Composition Of Phenolic Compounds Research Articles

Antibacterial Activities of Phenolic Compounds in Miang Extract: Growth Inhibition and Change in Protein Expression of Extensively Drug-Resistant Klebsiella pneumoniae.

The rising incidence of extensively drug-resistant (XDR) Klebsiella pneumoniae, including carbapenem- and colistin-resistant strains, leads to the limitation of available effective antibiotics. Miang, known as chewing tea, is produced from Camellia sinensis var. assamica or Assam tea leaves fermentation. Previous studies revealed that the extract of Miang contains various phenolic and flavonoid compounds with numerous biological activities including antibacterial activity. However, the antibacterial activity of Miang against XDR bacteria especially colistin-resistant strains had not been investigated. In this study, the compositions of phenolic and flavonoid compounds in fresh, steamed, and fermented Assam tea leaves were examined by HPLC, and their antibacterial activities were evaluated by the determination of the MIC and MBC. Pyrogallol was detected only in the extract from Miang and showed the highest activities with an MIC of 0.25 mg/mL and an MBC of 0.25-0.5 mg/mL against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, Escherichia coli ATCC 25922, colistin-resistant E. coli, and colistin-resistant K. pneumoniae. The effects on morphology and proteomic changes in K. pneumoniae NH54 treated with Miang extract were characterized by SEM and label-free quantitative shotgun proteomics analysis. The results revealed that Miang extract caused the decrease in bacterial cell wall integrity and cell lysis. The up- and downregulated expression with approximately a 2 to >5-fold change in proteins involved in peptidoglycan synthesis and outer membrane, carbohydrate, and amino acid metabolism were identified. These findings suggested that Miang containing pyrogallol and other secondary metabolites from fermentation has potential as an alternative candidate with an antibacterial agent or natural active pharmaceutical ingredient against XDR bacteria including colistin-resistant bacteria.

Changes in various secondary metabolites by crossing modern rose cultivars

ABSTRACT The aim of the study was to determine the content and composition of phenolic compounds in autochthonous rose hips (R. pendulina, R. spinosissima and R. gallica) and to compare them with the content of phenolic compounds in their cultivars (‘Harstad’, ‘Bourgogne’, ‘Mount Everest’, ‘Poppius’, ‘Frühlingsduft’, ‘Single Cherry’, ‘Frühlingsmorgen’, ‘ Violacea’ and ‘Splendens’) collected in Arboretum Volčji Potok in Slovenia. The total content of phenolic compounds in the flesh with skin was lowest in ‘Mount Everest’ (3603.57 mg · kg−1 f.w.), which is derived from R. pendulina, and highest in ‘Splendens’ (68789.39 mg · g−1 f.w.), which is derived from R. gallica. In seeds, the phenolic compound content was lower, as expected, ranging from 757.02 mg · kg−1 f.w. (‘Mount Everest’) to 6823.21 mg · kg−1 f.w. (‘Single Cherry’). It can be concluded that the cultivars differ significantly from each other due to the content of different bioactive compounds. Based on the obtained results, we cannot determine to which basic rose plant the cultivar belongs based only on the content of one analysed compound. The contents were very different because only one parent plant is known for a given cultivar and breeding programmes in roses were very narrowly focussed on specific targets.

Phenolic fingerprint of Macedonian propolis

Propolis is a chemically complex resinous material collected by honeybees (Apis mellifera) from tree buds and resins, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. Its chemical composition depends strongly on the plant sources available around the beehive, which have a direct impact оn the quality and bioactivity of the propolis. In this study, the composition of phenolic compounds in 13 Macedonian propolis extracts was investigated by HPLC-DAD-ESI-MS/MS. Overall, the UV spectra, the MS and MS/MS data allowed the identification of 36 compounds. The major constituents of propolis were phenolic acids (caffeic and coumaric) and their esters (methyl, (iso)prenyl, benzyl, phenylethyl, cinnamyl), flavonols (quercetin, kaemferol), flavones (chrysin, apigenin, acacetin), flavanonols (pinobanksin) flavanones (pinocembrin naringenin, hesperetin, pinostrobin) and their methylated/esterified derivatives. The results reveal that Macedonian propolis contains a diversity of phenolic compounds confirming that it is a poplar type of propolis with higher phenolic content (ranging from 43.75–637.94 mg/g) than reported in previous studies in the region and beyond in Europe (< 80 mg/g). This suggests the potential significance of Macedonian propolis as a valuable source of bioactive compounds with health benefits as well as for unlocking its economic potential for industry and beekeepers.

