Separation and characterization of phenolic compounds from U.S. pecans by liquid chromatography-tandem mass spectrometry

Extraction of bioactive compounds from pecan nutshell: An added-value and low-cost alternative for an industrial waste

The pecan nutshell [Carya illinoinensis (Wangenh) C. Koch] (PNS) is a source of bioactives with important beneficial properties for the human health. PNS represents between 40-50 % of total mass of the nut, resulting as waste without any added value for the food industry. Even though a variety of methods were already developed for bioactive extraction from this waste, unconventional methodologies, or those which apart from green chemistry principles, were discarded considering the cost of production, the sustainable development goals of United Nations and the feasibility of real inclusion of the technology in the food chain. Then, to add-value to this waste, a low-cost, green and easy-scalable extraction methodology was developed based on the determination of seven relevant factors by means of a factorial design and a Response Surface Methodology, allowing the extraction of bioactives with antioxidant capacity. The pecan nutshell extract had a high concentration of phenolic compounds (166 mg gallic acid equivalents-GAE/g dry weight-dw), flavonoids (90 mg catechin equivalent-CE/g dw) and condensed tannins (189 mg CE/g dw) -related also to the polymeric color (74.6 %)-, with high antioxidant capacities of ABTS+. radical inhibition (3665 µmol Trolox Equivalent-TE/g dw) and of iron reduction (1305 µmol TE/g dw). Several compounds associated with these determinations were identified by HPLC-ESI-MS/MS, such as [Epi]catechin-[Epi]catechin-[Epi]gallocatechin, myricetin, dihydroquercetins, dimers A and B of protoanthocyanidins, ellagitannins and ellagic acid derivatives. Hence, through the methodology developed here, we obtained a phenolic rich extract with possible benefits for human health, and of high industrial scalability for this co-product transformation.

Groundnut and tree nuts: a comprehensive review on their lipid components, phytochemicals, and nutraceutical properties

The health benefits of nut consumption have been extensively demonstrated in observational studies and intervention trials. Besides the high nutritional value, countless evidences show that incorporating nuts into the diet may contribute to health promotion and prevention of certain diseases. Such benefits have been mostly and certainly attributed not only to their richness in healthy lipids (plentiful in unsaturated fatty acids), but also to the presence of a vast array of phytochemicals, such as polar lipids, squalene, phytosterols, tocochromanols, and polyphenolic compounds. Thus, many nut chemical compounds apply well to the designation "nutraceuticals," a broad umbrella term used to describe any food component that, in addition to the basic nutritional value, can contribute extra health benefits. This contribution analyses the general chemical profile of groundnut and common tree nuts (almond, walnut, cashew, hazelnut, pistachio, macadamia, pecan), focusing on lipid components and phytochemicals, with a view on their bioactive properties. Relevant scientific literature linking consumption of nuts, and/or some of their components, with ameliorative and/or preventive effects on selected diseases - such as cancer, cardiovascular, metabolic, and neurodegenerative pathologies - was also reviewed. In addition, the bioactive properties were analyzed in the light of known mechanistic frameworks.

Variation in pigments in pecan testa during kernel development and storage

The pecan (Carya illinoinensis) is an important tree nut worldwide. Browning of the testa during storage considerably reduces its quality. However, the pigments that cause browning and their accumulation patterns are poorly understood. We analyzed the color changes in the testa during the five developmental stages of the kernel after storage at room temperature to compare differences in their color and identify the pigments. Samples exhibiting different colors along with their corresponding -80 °C storage samples were selected for metabolomic analysis. A total of 591 phenolic compounds were detected, 52 phenolics showed regulatory effects on testa discoloration, and 59 metabolites were identified as possible precursors of the pigments. This study revealed the most thorough phenolic composition of pecan to date. Further, the findings provide new insights into the mechanisms of testa browning, deepens our understanding of the bioactive value of pecans, and contributes to the breeding of less browning-susceptible varieties.

