Phenolic compounds in blackcurrant (Ribes nigrum L.) leaves relative to leaf position and harvest date

Ribes nigrum leaf extract downregulates pro-inflammatory gene expression and regulates redox balance in microglial cells

BACKGROUND

This study focuses on the investigation of the antioxidant and anti-inflammatory activities of alcohol extracts from Ribes nigrum leaves on murine BV-2 microglial Wt and Acyl-CoA oxidase 1 deficient (Acox1-/-) cell line models, useful for the investigation of some neurodegenerative disorders.

METHODS

The extract chemical composition was analyzed via LC-Q-Orbitrap HRMS. Various assays, including DPPH, MTT, and H2DCFDA, were used to assess the extract's antioxidant capacity, cell viability, and reactive oxygen species (ROS) production. Immunoblotting and RT-qPCR techniques were employed to measure protein expression and gene transcription in treated cells. Statistical analysis was conducted using GraphPad Prism, with significance determined at p < 0.05.

RESULTS

Investigations showed the presence of phenolic compounds in this extract, among which flavan-3-ols, flavonols, furanocoumarins, hydroxycinnamates were major components, which are known for their biological activity in various test systems. The MTT test revealed a concentration of 0.125 mg/mL of R. nigrum extract as the highest non-toxic. The investigated extract showed high antioxidant activity in chemical-based tests. The antioxidant potential of the R. nigrum leaf extract was furtherly explored using the BV-2 microglial cell line models. Moreover, the extract was found to alter the activity of the main antioxidant enzyme, catalase and fatty acid oxidation enzyme, Acyl-CoA oxidase 1 (ACOX1) as well as the expression of appropriate genes in Wt and Acox1-/- BV-2 microglial cells such as Cat, iNos, Il-1β, Tnf-α, and Abcd1. In Wt cells, after the 24-hour treatment with R. nigrum leaf extract, ACOX1 activity was downregulated, meanwhile the catalase activity remains unchanged. Further treatment led to the downregulation of catalase and the upregulation of ACOX1 activity. However, in Acox1-/- cells, which represent a model of oxidative stress, an increase in catalase activity was observed only after 48 h of treatment. It was also observed the reduced ROS and NO formation in cells, showing the pronounced antioxidant capacity of R. nigrum extract in the investigated cell-models.

CONCLUSION

Our study demonstrated the protective effects of R. nigrum leaf extracts on BV-2 microglial cells by reducing oxidative and nitrosative stress, decreasing pro-inflammatory gene expression, and normalizing peroxisomal function, highlighting the potential of these extracts as therapeutic agents for managing oxidative stress and inflammation.

The first complete mitochondrial genome of Grossulariaceae: Molecular features, structure recombination, and genetic evolution

BACKGROUND

Mitochondria play crucial roles in the growth, development, and adaptation of plants. Blackcurrant (Ribes nigrum L.) stands out as a significant berry species due to its rich nutritional profile, medicinal properties, and health benefits. Despite its importance, the mitochondrial genome of blackcurrant remains unassembled.

RESULTS

This study presents the first assembly of the mitochondrial genome of R. nigrum in the Grossulariaceae family. The genome spans 450,227 base pairs (bp) and encompasses 39 protein-coding genes (PCGs), 19 transfer RNAs (tRNAs), and three ribosomal RNAs (rRNAs). Protein-coding regions constitute 8.88% of the entire genome. Additionally, we identified 180 simple sequence repeats, 12 tandem repeats, and 432 pairs of dispersed repeats. Notably, the dispersed sequence R1 (cotig3, 1,129 bp) mediated genome recombination, resulting in the formation of two major conformations, namely master and double circles. Furthermore, we identified 731 C-to-U RNA editing sites within the PCGs. Among these, cox1-2, nad1-2, and nad4L-2 were associated with the creation of start codons, whereas atp6-718 and rps10-391 were linked to termination codons. We also detected fourteen plastome fragments within the mitogenome, constituting 1.11% of the total length. Phylogenetic analysis suggests that R. nigrum might have undergone multiple genomic reorganization and/or gene transfer events, resulting in the loss of two PCGs (rps2 and rps11) during its evolutionary history.

CONCLUSIONS

This investigation unveils the molecular characteristics of the R. nigrum mitogenome, shedding light on its evolutionary trajectory and phylogenetic implications. Furthermore, it serves as a valuable reference for evolutionary research and germplasm identification within the genus.

From by-products to new application opportunities: the enhancement of the leaves deriving from the fruit plants for new potential healthy products

In the last decades, the world population and demand for any kind of product have grown exponentially. The rhythm of production to satisfy the request of the population has become unsustainable and the concept of the linear economy, introduced after the Industrial Revolution, has been replaced by a new economic approach, the circular economy. In this new economic model, the concept of "the end of life" is substituted by the concept of restoration, providing a new life to many industrial wastes. Leaves are a by-product of several agricultural cultivations. In recent years, the scientific interest regarding leaf biochemical composition grew, recording that plant leaves may be considered an alternative source of bioactive substances. Plant leaves' main bioactive compounds are similar to those in fruits, i.e., phenolic acids and esters, flavonols, anthocyanins, and procyanidins. Bioactive compounds can positively influence human health; in fact, it is no coincidence that the leaves were used by our ancestors as a natural remedy for various pathological conditions. Therefore, leaves can be exploited to manufacture many products in food (e.g., being incorporated in food formulations as natural antioxidants, or used to create edible coatings or films for food packaging), cosmetic and pharmaceutical industries (e.g., promising ingredients in anti-aging cosmetics such as oils, serums, dermatological creams, bath gels, and other products). This review focuses on the leaves' main bioactive compounds and their beneficial health effects, indicating their applications until today to enhance them as a harvesting by-product and highlight their possible reuse for new potential healthy products.

