Phenological variations of secondary metabolites from Hypericum triquetrifolium Turra

The essential oils and phenolic constituents from the aerial parts of Hypericum triquetrifolium Turra, were analyzed at three developmental stages (vegetative, flowering and fruiting stages). The highest content of oil (0.12% w/w) was obtained at full flowering. Whatever the analyzed stage, n-octane, α-pinene, β-caryophyllene, 2-methyloctane, n-nonane, α-longipinene, caryophyllene oxide and β-pinene were found to be the main compounds. However, their percentages varied with the phenological cycle. Analysis by RP-HPLC-DAD of the methanolic extracts enabled us to identify 14 phenolic components and rutin, hyperoside, quercitrin and quercetin were reported as the main components. With the exception of chlorogenic acid, kaempferol and amentoflavone, the content of the remaining identified phenolic components varied with the phonological cycle.     

Essential‐Oil and Fatty‐Acid Composition,and Antioxidant Activity of Extracts of Ficaria kochii

The essential‐oil and fatty‐acid composition of the aerial parts of Ficaria kochii (Ledeb .) Iranshahr & Rech .f. native to Iran, and the antioxidant activity of various extracts of this plant were examined. The study by GC‐FID and GC/MS analysis of the essential oil resulted in the identification of 61 compounds, representing 86.01% of the total oil composition. Phytol (10.49%), farnesol (7.72%), methyl linoleate (5.57%), and α‐farnesene (4.96%) were the main components. The fatty‐acid composition of the aerial parts of F. kochii was also analyzed by GC/MS. The major components were palmitic acid (25.9%), linolenic acid (25.3%), and linoleic acid (17.5%). Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids. The possible antioxidant activity of various extracts (prepared by using solvents with different polarity) of the F. kochii aerial parts was evaluated by screening for their 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, Fe^III‐reducing power, total antioxidant activity, and inhibitory activity in the linoleic acid‐peroxidation system. H₂O proved to be the most efficient solvent for the extraction of antioxidants, as the H₂O extract contained the highest amount of phenolic compounds (2.78±0.23 GAE/g dry matter) and also exhibited the strongest antioxidant capacity in all the assays used. The results of the present investigation demonstrated that the aerial parts of F. kochii can be used as natural and safe nutrition supplement in place of synthetic ones.     

Chemical Composition,Antioxidant, and Antimicrobial Activities on Laserpitium carduchorum Hedge & Lamond Essential Oil and Extracts During Various Growing Stages

Laserpitium carduchorum is frequently used as a spice, and in Bane folk medicine, the aerial parts of this are used to treat urinary infections. Variation in the quantity and quality of the essential oil of Iranian L. carduchorum at different developmental growth stages including vegetative, flowering, and seed ripening is reported. In total, 33 compounds were identified and quantified in the oils of vegetative, flowering, and seed ripening stages, representing 97.8%, 98.8%, and 98.7% of the oils, respectively. α‐Pinene (45.1, 61.4, and 46.4%), sabinene (16.5, 10.3, and 17.5%), and limonene (6.4, 8.5, and 20.4%) were the main compounds in all samples. The antioxidant activities of different extracts of L. carduchorum at different developmental growth stages were examined by employing various established in vitro experiments including DPPH, FRAP, and TEAC assays. The amounts of total phenolics were also determined spectrophotometerically. Antimicrobial activities of different extracts and essential oils of L. carduchorum at different developmental growth stages were examined against five Gram‐positive and four Gram‐negative bacteria, as well as two fungi. The results showed that maximum antioxidant and antimicrobial activity of extracts were at the flowering stage of the plant. Maximum antimicrobial activity of essential oils was at seed ripening stage.     

A Potent Phytotoxic Substance in Aglaia odorata Lour.