Targeted metabolomics reveals key phenolic changes in pecan nut quality deterioration under different storage conditions

Pecan nuts are highly enriched in phenolic compounds, which contribute to the health benefits of pecans. Phenolic compounds represent the main oxidation reaction substrates, thus leading to quality deterioration, namely pellicle browning or a decrease in beneficial effects during pecan storage. Hence, four different storage conditions were performed for 180 d to simulate real production situations. Targeted metabolomics was chosen to identify the specific phenolic compounds involved in quality deterioration under different storage conditions in 0, 90, and 180 d samples. A total of 118 phenolic compounds were detected, nine of which were identified for the first time in pecan. The total phenolic content (TPC) and antioxidant capacities initially demonstrated high scores, after which they tended to decrease during the storage process. The significantly modified phenolic compounds during storage were selected as the metabolite markers of pecan quality deterioration, including catechin, procyanidin (PA) trimer, PA tetramer, trigalloyl hexahydroxydiphenoyl (HHDP) glucose, and tetragalloyl hexoside. Fresh pecan kernels resulted in more pronounced changes in hydrolysable tannins (HTs), whereas dry kernels resulted in the most accentuated changes in condensed tannins (CTs). To the best of our knowledge, this is the first attempt to study individual phenolic changes during storage of pecan in such massive amounts. The results can offer a valuable theoretical basis for future control of pecan quality deterioration through phenolics during storage.

Comparative Transcriptome Analysis Reveals Differential Regulation of Flavonoids Biosynthesis Between Kernels of Two Pecan Cultivars

Flavonoids influence the flavor and nutritional value of pecan nuts. However, limited information is available regarding the molecular mechanisms underlying pecan flavonoid biosynthesis. Here, we used a high ("YLC28") and a low ("Oconee") flavonoid content cultivar as the research objects. The changes in flavonoid content and the gene transcription patterns during kernel development were identified. Different accumulation patterns of total flavonoids (TF) and condensed tannins (CT) were observed between the two cultivars. The contents of TF and CT in "YLC28" were 1.76- and 2.67-fold higher levels than that of "Oconee" on 150 days after full bloom of female flowers, respectively. In total, 30 RNA-Seq libraries were constructed and sequenced. The upregulated genes in "YLC28" were highly enriched in flavonoid-related pathways. Thirty-three structural genes were identified, and the expression of two phenylalanine ammonia lyases, one chalcone synthase, one flavonoid 3',5'-hydroxylase, and one flavonol synthase exhibited high correlation (r ≥ 0.7, p < 0.01) with the condensed tannin content in "YLC28." A putative MYB transcription factor, CIL1093S0100, might act as a flavonoid biosynthesis repressor during kernel development. Altogether, these results will be useful for uncovering the molecular mechanisms of flavonoid biosynthesis and subsequently accelerating quality pecan breeding.

Simultaneous Extraction and Depolymerization of Condensed Tannins from Chinese Bayberry Leaves for Improved Bioavailability and Antioxidant Activity

Biorefineries of polyphenols from plant leaves maximize their commercial value for developing biomedicines and nutrients. However, condensed tannins (CTs) constitute extensive polyphenols from plant leaves, which hinders the maximization due to extremely low bioavailability. Therefore, a simple, and sustainable one-step method was established to simultaneously extract polyphenols and depolymerize CTs with only endogenous flavan-3-ols from Chinese bayberry leaves via acid catalysis, which markedly improved the bioavailability of total polyphenols. Afterward, purification of polyphenols from depolymerized extract was studied with specific polymeric resins. Silica C18 showed the highest absorption efficiency of total polyphenols, while Amberlite XAD-7 and XAD-2 presented high selectivity toward polyphenols with high and low molecular weight, respectively. Combined depolymerization of CTs and purification with Amberlite XAD-2 showed the highest bioavailability and cellular free-radical scavenging activity of total polyphenols, which proved to be an ideal methodology for improving the bioavailability and activity of polyphenols from plant leaves.

