Complete and circularized genome sequences of five nitrogen-fixing Bradyrhizobium sp. strains isolated from root nodules of peanut, Arachis hypogaea, cultivated in Tunisia.

This manuscript reports the complete and circularized Oxford Nanopore Technologies (ONT) long read-based genome sequences of five nitrogen-fixing symbionts belonging to the genus Bradyrhizobium, isolated from root nodules of peanut (Arachis hypogaea) grown on soil samples collected from Tunisia.

The Beneficial Effects of Inoculation with Selected Nodule-Associated PGPR on White Lupin Are Comparable to Those of Inoculation with Symbiotic Rhizobia.

Nodule endophytes and associated bacteria are non-symbiotic bacteria that colonize legume nodules. They accompany nodulating rhizobia and can form beneficial associations, as some of them are plant growth-promoting rhizobacteria (PGPR) that are able to promote germination and plant growth and increase tolerance to biotic and abiotic stress. White lupin (Lupinus albus) is a legume crop that is gaining relevance as a suitable alternative to soybean as a plant protein source. Eleven nodule-associated bacteria were isolated from white lupin nodules grown in a Tunisian soil. They belonged to the genera Rhizobium, Ensifer, Pseudomonas and Bacillus. Their plant growth-promoting (PGP) and enzymatic activities were tested in vitro. Strains Pseudomonas sp., L1 and L12, displayed most PGP activities tested, and were selected for in planta assays. Inoculation with strains L1 or L12 increased seed germination and had the same positive effects on all plant growth parameters as did inoculation with symbiotic Bradyrhizobium canariense, with no significant differences among treatments. Inoculation with efficient nitrogen-fixing rhizobia must compete with rhizobia present in the soil that sometimes nodulate efficiently but fix nitrogen poorly, leading to a low response to inoculation. In such cases, inoculation with highly effective PGPR might represent a feasible alternative to boost crop productivity.

Phytochemical Profiling and Biological Potential of Prunus dulcis Shell Extracts.

Prunus dulcis is one of the most widely cultivated species in the world. Its fruit (almond) is rich in various nutritious and bioactive compounds that exert several beneficial effects. The aim of this study was to determine the chemical profile and evaluate the biological potential in vitro of almond shell extracts. The chemical analysis of shell extracts led to the identification of 15 compounds by HPLC-DAD, of which 11 were first detected in the almond plant. Twenty-six volatile compounds were identified by the GC-MS technique; among them, seven were firstly detected in the studied plant. For the biological activities, the extracts demonstrated moderate inhibition potential against the antioxidant, antidiabetic, and cytotoxic activities. The methanol extract at 50 µg/mL showed the highest antioxidant (45%) and antidiabetic activities (45% against alpha-glucosidase and 31% against alpha-amylase extracts), while the cyclohexane and dichloromethane at 50 µg/mL showed the highest cytotoxic activity towards Hela (32.2% with cyclohexane) and RAW 264-7 (45% with dichloromethane). Overall, these findings demonstrate the potential of almond shell extracts as a source of bioactive compounds that could be applied in the pharmaceutical and medical fields.

Lupin, a Unique Legume That Is Nodulated by Multiple Microsymbionts: The Role of Horizontal Gene Transfer.

Lupin is a high-protein legume crop that grows in a wide range of edaphoclimatic conditions where other crops are not viable. Its unique seed nutrient profile can promote health benefits, and it has been proposed as a phytoremediation plant. Most rhizobia nodulating Lupinus species belong to the genus Bradyrhizobium, comprising strains that are phylogenetically related to B. cytisi, B. hipponenese, B. rifense, B. iriomotense/B. stylosanthis, B. diazoefficiens, B. japonicum, B. canariense/B. lupini, and B. retamae/B. valentinum. Lupins are also nodulated by fast-growing bacteria within the genera Microvirga, Ochrobactrum, Devosia, Phyllobacterium, Agrobacterium, Rhizobium, and Neorhizobium. Phylogenetic analyses of the nod and nif genes, involved in microbial colonization and symbiotic nitrogen fixation, respectively, suggest that fast-growing lupin-nodulating bacteria have acquired their symbiotic genes from rhizobial genera other than Bradyrhizobium. Horizontal transfer represents a key mechanism allowing lupin to form symbioses with bacteria that were previously considered as non-symbiotic or unable to nodulate lupin, which might favor lupin's adaptation to specific habitats. The characterization of yet-unstudied Lupinus species, including microsymbiont whole genome analyses, will most likely expand and modify the current lupin microsymbiont taxonomy, and provide additional knowledge that might help to further increase lupin's adaptability to marginal soils and climates.