Enhancing Secondary Metabolite Production in Pelargonium graveolens Hort. Cell Cultures: Eliciting Effects of Chitosan and Jasmonic Acid on Bioactive Compound Production

This study explores the effects of chitosan (CHT) and jasmonic acid (JA) elicitors on rose-scented geranium (Pelargonium graveolens Hort.) cell suspension cultures, aiming to enhance the production of phenolics and flavonoids and antioxidant properties. Elicitation with CHT and JA resulted in varied biomass yields and callus characteristics, with higher concentrations generally leading to increased phenolic accumulation. Optimal biomass was achieved with CHT4 (75 mg/mL) and JA3 (50 µM) treatments. HPLC-DAD analysis revealed changes in phenolic compound composition and quantities, with specific compounds induced by either CHT4 or JA3. For instance, gallic acid content increased significantly in CHT4-treated cells, while catechin content increased notably in both CHT4 and JA3 treatments. Antioxidant enzyme activities like superoxide dismutase and peroxidase increased with elicitor concentration, particularly in CHT4 and JA3 treatments. Both treatments exhibited potent antioxidant activity, with JA3 exhibiting the lowest IC50 value in the DPPH assay and highest total antioxidant capacity (TAC) values. Surprisingly, both CHT4 and JA3 extracts effectively inhibited tyrosinase activity. These findings underscore the efficacy of CHT and JA elicitors in enhancing phenolic and flavonoid production, boosting antioxidant capacity, and inhibiting tyrosinase activity in P. graveolens cultures, offering promising implications for further research and industrial applications in pharmaceutical and cosmetic sectors.

Barley-derived beer brewing by-products contain a high diversity of hydroxycinnamoylagmatines and their dimers

To aid valorisation of beer brewing by-products, more insight into their composition is essential. We have analysed the phenolic compound composition of four brewing by-products, namely barley rootlets, spent grain, hot trub, and cold trub. The main phenolics detected were hydroxycinnamoylagmatines and dimers thereof. Barley rootlets contained the highest hydroxycinnamoylagmatine content and cold trub the highest dimer content. Additionally, variations in (dimeric) hydroxycinnamoylagmatine composition and content were observed in fourteen barley rootlet samples. The most abundant compound in all rootlets was the glycosylated 4-O-7′/3-8′-linked heterodimer of coumaroylagmatine and feruloylagmatine, i.e. CouAgm-4-O-7′/3-8′-(4′Hex)-DFerAgm. Structures of glycosylated and hydroxylated derivatives of coumaroylagmatine were elucidated by NMR spectroscopy after their purification from a rootlet extract. An MS-based decision tree was developed, which aids in identifying hydroxycinnamoylagmatine dimers in complex mixtures. In conclusion, this study shows that the diversity of phenolamides and (neo)lignanamides in barley-derived by-products is larger than previously reported.

Variability in the Qualitative and Quantitative Composition of Phenolic Compounds and the In Vitro Antioxidant Activity of Sour Cherry (Prunus cerasus L.) Leaves.