Aglaia odorata Lour . (Meliaceae) was found to have very strong allelopathic activity and a bioherbicide PORGANIC^? was developed from its leaf extracts. However, the phytotoxic substances causing the strong allelopathic activity of the plants have not yet been determined. Therefore, we investigated allelopathic properties and phytotoxic substances in A. odorata. Aqueous EtOH extracts of A. odorata leaves inhibited root and shoot growth of garden cress (Lepidum sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), ryegrass (Lolium multiflorum), and Echinochloa crus‐galli with the extract concentration‐dependent manner. The extracts were then purified and a major phytotoxic substance with allelopathic activity was isolated and identified by spectral data as rocaglaol. Rocaglaol inhibited the growth of garden cress and E. crus‐galli at concentrations > 0.3 and 0.03 μm , respectively. The concentrations required for 50% inhibition ranged from 0.09 to 2.5 μm . The inhibitory activity of rocaglaol on the weed species, E. crus‐galli, was much greater than that of abscisic acid. These results suggest that rocaglaol may be a major contributor to the allelopathic effect of A. odorata and bioherbicide PORGANIC^?.     

Chemical Composition and Antimicrobial Activity of Achillea tenuifolia Lam. Essential Oil at Different Phenological Stages from Khoy

Achillea species and in particular Achillea tenuifolia Lam . is generally used as a food flavor and traditional remedies, especially in the initial developmental stage for medical conditions in the Mediterranean part of Iran. In this report, we extracted the essential oil from the aerial parts of A. tenuifolia (collected from Khoy), at various developmental stages (i. e., vegetative, flowering and fruiting), characterized them and studied their antibacterial activities. Of 46, 51 and 38 components found in the vegetative, flowering, and fruiting stages, respectively, 35 were present in all three stages, including oxygenated terpenes such as carvacrol (30.85–34.11), germacrene C (16.21–17.87), spathulenol (7.26–8.96), β‐sesquiphellandrene (4.11–4.25), τ‐muurolol (2.27–3.25) and α‐cadinol (2.01–3.29). We witnessed that the composition of the essential oils varies with phenological stages and geographic regions. The essential oil demonstrated substantial antibacterial properties against both Gram‐positive and Gram‐negative bacteria, indicated by disk method, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. Except Pseudomonas aeruginosa, the essential oils of various phenological stages showed higher antibacterial activity against tested bacteria, with Bacillus anthracis as the most sensitive strain. Moreover, although antibacterial characteristics of the essential oil from the vegetative and flowering stages were similar (p=0.91), they were significantly different from those of fruiting stage (p<0.005 in both MIC and MBC tests). This emphasizes the importance of the developmental stage of the plant in the biological properties of its essential oil and justifies the widespread application of this plant in the vegetative stage.     

Identification and bioactivity of the growth inhibitors in Tuber spp. methanolic extracts

The methanolic extracts of fresh fruiting bodies of Tuber melanosporum, T. aestivum, T. magnatum and T. borchii were evaluated for their free fatty acids (FFAs) content to test their contribution to truffle allelopathic activity. Linoleic acid was the major FFA detected in all truffle species. In addition to linoleic acid, oleic acid and palmitic acid were the other abundant FFAs in the Tuber spp. extracts. Looking at the total production, T. melanosporum and T. aestivum synthesized significantly higher amounts of all identified FFA than T. magnatum and T. borchii. The allelopathic activity, based on the specific activity (EC₅₀) of the identified compounds, was evaluated in the growth of Arabidopsis thaliana, Lotus corniculatus, Melica ciliata and Silene vulgaris. Linoleic acid had the lowest specific activity and palmitic acid had the highest. The black truffle extracts had a higher inhibitory activity than white truffles, and this could be explained by the high relative amount of FFAs in them.     

Branched-chain fatty acids: the case for a novel form of cell-cell signalling during Myxococcus xanthus development

The esg locus is required for the formation of muiti-cellular fruiting bodies and spores by the developmental bacterium Myxococcus xanthus Studies have suggested that esg mutants are defective in the production of an essential signal (E-signal) used in cell-cell communication and that E-signalling is required for the expression of many developmental genes. Recently we have determined that the esg locus encodes components of a branched-chain keto acid dehydrogenase. a multienzyme complex involved in branched-chain amino acid metabolism in many bacteria and higher organisms. During vegetative growth in M. xanthus. this enzyme complex appears to participate in the production of the branched-chain fatty acids found in this organism. M. xanthus fatty acids (including the branched-chain fatty acids) have been observed to have a variety of effects on developing cells. These effects include; (i) the lysis of M. xanthus cells (autocide activity), (ii) acceleration of the rate of sporulation and (iii) rescue of sporulation by certain development-defective mutants. These and other results suggest a model in which the branched-chain fatty acids. Synthesized during growth, are released from cellular phospholipid by a developmentally regulated phospholipase during fruiting-body formation. This model proposes that one or more of the branched-chain fatty acids that are released constitutes the E-signal which must be transmitted between cells to complete M. xanthus development.     