Study on the Chemical Composition and the Biological Activities of Vitis vinifera Stem Extracts.

Vitis vinifera (V. vinifera) is a herbaceous plant, cultivated worldwide and known for its biological benefits. The aim of this study is the investigation of the chemical composition as well as the determination of the biological potential of different grape stem extracts obtained by maceration and accelerated solvent extraction (ASE). The HPLC analysis of the tested extracts led to the identification of 28 compounds of which 17 were identified for the first time in grape plants, in addition to seven revealed in the stem part for the first time. Twenty-nine volatile molecules have been detected by GC-MS in the grape stem part; among them seven were identified for the first time in the grape plant. For the biological analysis, the ethyl acetate extract (EtOAc) obtained by maceration showed a significant potential regarding antioxidant activity (IC50 = 42.5 µg/mL), anti-Alzheimer (IC50 = 14.1 µg/mL), antidiabetic (IC50 = 13.4 µg/mL), cytotoxic with HCT-116 (IC50 = 12.5 µg/mL), and anti-inflammatory (IC50 = 26.6 µg/mL) activities, as well as showing the highest polyphenol content (207.9 mg GAE/g DW).

Draft Genome Sequences of Nitrogen-Fixing Bradyrhizobia Isolated from Root Nodules of Peanut, Arachis hypogaea, Cultivated in Southern Tunisia.

Here, we report the draft genome sequences of two nitrogen-fixing symbionts, Bradyrhizobium sp. strain sGM-13 and Bradyrhizobium sp. strain sBnM-33, isolated from root nodules of peanut grown on soil samples collected from two regions in South Tunisia. The draft genome sizes of these two strains are 8.31 × 106 bp and 8.97 × 106 bp, respectively.

Novel putative rhizobial species with different symbiovars nodulate Lotus creticus and their differential preference to distinctive soil properties.

Phylogenetically diverse rhizobial strains endemic to Tunisia were isolated from symbiotic nodules of Lotus creticus, growing in different arid extremophile geographical regions of Tunisia, and speciated using multiloci-phylogenetic analysis as Neorhizobium huautlense (LCK33, LCK35, LCO42 and LCO49), Ensifer numidicus (LCD22, LCD25, LCK22 and LCK25), Ensifer meliloti (LCK8, LCK9 and LCK12) and Mesorhizobium camelthorni (LCD11, LCD13, LCD31 and LCD33). In addition, phylogenetic analyses revealed eight additional strains with previously undescribed chromosomal lineages within the genera Ensifer (LCF5, LCF6 and LCF8),Rhizobium (LCF11, LCF12 and LCF14) and Mesorhizobium (LCF16 and LCF19). Analysis using the nodC gene identified five symbiovar groups, four of which were already known. The remaining group composed of two strains (LCD11 and LCD33) represented a new symbiovar of Mesorhizobium camelthorni, which we propose designating as sv. hedysari. Interestingly, we report that soil properties drive and structure the symbiosis of L. creticus and its rhizobia.

The ACC-Deaminase Producing Bacterium Variovorax sp. CT7.15 as a Tool for Improving Calicotome villosa Nodulation and Growth in Arid Regions of Tunisia.

Calicotome villosa is a spontaneous Mediterranean legume that can be a good candidate as pioneer plants to limit regression of vegetation cover and loss of biodiversity in Tunisian arid soils. In order to grow legumes in such soils, pairing rhizobia and nodule associated bacteria (NAB) might provide numerous advantages. In this work, cultivable biodiversity of rhizobial symbionts and NAB in nodules of C. villosa plants growing in five arid regions of south Tunisia was characterized. Phylogenetic analysis using 16S rDNA gene, dnak, recA and nodD sequences separated nodule-forming bacteria in six clades associated to genera Ensifer, Neorhizobium, Phyllobacterium and Rhizobium. Among NAB, the strain Variovorax sp. CT7.15 was selected due to its capacity to solubilise phosphate and, more interestingly, its high level of aminocyclopropane-1-carboxylate deaminase (ACC deaminase) activity. C. villosa plants were inoculated with representative rhizobia of each phylogenetic group and co-inoculated with the same rhizobia and strain CT7.15. Compared with single rhizobia inoculation, co-inoculation significantly improved plant growth and nodulation, ameliorated plant physiological state and increased nitrogen content in the plants, independently of the rhizobia used. These results support the benefits of pairing rhizobia and selected NAB to promote legume growth in arid or degraded soils.

