Quercus Sideroxyla Research Articles

Analysis of Antioxidant Constituents of Filtering Infusions from Oak (Quercus sideroxyla Bonpl. and Quercus eduardii Trel.) and Yerbaniz (Tagetes lucida (Sweet) Voss) as Monoamine Oxidase Inhibitors.

The antioxidant constituents of ancestral products with ethnobotanical backgrounds are candidates for the study of filtering infusions to aid in pharmacotherapies focused on the treatment of depression and anxiety. Monoamine oxidase A (MAO-A) is an enzyme that regulates the metabolic breakdown of serotonin and noradrenaline in the nervous system. The goal of this study was to evaluate in vitro and in silico the effect of antioxidant constituents of filtering infusions from yerbaniz (Tagetes lucida (Sweet) Voss) and oak (Quercus sideroxyla Bonpl. and Quercus eduardii Trel.) as monoamine oxidase inhibitors. Materials were dried, ground, and mixed according to a simplex-centroid mixture design for obtaining infusions. Differential analysis of the phenolic constituent's ratio in the different infusions indicates that among the main compounds contributing to MAO-A inhibition are the gallic, chlorogenic, quinic, and shikimic acids, quercetin glucuronide and some glycosylated derivatives of ellagic acid and ellagic acid methyl ether. Infusions of Q. sideroxyla Bonpl. leaves, because of their content (99.45 ± 5.17 µg/mg) and synergy between these constituents for MAO-A inhibition (52.82 ± 3.20%), have the potential to treat depression and anxiety. Therefore, future studies with pharmacological approaches are needed to validate them as therapeutic agents with applications in mental health care.

Natural durability of timber species exposed to xylophagous fungi in southern Durango, Mexico.

Wood is a natural resource used for construction and the manufacture of many products. This material is exposed to damage due to biotic and abiotic factors. An important biotic factor is wood-degrading fungi that generate large economic losses. The objectives of this study were to determine the effect of xylophagous fungi (Coniophora puteana and Trametes versicolor) on the natural durability of six timber species in southern Durango, Mexico, and to establish differences between fungal effects on each tree species. Samples of Pinus durangensis, P. cooperi, P. strobiformis, Juniperus deppeana, Quercus sideroxyla, and Alnus acuminata were exposed to fungi for 4 months under laboratory conditions according to European Standard EN350-1. Samples of Fagus sylvatica were used as control. Durability was determined as the percentage of wood mass loss for each species. Welch ANOVA tests were performed to establish differences among tree species. Welch t-tests were used to prove loss mass differences between fungi for each tree species. The most resistant species to C. puteana were P. durangensis, J. deppeana, P. cooperi and P. strobiformis, showing mean mass losses lower than 8.08%. The most resistant species to T. versicolor were J. deppeana, P. strobiformis and P. durangensis (mean mass losses lower than 7.39%). Pinus strobiformis and Q. sideroxyla were more susceptible to C. puteana effect; in contrast, P. durangensis and P. cooperi showed more damage due to T. versicolor degradation. Woods of P. durangensis, P. cooperi, P. strobiformis and Juniperus deppeana are well adapted to infection by these xylophagous fungi and are therefore highly recommended for commercial use in southern Durango, Mexico.

Evaluation of Four Types of Kilns Used to Produce Charcoal from Several Tree Species in Mexico

Charcoal production is an activity that dates back over the years. The objective of the study was to determine the temperature and heating ramp in industrial carbonization processes using different kiln types and to quantify its impact on yield and quality of charcoal from different firewood species. The selection of sites, kiln types, and species investigated was based on those with highest production in Mexico. Brazilian beehive kilns using Arbutus xalapensis, Quercus durifolia, and Quercus sideroxyla species were analyzed; modified Brazilian beehive kilns with Pithecellobium dulce and Tamarindus indica; Argentine half-orange kilns with Quercus magnoliifolia and Q. sideroxyla, industrial metal kilns with Brosimum alicastrum, Vitex gaumeri, Manilkara zapota, and Pouteria unilocularis. The process time, temperature, heating ramp, production yield, and quality of charcoal produced were determined. Data were analyzed in a completely random statistical design. The industrial type kilns showed the highest production yield (>35%), and the Brazilian beehive kilns obtained the longest carbonization time (>240 h). On the other hand, the modified Brazilian beehive kilns obtained the best energetic characteristics (>75% fixed carbon and <16% volatile material). A carbonization process with a slow heating ramp (<1 °C min−1) and temperatures of 500–600 °C can generate a charcoal with export quality.