Purified antioxidant from the medicinal mushroom Phellinus pini protects rat H9c2 cell against H2 O2 -induced oxidative stress

In this study, through the combination of AB-8 macroporous resin, Sephadex LH-20 column chromatography and semi-preparative HPLC, an antioxidant component was purified from the crude extract of Phellinus pini, thereby evaluating the cardioprotective effect of the fraction. As a result, total phenolic content of the 60% ethanol elution was increased by 4.8-fold after one run treatment on Sephadex LH-20 chromatography with gradient elution. After semi-preparative HPLC separation, the first peak (PP-S4-1) showed that inhibition ratio of erythrocyte hemolysis was 91.9%, and inhibition ratio of lipid peroxidation was also increased by 87.6%, at 50 μg/ml (p < .01). Based on the results of ESI-MS, ¹ HNMR, ¹³ CNMR, and RP-HPLC compared to many published results, PP-S4-1was identified as catechin (MW 290.015, C₁₅ H₁₄ O₆ ). The results showed that PP-S4-1 pretreatment made cell viability increased, and the generation of reactive oxygen species (ROS) inhibited. Meanwhile, PP-S4-1 remarkably decreased the fluorescence intensity of Ca²⁺ , and increased mitochondrial membrane potential (MMP; ΔΨm). In addition, PP-S4-1 could significantly inhibit the decrease of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity as well as the increase of MDA content in H9c2 cells induced by H₂ O₂ . Moreover, pretreatment with PP-S4-1 significantly improved the morphological changes and prevented H₂ O₂ -induced DNA damage. Therefore, this study clarifies the ability of PP-S4-1 to treat H9c2 cell oxidative stress damage induced by H₂ O₂ through its antioxidant effect. PRACTICAL APPLICATIONS: This research is not only helpful to elaborate the cardioprotective effect of Phellinus pini but also can contribute to the development of health foods or drug supplements for heart disease in the future. This is the first report dealing with phenolic component and cardioprotective activity of a medicinal mushroom P. pini belonging to the genus Phellinus.

Diversity of Chemical Structures and Biosynthesis of Polyphenols in Nut-Bearing Species

Nuts, such as peanut, almond, and chestnut, are valuable food crops for humans being important sources of fatty acids, vitamins, minerals, and polyphenols. Polyphenols, such as flavonoids, stilbenoids, and hydroxycinnamates, represent a group of plant-specialized (secondary) metabolites which are characterized as health-beneficial antioxidants within the human diet as well as physiological stress protectants within the plant. In food chemistry research, a multitude of polyphenols contained in culinary nuts have been studied leading to the identification of their chemical properties and bioactivities. Although functional elucidation of the biosynthetic genes of polyphenols in nut species is crucially important for crop improvement in the creation of higher-quality nuts and stress-tolerant cultivars, the chemical diversity of nut polyphenols and the key biosynthetic genes responsible for their production are still largely uncharacterized. However, current technical advances in whole-genome sequencing have facilitated that nut plant species became model plants for omics-based approaches. Here, we review the chemical diversity of seed polyphenols in majorly consumed nut species coupled to insights into their biological activities. Furthermore, we present an example of the annotation of key genes involved in polyphenolic biosynthesis in peanut using comparative genomics as a case study outlining how we are approaching omics-based approaches of the nut plant species.

Metabolic profiling revealed the organ-specific distribution differences of tannins and flavonols in pecan

Carya illinoinensis is rich in phenolic metabolites such as tannins and flavonols, but both the composition and the distribution of these nutritional constituents in most pecan organs were still unclear. In this experiment, a comprehensive qualification and quantification of phenolic metabolites in eight organs of pecan were conducted for the first time. Ninety-seven phenolic metabolites were identified, in which twelve were identified for the first time in pecan, including a series of ellagitannins with high molecular weight. Hydrolysable tannin was the dominant kind of phenolic metabolites in pecan. The metabolic profiles of tannins in pecan were extended. Thirty-three phenolic metabolites were quantified, among them the highest content was ellagic acid pentose in testa. From this experiment, we can see that the distribution of phenolic metabolites in pecan was organ-specific, tannins tend to accumulate in pecan testa with both diverse structures and high contents, while flavonols tend to accumulate in organs such as branch, bark, or leaf. Among all organs, testa contained the highest content of phenolics, which might play important roles in protecting pecan kernel from diseases and insects. A massive phenolic metabolites' matrix in different pecan organs was built in this experiment, which should be useful for related researches in the future and help provide a theoretical basis for using these organs as functional foods.