Sour cherry (Prunus cerasus L.) is a deciduous tree belonging to the Rosaceae Juss. family. Cherry leaves are an underutilized source of biologically active compounds. The aim of this study was to determine the composition of the phenolic compounds, as well as the total antioxidant activity, in leaf samples of P. cerasus cultivars and to elucidate the cultivars with particular phytochemical compositions. The phytochemical profiles of P. cerasus leaves vary significantly in a cultivar-dependent manner. The total content of identified phenolic compounds varied from 8.254 to 16.199 mg/g in the cherry leaves. Chlorogenic acid ranged between 1413.3 µg/g ('North Star') and 8028.0 µg/g ('Note'). The total content of flavonols varied from 4172.5 µg/g ('Vytenu zvaigzde') to 9030.7 µg/g ('Tikhonovskaya'). The total content of identified proanthocyanidins varied from 122.3 µg/g ('Note') to 684.8 µg/g ('Kelleris'). The highest levels of phloridzin (38.1 ± 0.9 µg/g) were found in samples of 'Molodezhnaya', while the lowest level of this compound was determined in the leaf samples of 'Turgenevka' (6.7 ± 0.2). The strongest antiradical (138.0 ± 4.0 µmol TE/g, p < 0.05) and reducing (364.9 ± 10.5 µmol TE/g, p < 0.05) activity in vitro was exhibited by the cultivar 'Vytenu zvaigzde' cherry leaf sample extracts. 'Kelleris', 'Note', and 'Tikhonovskaya' distinguish themselves with peculiar phytochemical compositions.

Total Content and Composition of Phenolic Compounds from Filipendula Genus Plants and Their Potential Health-Promoting Properties.

This current article was dedicated to the determination of the composition of phenolic compounds in extracts of four species of the genus Filipendula in order to establish a connection between the composition of polyphenols and biological effects. A chemical analysis revealed that the composition of the extracts studied depended both on the plant species and its part (leaf or flower) and on the extractant used. All four species of Filipendula were rich sources of phenolic compounds and contained hydrolyzable tannins, condensed tannins, phenolic acids and their derivatives, and flavonoids. The activities included data on those that are most important for creating functional foods with Filipendula plant components: the influence on blood coagulation measured by prothrombin and activated partial thromboplastin time, and on the activity of the digestive enzymes (pancreatic amylase and lipase). It was established that plant species, their parts, and extraction methods contribute meaningfully to biological activity. The most prominent result is as follows: the plant organ determines the selective inhibition of either amylase or lipase; thus, the anticoagulant activities of F. camtschatica and F. stepposa hold promise for health-promoting food formulations associated with general metabolic disorders.

Phenolic profiles differentiate wild bilberry and cultivated blueberry fruit

The dark fruit of European wild-grown blueberry known as common bilberry (Vaccinium myrtillus L.) is associated with many health-promoting properties and has a steadily growing global market, especially in the food supplement sector. The adulteration of bilberry products with some less expensive fruits and berries with an intense color is a well-known problem. Phytochemical profiling is a viable option to discern different plant species from each other. In this study, the chemical composition of the fruit of wild bilberry and its close relative, cultivated blueberry (Vaccinium sp.), were analyzed and compared. A large number of samples of different geographical origin was collected. The major phenolics, including anthocyanins, chlorogenic acid, and condensed tannins, were determined by liquid chromatography using various detection methods. Significant differences were found in the phenolic profiles between wild-grown bilberry and cultivated blueberry. Principal component analysis indicated that it was possible to distinguish bilberry from cultivated blueberry based solely on their anthocyanin or tannin profiles. However, the geographical origin of the berries could not be identified according to their phenolic compound composition.

Phenolic compounds in sea buckthorn (Hippophae rhamnoides L.) and their health‐promoting activities: a review

SummarySea buckthorn (SB) is used in cuisines and herbal remedies due to its remarkable nutritional composition and health‐enhancing properties. The phenolic compounds present in SB plant include phenolic acids (gallic, p‐coumaric, protocatechuic and ferulic acids), flavonols (isorhamnetin, quercetin and kaempferol), flavan‐3‐ols and polymeric procyanidins. The highest content of these compounds was reported in branches and leaves than corresponding edible parts of the plant. The antioxidant properties of SB are related to content and composition of phenolic compounds in different plant parts. The studies reported SB flavonoids (isorhamnetin and quercetin) as main phenolic compounds with medicinal potential and health‐promoting effects. The present review summarises information available in recent studies on phenolic composition, phenolic content, flavonoid content, antioxidant activity and health‐promoting activities (anti‐oxidant, hepatoprotective, cardioprotective, anti‐inflammatory, anti‐diabetic and obesity management) of SB that can be used in curtailing various acute and chronic maladies. SB can be projected as a promising source of bioactive constituents with the potential to be used in healthy foods for beneficial effects on human health.