Phenolic Compounds in Fractionated Blackcurrant Leaf Extracts in Relation to the Biological Activity of the Extracts

The aim of this study was to determine the relationship between antioxidant and anticancer properties of extracts from blackcurrant (Ribes nigrum L.) leaves and their fractions and chemical contents. Dried ethanolic extract was divided into three fractions using solid phase extraction: aqueous (F1), 40% MeOH (F2), and 70% MeOH (F3). Both the extract and the fractions were analyzed in terms of antiradical activity (DPPH• and ABTS+•), total phenolic compounds, and total flavonoids. The antitumor potential of the fractions was evaluated in vitro on human colorectal (HCT 116) and prostate (PC-3) cancer cells. Phenolics were identified using HPLC-QTOF-MS, and twelve compounds were quantified by HPLC-DAD. Finally, principal component analysis was carried out to assess the relationship between the tested factors. The results confirmed that blackcurrant leaves are a rich source of phenolics with high antioxidant activity and anticancer properties. It was demonstrated that the F2 fraction had the highest content of phenolics and the highest antiradical activity. Additionally, only this fraction showed cytotoxic activity against HCT 116 cells. It was confirmed that both the blackcurrant leaf extract and its fractions are a promising source of condensed active compounds and can be used as natural functional food additives.

Evaluation of the Harvest Dates for Three Major Cultivars of Blue Honeysuckle (Lonicera caerulea L.) in China

Blue honeysuckle (Lonicera caerulea L.) is an emerging fruit crop; however, determining its proper harvest time in commercial cultivation remains challenging due to its rapid fruit development characteristics. In this study, we investigated 17 agronomic traits of three blue honeysuckle cultivars harvested on 5 successive dates within their respective harvest windows. 'Lanjingling', 'Wulan', and 'Berel' showed solid-acid ratios (SS:TA) ranging from 10.00 to 16.01, 8.13 to 10.23, and 5.77 to 7.11, respectively; anthocyanin contents ranged from 233.85 to 276.83 mg/100 g, 236.38 to 312.23 mg/100 g, and 235.71 to 334.98 mg/100 g, respectively; vitamin C contents ranged from 88.43 to 99.68 mg/100 g, 108.13 to 191.23 mg/100 g, and 89.71 to 120.40 mg/100 g, respectively; phenolic contents ranged from 25.22 to 37.59 mg/g, 25.40 to 36.52 mg/g, and 37.66 to 50.00 mg/g, respectively. The results revealed the SS:TA value consistently increased with delayed harvesting and were significantly negatively correlated with fruit firmness, total acidity, shelf life, and respiration intensity, suggesting it is an ideal maturity indicator for blue honeysuckle berries. The factor analysis suggests that the suitable harvest date for 'Lanjingling' could be either 47 days after flowering (DAF) with an SS:TA value of approximately 10.0, characterized by high firmness, extended shelf life, and elevated levels of anthocyanins and phenolics; or 67 DAF (SS:TA ≈ 16.0), characterized by high vitamin C content and sweetness, and larger size and weight. For 'Wulan', it suggests the suitable harvest date is either 54 DAF (SS:TA ≈ 9.0), yielding fruit with high levels of anthocyanins and vitamin C; or 62 DAF (SS:TA > 10.0), yielding fruit with high sweetness and large size and weight. For 'Berel', it is suggested to be either 52 DAF (SS:TA ≈ 6.5), resulting in fruit with high levels of anthocyanins and vitamin C; or 62 DAF (SS:TA > 7.0), resulting in balanced levels of the fruit quality traits.

Biochemical Composition and Biological Activities of Various Population of Brassica tournefortii Growing Wild in Tunisia

Brassica tournefortii Gouan, commonly known (Aslooz) in Tunisia, is an annual plant, native to the North Africa and Middle East. Brassica species are used as food, their young leaves can be cooked, providing nutrients and health-giving phytochemicals such as phenolic compounds, polyphenols and carotenoids. Phytochemical composition and bioactivity of Brassica tournefortii leaf extracts, collected from four different bioclimatic zones in Tunisia, are investigated in the present study. Results showed that location and climatic variations can alter the phytochemical composition of B. tournefortii. Interestingly, HPLC analysis enabled identifying lutein and beta-carotene at high concentrations, especially in extracts of B. tournefortii collected from Gabes (B2) (344 µg/g of lutein) and B. tournefortii collected from Zarzis (B3) (1364 µg/g of beta-carotene). In particular, the antioxidant activity measured by DPPH assay showed that the extract of the plants collected from the growing region of Zarzis exhibits the highest antioxidant activities (0.99 mg/mL). All the Brassica tournefortii extracts showed a relevant antiproliferative activity, especially toward the Caco-2 cell line. These preliminary data resulted in being useful to correlate growth environmental conditions with different accumulation of metabolites in Brassica species still being poorly studied.

Does Shoot Age Influence Biological and Chemical Properties in Black Currant (Ribes nigrum L.) Cultivars?