Assessment of Pellets from Three Forest Species: From Raw Material to End Use

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

Effect of forest management on tree diversity in temperate ecosystem forests in northern Mexico.

An important challenge for silvicultural practices is the conservation of tree diversity while fulfilling the traditional objectives of forest management, most notably timber harvesting. The purpose of this study was to compare the tree diversity before and after the application of silvicultural treatments in a temperate forest in northern Mexico. Fifteen experimental plots, each measuring 2500 m2, were established to evaluate the immediate effect of four silvicultural treatments. These treatments were identified by their levels of management: intensive (clearcut, removal 100%), semi-intensive (removal of 59–61% of basal area), conservative (removal of 29–31% of basal area), and a control group. New forest guidelines, in contrast to conventional approaches, were applied to the semi-intensive and conservative treatments based on health and diversity conditions. Basal area, canopy cover, tree and total volume were measured in each plot. The Importance Value Index, alpha diversity, and evenness were estimated before and after treatments. Eighteen species belonging to five genera and five families were found in the study area. The species with the highest ecological values were Pinus durangensis, P. teocote, Quercus sideroxyla, and Quercus convallata with IVI numbers between 13.6 and 24.5%. Alpha diversity was intermediate (Margalef: 2.9 to 3.8), while dominance and evenness were above average compared to other studies (Simpson: 0.69 to 0.77; Shannon-Wiener: 1.44 to 1.6; Pielou: 0.76 to 0.85). The species evenness index in the conservative treatment was high (Sorensen, Jaccard, quantitative Sorensen and Morisita-Horn; 88 to 99%), although abundance decreased. Overall, there were no significant differences in IVI values and diversity indicators before and after treatments, with the exception of the clearcut treatment. When associating the diversity indices with stand variables, only the Pielou’s evenness index showed a significant relationship between them. We concluded that both the conservative and semi-intensive treatments did not generate significant changes in tree diversity, but the former had slightly higher alpha diversity indices. These results can provide a better insight on silvicultural practices and their effects on species composition.

Cambios en la composición y estructura de especies arbóreas en un bosque templado de Durango, México

Antecedentes y Objetivos: El manejo forestal ocasiona cambios en la composición, estructura y funcionamiento del bosque. El objetivo de este estudio fue comparar la estructura de especies arbóreas en un periodo de 10 años en un bosque de Durango, México. Métodos: Los datos provienen de árboles con DAP mayor o igual a 7.5 cm (a una altura >1.3 m), ubicados en sitios permanentes que fueron evaluados en intervalos de cinco años (2007, 2012 y 2017). Se definieron tres estratos de altura para cada año de medición, bajo la metodología del índice de perfil vertical (A) de Pretzsch tomando en cuenta la altura mayor de cada medición. En cada estrato se evaluó la estructura a través del índice de valor de importancia (IVI), la diversidad alfa (α) con la riqueza de especies (S) y el índice de Shannon-Wiener (H’). Todas las variables dasométricas por estrato de cada medición se compararon con un ANOVA de un factor para determinar la existencia de diferencias estadísticamente significativas entre evaluaciones. Resultados clave: Aunque hubo un aumento en el área basal, el volumen y la cobertura de 2007 a 2017, este no fue estadísticamente significativo. Los estratos II y III presentaron el mayor aumento en el área basal y el volumen. La cobertura fue superior a 100%, presentando mejor contribución el estrato III. La composición de especies fue similar en las tres mediciones, siendo el estrato III el más diverso. Pinus durangensis fue la especie de mayor importancia ecológica en los estratos I y II, mientras que Quercus sideroxyla presentó relevancia alta en el III. Conclusiones: La comparación realizada en un periodo de 10 años (2007-2017) permitió determinar que la vegetación arbórea de la comunidad evaluada se mantiene sin cambios respecto a la diversidad de especies, mientras que el área basal y el volumen tienden a aumentar.

