Bauhinia forficata Link Infusions: Chemical and Bioactivity of Volatile and Non-Volatile Fractions

This study aimed to evaluate Bauhinia forficata infusions prepared using samples available in Rio de Janeiro, Brazil. As such, infusions at 5% (w/v) of different brands and batches commercialized in the city (CS1, CS2, CS3, and CS4) and samples of plant material botanically identified (BS) were evaluated to determine their total phenolic and flavonoid contents (TPC and TFC), antioxidant capacity (ABTS^•+, DPPH^•, and FRAP assays), phytochemical profile, volatile compounds, and inhibitory effects against the α-amylase enzyme. The results showed that infusions prepared using BS samples had lower TPC, TFC and antioxidant potential than the commercial samples (p < 0.05). The batch averages presented high standard deviations mainly for the commercial samples, corroborating sample heterogeneity. Sample volatile fractions were mainly composed of terpenes (40 compounds identified). In the non-volatile fraction, 20 compounds were identified, with emphasis on the CS3 sample, which comprised most of the compounds, mainly flavonoid derivatives. PCA analysis demonstrated more chemical diversity in non-volatile than volatile compounds. The samples also inhibited the α-amylase enzyme (IC₅₀ value: 0.235–0.801 mg RE/mL). Despite the differences observed in this work, B. forficata is recognized as a source of bioactive compounds that can increase the intake of antioxidant compounds by the population.     

Variability in the Chemical Composition of Myrcia sylvatica (G. Mey) DC. Essential Oils Growing in the Brazilian Amazon

Myrcia sylvatica (G. Mey) DC. is known as “insulin plant” because local communities use the infusions of various organs empirically to treat diabetes. The leaves of seven specimens of Myrcia sylvatica (Msy-01 to Msy-07) were collected in the Brazilian Amazon. Furthermore, the essential oils were extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry, and their chemical compositions were submitted to multivariate analysis (Principal Component Analysis and Hierarchical Cluster Analysis). The multivariate analysis displayed the formation of four chemical profiles (chemotypes), described for the first time as follows: chemotype I (specimen Msy-01) was characterized by germacrene B (24.5%), γ-elemene (12.5%), and β-caryophyllene (10.0%); chemotype II (specimens Msy-03, -06 and -07) by spathulenol (11.1–16.0%), germacrene B (7.8–20.7%), and γ-elemene (2.9–7.6%); chemotype III (Msy-04 and -05) by spathulenol (9.8–10.1%), β-caryophyllene (2.5–10.1%), and δ-cadinene (4.8-5.6%); and chemotype IV, (Msy-02) by spathulenol (13.4%), caryophyllene oxide (15.0%), and α-cadinol (8.9%). There is a chemical variability in the essential oils of Myrcia sylvatica occurring in the Amazon region.     

Upcycling Rocha do Oeste Pear Pomace as a Sustainable Food Ingredient: Composition,Rheological Behavior and Microstructure Alone and Combined with Yeast Protein Extract

This work explores the potential of Rocha do Oeste pear pomace to be used as a sustainable and healthy food ingredient. Moreover, the enrichment with yeast protein extract (YPE) may be useful to design innovative food products. The main goals of this study were to assess pear pomace concerning: (i) chemical composition and antioxidant capacity; (ii) rheology, texture, and microstructure characterization (alone or enriched with YPE), before and after heating. The results showed that pear pomace was a rich source of dietary fibers (74.5% DW), with phenolic compounds (3.9 mg chlorogenic acid equivalents/g dry weight), also presenting antiradical activity (3.90 μmol Trolox equivalents/g DW). Pear pomace showed a shear thinning behavior and a typical soft-gel behavior, which was not affected by YPE enrichment, thus suggesting that YPE did not affect pear pomace technological properties. Thermal treatment also did not alter pear pomace rheological properties. YPE addition induced a decrease in the apparent viscosity and a destabilizing effect, compared to the samples that were subjected to thermal processing. These results highlight the importance of pear pomace and the use of YPE for protein enrichment, opening new opportunities for their exploitation.     

Tunable emission of AgIn5S8 and ZnAgIn5S8 nanocrystals: electrosynthesis,characterization and optical application