The aim of this study was to examine the influence of shoot age on the biological and chemical properties of 13 black currant cultivars with different origins and ripening times. Phenological observations together with examined pomological and chemical characteristics were studied in two consecutive years at the experimental field near Belgrade, Serbia. The total content of phenols was estimated spectrophotometrically by the Folin-Ciocalteu method, while quantitative analysis of anthocyanin and flavonols aglycones was performed using a high-performance liquid chromatographic (HPLC) method. Principal component analysis was performed to establish differences in biological and chemical properties of black currants. Three-year-old shoots had an earlier start of all examined phenological stages, better generative potential, higher yields, while clusters and berries from 2-year-old shoots had significantly higher values for physical properties, total phenols, anthocyanin and flavanols aglycones and antiradical capacity. Late ripening cultivars had higher contents of all chemical compounds. The berries on 2-year-old shoots had total phenolics that ranged between 123.0 ('Titania') and 298.3 mg/100 g fresh weight (FW) ('Ometa'), while total anthocyanins ranged between 398.5 ('Ojebyn') and 1160.8 mg/kg FW ('Ometa'). According to the obtained results, cultivars 'Ometa', 'Ben Lomond', 'Tsema' and 'Malling Juel' can be recommended as the most promising for growing in the continental climate because they stood out with higher generative potential and yield, physical traits of cluster and berry, higher level of primary and secondary metabolites and DPPH activity in their berries.

Metabolites of Siberian Raspberries: LC-MS Profile, Seasonal Variation, Antioxidant Activity and, Thermal Stability of Rubus matsumuranus Phenolome

Rubus matsumuranus H. Lev. & Vaniot, a famous Siberian shrub of the Rosaceae family, is used in the folk medicine of nomads (Buryats, Yakuts, Soyots, and Mongols) as a remedy for the treatment of diseases of the respiratory and hepatobiliary systems. The lack of scientific information on R. matsumuranus leaves contributed to the investigation of the metabolomic profile and biological activity of this plant. In this study, metabolites of R. matsumuranus leaves in three stages (active growth, flowering, and fruiting) were characterised using high-performance liquid chromatography with photodiode array and electrospray ionisation triple quadrupole mass spectrometric detection (HPLC-PDA-ESI-tQ-MS). In total, 63 compounds were identified, including gallic acid derivatives, hydroxycinnamates, catechins, procyanidins, flavonols, and ellagitannins. Lambertianin C (57.11 mg/g of dry weight, DW), miquelianin (39.63 mg/g DW), and kaempferol-3-O-glucuronide (31.18 mg/g DW) were the major compounds in R. matsumuranus leaves. As a result of the HPLC-PDA-based assay to determine the antioxidant activity, it was revealed that lambertianin A, sanguiin H6, lambertianin C, and sanguiin H11 were effective scavengers of free radicals (2,2-diphenyl-1-picrylhydrazyl, DPPH•) and possessed Fe2+-chelating activity. After an investigation of the phenolic content in infusions and decoctions obtained by extraction with water at different temperatures, it was revealed that a hot infusion (80 °C) is a phenolic-rich preparation of R. matsumuranus leaves. Our research suggests that R. matsumuranus leaves are a rich source of phenolic compounds with high antioxidant properties and that this could be a prospective plant for new functional products.

Phenolic compounds in Nordic berry species and their application as potential natural food preservatives

An increasing demand for natural food preservatives is raised by consumers. For Nordic berry species, abundance of phenolic compounds and potent activities of anti-oxidation and anti-bacteria enables a great potential as food preservatives. This review provides a systematic examination of current literature on phenolic profiles, anti-oxidative and anti-bacterial activities of various extracts of Nordic berry species, as well as the impact of various structure features of phenolics on the bioactivities. Special attention is placed on exploitation of leaves of berry species and pomaces after juice-pressing as side-streams of berry production and processing. The current progress and challenges in application of Nordic berry species as food preservatives are discussed. To fully explore the potential application of Nordic berry species in food industry and especially to valorize the side-streams of berry cultivation (leaves) and juice-pressing industry (pomaces), it is crucial to obtain extracts and fractions with targeted phenolic composition, which have high food preserving efficacy and minimal impact on sensory qualities of food products.

Quantitative Analysis of UV-B Radiation Interception in 3D Plant Structures and Intraindividual Distribution of Phenolic Contents

Ultraviolet-B (UV-B) acts as a regulatory stimulus, inducing the dose-dependent biosynthesis of phenolic compounds such as flavonoids at the leaf level. However, the heterogeneity of biosynthesis activation generated within a whole plant is not fully understood until now and cannot be interpreted without quantification of UV-B radiation interception. In this study, we analyzed the spatial UV-B radiation interception of kales (Brassica oleracea L. var. Acephala) grown under supplemental UV-B LED using ray-tracing simulation with 3-dimension-scanned models and leaf optical properties. The UV-B-induced phenolic compounds and flavonoids accumulated more, with higher UV-B interception and younger leaves. To distinguish the effects of UV-B energy and leaf developmental age, the contents were regressed separately and simultaneously. The effect of intercepted UV-B on flavonoid content was 4.9-fold that of leaf age, but the effects on phenolic compound biosynthesis were similar. This study confirmed the feasibility and relevance of UV-B radiation interception analysis and paves the way to explore the physical and physiological base determining the intraindividual distribution of phenolic compound in controlled environments.