Characterization, Bioaccesibility and Antioxidant Activities of Phenolic Compounds Recovered from Yellow pea (Pisum sativum) Flour and Protein Isolate.

This study focused on studying the bioaccesible phenolic compounds (PCs) from yellow pea flour (F) and protein isolate (I). Total phenolic contents (TPC), PCs composition and antioxidant activities were analysed in ethanol 60% extracts obtained by applying ultrasound assisted extraction (UAE, 15min/40% amplitude). The preparation of I under alkaline conditions and the elimination of some soluble components at lower pH produced a change of PCs profile and antioxidant activity. After simulated gastrointestinal digestion (SGID) of both ingredients to obtain the digests FD and ID, notable changes in the PCs concentration and profiles could be demonstrated. FD presented a higher ORAC activity than ID (IC50 = 0.022 and 0.039mg GAE/g dm, respectively), but lower ABTS•+ activity (IC50 = 0.8 and 0.3mg GAE/g dm, respectively). After treatment with cholestyramine of extracts from FD and ID in order to eliminate bile salts and obtain the bioaccesible fractions FDb and IDb, ROS scavenging in H2O2-induced Caco2-TC7 cells was evaluated, registering a greater activity for ID respect to FD (IC50 = 0.042 and 0.017mg GAE/mL, respectively). These activities could be attributed to the major bioaccesible PCs: OH-tyrosol, polydatin, trans-resveratrol, rutin, (-)-epicatechin and (-)-gallocatechin gallate for FD; syringic (the most concentrated) and ellagic acids, trans-resveratrol, and (-)-gallocatechin gallate for ID, but probably other compounds such as peptides or amino acids can also contribute.

Improving Soluble Phenolic Profile and Antioxidant Activity of Grape Pomace Seeds through Fungal Solid-State Fermentation.

Grape pomace seeds contain abundant phenolic compounds, which are also present in both soluble and insoluble forms, similar to many other plant matrices. To further increase the extractable soluble phenolics and their antioxidant activities, grape pomace seeds were fermented with different fungi. Results showed that solid-state fermentation (SSF) with Aspergillus niger, Monascus anka, and Eurotium cristatum at 28 °C and 65% humidity had a significantly positive impact on the release of soluble phenolics in grape pomace seeds. Specifically, SSF with M. anka increased the soluble phenolic contents by 6.42 times (calculated as total phenolic content) and 6.68 times (calculated as total flavonoid content), leading to an overall improvement of antioxidant activities, including DPPH (increased by 2.14 times) and ABTS (increased by 3.64 times) radical scavenging activity. Furthermore, substantial changes were observed in the composition and content of individual phenolic compounds in the soluble fraction, with significantly heightened levels of specific phenolics such as chlorogenic acid, syringic acid, ferulic acid, epicatechin gallate, and resveratrol. Notably, during M. anka SSF, positive correlations were identified between the soluble phenolic content and hydrolase activities. In particular, there is a strong positive correlation between glycosidase and soluble phenols (r = 0.900). The findings present an effective strategy for improving the soluble phenolic profiles and bioactivities of grape pomace seeds through fungal SSF, thereby facilitating the valorization of winemaking by-products.

Distribution of antioxidants and phenolic compounds in flour milling fractions from hard red winter wheat

Mature wheat kernels contain three main parts: endosperm, bran, and germ. Flour milling results in multiple streams that are chemically different; however, the distribution of antioxidants and phenolic compounds has not been well documented in terms of conventional milling by-product streams. In this study, multiple analytical methods were used to investigate antioxidant activity and phenolic compound compositions of hard red winter wheat (whole ground wheat), the parts of a wheat kernel (bran, flour, germ), and wheat by-product streams (mill feed, red dog, shorts) for the first time. For each mill stream, phenolic compounds (total, flavonoid, and anthocyanin contents) were determined and antioxidant activities were evaluated with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, ferric reducing/antioxidant power (FRAP), and total antioxidant capacity assays. Significant differences (P < 0.05) were observed in phenolic concentrations among fractions of bran, flour, and germ milled from the same kernels and noted that germ accounts for the majority of antioxidant properties, whereas bran contains a substantial portion of phenolic compounds and anthocyanins. Mill feed was high in phenolic content (5.29 mg FAE/g), total antioxidant capacity (866 mg/g), and antioxidant activity (up to 75% DPPH inhibition and 20.26 μmol FeSO4/g). The comprehensive information on distribution of antioxidants and phenolic compounds provides insights for future human consumption of commonly produced co-products from flour milling, and for selecting and using different milling fractions to make foods with improved nutritional properties.