Phenolic Compounds from Nuts: Extraction, Chemical Profiles, and Bioactivity

Nuts contain a vast array of phenolic compounds having important biological properties. They include substances allocated into the five major groups named phenolic acids, flavonoids, tannins, phenolic lignans, and stilbene derivatives. The complexity in composition does not allow for setting a universal extraction procedure suitable for extraction of all nut phenolics. The use of non-conventional extraction techniques, such as those based on microwave, ultrasound, and compressed fluids, combined with generally recognized as safe solvents is gaining major interest. With regard to the latter, ethanol, water, and ethanol-water mixtures have proven to be effective as extracting solvents and allow for clean, safe, and low-cost extraction operations. In recent years, there has been an increasing interest in biological properties of natural phenolic compounds, especially on their role in the prevention of several diseases in which oxidative stress reactions are involved. This review provides an updated and comprehensive overview on nut phenolic extraction and their chemical profiles and bioactive properties.

Identificación de compuestos fenólicos en extractos de almendra (Prunus dulcis) y nuez pecana (Carya illinoinensis) mediante cromatografía líquida acoplada a espectrometría de masas en tándem (HPLC-MS/MS)

La almendra y nuez pecana son alimentos funcionales, cuyo consumo habitual puede prevenir el desarrollo de numerosas enfermedades crónico-degenerativas. Los compuestos fenólicos (CF) son algunos de los que poseen mayor actividad biológica en estos frutos secos, pero su identificación y caracterización siempre representa un reto analítico. El objetivo del presente trabajo fue caracterizar el perfil de los CF, mediante HPLC acoplado a espectrometría de masas en tándem (MS/MS) de dos tipos de extractos de nuez pecana y almendra, un extracto etanólico y uno acetónico. Se identificaron, mediante HPLC acoplado a espectrometría de masas de alta resolución (Q-TOF), 29 compuestos en almendra (22 estuvieron en el extracto acetónico y 24 en el etanólico) y 43 en nuez pecana (39 en el acetónico y 37 en el etanólico). La identidad de 6 compuestos de la almendra y 20 de nuez pecana se confirmó mediante el análisis de sus patrones de fragmentación en el modo MS/MS del equipo. El perfil de los CF fue claramente diferente entre almendra y nuez, pero muy parecido entre ambos tipos de solventes empleados (acetona y etanol), para un mismo fruto seco. En la almendra predominó la presencia de flavonoles y flavanonas, mientras que en nuez pecana predominaron taninos hidrolizables (sobre todo elagitaninos y derivados simples del ácido elágico) y condensados (hasta tetrámeros). En este estudio se describe por primera vez la identificación de tres elagitaninos en nuez pecana.

Isolation and Characterization of Three Chalcone Synthase Genes in Pecan (Carya illinoinensis)

Phenolics are a group of important plant secondary metabolites that have been proven to possess remarkable antioxidant activity and to be beneficial for human health. Pecan nuts are an excellent source of dietary phenolics. In recent years, many studies have focused on the separation and biochemical analysis of pecan phenolics, but the molecular mechanisms of phenolic metabolism in pecans have not been fully elucidated, which significantly hinders quality breeding research for this plant. Chalcone synthase (CHS) plays crucial roles in phenolic biosynthesis. In this study, three Carya illinoinensisCHSs (CiCHS1, CiCHS2, and CiCHS3), were isolated and analyzed. CiCHS2 and CiCHS3 present high expression levels in different tissues, and they are also highly expressed at the initial developmental stages of kernels in three pecan genotypes. A correlation analysis was performed between the phenolic content and CHSs expression values during kernel development. The results indicated that the expression variations of CiCHS2 and CiCHS3 are significantly related to changes in total phenolic content. Therefore, CiCHSs play crucial roles in phenolic components synthesis in pecan. We believe that the isolation of CiCHSs is helpful for understanding phenolic metabolism in C. illinoinensis, which will improve quality breeding and resistance breeding studies in this plant.