Water-Based Extraction of Bioactive Principles from Blackcurrant Leaves and Chrysanthellum americanum: A Comparative Study

The water-based extraction of bioactive components from flavonoid-rich medicinal plants is a key step that should be better investigated. This is especially true when dealing with easy-to-use home-made conditions of extractions, which are known to be a bottleneck in the course for a better control and optimization of the daily uptake of active components from medicinal plants. In this work, the water-based extraction of Blackcurrant (Ribes nigrum) leaves (BC) and Chrysanthellum americanum (CA), known to have complementary pharmacological properties, was studied and compared with a previous work performed on the extraction of Hawthorn (Crataegus, HAW). Various extraction modes in water (infusion, percolation, maceration, ultrasounds, microwaves) were compared for the extraction of bioactive principles contained in BC and CA in terms of extraction yield, of amount of flavonoids, phenolic compounds, and proanthocyanidin oligomers, and of UHPLC profiles of the extracted compounds. The qualitative and quantitative aspects of the extraction, in addition to the kinetic of extraction, were studied. The optimized easy-to-use-at-home extraction protocol developed for HAW was found very efficient to easily extract bioactive components from BC and CA plants. UHPLC-ESI-MS and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were also implemented to get more qualitative information on the specific and common chemical compositions of the three plants (including HAW). Their antihyaluronidase, antioxidant, and antihypertensive activities were also determined and compared, demonstrating similar activities as the reference compound for some of these plants.

Bioactive Compounds from Leaves and Twigs of Guayule Grown in a Mediterranean Environment

Guayule (Parthenium argentatum) is one of the most promising alternatives to produce natural rubber. As the guayule leaves represent a waste byproduct in the rubber extraction process, their exploitation might contribute to the valorization of the whole plant biomass. The specific aim of our study was to determine the antioxidant capacity and the content of phenolic compounds in leaves and twigs of different guayule lines cultivated in a Mediterranean environment. The antioxidant capacity and the contents of phenolic were affected significantly by guayule accession and harvest time. Overall means in twigs represented about 60% of the corresponding leaf values for antioxidant capacity as DPPH (1,1-diphenyl-2-picrylhydrazyl) and not tannic phenolic and about 55% as ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt), total phenolic, tannic phenolic and total flavonoid contents. Five individual phenolic compounds were identified in methanolic extracts of leaves. Neochlorogenic acid (62.5–174.8 mg g⁻¹ DW) and chlorogenic acid (28.6–41.1 mg g⁻¹ DW) were the most abundant phenolic acids. In addition to the compounds quantified in leaves, cynarin was identified only in twigs and for the first time in guayule biomass. Our results indicate that guayule leaves and twigs represent a rich source of antioxidants for potential applications in fodder, nutraceutical and pharmacological sectors.

Estimating Plant Nitrogen Concentration of Maize Using a Leaf Fluorescence Sensor across Growth Stages

Nitrogen (N) is one of the most essential nutrients that can significantly affect crop grain yield and quality. The implementation of proximal and remote sensing technologies in precision agriculture has provided new opportunities for non-destructive and real-time diagnosis of crop N status and precision N management. Notably, leaf fluorescence sensors have shown high potential in the accurate estimation of plant N status. However, most studies using leaf fluorescence sensors have mainly focused on the estimation of leaf N concentration (LNC) rather than plant N concentration (PNC). The objectives of this study were to (1) determine the relationship of maize (Zea mays L.) LNC and PNC, (2) evaluate the main factors influencing the variations of leaf fluorescence sensor parameters, and (3) establish a general model to estimate PNC directly across growth stages. A leaf fluorescence sensor, Dualex 4, was used to test maize leaves with three different positions across four growth stages in two fields with different soil types, planting densities, and N application rates in Northeast China in 2016 and 2017. The results indicated that the total leaf N concentration (TLNC) and PNC had a strong correlation (R2 = 0.91 to 0.98) with the single leaf N concentration (SLNC). The TLNC and PNC were affected by maize growth stage and N application rate but not the soil type. When used in combination with the days after sowing (DAS) parameter, modified Dualex 4 indices showed strong relationships with TLNC and PNC across growth stages. Both modified chlorophyll concentration (mChl) and modified N balance index (mNBI) were reliable predictors of PNC. Good results could be achieved by using information obtained only from the newly fully expanded leaves before the tasseling stage (VT) and the leaves above panicle at the VT stage to estimate PNC. It is concluded that when used together with DAS, the leaf fluorescence sensor (Dualex 4) can be used to reliably estimate maize PNC across growth stages.

Phenolic Composition, Mineral Content, and Beneficial Bioactivities of Leaf Extracts from Black Currant (Ribes nigrum L.), Raspberry (Rubus idaeus), and Aronia (Aronia melanocarpa)

Currently, the incidence of lifestyle diseases is increasing due to inappropriate nutrition and environmental pollution. To prevent these diseases, various groups of bioactive compounds are needed with a broad spectrum of action and without adverse side effects. Polyphenolic compounds are the most widely studied group of this type of compounds. They occur widely in plants, but their content depends on many factors, including the type of plant, climatic conditions, and the date of harvest. The spectrum of bioactivity of phenolic compounds is determined by their chemical structure, concentration, and interaction with other compounds. Traditional recipes have been studied to search for active plant ingredients. Leaves of shrubs and fruit trees were used in folk medicine as a panacea for many diseases and have been forgotten with time, but their benefits are now being rediscovered. In recent years, much new information about biological activity of phenolic compounds from berry bushes (black currant, raspberry, and aronia) was published. This was reviewed and discussed in this article. The mineral content of their leaves was also summarized because minerals constitute a significant component of plant infusions. It has been shown that high antioxidant and biological activity of leaf extracts results from the presence of active phenolic compounds, which occur in definitely higher amounts than in fruits. Therefore, the leaves of berry bushes seem to be a promising source of substances that can be used as replacements for synthetic agents in the treatment and prevention of lifestyle diseases.