Changes in phenolic composition, antioxidant, sensory and microbiological properties during fermentation and storage of maize products

In this study, we assessed the potential of maize (Zea mays) flour to serve as a substrate for the growth, metabolism, and survival of the Fresco culture cocci (Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. cremoris and Streptococcus thermophilus) and Bifidobacterium spp. (B. choerinum K1/1, B. pseudolongum K4/4, B. animalis subsp. animalis J3II, B. thermophilum DSM 20212), which could result in improved nutritional and sensory properties. Maize dairy-free mashes (flavoured with saccharose or caramel) were effectively fermented with Fresco culture for 8 h at 37 °C (3 log increase of counts on average). The functionality of products was proven within the cold storage period (21 days at 6 °C) when viable cell densities of potentially probiotic bacteria were sufficient to demonstrate health-promoting effects (> 5 log CFU/mL). Fermentation process positively changed the contents and compositions of phenolic compounds. Total phenolic content was higher by about 11.5–94.68% in comparison to initial values (0 h). Caffeic acid recorded the highest increase, by about 21.7–151.7%. The antioxidant activity of fermented mashes was also improved. Overall sensory acceptance was enhanced from 2.1 (8 h) to 3.1–3.6 from 4.0 (21 d), which revealed pleasant acceptance of the final caramel products.Graphical

Changes in Chemical Composition of Red and Black Currant Fruits and Leaves During Berry Ripening

ABSTRACT The composition and variations of sugars, organic acids and phenolic compounds of red and black currant fruits and leaves were studied during the last four weeks of ripening. The results showed that sugar content increased during berry ripening in both species. In comparison, organic acids decreased in red currant, whereas no differences between sampling dates were observed in black currant. Forty-seven individual phenolic compounds, belonging to anthocyanins, flavonols, flavanols, hydroxycinnamic acid derivatives and flavanones were identified in red currant fruits and 52 in black currant fruits by HPLC-MS analysis. In black currant fruits, the major phenolic compounds were anthocyanins (81.51–85.15% of total phenolics), which increased during ripening until the last sampling date. In both red and black currant leaves, 47 phenolic compounds were identified. The content of phenolic compounds in red currant leaves was 1.31-fold to 1.90-fold higher compared to the content in black currant leaves. The most abundant phenolics in both currant leaves were flavonol glycosides, accounting for 58.5–67.9% of total phenolics, and their content was the highest at the end of berry ripening.

Phenolic, Nutritional and Sensory Characteristics of Bakery Foods Formulated with Grape Pomace.

The potentiality of cv. Malbec grape pomace (GP) as a functional ingredient in the formulation of bakery foods (muffins, biscuits and cereal bars) was studied. The effect of GP addition on the phenolic compounds (PCs) composition, nutritional and sensory properties were evaluated. The addition of GP increased the content of dietary fiber, proteins, ash, total phenolic content (TPC), antiradical capacity (AC), anthocyanins and non-anthocyanin PCs while decreasing the carbohydrates content. The main PCs given by the GP to supplemented foods were quercetin-3-O-glucoside, rutin, caffeic acid, syringic acid and (+)-catechin. For anthocyanins, the acylated derivatives were more stable to heat treatment (baking) in food processing which was evidenced by a higher proportion of these PCs compounds when compared to the same derivatives quantified in GP. In general, when the TPC or individual concentrations of PCs were analyzed in a nutritional or functional context, one portion of the supplemented foods showed levels high enough to satisfy the recommended dose per day of these bioactive compounds. Additionally, the foods were well received by consumers during the sensory evaluation and supplemented biscuits received the highest acceptability. This study demonstrated that GP could be a viable functional ingredient in bakery foods to incorporate components like PCs and dietary fiber into traditional consumers' diets.