Calamintha nepeta L. (Savi) as source of phytotoxic compounds: bio-guided fractionation in identifying biological active molecules

Calamintha nepeta L. (Savi), known as Lesser Catmint, is a Mediterranean species belonging to the Labiatae family, considered an important source of natural compounds. Since little is known about phytotoxic potential of Lesser Catmint, the bio-guided fractionation method was employed to isolate and identify some compounds, prerequisite for their possible future use in weed management. Leaves and stems of catmint were extracted with methanol and fractionated using n-hexane, chloroform, ethyl acetate and n-butanol, solvents with different polarity. The potential phytotoxicity of the methanolic extract and its fractions, evaluated by ED₅₀ values comparison, was assayed in vitro on seed germination and root growth of lettuce (Lactuca sativa L.). Germination and root growth of lettuce were strongly inhibited by catmint methanolic extract and its fractions, showing the following hierarchy of phytotoxicity for both physiological processes: ethyl acetate ≥ n-hexane > chloroform ≥ n-butanol. In the most active fraction, analyzed by HPLC, 5 poliphenols, gallic, vanillic, syringic, p-coumaric and ferulic acids, were identified and quantified. Whereas, the n-hexane fraction was a mixture of 32 chemicals, mainly composed of terpenoids and fatty acids, as analyzed by gas chromatography–mass spectrometry (GC–MS). Further, GC analysis allowed to quantify 5 compounds: camphor, trans-caryophyllene, menthol, farnesene and pulegone. Furthermore, both fractions inhibited seed germination and root growth of two of the most common weeds, Amaranthus retroflexus and Echinochloa crus-galli. The results confirmed the phytotoxic activity of C. nepeta L. (Savi) due to the presence of different molecule classes with biological activity and their potential future application as bio-herbicides.     

Impact of Mushrooms’ Vegetative Places and Morphological Parts of a Fruiting Body on the Fatty Acids Profile of Wild Leccinum aurantiacum and Leccinum versipelle

The aim of this study was to indicate potential differences in composition of fatty acids between two mushroom species as well as to examine the impact of mushrooms’ vegetative places and morphological parts of a fruiting body on the fatty acids profile. The research material consisted of 72 samples of wild Leccinum aurantiacum and Leccinum versipelle in the form of caps and stipes, collected from three selected regions of Poland. Determination of the examined compounds was performed by gas chromatography (FID). Linoleic (C18 : 2), oleic (C18 : 1) and palmitic (C16:0) acids were the predominant compounds in all samples under study. The profile of fatty acids in Leccinum aurantiacum and Leccinum versipelle was varied depending on mushroom species, a region and morphological parts of a fruiting body. The high content of polyunsaturated fatty acids in polish L. aurantiacum and L. versipelle provides that the mushroom may be recommended in different types of diets.     

Effect of Growth Stage on Essential‐Oil Yield and Composition of Daucus sahariensis

The essential oils obtained by hydrodistillation from Daucus sahariensis Murb . harvested at three different growth stages were characterized by GC/MS analysis. In total, 88 compounds were identified, with myristicin (29.8–51.7%), myrcene (6.7–31.1%), α‐pinene (11.6–14.8%), and limonene (5.3–11.5%) as main constituents. Monoterpene hydrocarbons were the most represented compounds in the oils of the plant samples collected during the flower‐budding and full‐flowering periods. On the contrary, during the fruiting stage, the oils were dominated by phenylpropanoids. The essential oils were subject of considerable variation in their composition during the various developmental stages, particularly concerning the content of myrcene that decreased significantly passing from the vegetative to the fruiting stage. Conversely, for myristicin, the opposite trend was observed. Furthermore, the essential‐oil yields were quite low during the flower‐budding phase (0.27%), but rapidly increased during plant development (0.63 and 0.68% for the flowering and fruiting phases, resp.).     