Comparative metabolomics of Tilia platyphyllos Scop. bracts during phenological development

The medicinal plant drug "Tiliae flos" consists of the botanical flowers and bracts of Tilia sp., gathered almost exclusively during flowering. In this study, we examined the changes in the metabolome of specialized products in the bracts of Tilia platyphyllos from the appearance of the organ till the onset of senescence by LC-ESI-MS and data mining. A set of 504 natural products were detected, 241 of which showed significant seasonal variation (p < 9.92E-5). Seven compounds were quantified and an additional 45 were putatively identified. These included flavonoid glycosides, catechins, procyanidins, quinic acid derivatives (including chlorogenic acid) and coumarins. Compared to bracts during flowering, young tissues were characterized by a relatively high diversity of polyphenolic substances. Higher amounts of flavonol glycosides (quercetin, kaempferol), catechins and derivatives have been observed. Deoxyhexosides were almost exclusive to this phenological stage. Changes of about one order of magnitude were not uncommon. For some substances, 5-fold differences were observed (calibration with authentic standards). Some compounds (e.g. the coumarin fraxin) were more prominent at the late fruit growth stage. It was shown that bracts gathered before or after flowering could potentially be therapeutically useful. Changes are rapid during the early phase of bract development: three different groups of compounds presented their maxima during the first 32 days. Considering seasonal variation is of extreme importance during bioactivity tests and screening candidate sources for bioactive natural products. In the case of T. platyphyllos, young and old bracts can be of interest because of their high diversity of distinct specialized metabolites.

Seasonal Changes in the Metabolic Profiles and Biological Activity in Leaves of Diospyros digyna and D. rekoi "Zapote" Trees

Leaves of semi-domesticated Diospyros digyna and wild D. rekoi trees, sampled seasonally in Mexico in 2014, were analyzed. Metabolic fingerprints revealed higher metabolite diversity in D. rekoi leaves. The TLC bands characteristic of glycosylated flavonoids, predominant in this species, matched the detection of quercetin and quercetin 3-O-glucuronides by liquid chromatography (UPLC-MS) of spring leaf extracts (LEs). Further gas chromatography (GC-MS) analysis revealed abundant fatty acids, organic acids, and secondary metabolites including trigonelline, p-coumaric, and ferulic and nicotinic acids. Phenolic-like compounds prevailed in D. digyna LEs, while unidentified triterpenoids and dihydroxylated coumarins were detected by UPLC-MS and GC-MS. A paucity of leaf metabolites in leaves of this species, compared to D. rekoi, was evident. Higher antioxidant capacity (AOC) was detected in D. digyna LEs. The AOC was season-independent in D. digyna but not in D. rekoi. The AOC in both species was concentrated in distinct TLC single bands, although seasonal variation in band intensity was observed among trees sampled. The AOC in D. digyna LEs could be ascribed to the coumarin esculetin. The LEs moderately inhibited phytopathogenic bacteria but not fungi. Leaf chemistry differences in these Mesoamerican Diospyros species substantiated previous variability reported in tree physiology and fruit physical chemistry, postulated to result from domestication and seasonality.

Effect of Seasonal and Regional Variations on Phenolic Compounds of Deverra scoparia (Flowers/Seeds) Methanolic Extract and the Evaluation of Its in Vitro Antioxidant Activity

The widespread use of Deverra scoparia Coss. & Durieu in Algerian folk-medicine as a remedy can be relatively attributed to its total phenolic compounds. The current study aimed to provide a scientific basis for optimal collection and usage of Deverra scoparia Coss. & Durieu plant. Hence, 37 samples were gathered from nine sites in Algeria during two seasons 2016 and 2017, then exposed to a green extraction. Total phenolic (TPC), flavonoid (FC) and condensed tannins (CTC) content were estimated spectrophotometrically. The antioxidant activity was measured using five different methods, DPPH^. , ABTS^.+ , FRAP, CUPRAC and Fe²⁺ -chelating. The results have revealed considerable amounts of TPC varied from 804 to 1544 mg GAE/100 g dry matter, FC started from 187 up to 410 mg QE/100 g dry matter and CTC varied from 111 to 394 mg CE/100 g dry matter. The best IC₅₀ values (μg/mL) of DPPH^. , ABTS^•+ , FRAP, CUPRAC and Fe²⁺ -chelating tests were 56.62, 5.41, 21.26, 52.93 and 78.10, respectively. Moreover, high correlations were found between CTC and most of the antioxidant tests. Hence, CTC are suggested to be the principal group of antioxidant activity in Deverra scoparia Coss. & Durieu extracts.

Antibacterial and antioxidative properties of different parts of garden rhubarb, blackcurrant, chokeberry and blue honeysuckle

BACKGROUND

It is important to find plant materials that can inhibit the growth of Listeria monocytogenes and other food-spoiling bacteria both in vitro and in situ. The aim of the study was to compare antibacterial and antioxidative activity of selected plant-ethanol infusions: leaves and berries of blackcurrant (Ribes nigrum L.), berries of chokeberry (Aronia melanocarpa (Michx.) Elliott) and blue honeysuckle (Lonicera caerulea L. var. edulis); petioles and dark and light roots of garden rhubarb (Rheum rhaponticum L.) for potential use in food matrices as antibacterial and antioxidative additives.

RESULTS

The strongest bacterial growth inhibition was observed in 96% ethanol infusions of the dark roots of rhubarbs. In 96% ethanol, nine out of ten studied plant infusions had antibacterial effect against L. monocytogenes, but in 20% ethanol only the infusions of dark rhubarb roots had a similar effect. Chokeberry and other berries had the highest antioxidative activity, both in 20% and 96% ethanol infusions.