Un modelo aproximado de crecimiento en altura e índice de sitio para Quercus sideroxyla Bonpl. en rodales mezclados de Durango, México

Introduction: Predictions of dominant or co-dominant height are an important element in planning forest management with timber production objectives. Objective: To develop dominant height growth and site index (SI) equations for Quercus sideroxyla Bonpl. Materials and methods: The height current annual increment model was fitted, and the age of the sections was estimated from a database of 29 stem-mapped plots. A taper analysis data of 37 trees was also used to reconstruct dominant height growth trajectories. Three equations based on algebraic difference approach (ADA; one anamorphic and two polymorphic) and an equation based on generalized algebraic difference approach (GADA) were used to simultaneously model the dominant height and SI. Results and discussion: The ADA polymorphic equations were statistically better than the anamorphic equation, according to the adjusted coefficient of determination, root mean square error, mean bias, Akaike’s information criterion and log-likelihood; however, the GADA equation was better than the ADA equations. The growth curves were biologically realistic and showed SI classes at a base age of 60 years. Conclusions: The developed equations can be used for decision making in forest management when Q. sideroxyla shows dominance over Pinus species and the main objective is timber production.

The Bioenergetic Potential of Four Oak Species from Northeastern Mexico

Lack of knowledge regarding the fuel quality of diverse tree species prevents their use. Furthermore, the potential use of wood with the bark of different tree species for pellet production is still relatively unexplored in the scientific literature. In Mexico, the sawdust of Quercus genus (oak) is underutilized, despite it being an important forest resource, due to some anatomical and technological characteristics. The sawdust of Quercus with bark is also considered to have a low economic value. The objective of this study was to analyze the energy characteristics of barked and debarked Quercus sideroxyla, Q. rugosa, Q. laeta, and Q. conzattii in order to evaluate their potential for pellet production. Granulometric distribution, bulk density, proximal analysis, and calorific value tests were carried out. The sawdust of the four tree species studied was in accordance with the limits established by the standard EN 14961-2. Sawdust with a particle size of 0.425 mm had the highest percentage of retained mass (30.33%) (p < 0.05) in the granulometry test. There were no statistical differences in granulometry (p > 0.05) between barked and debarked sawdust for all Quercus species. Barked sawdust presented higher bulk density (p < 0.05) than debarked sawdust (246 and 224 kg/m3, respectively). The moisture content did not show statistical differences (p > 0.05) between barked and debarked sawdust. The volatile material was higher (p < 0.05) in debarked sawdust (88.7%) than in barked sawdust (85.0%). The ash content was below 0.5%. The fixed carbon was higher (p < 0.05) in barked sawdust (14.6%). The calorific value was higher (p < 0.05) in barked sawdust and for the Q. rugosa species (19.5 MJ/kg). The results suggest that the oak species analyzed, both barked and debarked, showed good potential for pellet production. Future studies should quantify fuel quality for a variety of diameter distributions, and analyze pellet mechanical properties and ash slagging risk.

ESTIMACIÓN DE VOLUMEN, BIOMASA Y CONTENIDO DE CARBONO EN UN BOSQUE DE CLIMA TEMPLADO-FRÍO DE DURANGO, MÉXICO

La información sobre el volumen y la biomasa de los árboles es importante para determinar la retención de carbono en bosques. El objetivo del presente estudio fue estimar el volumen, biomasa y contenido de carbono de especies arbóreas en un bosque de Durango, México. Se establecieron nueve sitios de muestreo de 50 × 50 m y se realizó un censo de todas las especies arbóreas. Para cada uno de los árboles muestreados se registró la especie, se midió el diámetro normal y la altura total. Para cada una de las especies se determinó su volumen y biomasa total a través de ecuaciones alométricas generadas pordiferentes autores. Para determinar el contenido de carbono se multiplicó el valor de la biomasa por el factor 0.5, ya que según resultados de varios autores este valor representa la concentración promedio de carbono para especies de coníferas y hojosas. En total se registraron 11 especies, pertenecientes a cuatro géneros y cuatro familias. El bosque presenta una densidad de 575 árboles ha-1, un volumen total de 207.36 m3 ha-1 y una concentración de biomasa total de 130.28 Mg ha-1. Con relación al carbono, se estimó un total de 65.14 Mg ha-1. Las especies con mayor volumen, biomasa y carbono acumulado fueron Pinus durangensis, P. cooperi y Quercus sideroxyla. El área basal es la mejor variable indicadora del contenido de carbono en el área de estudio.