Allelopathic activity of different plant parts of <Emphasis Type="Italic">Peganum harmala</Emphasis> L. and identification of their growth inhibitors substances

This study was conducted to evaluate the inhibitory potential of P. harmala leaf, stem and root extract on germination and growth of Avena fatua L. and Convolvulus arvensis L., as well as identification of the phytotoxic substances responsible for this activity. According to our results, the degree of toxicity of different P. harmala plant parts can be arranged in the following order: leaves > stems > roots. The two test species differed in their sensitivity to P. harmala extracts. Inhibitory effect on shoot length and seedling dry weight was more pronounced in C. arvensis, whereas higher reduction in germination, root length and total chlorophyll content occurred in A. fatua. A significant amount of water-soluble phenolic acids were found in P. harmala plant extracts. Total phenolic acids content was higher in leaf extracts when compared to that of stem or root extracts. Seven phenolic acids including gallic acid, vanillic acid, 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, caffeic acid, syringic acid and ferulic acid were found in P. harmala leaf extracts. On the other hand, we identified four phenolic acids from stem (galllic acid, vanillic acid, 3,4-dihydroxybenzoic acid and caffeic acid) and root (galllic acid, 4-hydroxybenzoic acid, syringic acid and cinnamic acid) extracts. The greater number of growth inhibitors detected in the leaves might explain the stronger inhibitory activity. Overall, our results suggest that P. harmala might be used as a natural herbicide for weed control and consequently reduce dependence on synthetic herbicides.     

Assessment of Allelopathic Potential of Root Exudate of Rice Seedlings

To determine the allelopathic potential of root exudate from early developmental stage of rice (Oryza sativa L), 6-d-old seedlings of eight cultivars were grown with 3-d-old alfalfa (Medicago sativa L.), cress (Lepidium sativum L.) or lettuce (Lactuca sativa L.) seedlings in Petri dishes under controlled condition. All rice cultivars (cv. Norin 8, Kamenoo, Nipponbare, Kinuhikari, Koshihikari, Sasanishiki, Yukihikari and Hinohikari) inhibited growth of roots, shoots and fresh mass of alfalfa, cress and lettuce seedlings. Effectiveness of cv. Koshihikari was the greatest and more than 60% inhibition was recorded in all bioassays, followed by that of cv. Norin 8 of which effectiveness was more than 40%.     

Variation in antioxidant activity and phenolic content in different organs of two Tunisian cultivars of Olea europaea L.

This paper reports a comparative study based on the antioxidant compounds, total phenol content and antioxidant activities of leaves, stems and fruits from the main Tunisian cultivars, ‘chetoui’ and ‘chemchali’, grown in two different locations, north and south of Tunisia. The repartition of olive phenolic compounds was organ dependant. Therefore, the HPLC analysis indicated that the olive organs from the northern cultivar had the highest level of hydroxybenzoic acids, hydroxycinnamic acids and flavonoid class; which were less in the southern cultivar. Principal component analysis of the phenolic compounds showed discrimination between methanol extracts of the organs olive. Significant differences (p < 0.05) in the levels of phenols, orthodiphenols and flavonoids were found between cultivars and between organs. Antioxidant activities of the methanolic extract from aerial parts of the two studied cultivars were evaluated using 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assays. In all tests, methanolic extracts of different olive parts showed higher antioxidant activity. These results can be used to discriminate and to characterize the ‘chetoui’ and ‘chemchali’ aerial parts.     