Draft Genome Sequence of Phyllobacterium endophythicum mTS5, Isolated from Lupinus micranthus in Tunisia.

We report here the draft genome sequence of Phyllobacterium endophyticum mTS5, isolated from a Lupinus micranthus root nodule. The genome consists of 5,454,168 bp, with a GC content of 57%, and contains 5,676 protein-coding sequences.

Microvirga tunisiensis sp. nov., a root nodule symbiotic bacterium isolated from Lupinus micranthus and L. luteus grown in Northern Tunisia.

Three bacterial strains, LmiM8T, LmiE10 and LluTb3, isolated from nitrogen-fixing nodules of Lupinus micranthus (Lmi strains) and L. luteus (Llu strain) growing in Northern Tunisia were analysed using genetic, phenotypic and symbiotic approaches. Phylogenetic analyses based on rrs and concatenated gyrB and dnaK genes suggested that these Lupinus strains constitute a new Microvirga species with identities ranging from 95 to 83% to its closest relatives Microvirga makkahensis, M. vignae, M. zambiensis, M. ossetica, and M. lotononidis. The genome sequences of strains LmiM8T and LmiE10 exhibited pairwise Average Nucleotide Identities (ANIb) above 99.5%, significantly distant (73-89% pairwise ANIb) from other Microvirga species sequenced (M. zambiensis and M. ossetica). A phylogenetic analysis based on the symbiosis-related gene nodA placed the sequences of the new species in a divergent clade close to Mesorhizobium, Microvirga and Bradyrhizobium strains, suggesting that the M. tunisiensis strains represent a new symbiovar different from the Bradyrhizobium symbiovars defined to date. In contrast, the phylogeny derived from another symbiosis-related gene, nifH, reproduced the housekeeping genes phylogenies. The study of morphological, phenotypical and physiological features, including cellular fatty acid composition of the novel isolates demonstrated their unique profile regarding close reference Microvirga strains. Strains LmiM8T, LmiE10 and LluTb3 were able to nodulate several Lupinus spp. Based on genetic, genomic and phenotypic data presented in this study, these strains should be grouped within a new species for which the name Microvirga tunisiensis sp. nov. is proposed (type strain LmiM8T=CECT 9163T, LMG 29689T).

Phylogeography of the Bradyrhizobium spp. Associated With Peanut, Arachis hypogaea: Fellow Travelers or New Associations?

Legume plants have colonized almost all terrestrial biotopes. Their ecological success is partly due to the selective advantage provided by their symbiotic association with nitrogen-fixing bacteria called rhizobia, which allow legumes to thrive on marginal lands and nitrogen depleted soils where non-symbiotic plants cannot grow. Additionally, their symbiotic capacities result in a high protein content in their aerial parts and seeds. This interesting nutritional value has led to the domestication and agricultural exploitation of several legumes grown for seeds and/or fodder for human and domestic animal consumption. Several cultivated legume species are thus grown far beyond their natural geographic range. Other legume species have become invasives, spreading into new habitats. The cultivation and establishment of legume species outside of their original range requires either that they are introduced or cultivated along with their original symbiotic partner or that they find an efficient symbiotic partner in their introduced habitat. The peanut, Arachis hypogaea, a native of South America, is now cultivated throughout the world. This species forms root nodules with Bradyrhizobium, but it is unclear whether these came with the seeds from their native range or were acquired locally. Here we propose to investigate the phylogeography of Bradyrhizobium spp. associated with a number of different wild and cultivated legume species from a range of geographical areas, including numerous strains isolated from peanut roots across the areas of peanut cultivation. This will allow us to address the question of whether introduced/cultivated peanuts associate with bacteria from their original geographic range, i.e., were introduced together with their original bacterial symbionts, or whether they acquired their current associations de novo from the bacterial community within the area of introduction. We will base the phylogenetic analysis on sequence data from both housekeeping and core genes and a symbiotic gene (nif). Differences between the phylogenetic signal of symbiotic and non-symbiotic genes could result from horizontal transfer of symbiosis capacity. Thus this study will also allow us to elucidate the processes by which this symbiotic association has evolved within this group of Bradyrhizobium spp.