Estructura y composición de la vegetación en cuatro sitios de la Sierra Madre Occidental

Con el objetivo de evaluar la estructura y composición de especies en bosques de El Salto, Pueblo Nuevo, Durango, se establecieron cuatro sitios de estudio (2 500 m2), donde se ubicaron aleatoriamente 10 parcelas de 100 m2. Las variables registradas fueron altura (m), diámetro a la altura de pecho (cm) y área de copa (m2); la dominancia se calculó a partir del área basal y la densidad, de acuerdo con el número de árboles; se determinó el índice de valor de importancia (IVI). La diversidad y la riqueza de especies se estimaron utilizando los índices de Shannon-Wiener (H´) y Margalef (DMg). La similitud se obtuvo con el modelo de Bray-Curtis. Se identificaron 18 especies distribuidas en nueve géneros. El sitio 2 presentó la mayor diversidad (9 especies), y el de menor correspondió al S1 (6 taxones). En este y en el S3, Quercus sideroxyla registró el valor más alto de importancia ecológica; en S2, le correspondió a Quercus durifolia y en S2 a Pinus cooperi. El índice de Shannon-Wiener (1.51) y el de Margalef (1.79) más grandes se obtuvieron en este último sitio y el menor (0.93) en el ejido Banderas; mientras que el más bajo (0.97) para el de Margalef en el ejido El Brillante. El modelo de Bray-Curtis evidenció semejanza entre S1 y S3, con un valor de 25.59 %. Valores que indican tendencia a la heterogeneidad de los sitios.

Aporte y descomposición de hojarasca en bosques templados de la región de El Salto, Durango

A fin de conocer el aporte y descomposición de hojarasca como un proceso ecosistémico a través del cual se transfieren nutrientes al suelo, se evaluaron dos sitios de estudio (2 500 m2) durante un año: El Brillante, donde la estructura forestal está condicionada por Quercus sideroxyla y Pinus cooperi var. Ornelasii; y Santa Bárbara, con Cupressus lusitanica y Pseudotsuga menziesii y diferente composición de especies; en cada uno se instalaron 10 colectores de hojarasca de 1 m2, en los que la recolecta se hizo quincenalmente. Dicho material fue separado en componentes: hojas, estructuras reproductivas, ramas, corteza, insectos, heces y otros (musgo, resina y tejido no identificado). Para medir la descomposición foliar se distribuyeron, por sitio, 160 bolsas con 10 g de hojarasca seca que se revisaron cada mes. La producción de hojarasca total fue de 5.9 (El Brillante) y de 3.6 Mg ha-1 año-1 (Santa Bárbara). Mediante un análisis de regresión, el modelo Exponencial Negativo Simple fue el mejor para describir la relación entre el peso inicial y final en la descomposición. Para la descomposición de 50 y 90 % de la masa de las hojas, el tiempo requerido fue de 1.6 y 10.8 años, respectivamente. El Brillante tiene una mayor producción de hojarasca; sin embargo, el proceso de descomposición es semejante al de Santa Bárbara. La comparación de promedios en el aporte de hojarasca y descomposición de la fracción foliar para los sitios de estudio se realizó con la prueba no paramétrica de U de Mann-Whitney.

Desarrollo de ecuaciones alométricas de biomasa para la regeneración de cuatro especies en Durango, México

El objetivo del trabajo consistió en el desarrollo de ecuaciones alométricas para estimar la biomasa aérea por fracciones de grosor de la regeneración de Arbutus arizonica, Juniperus deppeana, Quercus sideroxyla y Pinus cooperi en la Unidad de Manejo Forestal (Umafor 1008) en el estado de Durango. Se utilizaron datos provenientes de 114 individuos (25, 29, 30 y 30, respectivamente), colectados mediante un muestreo destructivo para ajustar los modelos. La aditividad de las ecuaciones de estimación de biomasa se aseguró mediante el ajuste simultáneo de todas las ecuaciones, con el procedimiento estadístico denominado 3SLS (Three-Stage Least Squares). Los modelos desarrollados permiten estimar la biomasa en peso seco de los componentes, peso total, hojas, ramillas (< 0.5 cm), ramas finas (0.51 – 2.5 cm), ramas gruesas y tronco (> 2.51 cm). Las ecuaciones alométricas con mejor ajuste correspondieron al peso total, con valores de coeficiente de determinación ajustado de 0.97, 0.94, 0.95 y 0.97 para Arbutus, Juniperus, Quercus y Pinus cooperi, respectivamente. En general las ecuaciones mostraron un ajuste satisfactorio en cada una de las fracciones; con ellas se podrán hacer estimaciones no destructivas de la biomasa por categoría de grosor de la regeneración de las cuatro especies estudiadas, lo que mejorará las predicciones de biomasa y almacén de carbono por fracciones en los bosques con presencia de los cuatro taxa estudiados.

