytes exhibited R(2)>0.80. The range error ratios varied from 4.5 to 16.0. Based on the results of external validation, the statistical tests and figures of merit, NIR spectroscopy proved to be useful for chemical prediction of banana and coffee residues and can be used as a faster and more economical alternative to the standard methodologies.