Ternary AgIn₅S₈ (AIS) and quaternary ZnAgIn₅S₈-alloy (ZAIS) nanocrystals, stabilized by L-glutathione, were produced by a clean and eco-friendly electrochemical method, eliminating the need of reducing agents. AIS-GSH colloidal solution was obtained by constant current electrolysis (i = 30 mA) in cavity cell. S^2? ions (0.051 mmol) were generated into a graphite powder macroelectrode, reacting in the intermediate compartment of the cell containing Ag⁺/In³⁺ aqueous solution at different ratios (0.5, 0.28, 0.18, and 0.14), and 0.025 mmol/L^?1 glutathione (GSH). ZAIS-GSH NCs were synthesized in the same cavity cell containing the previously prepared AIS-GSH solution. A paired electrolysis (i = 30 mA) was used for simultaneous production of Zn²⁺ and S^2? (Zn⁰ sacrificial anode and graphite powder macroelectrode/S⁰ cathode). The electrochemical method promoted a high reproducibility and efficient luminescence in the preparations of NCs. The sizes of the AIS-GSH and ZAIS-GSH nanoparticles were determined by HRTM (3.4 and 4.0 nm, respectively), and quantum yields reaching 16% (AIS-GSH, Ag⁺/In³⁺ = 0.18). The spectrophotometric characterization showed that Ag⁺/In³⁺ ratio can be used for the tuning of the AIS-GSH nanoparticle emission wavelength, which is associated to electronic defects introduced in the NCs lattice. XRD/EDS analysis of ZAIS-GSH nanoparticles point out to Zn²⁺ ion-exchange into the AIS-GSH lattice. XPS analysis was carried out at different etching levels of the ZAIS nanocrystals surface, making possible to identify the 2p Zn doublet signal, indicating two different Zn²⁺ sites in the alloy structure. Time-resolved spectroscopy measurements/decay curves were carried out to evaluate the effect of silver amount on radioactive and non-radioactive terms. Additionally, the AIS-GSH and ZAIS-GSH photoluminescence and stability were used to produce the active parts of commercial white LEDs, and modulate the colour perception from the respective emission bands.     

Reaction–Diffusion models: From particle systems to SDE’s

Let $V$ be any finite set and $p(?,?)$ a transition kernel on it. We present a construction of a family of Reaction–Diffusion models that converge after scaling to the solution to the $\left|V\right|$-dimensional SDE: $d{\zeta }_t=\left[{\Delta }_p{\zeta }_t?\beta ?{\zeta }_t^k\right]dt+\sqrt{\alpha ?{\zeta }_t^{?}}d{B}_t$with arbitrary initial condition ${\zeta }_0\in {\mathbb{R}}^V$. Here, ${\Delta }_p$ is the diffusion on $V$ corresponding to $p$, $\alpha$, $\beta$ are positive real numbers and $k$, $?$ are positive integers.     

Are lower epiphytes really that better than higher plants for indicating airborne contaminants? An insight into the elemental contents of lichen thalli and tree bark by INAA

Few dedicated attempts at comparing the monitoring performance of lower and higher plants have been carried out so far. As a contribution to such an issue, this paper looks into the relative magnitude of elemental signals from epiphytic lichens (Parmelia spp.) and olive tree (Olea europaea Linn.) bark, determined by INAA. A representative set of 12 elements - As, Ba, Br, Ca, Cl, K, Mg, Mn, Na, Sr, V, Zn - was used for an ab initio comparison between raw data and Rb-normalized data, using distribution-free statistics. Correlation analysis shows an overall improvement in the degree of association between bark and lichen signals when proceeding from raw data to relative enrichment. Apart from Cl, no element is enriched in lichens to a higher extent than in bark. Sign tests are quite conclusive: bark factors are either statistically greater than or equal to lichens'. These findings prompt a word of caution when dealing with biological monitoring data, without accounting for soil, rock or litter inputs into the biomonitors' elemental pools.     

Synthesis of a new catechin-pyrylium derived pigment

A new catechin-pyrylium derived pigment compound was synthesised from the reaction of catechin with sinapaldehyde in acidic conditions and its structure has been characterised by UV-vis, MS and NMR spectroscopy. Similar compounds could be expected to be formed in wines and contribute to changes in colour and astringency during ageing.     

MCTTFA applied to differential biomonitoring in Sado estuary region

Transplants of the epiphytic lichen Parmelia sulcata were suspended in nylon bags within a rectangle of 15 km wide and 25 km long on a grid 2.5 km'2.5 km in the Sado estuary region. The transplants were oriented towards the wind (F) and opposing the wind (T) and were collected after 3, 6 and 9 months of exposure. Samples were analyzed by INAA and PIXE. Source identification was made by Monte Carlo Target Transformation Factor Analysis (MCTTFA) using three different combinations of data (all data, F data and T data). Five factors were identified for all the combinations performed. For two factors, F and T differentiation was observed.     

Comparison of microbial activity in some Brazilian soils by microcalorimetric and respirometric methods

The microbial activity in a Rhodic eutrudox (R), a Typic eutrudox (V) and a Quartzipsamment (Q) was monitored by respirometric and calorimetric methods. CO₂ evolution was monitored for 98 days by titrimetry and conductimetry for control amended samples (A) with 25% of cattle manure (E), municipal refuse compost (L), earthworm casts (H) or 1.25 kg ha⁻¹ of trifluralin (T). Average values of all treatments through respiration at the end of the incubation period were 5.24±0.34, 6.13±0.31 and 6.50±0.33, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, by titrimetry and 8.89±0.44, 10.41±0.54 and 10.41±0.52, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, for conductimetry. Excellent correlation (r=1.00) between titrimetry and conductimetry was observed. The decreasing order for respiration was E, H, L and T. After each incubation time, the conductimetric values were higher than those for titrimetry, for all treatments of these Brazilian soils. Average values of the exothermic thermal effect were: 0.58±0.02, 0.60±0.02 and 0.67±0.01 kJ g⁻¹ soil, for R, V and Q, respectively, for 103 days. A significant correlation coefficient of 0.91 and P<0.0001 between calorimetric and respirometric values over 98 days was observed. Based on the obtained calorimetric results, it can be proposed that this technique should be as a useful analytical method for determining the microbial activity in soils.