COMPARISON OF THE PHENOLIC COMPOUNDS CONTENT AND COMPOSITION IN SYNECHOCYSTIS SP. AND DESERTIFILUM THARENSE

The content and composition of phenolic compounds in Synechocystis sp. PCC 6803 GT-L and Desertifilum tharense were studied for the first time. A spectrophotometric method was used to determine the phenolic compounds content, thin-layer chromatography and UV spectrometry to study their composition. A higher accumulation of these secondary metabolites was found in Synechocystis sp., which was almost twice as high as that in Desertifilum tharense. In both cases, the higher content of phenolic compounds was observed in the linear phase of cyanobacteria growth (3 days). Synechocystis sp. and Desertifilum tharense characterized by the formation of phenolics (4 and 7 compounds, respectively), which contain p-oxybenzoic or p-coumaric acids – the initial stages’metabolites of the phenolic compounds biogenesis.

The composition of phenolic compounds in Chinese olive (Canarium album L.) cultivars and their contribution to the anti-inflammatory properties of the cultivars.

This study aimed to explore the phenolic compounds (PCs) present in three Chinese olive (Canarium album L.) cultivars and the contribution of these PCs to the anti-inflammatory activities of the cultivars. Ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap/mass spectrometry (UPLC-Q-Exactive/MS) was used to identify and quantify the PCs present in three Chinese olive cultivars, "Na zhong," "Tan xiang," and "Xiang zhong". 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate) (ABTS); and oxygen radical absorption capacity (ORAC) assays were used to assess the antioxidant activities of the PCs. Furthermore, we analyzed the anti-inflammatory action of these PCs using lipopolysaccharide (LPS)-induced RAW264.7 cells. A total of 44 PCs were identified in the three cultivars. Of these, 17 PCs were previously unidentified in Chinese olive. Among the cultivars, the free phenolics (FPs) of "Tan xiang" showed the strongest antioxidant activity. All cultivars have shown significant inhibition of TNF-α and IL-6 production. Clustering correlation analysis showed galloyl-bis-HHDP-glucose and paeonol have significant anti-inflammatory ability in FPs. Quininic, galloylquinic acid, 4-hydroxycinnamic acid and gallic acid hexoside have shown significant inhibition of IL-6 production in BPs. Furthermore, gallic acid, catechin, syringic acid, and nobiletin exhibit negative correlation in FPs and positive correlation in BPs of cytokine production, while corilagin and methyl ellagic acid pentoside exhibited opposite correlation. In summary, this study contributed to the literature on PCs in Chinese olives and the potential health benefits of FPs and BPs.

Nutraceutical Potential of Underutilized Tropical Fruits and Their Byproducts: Phenolic Profile, Antioxidant Capacity, and Biological Activity of Jerivá (Syagrus romanzoffiana) and Butiá (Butia catarinensis).

Jerivá and butiá are under-valued tropical fruits lacking scientific evidence about their nutraceutical potential. Therefore, they were investigated for their phenolic compound composition and biological activities. Free, esterified, and insoluble-bound polyphenols were obtained from powdered jerivá and butiá pomace and seeds. The total phenolic estimation in seeds (jerivá, 36.45 mg GAE/g; butiá, 45.79 mg GAE/g) exceeded pomaces (jerivá, 23.77 mg GAE/g; butiá, 18.69 mg GAE/g). Phenolic extracts demonstrated antidiabetic and antiobesity potential, inhibiting α-glucosidase (30.51-98.43%) and pancreatic lipase (19.66-41.98%). They also suppressed free radical-induced damage to DNA (21.46-92.48%) and LDL-cholesterol (8.27-23.20%). Identified phenolics (51) included multiple phenolic acids, flavonoids, and tannins, predominantly gallic acid derivatives/conjugates. This is the first study to provide a detailed description of the phenolic profile of these fruits and their byproducts coupled with their bioactivities. Butiá and jerivá were demonstrated to be outstanding sources of polyphenols with high nutraceutical potential for bioeconomic exploration.

Bacterial Endophytes from Legumes Native to Arid Environments Are Promising Tools to Improve Mesorhizobium-Chickpea Symbiosis under Salinity.