Arbuscular mycorrhizal fungi in soil, roots and rhizosphere of Medicago truncatula: diversity and heterogeneity under semi-arid conditions.

Mycorrhizal symbioses are considered indicators of ecosystem biodiversity. However, their diversity and relevance in arid and semi-arid ecosystems are poorly understood. This study addressed this subject, the main objective being to evaluate arbuscular mycorrhizal fungi (AMF) diversity and heterogeneity in a semi-arid region. Samples of bulk and rhizosphere soil and fine roots of Medicago truncatula were collected at four different sites with the same aridity index (6.1), in Bou-Hedma National Park, Tunisia, a semi-arid ecosystem. AMF taxa were assessed by 454- pyrosequencing and identified by BLAST matching of operational taxonomic units (OTUs) against the MaarjAM database, targeting AMF SSU rRNA gene diversity. Roots were the hotspots of AMF diversity (107 OTUs out of a total of 138). Of the 138 OTUs, 113 found correspondence in the MaarjAM database, with 32 AMF virtual taxa (VTX),19 Site-exclusive (SE) and 13 common to at least two sites (Non-site exclusive, NSE); the remaining 25 OTUs grouped in 16 putative new AMF taxa (pNTX), each one consisting of OTUs sharing pairwise distances not higher than 3%. We found a high diversity and heterogeneity of AMF across the four sites, which showed, in a regression analysis, significant relation to six out of the eight environmental parameters evaluated: grazing activity and soil texture, electrical conductivity, organic matter, total phosphorus and total nitrogen. AMF colonization of plants also presented significant differences among the four sites, as well as spore density, microbial biomass and several enzymatic activities (dehydrogenase, ß-glucosidase and phosphatase) evaluated in rhizosphere soils. The four sites clustered in two groups in a hierarchical clustering evaluation based on their AMF diversity (total numbers of OTU, VTX and pNTX) and the parameters referred above. The crucial role of abiotic factors, other than aridity index, on AMF community composition, was evidenced by the high heterogeneity found between AMF communities across sites under identical aridity conditions.

Definition of two new symbiovars, sv. lupini and sv. mediterranense, within the genera Bradyrhizobium and Phyllobacterium efficiently nodulating Lupinus micranthus in Tunisia.

In this study, a polyphasic approach was used to analyze three representative strains (LmiH4, LmiM2 and LmiT21) from a collection of six previously described strains isolated in Tunisia from root nodules of Lupinus micranthus. The phylogenetic analysis of the concatenated rrs, recA and glnII genes showed that strain LmiH4 had 100% concatenated gene sequence identity with the type strain Bradyrhizobium retamae Ro19T. Similarly, strain LmiM2 shared 100% concatenated gene sequence identity with the species Bradyrhizobium valentinum LmjM3T. However, strain LmiT21 showed an identical concatenated gene sequence with reference strain Phyllobacterium sophorae CCBAU03422T. The recA-glnII concatenated protein-coding genes used produced incongruent phylogenies compared with 16S rDNA phylogeny. The nodC gene analysis showed that the strains were phylogenetically divergent to the Bradyrhizobium symbiovars defined to date, and represented two new symbiovars. Plant infection analysis revealed that the three strains showed moderate host range and symbiotic specificities. Based on their symbiotic characteristics, we propose that the three strains isolated from Lupinus micranthus nodules belong to two new symbiovars, with the first denominated lupini within the two species Bradyrhizobium valentinum (type strain LmiM2) and B. retamae (type strain LmiH4), and the second denominated mediterranense within the species P. sophorae (type strain LmiT21).

Members of Microvirga and Bradyrhizobium genera are native endosymbiotic bacteria nodulating Lupinus luteus in Northern Tunisian soils.

The genetic diversity of bacterial populations nodulating Lupinus luteus (yellow lupine) in Northern Tunisia was examined. Phylogenetic analyses of 43 isolates based on recA and gyrB partial sequences grouped them in three clusters, two of which belong to genus Bradyrhizobium (41 isolates) and one, remarkably, to Microvirga (2 isolates), a genus never previously described as microsymbiont of this lupine species. Representatives of the three clusters were analysed in-depth by multilocus sequence analysis of five housekeeping genes (rrs, recA, glnII, gyrB and dnaK). Surprisingly, the Bradyrhizobium cluster with the two isolates LluI4 and LluTb2 may constitute a new species defined by a separate position between Bradyrhizobium manausense and B. denitrificans. A nodC-based phylogeny identified only two groups: one formed by Bradyrhizobium strains included in the symbiovar genistearum and the other by the Microvirga strains. Symbiotic behaviour of representative isolates was tested, and among the seven legumes inoculated only a difference was observed i.e. the Bradyrhizobium strains nodulated Ornithopus compressus unlike the two strains of Microvirga. On the basis of these data, we conclude that L. luteus root nodule symbionts in Northern Tunisia are mostly strains within the B. canariense/B. lupini lineages, and the remaining strains belong to two groups not previously identified as L. luteus endosymbionts: one corresponding to a new clade of Bradyrhizobium and the other to the genus Microvirga.