Cellular evaluation of the antioxidant activity of U.S. Pecans [Carya illinoinensis (Wangenh.) K. Koch]

Clinical trials show an inverse relationship between the consumption of antioxidant-rich tree nuts and the development of chronic diseases. This study examined antioxidant efficacy of U.S. pecans using a modified cellular antioxidant activity (CAA) assay with comparisons to data from in vitro antioxidant assays (hydrophilic-oxygen radical absorbance capacity {H-ORAC_FL} and ferric reducing antioxidant power {FRAP}). Crude phenolic extracts from both raw and roasted pecans were analyzed. In the CAA assay, pecan phenolics were taken up by human colorectal adenocarcinoma (Caco-2) cells and bestowed CAA, determined by monitoring the fluorescence of 2',7'-dichlorofluorescein. Phenolics (25-100 μg/mL) demonstrated a reduction in fluorescence by 37-69% for raw and 26-68% for roasted pecans. The primary active phenolic constituents were determined by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) to be epi(catechin) dimers and trimers. These oligomeric procyanidins, ranging in size from 560 to 840 g/mol appear to be small enough for cellular uptake, showing pecans are an effective antioxidant in biological systems, regardless of roasting.

Dynamic Changes in Phenolics and Antioxidant Capacity during Pecan (Carya illinoinensis) Kernel Ripening and Its Phenolics Profiles

Pecan (Carya illinoinensis) kernels have a high phenolics content and a high antioxidant capacity compared to other nuts-traits that have attracted great interest of late. Changes in the total phenolic content (TPC), condensed tannins (CT), total flavonoid content (TFC), five individual phenolics, and antioxidant capacity of five pecan cultivars were investigated during the process of kernel ripening. Ultra-performance liquid chromatography coupled with quadruple time-of-flight mass (UPLC-Q/TOF-MS) was also used to analyze the phenolics profiles in mixed pecan kernels. TPC, CT, TFC, individual phenolics, and antioxidant capacity were changed in similar patterns, with values highest at the water or milk stages, lowest at milk or dough stages, and slightly varied at kernel stages. Forty phenolics were tentatively identified in pecan kernels, of which two were first reported in the genus Carya, six were first reported in Carya illinoinensis, and one was first reported in its kernel. The findings on these new phenolic compounds provide proof of the high antioxidant capacity of pecan kernels.

Evaluation of nutritional value, characteristics, functional properties of Cymodocea nodosa and its benefits on health diseases

Background

Nutritional fact study has prime importance to make the species edible and commercially viable to the food consumers. This is the first report that indicates the chemical characterization, functional, antioxidant and antihypertensive properties of Cymodocea nodosa to evaluate its nutritional status.

Methods

Physico-chemical determination was determined by colorimetric and spectroscopic analysis. The functional and texture properties were evaluated since a desirable texture should be retained. Bioactive substances were determined by liquid chromatography-high resolution electrospray ionization mass spectrometry HPLC-DAD-ESI/MS2 analysis. Health benefit of this plant was highlighting by the antioxidant and antihypertensive potentials.

Results

Results showed that the seagrass powder was characterized by a high content of fibers (56.4%), the fatty acids profile was dominated by the oleic acid, which represents about 62.0% of the total fatty acids and the functional properties proved important values of swelling capacity (6.71 ± 0.2) and water holding capacity (12.26 ± 0.25), that were comparable to those of some foodstuffs. Finally, the physico-chemical analysis shows the wealth in phenolic compounds, that could be explained by the high antioxidant and antihypertensive ability which was concentration dependent.

Conclusion

The results from this study suggested that this marine plant could be utilized as a healthy food item for human consumption.

Phenolic profiles and antioxidant activity of Turkish Tombul hazelnut samples (natural, roasted, and roasted hazelnut skin)

The phenolic profiles and antioxidant status of hazelnut samples [natural (raw) hazelnut, roasted hazelnut, and roasted hazelnut skin] were compared. Free and bound (ester-linked and glycoside-linked) phenolic acids were examined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comprehensive identification of phenolics was carried out using Q-exactive hybrid quadrupole-orbitrap mass spectrometer (Q-OT-MS). Samples were also assessed for their total phenolics and antioxidant activities using three different assays. Ten free and bound phenolic acids were quantified in hazelnut samples. Roasted hazelnut skin contained the highest content of total phenolic acids, followed by natural and roasted hazelnuts. The majority of phenolic acids were present in the bound form. Using a Q-OT-MS, 22 compounds were tentatively identified, 16 of which were identified for the first time in hazelnut samples. The newly identified compounds consisted of flavonoids, phenolic acids and related compounds, hydrolysable tannins and related compounds, and other phenolics. Three antioxidant assays demonstrated similar trends that roasted hazelnut skin rendered the highest activity. The present work suggests that roasted hazelnut skin is a rich source of phenolics and can be considered as a value-added co-product for use as functional food ingredient and antioxidant.