Symbiotic nitrogen fixation is a major contributor of N in agricultural ecosystems, but the establishment of legume-rhizobium symbiosis is highly affected by soil salinity. Our interest is focused on the use of non-rhizobial endophytes to assist the symbiosis between chickpea and its microsymbiont under salinity to avoid loss of production and fertility. Our aims were (1) to investigate the impact of salinity on both symbiotic partners; including on early events of the Mesorhizobium-chickpea symbiosis, and (2) to evaluate the potential of four non-rhizobial endophytes isolated from legumes native to arid regions (Phyllobacterium salinisoli, P. ifriqiyense, Xanthomonas translucens, and Cupriavidus respiraculi) to promote chickpea growth and nodulation under salinity. Our results show a significant reduction in chickpea seed germination rate and in the microsymbiont Mesorhizobium ciceri LMS-1 growth under different levels of salinity. The composition of phenolic compounds in chickpea root exudates significantly changed when the plants were subjected to salinity, which in turn affected the nod genes expression in LMS-1. Furthermore, the LMS-1 response to root exudate stimuli was suppressed by the presence of salinity (250 mM NaCl). On the contrary, a significant upregulation of exoY and otsA genes, which are involved in exopolysaccharide and trehalose biosynthesis, respectively, was registered in salt-stressed LMS-1 cells. In addition, chickpea co-inoculation with LMS-1 along with the consortium containing two non-rhizobial bacterial endophytes, P. salinisoli and X. translucens, resulted in significant improvement of the chickpea growth and the symbiotic performance of LMS-1 under salinity. These results indicate that this non-rhizobial endophytic consortium may be an appropriate ecological and safe tool to improve chickpea growth and its adaptation to salt-degraded soils.

Antifungal activity of Carya illinoinensis extracts against Alternaria alternata pathogen and their cytotoxicity effects on HEK-293T cells: HPLC analysis of bioactive compounds

Derivatives of Carya illinoinensis (pecan) are used as dietary supplements and their leaf and nuts-in-shuck extracts are used in the treatment of various pathologies due to their significant composition in phenolic compounds that act as natural antifungal and anticancer agents. This study aimed to evaluate the antifungal activity of acetone extracts (AEs) from leaves (L) and nuts-in-shucks (S) of cultivars (cv.) Wichita (Wic) and Ukulinga (Uku) of South African C. illinoinensis against A. alternata pathogen. The AEs of Wic-L and Uku-L showed higher antifungal efficacy against all tested A. alternata isolates, with inhibition zones ranging from 11 to 39 mm. Acetone crude extracts of cv. Wichita and cv. Ukulinga showed efficacy against the isolates and were significantly different (p < 0.001). Scanning electron microscopy (SEM) showed major morphological damages on the conidia from assayed cultures, which resulted in inhibition. We further evaluated the in vitro cytotoxic effects of Carya illinoinensis on human embryonic kidney 293 (HEK-293T) cell lines with methanolic extracts (MEs). HEK-293T cell lines (10 × 103 cells/well) were treated with each sample of the extracts at various concentration (1.56, 6.25, 12.5, 25, 50, and 100 µg/mL) and cell viability was quantitated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after 48 h. The HEK-293 cell viabilities when exposed to MEs of Wic-L, Wic-S, and Uku-L were 88.2%, 75.2%, and 86.3% respectively, confirming non-toxic properties in accordance with International Organisation for Standardization (ISO) norms. However, the viability of cell culture after the treatment with MEs of Uku-S was 37% and was as toxic. We further used High-performance liquid chromatography (HPLC) to investigate individual phenolic constituents and total phenolic content in the leaves and shucks of both cultivars. Twelve individual phenols were detected through HPLC analysis in the respective extracts. The total phenolic content was higher in the extracts of Wic-L (102.19 mg GAE/g) and Uku-L (110.13 mg GAE/g) relative to the Wic-S (62.03 mg GAE/g) and Uku-S (85.07 mg GAE/g) extracts. Finally, these findings highlighted the possibility of pecan leaf extracts as a potential natural bioactive antifungal agent against black spot disease on pecans in South Africa.