Diverse Bacteria Affiliated with the Genera Microvirga, Phyllobacterium, and Bradyrhizobium Nodulate Lupinus micranthus Growing in Soils of Northern Tunisia.

The genetic diversity of bacterial populations nodulating Lupinus micranthus in five geographical sites from northern Tunisia was examined. Phylogenetic analyses of 50 isolates based on partial sequences of recA and gyrB grouped strains into seven clusters, five of which belong to the genus Bradyrhizobium (28 isolates), one to Phyllobacterium (2 isolates), and one, remarkably, to Microvirga (20 isolates). The largest Bradyrhizobium cluster (17 isolates) grouped with the B. lupini species, and the other five clusters were close to different recently defined Bradyrhizobium species. Isolates close to Microvirga were obtained from nodules of plants from four of the five sites sampled. We carried out an in-depth phylogenetic study with representatives of the seven clusters using sequences from housekeeping genes (rrs, recA, glnII, gyrB, and dnaK) and obtained consistent results. A phylogeny based on the sequence of the symbiotic gene nodC identified four groups, three formed by Bradyrhizobium isolates and one by the Microvirga and Phyllobacterium isolates. Symbiotic behaviors of the representative strains were tested, and some congruence between symbiovars and symbiotic performance was observed. These data indicate a remarkable diversity of L. micranthus root nodule symbionts in northern Tunisia, including strains from the Bradyrhizobiaceae, Methylobacteriaceae, and Phyllobacteriaceae families, in contrast with those of the rhizobial populations nodulating lupines in the Old World, including L. micranthus from other Mediterranean areas, which are nodulated mostly by Bradyrhizobium strains.IMPORTANCELupinus micranthus is a legume broadly distributed in the Mediterranean region and plays an important role in soil fertility and vegetation coverage by fixing nitrogen and solubilizing phosphate in semiarid areas. Direct sowing to extend the distribution of this indigenous legume can contribute to the prevention of soil erosion in pre-Saharan lands of Tunisia. However, rhizobial populations associated with L. micranthus are poorly understood. In this context, the diversity of endosymbionts of this legume was investigated. Most Lupinus species are nodulated by Bradyrhizobium strains. This work showed that about half of the isolates from northern Tunisian soils were in fact Bradyrhizobium symbionts, but the other half were found unexpectedly to be bacteria within the genera Microvirga and Phyllobacterium These unusual endosymbionts may have a great ecological relevance. Inoculation with the appropriate selected symbiotic bacterial partners will increase L. micranthus survival with consequent advantages for the environment in semiarid areas of Tunisia.

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils.

Fifty seven bacterial isolates from root nodules of two spontaneous legumes (Astragalus corrugatus and Hippocrepis areolata) growing in the arid areas of Tunisia were characterized by phenotypic features, 16S rDNA PCR-RFLP and 16S rRNA gene sequencing. Phenotypically, our results indicate that A. corrugatus and H. areolata isolates showed heterogenic responses to the different phenotypic features. All isolates were acid producers, fast growers and all of them used different compounds as sole carbon and nitrogen source. The majority of isolate grew at pHs between 6 and 9, at temperatures up to 40°C and tolerated 3% NaCl concentrations. Phylogenetically, the new isolates were affiliated to four genera Sinorhizobium, Rhizobium, Mesorhizobium and Agrobacterium. About 73% of the isolates were species within the genera Sinorhizobium and Rhizobium. The isolates which failed to nodulate their host plants of origin were associated to Agrobacterium genus (three isolates).

Bradyrhizobium BclA Is a Peptide Transporter Required for Bacterial Differentiation in Symbiosis with Aeschynomene Legumes.

Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged, and polyploid state. The bacterial symbionts, on their side, evolved functions for the response to the NCR peptides. Here, we identified the bclA gene of Bradyrhizobium sp. strains ORS278 and ORS285, which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR peptide-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti, which has a similar symbiotic function in the interaction with Medicago legumes.

Extreme specificity of NCR gene expression in Medicago truncatula.

BACKGROUND: Legumes form root nodules to house nitrogen fixing bacteria of the rhizobium family. The rhizobia are located intracellularly in the symbiotic nodule cells. In the legume Medicago truncatula these cells produce high amounts of Nodule-specific Cysteine-Rich (NCR) peptides which induce differentiation of the rhizobia into enlarged, polyploid and non-cultivable bacterial cells. NCRs are similar to innate immunity antimicrobial peptides. The NCR gene family is extremely large in Medicago with about 600 genes. RESULTS: Here we used the Medicago truncatula Gene Expression Atlas (MtGEA) and other published microarray data to analyze the expression of 334 NCR genes in 267 different experimental conditions. We find that all but five of these genes are expressed in nodules but in no other plant organ or in response to any other biotic interaction or abiotic stress tested. During symbiosis, none of the genes are induced by Nod factors. The NCR genes are activated in successive waves during nodule organogenesis, correlated with bacterial infection of the nodule cells and with a specific spatial localization of their transcripts from the apical to the proximal nodule zones. However, NCR expression is not associated with nodule senescence. According to their Shannon entropy, a measure expressing tissue specificity of gene expression, the NCR genes are among the most specifically expressed genes in M. truncatula. Moreover, when activated in nodules, their expression level is among the highest of all genes. CONCLUSIONS: Together, these data show that the NCR gene expression is subject to an extreme tight regulation and is only activated during nodule organogenesis in the polyploid symbiotic cells.

Seeds of Peganum Harmala L. chemical analysis, antimalarial and antioxidant activities, and cytotoxicity against human breast cancer cells.

The present study evaluated the levels of total phenolics, flavonoids, tannins and anthocyanins from Peganum harmala L. seeds and determined their antioxidant, antiplasmodial and anticancer potentials. Antioxidant activity was determined by DPPH and ABTS assays. Extracts of P. harmala seeds from Oudref and Djerba (two places in Tunisia) were obtained by successive extraction solvents: petroleum ether, chloroform, ethyl acetate, ethanol and water. Their composition was evaluated for phenolics (gallic acid equivalent 2.48 to 72.52 g/kg), tannins (catechin equivalent 0 to 25.27 g/kg), anthocyanins (cyanidin equivalent 0 to 20.56 mg/kg) and flavonoids (quercetin equivalent 0 to 3.12 g/kg). Ethanolic extract exerted the highest activities against a chloroquine-resistant strain of Plasmodium falciparum (IC50=23 mg/L), against human breast cancer cells MCF7 (IC50=32 mg/L) and against free radical (IC50=19.09±3.07 mg/L). Correlations were studied between each chemical family and the three activities. Total phenolics content exhibited the highest correlation with antiplasmodial activity (R²=0.92) and with anticancer activity (R²=0.86), respectively.

Chemical composition and antioxidant, anti-inflammatory, and antiproliferation activities of pomegranate (Punica granatum) flowers.

The chemical composition, antioxidant (DPPH and ABTS assays), anti-inflammatory (5-LOX), and cytotoxic (MCF-7) activities from flowers of seven pomegranate varieties (Punica granatum) were investigated. The highest phenolics (330.9±11.3 mg gallic acid equivalent/g dry weight (dw)), flavonoids (29.5±0.8 mg quercetin equivalent/g dw), tannins (30.6±0.6 mg catechin equivalent/g dw), and anthocyanins (0.70±0.03 mg cyanidin-3-glucoside equivalent/g dw) content were determined in the Chetoui (CH) variety. It was found that Garsi (GR) (IC50=4.9±0.2 mg/L by ABTS assay) and Zaghwani (ZG) (IC50=3.9±0.2 mg/L by ABTS assay) varieties exhibited the highest antioxidant activity. For the anti-inflammatory activity, all varieties were active; the ZH variety was the strongest (2.5±0.1 mg/L). The CH, ES, and RA pomegranate varieties were not active against human breast cancer cells MCF-7, whereas inhibition was more evident with extracts from ZH and GR varieties (IC50=33.00±2.64 and 35.00±4.58 mg/L, respectively). Statistical analysis showed that the variety factor influenced significantly (P<.01) the chemical composition and biological activities of pomegranate flowers.