Separation of Ellagitannin-Rich Phenolics from U.S. Pecans and Chinese Hickory Nuts Using Fused-Core HPLC Columns and Their Characterization

U.S. pecans and Chinese hickory nuts possess a wide array of phenolic constituents with potential health benefits including phenolic acids and proanthocyanidins. Only limited information is available, however, on their compositions. The present study optimized the separation performance and characterized the low-molecular-weight phenolic fractions of these nuts with C18 and pentafluorophenyl (PFP) fused-core LC columns by employing a kinetic approach. Although both types of reversed-phase columns demonstrated similar performance in general, the PFP column furnished greater plate numbers and superior peak shapes for the low-molecular-weight fractions as well as overall separations of ellagic acid derivatives. The high-molecular-weight fraction of pecans, analyzed by a 3-μm HILIC column, possessed more proanthocyanidins than the Chinese hickory nuts with dimers and trimers (31.4 and 18.34 mg/g crude extract, respectively) being present at the greatest levels. Chinese hickory nuts had lower proanthocyanidin content but possessed tetramers and pentamers at 4.46 and 4.01 mg/g crude extract, respectively.

Antioxidant properties and UPLC-MS/MS profiling of phenolics in jacquemont's hazelnut kernels (Corylus jacquemontii) and its byproducts from western Himalaya

A rapid and selective analytical method was developed to simultaneously quantify seven polyphenolic compounds (gallic acid, catechin, epicatechin, quercetin, kaempferol, syringic acid and p-coumaric acid). 15 phenolics of diverse groups in 80 % ethanolic extracts of jacquemont's hazelnut (Corylus jacquemontii) kernels and its byproducts from western Himalaya using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) were identified. The developed analytical method showed excellent linearity, repeatability and accuracy. Total phenols concentrations were found to be 4446, 1199 and 105 mg gallic acid equivalent (GAE)/Kg of dried extract for jacquemont's hazelnut skin, hard shell and kernels respectively. Antioxidant potential of defatted, raw jacquemont's hazelnut skin, hard shell and kernel extracts assessed by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods were increased in a dose-dependent manner. The IC₅₀ values were observed as 23.12, 51.32, 136.46 and 45.73, 63.65, 169.30 μg/ml for jacquemont's hazelnut skin, hard shell, kernels by DPPH and ABTS assays, respectively. The high phenolic contents in jacquemont's hazelnut skin contributed towards their free radical scavenging capacities.

Effect of pecan phenolics on the release of nitric oxide from murine RAW 264.7 macrophage cells

Inflammation is linked to numerous chronic disease states. Phenolic compounds have attracted attention because a number of these compounds possess anti-inflammatory properties. A phenolic crude extract was prepared from pecans and separated by Sephadex LH-20 column chromatography into low- and high-molecular-weight (LMW/HMW) fractions. Anti-inflammatory properties of these fractions were assessed in LPS-stimulated RAW 264.7 murine macrophage cells. NO and reactive oxygen species (ROS) production was monitored after 3 different experimental protocols: (1) pre-treatment with Escherichia coli O111:B4 lipopolysaccharide (LPS); (2) pre-treatment with a pecan crude extract and its fractions; and (3) co-incubation of LPS with a pecan crude extract and its fractions. The LMW fraction displayed a dose-dependent decrease in NO production and a significant decrease from the LPS control in ROS production when cells were either co-incubated with or pre-treated with LPS. The phenolics were characterized by HPLC to help identify those responsible for the observed effect.

Phenolic content and anti-hyperglycemic activity of pecan cultivars from Egypt

CONTEXT

Pecans are commonly used nuts with important health benefits such as anti-hyperglycemic and anti-hyperlipidemic effects.