Variation of bioactive secondary metabolites in <Emphasis Type="Italic">Hypericum origanifolium</Emphasis> during its phenological cycle

The genus Hypericum has received considerable interest from scientists, as it contains the variety of structurally diverse natural products which possess a wide array of biological properties. The present study was conducted to determine ontogenetic and morphogenetic variation of hypericin, chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin and quercetin content in Hypericum origanifolium growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Hypericin, quercetin and quercitrin content in whole plant increased during course of ontogenesis and the highest level was reached in blooming stage. On the contrary, hyperoside content of whole plant decreased linearly with advancing of development stages and the highest level was observed at vegetative stage. Plants produced similar amount of chlorogenic acid at all stages of plant phenology except for mature fruiting at which the amount of this compound was decreased sharply. Among different tissues, reproductive parts accumulated the highest level of hypericin, quercetin and quercitrin, however, leaves produced substantially higher amount of chlorogenic acid and hyperoside. Rutin and apigenin-7-O-glucoside were detectable in all tissues only during fruit maturation. The presence and variation of these bioactive substances in H. origanifolium were reported for the first time.     

Effect of salt stress on growth, fatty acids and essential oils in safflower (Carthamus tinctorius L.)

This study examined the influence of salt treatment on the growth parameters (fresh and dry weights), the mineral content (K⁺ and Na⁺), total lipid contents, fatty acid composition, yields and chemical composition of the essential oil of safflower (Carthamus tinctorius L.) grown in hydroponics for 2 weeks. Results showed that the application of 50 mM NaCl reduced the fresh weight of aerial parts (shoots and leaves) while it enhanced those of the roots. The reduction of dry weight was found to be more pronounced in the aerial parts. Salt treatment increased markedly the concentrations of Na⁺ in both plant parts while it reduced those of K⁺ which resulted in a sharp reduction of K⁺/Na⁺ ratio. In response to salt treatment, total lipids contents decreased in both plant parts and great qualitative changes in the fatty acids profiles were observed. Whatever the plant parts analysed, a redirection of the lipidic metabolism towards synthesis of unsaturated fatty acids as revealed by the increase of double bond index and linoleic desaturation ratio was pointed out. The increased unsaturation index was found to be more important in roots than in aerial parts. Such treatment also reduced the essential oil yields and induced marked quantitative changes in the chemical composition of the essential oils from both plant parts. Of all the identified components, oxygenated components display a prominent salt-induced synthesis and/or accumulation in both roots and aerial parts.     

Allelopathic Potential and Mechanism of Rosebay Willowherb [<i>Chamaenerion angustifolium</i> (L.) Scop.] Demonstrated on Model Plant Lettuce

Allelopathic plants are important resources for the discovery of bioherbicides. Rosebay willowherb [Chamaenerion angustifolium (L.) Scop. syn. Epilobium angustifolium L.] widely distributes in Western Asia, Europe, and North America, and behaves as a dominant species within the community due to the production of substances that restrict growth of other plants. This study aims at investigating the allelopathic potential of rosebay willowherb by evaluation of the effects of aqueous extracts from different parts on seed germination and seedling growth in lettuce (Lactuca sativa L.), as well as measuring the accumulation of reactive oxygen species and structural analysis of root tips via scanning electron and transmission electron microscopy. It was observed that the aqueous extracts from the leaves of rosebay willowherb had the strongest inhibitory effect on the germination index, germination energy and total germination of lettuce seeds, followed by capsular fruits and flowers, and the inhibition effect of stems was the weakest. All aqueous extracts (100 mg/mL) showed a significant inhibitory effect on radicle elongation of lettuce seedlings. Additionally, after treatment with the aqueous extract of rosebay willowherb leaves, accumulation of reactive oxygen species increased in columella cells, which correlated with disruption of root tip structure.     

Chemical profiling and in vitro biological effects of Cardiospermum halicacabum L. (Sapindaceae) aerial parts and seeds for applications in neurodegenerative disorders

Abstract

Cardiospermum halicacabum is widely used in traditional medicine. Previous studies have focused on the aerial parts, while the seeds have been poorly investigated. This work aimed to analyse the chemical composition of extracts from aerial parts and seeds obtained using Naviglio and Soxhlet (PN, PS, and SN, SS, respectively), the inhibitory properties against tyrosinase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) and the antioxidant effects. PN total extract showed significant anti-tyrosinase activity (IC₅₀ value of 10.8?µg/mL). After partitioning with n-hexane, an HPLC method for analysing chemical constituents was established. Apigenin, luteolin, and apigenin-7-O-glucoside are the predominant constituents. SN n-hexane fraction was the most active inhibitor of BChE (IC₅₀ of 57.9?µg/mL). Gas chromatography-mass spectrometry analysis revealed fatty acids, including eicosanoic acid, methyl 11-eicosenoate and oleic acid, as the major constituents. These findings suggest the potentiality of both seeds and aerial parts of C. halicacabum in the treatment of neurological disorders.     