CONCLUSION

The combination of dark rhubarb roots or petioles and berries of black chokeberry, blackcurrant or some other anthocyanin-rich berries would have potential as both antibacterial and antioxidative additives in food. © 2018 Society of Chemical Industry.

Induction of phenolic compounds by UV and PAR is modulated by leaf ontogeny and barley genotype

We investigated the effect of leaf ontogeny and barley genotype on the accumulation of phenolic compounds (PhCs) induced by ultraviolet (UV) and photosynthetically active radiation (PAR). We hypothesized that different groups of PhCs are induced in leaves differing in ontogeny, and that this has consequences for protective functions and the need for other protection mechanisms. Generally, lower constitutive contents of PhCs (under conditions of UV exclusion and reduced PAR) were found in a UV-sensitive genotype (Barke) compared to a tolerant genotype (Bonus). However, UV and PAR induced accumulation of PhCs exceeded the constitutive amounts several fold. Specifically, lutonarin, 3-feruloylquinic acid, unidentified hydroxycinnamic acid and luteolin derivatives were markedly enhanced by high PAR and UV irradiances. Leaves developed during UV and PAR treatments had higher PhCs contents than mature leaves already fully developed at the onset of the UV and PAR treatment. UV and PAR treatments had, however, a minor effect on saponarin and unidentified apigenin derivatives which occur particularly in mature leaves of the tolerant genotype Bonus. In addition, high UV and PAR intensities increased the total content of xanthophylls (VAZ), while chlorophyll content was reduced, particularly in developing leaves. A redundancy analysis revealed positive associations between most of PhCs and VAZ and a negative association between total chlorophylls and carotenoids. Non-linear relationships between VAZ and lutonarin and other PhCs indicate that VAZ accumulation can compensate for the insufficient efficiency of anti-oxidative protection mediated by PhCs. Accordingly, we conclude that UV and PAR-induced accumulation of PhCs is affected by leaf ontogeny, however, this effect is compound-specific.

Phytochemical Composition of Solanum retroflexum Analysed with the Aid of Ultra-Performance Liquid Chromatography Hyphenated to Quadrupole-Time-of-Flight Mass Spectrometry (UPLC-qTOF-MS)

Solanum retroflexum (nightshade) is an edible plant that is consumed in some regions of South Africa. Its leaves are a good source of vitamins, proteins, and minerals. It appears that there is no scientific report about the phytochemical composition of S. retroflexum. Here, ultra-performance liquid chromatography coupled to quadruple-time-of-flight mass spectrometry (UPLC-qTOF-MS) technique was use to achieve an untargeted metabolite fingerprinting of this plant. A total of 30 phytochemicals, including alkaloids, flavonoids, and cinnamic acids derivatives, were identified from the methanolic leaf extracts. The concentration of solvent did not affect the type of compounds extracted. The extraction resulted in qualitative yields of molecules such as quercetin-3-rutinoside, kaempferol-3-0-rutinoside, kaempferol-3-0-glucoside, 3-caffeoylquinic acid, 5-caffeoylquinic acid, and 3, 4-di-caffeoylquinic acid. The present study confirms the presence of phytochemical compounds in S. retroflexum similar to other Solanum plants.

Seasonal, gender and regional variations in total phenolic, flavonoid, and condensed tannins contents and in antioxidant properties from Pistacia atlantica ssp. leaves

CONTEXT

The widespread use of Pistacia atlantica Desf. ssp. (Anacardiaceae) in traditional medicine can be partly attributed to the content of its secondary metabolites, in particular, the phenolic compounds.

OBJECTIVE

The effects of harvest period, growing region and gender on the phenolic compounds, flavonoids and condensed tannins contents were studied, as well as on the antioxidant activities of P. atlantica leaves in order to provide a scientific basis for optimal collection.

MATERIALS AND METHODS

Leaves were collected monthly from April to October 2010 in two Algerian sites. The powdered leaves were used for preparing the ethyl acetate extract. Contents of total phenolics (TPC), flavonoids (FC) and condensed tannins (CTC) were determined spectrophotometrically. Antioxidant activity was evaluated through radical scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (250 μM) and the reducing power capacity (RPC) determination by K3Fe(CN)6 (1%).

RESULTS

The TPC was found to vary from 79 ± 13 to 259 ± 8 mg gallic acid equivalents/g of dry weight (DW) during the study period. The RSA and RPC varied between 262 ± 18 and 675 ± 21 mg Ascorbic Acid Equivalent (AAE)/g DW, and from 259 ± 16 to 983 ± 20 mg AAE/g DW, respectively. A seasonal pattern was observed consisting of a decrease in TPC content and RPC from spring to autumn. The FC, CTC and RSA did not show a seasonal pattern.

DISCUSSION AND CONCLUSION

Our findings showed that secondary metabolite content and antioxidant activities of P. atlantica leaves were more influenced by harvest time and growing region than by gender.

Antioxidant capacity and major phenol compounds of horticultural plant materials not usually used

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Antioxidant properties and phenols in plant materials not usually used were studied.

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Folin-Ciocalteu, FRAP and ABTS measures correlate with different phenol compounds.

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Large differences in antioxidant properties were found between and within species.

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Sea buckthorn and black currant leaves had the highest antioxidant capacity.