Durabilidad natural de la madera de siete especies forestales de El Salto, Durango

Para sentar las bases de una adecuada utilización de la madera, es importante conocer su durabilidad natural bajo la acción de agentes bióticos y abióticos, por lo que el objetivo de este estudio fue determinarla en madera de Pinus durangensis, P. cooperi, P. strobiformis, P. teocote, Juniperus deppeana, Arbutus spp. y Quercus sideroxyla procedente de la región de El Salto, Durango, mediante evaluaciones rápidas (microcosmos terrestre y exposición a hongos degradadores). La durabilidad en microcosmos terrestres se consideró como las pérdidas de masa y de módulo de elasticidad dinámico (MOEdin). Para la exposición a los hongos solo se tomó en cuenta la pérdida de masa. Los resultados de la durabilidad en microcosmos terrestre, de acuerdo con la Norma Europea EN 350-1, clasifican a la madera en tres categorías: moderadamente durable (Juniperus deppeana, P. cooperi y P. durangensis), poco durable (P. teocote) y no durable (P. strobiformis, Quercus sideroxyla y Arbutus spp.). En relación a la pérdida del MOEdin, las cuatro especies de pino y Juniperus deppeana registraron el menor valor, con 8.77 % en promedio; mientras que Quercus sideroxyla y Arbutus spp. Registraron hasta 25.63 %. En cuanto a la exposición a hongos, Trametes versicolor degradó en mayor medida la madera, con 16.15 % de pérdida de masa, destaca Quercus sideroxyla, con 32.57 %.

Kinetic study of the pyrolysis of Pinus cooperi and Quercus sideroxyla to obtain bio-oil and a thermodynamic analysis for hydrogen production

Pyrolysis of forestry residues produces bio-oil compounds and potentially employed in H2 production. This research is aimed to perform a kinetic study and obtain optimum reaction conditions (ORC) for the pyrolysis of the Mexican Pinus cooperi (PC) and Quercus sideroxyla (QS) forest species to obtain the maximum amount of volatile matter (condensable and non-condensable). Samples of forest biomass were crushed and sieved to 300 ≥ dp ≥ 400 μm and 600 ≥ dp ≥ 700 μm and evaluated in a reactor under a N2 flowrate at 50, 100 and 150 ml/min, and heating rates (β) of 1, 5, 10, 15, 20 and 25 °C/min from 25 to 700 °C. Results show that ORC were: 300 ≥ dp ≥ 400 μm, 150 ml/min and β = 25 °C/min, for both species. Kinetic study of the pyrolysis shown an Ea = 153.6 kJ/mol for PC and 200.51 kJ/mol for QS, respectively and n = 1 for both species. Preliminary thermodynamic analysis of steam reforming and CO2 absorption (Na2ZrO3) of bio-oil resulted in a maximum of 98.57% hydrogen production.

Evaluation of Hypoglycemic and Genotoxic Effect of Polyphenolic Bark Extract from Quercus sideroxyla.

Quercus sideroxyla is a wood species whose bark has phenolic compound and should be considered to be bioactive; the hypoglycemic and genotoxic properties of Q. sideroxyla bark were evaluated in this study. Total phenolic compound was determined in crude extract (CE) and organic extract (OE). The OE has the highest amount of phenols (724.1 ± 12.0 GAE/g). Besides, both CE and OE demonstrated effect over the inhibition of α-amylase in vitro. Hypoglycemic activity was assessed by glucose tolerance curve and the area under curve (UAC); OE showed the highest hypoglycemic activity. In addition, diabetes was induced by streptozotocin (65 mg/kg) and the extracts (50 mg/kg) were administered for 10 days; OE showed hypoglycemic effect compared with diabetic control and decreased hepatic lipid peroxidation. Acute toxicity and genotoxicity were evaluated in CE; results of acute toxicity did not show any mortality. Besides, the comet assay showed that CE at a dose of 100 mg/kg did not show any genotoxic effect when evaluated at 24 h, whereas it induced slight damage at 200 mg/kg, with the formation of type 1 comets.