OBJECTIVE

A comparative investigation of the antihyperglycemic and total phenolic content of the leaves and shells of four pecan cultivars growing in Egypt was carried out. The selected cultivars (cv.) were Carya illinoinensis Wangneh. K. Koch. cv. Wichita, cv. WesternSchely, cv. Cherokee, and cv. Sioux family Juglandaceae.

MATERIALS AND METHODS

Total phenolic and flavonoid contents of the leaves and shells of pecan cultivars were carried out using Folin-Ciocalteu's and aluminum chloride assays, respectively. Moreover, HPLC profiling of phenolic and flavonoid contents was carried out using RP-HPLC-UV. In addition, in vivo anti-hyperglycemic activity of the ethanolic extracts (125 mg/kg bw, p.o.) of C. illinoinensis cultivars was carried out using streptozotocin (STZ)-induced diabetes in Sprague-Dawley rats for 4 weeks.

RESULTS AND DISCUSSION

Phenolic contents were higher in shells than leaves in all studied cultivars, while flavonoids were higher in leaves. Leaves and shells of cv. Sioux showed the highest phenolics (251.7 µg gallic acid equivalent (GAE)/g), and flavonoid contents (103.27 µg rutin equivalent (RE)/g and 210.67 µg quercetin equivalent (QE)/g), respectively. The HPLC profiling of C. illinoinensis cultivars resulted in the identification of eight flavonoids (five of these compounds are identified for the first time from pecan), and 15 phenolic acids (six are identified for the first time from pecan). Leaves of cv. Sioux revealed the most potent decrease in blood glucose and glycated hemoglobin (HbA1c%) (194.9 mg/dl and 6.52%, respectively), among other tested cultivars. Moreover, leaves of cv. Sioux significantly elevated serum total antioxidant capacity (TAC) and reduced glutathione (GSH) (0.33 mMol/l and 30.68 mg/dl, respectively), and significantly suppressed the markers of both lipid peroxidation (malondialdehyde, MDA) and protein oxidation (protein carbonyl, PC) (14.25 µmol/ml and 3.18 nmol/mg protein, respectively).

CONCLUSION

Different pecan cultivars showed significant variation in its phenolic and flavonoid contents and consequently their antioxidant and anti-hyperglycemic effects.

Quantitative analysis of cyclic dimer fatty acid content in the dimerization product by proton NMR spectroscopy

In this work, (1)H NMR is utilized for the quantitative analysis of a specific cyclic dimer fatty acid in a dimer acid mixture using the pseudo-standard material of mesitylene on the basis of its structural similarity. Mesitylene and cyclic dimer acid levels were determined using the signal of the proton on the cyclic ring (δ=6.8) referenced to the signal of maleic acid (δ=6.2). The content of the cyclic dimer fatty acid was successfully determined through the standard curve of mesitylene and the reported equation. Using the linearity of the mesitylene curve, the cyclic dimer fatty acid in the oil mixture was quantified. The results suggest that the proposed method can be used to quantify cyclic compounds in mixtures to optimize the dimerization process.

Antiviral Action of Hydromethanolic Extract of Geopropolis from Scaptotrigona postica against Antiherpes Simplex Virus (HSV-1)

The studies on chemical composition and biological activity of propolis had focused mainly on species Apis mellifera L. (Hymenoptera: Apidae). There are few studies about the uncommon propolis collected by stingless bees of the Meliponini tribe known as geopropolis. The geopropolis from Scaptotrigona postica was collected in the region of Barra do Corda, Maranhão state, Brazil. The chemical analysis of hydromethanolic extract of this geopropolis (HMG) was carried out through HPLC-DAD-ESI-MS/MS and the main constituents found were pyrrolizidine alkaloids and C-glycosyl flavones. The presence of alkaloids in extracts of propolis is detected for the first time in this sample. The antiviral activity of HMG was evaluated through viral DNA quantification experiments and electron microscopy experiments. Quantification of viral DNA from herpes virus showed reduction of about 98% in all conditions and concentration tested of the HMG extract. The results obtained were corroborated by transmission electron microscopy, in which the images did not show particle or viral replication complex. The antiviral activity of C-glycosyl flavones was reported for a variety of viruses, being observed at different points in the viral replication. This work is the first report about the antiviral activity of geopropolis from Scaptotrigona postica, in vitro, against antiherpes simplex virus (HSV).