Horticultural plant materials not usually used from onion, carrot, beetroot, sea buckthorn, black and red currants as well as a wastewater powder from olive oil production were analyzed for total phenols content (FC), ferric reducing ability of plasma (FRAP), radical scavenging capacity (ABTS), and for major phenolic compounds by HPLC-MS. Antioxidant capacity and phenol content varied significantly between species and cultivars, with extracts of sea buckthorn leaves being superior. In different species, different phenolic compounds were closely associated with FRAP, ABTS and FC. For instance, hydrolysable tannins were major antioxidants in sea buckthorn whereas quercetin was the major antioxidant in onion peel and skin. This study shows that horticultural plant materials usually left in the field or waste materials from processing may have high antioxidant properties, and that extracts of these materials therefore could be of potential interest for development of antioxidant food additives.

Non-targeted metabolite profiling highlights the potential of strawberry leaves as a resource for specific bioactive compounds

BACKGROUND

The non-edible parts of horticultural crops, such as leaves, contain substantial amounts of valuable bioactive compounds which are currently only little exploited. For example, strawberry (Fragaria × ananassa) leaves may be a promising bioresource for diverse health-related applications. However, product standardization sets a real challenge, especially when the leaf material comes from varying cultivars. The first step towards better quality control of berry fruit leaf-based ingredients and supplements is to understand metabolites present and their stability in different plant cultivars, so this study surveyed the distribution of potentially bioactive strawberry leaf metabolites in six different strawberry cultivars. Non-targeted metabolite profiling analysis using LC/qTOF-ESI-MS with data processing via principal component analysis and k-means clustering analysis was utilized to examine differences and commonalities between the leaf metabolite profiles.

RESULTS

Quercetin and kaempferol derivatives were the dominant flavonol groups in strawberry leaves. Previously described and novel caffeic and chlorogenic acid derivatives were among the major phenolic acids. In addition, ellagitannins were one of the distinguishing compound classes in strawberry leaves. In general, strawberry leaves also contained high levels of octadecatrienoic acid derivatives, precursors of valuable odour compounds.

CONCLUSION

The specific bioactive compounds found in the leaves of different strawberry cultivars offer the potential for the selection of optimized leaf materials for added-value food and non-food applications. © 2016 Society of Chemical Industry.

In vitro cultures of Bacopa monnieri and an analysis of selected groups of biologically active metabolites in their biomass

CONTEXT

Bacopa monnieri L. Pennell (Scrophulariaceae) is one of the most important plants in the system of Indian medicine (Ayurveda).

OBJECTIVE

This paper studies the optimal growth of B. monnieri for effective accumulation of metabolites. Biomass growth of this plant could be accomplished in liquid cultures on Murashige & Skoog medium.

MATERIALS AND METHODS

Powdered shoots of in vitro cultures of B. monnieri were extracted by methanol for indole compounds, phenolic compounds and bacosides for RP-HPLC analysis. Fatty acid analysis was performed via gas chromatography. Anti-inflammatory effect of B. monnieri extracts was evaluated in the A549 cells. COX-2 and cPGES expression was analyzed using Western blots.

RESULTS

l-Tryptophan and serotonin were found in biomass from in vitro cultures of B. monnieri on MS medium and in biomass from the MS mediums enriched with the different additions such as of 0.1 g/L magnesium sulphate, 0.1 g/L zinc hydroaspartate, 0.1 g/L l-tryptophan, 0.25 g/L serine, 0.5 g/L serine and 0.5 mg/L anthranilic acid. The content of l-tryptophan and serotonin compounds was significant in biomass from medium with the addition of 0.1 g/L zinc hydroaspartate (0.72 mg/g dry weight and 1.19, respectively). Phenolic compounds identified in biomass from the same variants of MS medium were chlorogenic acid (ranging from 0.20 to 0.70 mg/g dry weight), neochlorogenic acid (ranging from 0.11 to 0.40 mg/g dry weight) and caffeic acid (ranging from 0.01 to 0.04 mg/g dry weight). The main group of fatty acids in biomass was saturated fatty acids (53.4%). The predominant fatty acid was palmitic acid. A significant decrease of COX-2 and cPGES expression was observed in the A549 cells activated with LPS and treated with B. monnieri extracts.

DISCUSSION AND CONCLUSIONS

As far as we know, this is the first analysis of indole compounds and phenolic acids in this plant. The multi-therapeutic effect of B. monnieri is expressed by the activity of bacosides. Information about the presence of indole and phenolic compounds, and fatty acids in this plant is limited, but the content of these compounds might participate in the physiological activity of B. monnieri.

Antioxidant and Myocardial Preservation Activities of Natural Phytochemicals from Mung Bean (Vigna radiata L.) Seeds

Mung bean (Vigna radiata L.) seeds (MBS) contain abundant nutrients with biological activities. This study was aimed to isolate key bioactive components from MBS with antioxidant and myocardial preservation activities. A new flavonoid C-glycoside, isovitexin-6″-O-α-l-glucoside, and 14 known compounds were obtained. Their structures were identified by extensive 1D and 2D NMR and FT-ICR-MS spectroscopic analyses. The antioxidant activities of these compounds were evaluated. Compounds 1-5 and 7-10 displayed 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS(•+)) scavenging activity, but only 5 and 7 exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) scavenging activity. The myocardial preservation effect of 2, 3, and MBS were investigated by measuring the serum levels of LDH, CK, and AST as well as the tissue level of MDA and SOD. The results demonstrated that 2, 3, and MBS had a significant protective effect against ISO-induced myocardial ischemia. MBS can be regarded as a potential new source of antioxidants and myocardial preservation agents.