Polyphenolic content and antioxidant activity of leaf extracts from Quercus durifolia, Quercus eduardii, Quercus sideroxyla and Quercus resinosa

The phenolic content and antioxidant activities of extracts from Quercus durifolia, Quercus resinosa, Quercus eduardii and Quercus sideroxyla leaves were studied. Extracts were obtained by successive extraction with aqueous acetone (70%) followed by methanol (50%). Antioxidant activities were determined using a single electron transfer (SET) and hydrogen atom transfer (HAT) based assays. For SET-based the assays performed were, 2,2-diphenyl-1-picryl hydrazine (DPPH) inhibition expressed as IC50, redox potential, as mV, inhibition of the low density lipoprotein (LDL) oxidation, as % of inhibition. For HAT-based assay, crocin bleaching technique was applied; a kinetics approach was used for the evaluation of total antioxidant capacity and the results presented in terms of equivalence by weight of a reference antioxidant. Acetone extracts (PFQA) from leaves of all Quercus species showed the best antioxidant capacity. Q. resinosa (PFQr) exhibited the best antioxidant capacity among the Quercus species analyzed either in acetone or methanol extracts (PFQM). Distinctive results are: DPPH IC50, PFQrA = 78.3 µg/g, PFQrM = 250.7 µg/g; In Redox potential, PFQrA = 147.0 mV, PFQrM = 201.6 mV; In LDL oxidation inhibition: 98.2% and in inhibition of crocin bleaching, PFQrA = 1.08 g, PFQrM = 0.98 g. In conclusion, Quercusleaves might be used as potential source of polyphenolic antioxidants. Key words: Quercus sp., SET-based assay, HAT-based assay, phenolic compounds, antioxidant activity.

Evaluation of a charcoal production process from forest residues of Quercus sideroxyla Humb., & Bonpl. in a Brazilian beehive kiln

Carbonization process from Brazilian beehive ovens and quality of charcoal from residues of branches and cracked firewood from Quercus sideroxyla were evaluated. Oven temperature and time, charcoal yields, quality and calorific value were also assessed. In addition, charcoal quality was determined using proximate and elemental analysis. Moreover, charcoal was classified according to its size. Since values for immediate and elemental analysis were expressed as percentage, data were transformed using the arcsine square root function for each studied variable. The relationship between temperature and time process for cracked firewood and branches were R2=0.99; p<0.0001 and R2=0.98; p<0.0001, respectively. The carbonization of cracked firewood was slower (131.6h), oven temperature reached 975°C and had higher yield (5.4m3t−1), compared to branches (86.7h, 1007°C and 9.2m3t−1, respectively). The best charcoal quality was obtained from the middle section of the oven when using cracked firewood; with a mean calorific value of 32,000Jg−1, moisture content 3.3%, volatile materials 19.0%, ash 5.2%, fixed carbon 72.2%, and carbon 89.41%. Elemental analysis had the following mean values: H=2.95%, O=2.93%, N=0.2%, and S=0.01%. The quality size of the charcoal of branches was acceptable according to France and Belgium standards. The quality of charcoal produced from branches can be improved by controlling air intakes to prevent increments in temperature.

Antioxidant activity of fractions from Quercus sideroxyla bark and identification of proanthocyanidins by HPLC-DAD and HPLC-MS

Abstract The most active phenolics in Quercus sideroxyla Humb. &amp; Bonpl. residual bark were identified and evaluated following a chromatographic fractionation. Bark powder was defatted with hexane and crude extract (CE) was obtained by extraction with aqueous acetone (70%). A liquid partition with ethyl acetate was performed to produce an organic extract (OE), which was subsequently purified by column chromatography (Toyopearl HW-40F, methanol), and resulted in six methanolic fractions (MF1 to MF6) and an oligomeric fraction (OLF) eluted with acetone 67%. Extraction yields, total phenolic and flavanol contents were determined. The antioxidant activity of bark extracts was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox (6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic-acid)-equivalent antioxidant capacity (TEAC), and ferric ion reducing antioxidant power (FRAP) assays. Their median effective concentration (EC50) data and rate constants for DPPH radical scavenging were also estimated. Identification of major phenolics was carried out by high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography with electrospray ionization coupled to mass spectrometry (HPLC-ESI-MS) instruments. Bioactive gallic acid, catechin, epicatechin, gallocatechin, catechin gallate, dimeric procyanidins, galloylated dimeric proanthocyanidins, trimeric procyanidins, and tetrameric proanthocyanidins were detected and identified in Q. sideroxyla bark extracts. MF2 was the most active fraction containing gallocatechin as its major compound; MF5 and OLF contain galloylated procyanidins, which may explain their higher antiradical activity. OLF besides galloylated procyanidins has gallocatechin, which presumably contributes to its higher antiradical activity. Consequently, Q. sideroxyla bark could be a good source of therapeutic health products or nutraceutical ingredients that may exert a potential prevention or treatment action against diseases in biological systems.