Phytotoxic activity of Cachrys pungens Jan,a mediterranean species: separation,identification and quantification of potential allelochemicals

In continuous research for bioactive compounds obtained from plants to use for weed control in sustainable agriculture, the aerial parts of Cachrys pungens Jan (Umbelliferae) were extracted with methanol and then fractionated using hexane, chloroform (CHCl₃) and ethyl acetate (AcOEt). The potential phytotoxicity of total methanolic extract and each fraction was assayed in vitro on seed germination and root elongation of lettuce (Lactuca sativa L.) and the most active fractions were assayed on three of the most common weeds (Lolium perenne, Amaranthus retroflexus, Echinochloa crus-galli). Non linear regression that allowed to obtain the ED₅₀ index for both physiological processes was applied. The fraction bioassays indicated the following hierarchy of phytotoxicity for both processes: CHCl₃ ≥ AcOEt > hexane. Moreover, in the present work was chemically characterized for the first time (through HPTLC) the polar fraction of this species pointing out the high presence of flavonoids and phenolic acids. In particular six of them have been chemically characterized and quantified (naringin, quercetin, catechin, caffeic acid, ferulic acid and gallic acid). These results make C. pungens Jan a potential source of natural compounds employable for an eco-friendly agriculture.     

Plant growth inhibitory activity of Ophiopogon japonicus Ker-Gawler and role of phenolic acids and their analogues: a comparative study

Allelopathic potential of Ophiopogon japonicus was investigated. The methanolic extract of O. japonicus roots strongly inhibited root and hypocotyls growth of lettuce. Sequential partitioning of the methanol extract with organic solvents showed that the diethyl ether and n-butanol extract possess strong plant growth inhibitory activities. The allelopathic constituents of the diethyl ether extract were isolated and identified as salicylic acid and p-hydroxybenzoic acid by NMR spectroscopy. Both of these phenolic acids were found in the aqueous extracts of leaves as well. The concentration of salicylic acid in roots and leaves were estimated as 0.011 and 0.02%, respectively, and it inhibited the root and shoot of tested plants by 50% even at less than 3 ppm. The p-hydroxybenzoic acid on the other hand was in less abundance (0.005%) and inhibited the plant growth to a lesser extent. The biological activity of commercially available O-methyl derivatives of these phenolic acids was also determined to establish structure–activity relationship. Among these, salicylic acid was found to be the most active one. These results suggest that Ophiopogon japonicus produces plant growth inhibitors, which are responsible for its potential allelopathic activity.     

<Emphasis Type="Italic">Artemisia arborescens</Emphasis> L. leaf litter: phytotoxic activity and phytochemical characterization

Artemisia arborescens L. is a perennial fast-growing Mediterranean shrub, which releases abundant leaf litter upon soil surface throughout the year. The paper aimed to both evaluate the phytotoxic potential and identify major compounds occurring in the plant leaf litter. Following methanolic maceration of the leaf litter, the crude extract was then sequentially extracted with hexane, chloroform and ethyl acetate through a bio-guided fractionation method. The phytotoxic potential of the methanolic extract and its solvent fractions was assessed in vitro on germination and root growth of two sensitive (Lactuca sativa L., Raphanus sativus L.) and native (Amaranthus retroflexus L., Cynodon dactylon (L.) Pers.) species. Moreover, the most active fractions were chemically characterized by GC–MS and HPTLC analysis. In all species, the physiological processes were highly inhibited by both the methanolic extract and its solvent fractions. Several classes of biologically active phytochemicals such as terpenoids, fatty acids, lignans and phenolic compounds were identified in all fractions. Artemisia arborescens leaf litter could be considered an important source of biologically active phytochemicals, which may have a significant allelopathic impact towards neighbouring species once released into the environment.