Berry Leaves: An Alternative Source of Bioactive Natural Products of Nutritional and Medicinal Value

Berry fruits are recognized, worldwide, as “superfoods” due to the high content of bioactive natural products and the health benefits deriving from their consumption. Berry leaves are byproducts of berry cultivation; their traditional therapeutic use against several diseases, such as the common cold, inflammation, diabetes, and ocular dysfunction, has been almost forgotten nowadays. Nevertheless, the scientific interest regarding the leaf composition and beneficial properties grows, documenting that berry leaves may be considered an alternative source of bioactives. The main bioactive compounds in berry leaves are similar as in berry fruits, i.e., phenolic acids and esters, flavonols, anthocyanins, and procyanidins. The leaves are one of the richest sources of chlorogenic acid. In various studies, these secondary metabolites have demonstrated antioxidant, anti-inflammatory, cardioprotective, and neuroprotective properties. This review focuses on the phytochemical composition of the leaves of the commonest berry species, i.e., blackcurrant, blackberry, raspberry, bilberry, blueberry, cranberry, and lingonberry leaves, and presents their traditional medicinal uses and their biological activities in vitro and in vivo.

Small-Scale Habitat-Specific Variation and Adaptive Divergence of Photosynthetic Pigments in Different Alkali Soils in Reed Identified by Common Garden and Genetic Tests

Flexibility of photosynthetic pigment traits is an important adaptive mechanism through which plants can increase mean fitness in a variable environment. Unlike morphological traits in plants, photosythesis has been shown to exhibit phenotypic plasticity, responding rapidly to environmental conditions. Meanwhile, local adaptation at small scales is considered to be rare. Thus, detecting the small-scale adaptive divergence of photosynthetic pigments presents a challenge. Leaf concentrations of photosynthetic pigments under stressful conditions may be reduced or maintained. Concentrations of some pigments and/or ratio of Chlorophyll a (Chla) to Chlorophyll b (Chlb) do not change markedly in some species, such as the common reed, Phragmites australis, a cosmopolitan grass and common invader. Little is known about photosynthetic responses of this plant to varying levels of alkali salt. Few studies have attempted to account for the relationship between pigment accumulation and leaf position in wild plant populations in grasslands. In this study, photosynthetic pigment concentrations and the total Chl(a+b)/Car ratio decreased as the growing season progressed and were shown to be significantly lower in the habitat with a higher soil pH value and less moisture when compared between habitats. The Chla/Chlb ratio did not differ significantly between habitats, although it increased significantly over time. Leaves in the middle position may be functionally important in the response to soil conditions because only pigment concentrations and the Chl(a+b)/Car ratio of those leaves varied between habitats significantly. The outlier loci, used to evaluate molecular signatures of selection, were detected by Arlequin, Bayescan, and Bayenv analyses. In the simulated habitats of common garden, the local genotypes had higher values of Chla, Chlb, Chl(a+b), Car in their home habitat than did genotypes originating from the other habitat. Q_ST-F_ST comparisons provided evidence of divergent selection. It appears likely that soil moisture, pH and electric conductivity drove local adaptation. Combined approaches that utilize information on phenotypes from field and common garden experiments, genome-wide markers, and environmental data will be the most informative for understanding the adaptive nature of the intraspecific divergence.

Flavonol Glycosides in Currant Leaves and Variation with Growth Season, Growth Location, and Leaf Position

Flavonol glycosides (FG) were analyzed in the leaves of six currant cultivars (Ribes spp.) with HPLC-DAD, HPLC-MS/MS, and NMR. The average amounts of the 12 major, identified FG constituted 86-93% (9.6-14.1 mg/g DW) of the total of 27 FG found. Quercetin and kaempferol were the major aglycones with trace amounts of myricetin. Quercetin-3-O-(2,6-α-dirhamnopyranosyl-β-glucopyranoside), quercetin-3-O-(2-β-xylopyranosyl-6-α-rhamnopyranosyl-β-glucopyranoside), and kaempferol-3-O-(3,6-α-dirhamnopyranosyl-β-glucopyranoside) were identified for the first time in currant leaves and existed in a white currant cultivar 'White Dutch' only. Kaempferol-3-O-β-(6'-malonyl)glucopyranoside was also a new compound existing in abundance in five cultivars but not in the white one. The results show the primary importance of the genetic background of the cultivars. The content of malonylated FG of special importance in cardiovascular health decreased regularly during summer. Time of collection and leaf position were more prominent factors affecting the composition than were the year of harvest or the growth latitude. Randomly collected leaves differed in their FG profiles from those collected from the middle position of new branches.

Food Byproducts as a New and Cheap Source of Bioactive Compounds: Lignans with Antioxidant and Anti-inflammatory Properties from Crataegus pinnatifida Seeds

During the process of manufacturing hawthorn (Crataegus pinnatifida) juice and jam, a significant quantity of byproducts (leaves, seeds) is generated. The antioxidant and anti-inflammatory bioassay-guided fractionation of the extract of hawthorn seeds has led to the isolation of eight new lignans, hawthornnins A-H (1-8), and seven known analogues (9-15). Their structures were elucidated by spectroscopic techniques, including 1D and 2D NMR and CD spectra. The radical-scavenging effects of all isolated compounds were investigated. 1-6 and 8 showed moderate activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas 1-6 and 14 displayed good 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical-scavenging activities that were even more potent than that of trolox. In addition, all isolates were evaluated for their anti-inflammatory activities by detecting the nitric oxide (NO) and tumor necrosis factor α (TNF-α) production by the LPS-induced murine macrophage cell line RAW264.7, and compounds 1-7, 13, and 14 exhibited potent inhibition of NO and TNF-α production. The structure-activity relationships of isolated lignans were also examined, and the results obtained show that C. pinnatifida seeds can be regarded as a potential new and cheap source of antioxidants and inflammation inhibitors.