Low Extract Concentrations Research Articles

Protective effect of Terminalia catappa leaf extracts against Saprolegniosis on angelfish eggs

The Saprolegniosis causes major reduction egg hatching rate by angelfish (Pterophyllum scalare); therefore, we investigated the effectiveness of two Terminalia catappa extracts (27 ℃ and 80 ℃) against S. parasitica on fish eggs. Mycelium growth was evaluated in vitro at 0, 2.5, 5.0 and 10 g/L for 96 h, in solid and liquid medium culture. In an in vivo assay, we tested lower concentrations of hot extract (25, 50 and 100 mg/L) to prevent infection by zoospores. The hot aqueous extract was the most effective, and the concentrations of 5 and 10 g/L demonstrated great efficiency in liquid medium. In vivo conditions, 50 and 100 mg/L of hot extract provided more viable eggs, greater percentage of total larvae and lower percentage of infected eggs. Thus, the hot extract should be used instead of the room-temperature extract as a prophylactic measure, to prevent saprolegniosis in P. scalare eggs and improving the hatching rate.

Effects of Phenolic Enrichment on Antioxidant Activity of Mayonnaise

The aim of this work was to evaluate the effect of phenolic extract addition on the oxidative stability and antioxidant activity of mayonnaise. The mayonnaise was enriched with different concentrations (50, 150 and 300 mg kg-1) of Olive Leaf phenolic commercial extract and stored at 30°C for 30 days. Its quality was monitored for microbiological and sensory parameters, individual phenolic content, oxidative stability, antioxidant parameters. The analysis quantitative showed that all added phenolic compounds were transferred to the oil fraction., particularly a high concentration of hydroxytyrosol acetyl derivative (Hy-Ac) was detected (0.88 g 100 g-1). The addition of 150 mg kg-1 of extract allowed to obtain a mayonnaise more stable to oxidation, as demonstrated by a constant induction period over time. Hydroxytyrosol and hydroxyl acetyl derivate functionalized and improved the antioxidant activity of the analyzed samples as confirmed by their correlation with DPPH assay. Enriched mayonnaises showed good pH values and no microbial contamination was revealed. Furthermore, for the production of enriched mayonnaise is better to use lower concentration of phenolic extract (50 mg kg-1). An excessive use of extract can change the taste of the final product, making it unacceptable for the consumer.

Biological effects of secondary metabolites of Inula racemosa on the parasitoid Bracon hebetor

AbstractSecondary plant metabolites play an important role in mediating interactions among plants, insect herbivores, and their parasitoids. These defensive compounds not only affect the growth and development of herbivores, but also influence their natural enemies. In the present study, the diet‐mediated effect of hexane extract of Inula racemosa (Hooker fil.) (Asteraceae) was evaluated on the growth and development of the gregarious ectoparasitoid Bracon hebetor (Say) (Hymenoptera: Braconidae) using a polyphagous pest, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), as its host. The influence of various concentrations of I. racemosa extract was recorded on B. hebetor’s parasitization behavior on its host larvae. The parasitism rate of naive female wasps decreased significantly when host larvae were reared on treated diet, but no adverse effect of plant extract was recorded on the viability of eggs. Detrimental effects of the plant extract were also detected in the form of reduced survival and delayed development of the parasitoid. Ingestion of hexane‐extract‐supplemented diet by S. litura adversely affected the emergence and parasitism rate of adults from the first generation of B. hebetor. In conclusion, consumption of I. racemosa extract by S. litura had a negative impact on various biological parameters of B. hebetor, although lower concentrations of plant extract had no adverse effects. There is a need to study the possible effects of secondary metabolites on these trophic interactions under natural conditions.

Nutritional composition and antioxidant properties of three varieties of carrot (Daucus carota)

Carrots are a potentially rich source of antioxidants in addition to their nutritional properties. In this study, the nutritional composition and antioxidant properties of three varieties of carrots, namely Kuroda, Pamela and Amazonia cultivated in Ghana were determined. The peroxide scavenging method was used to determine the antioxidant properties of the ethanolic extracts of the carrot varieties at different concentrations. The protein, crude fibre, fat and carbohydrate contents of the carrot varieties ranged 6.46 – 10.73 %, 7.18 – 8.87 %, 1.97 – 4.31 % and 6.25 – 8.39 % respectively. The three varieties had high moisture contents ranging from 69.06 to 75.30 %. The antioxidant properties were high even at low concentrations of extract, and their activity increased with time in the order Amazonia > kuroda > pamela. Amazonia had the highest fibre, protein and carbohydrate contents and the lowest moisture content, making it the most preferred variety.

Biointerference relationship between the macroalga Ulva lactuca and two green microalgae

Allelopathy is considered as a physiological phenomenon with ecological implications that have stimulatory or inhibitory effects on organisms. The aim of the present study was focused on the effect of Ulva lactuca aqueous extract on growth and some physiological and metabolic aspects as well as gene expression of both Dunaliella salina and Chlorella salina. Linoleic acid ethyl ester; Propanoic acid, 3-(methylthio); Ethanol, 2-(9-octadecenyloxy)-, (Z); Oleic Acid; and 9-Octadecynoic acid, methyl ester were active phytochemical compounds detected from the gas chromatography-mass spectrometry (GC–MS) analysis for the donor species aqueous extract. Data revealed that U. lactuca contains appreciable amounts of Mg, K, Ca, Na and Fe. Results showed a dramatic effect of U. lactuca extracts on growth of both D. salina and C. salina, which significantly increased at low extract concentrations and vice versa. The activity of total antioxidants achieved a gradual increase by increasing the extract concentration. Furthermore, the two recipient algae attained the highest value of protein polymorphism under 10% extract concentration. Sequences of soluble inorganic pyrophosphatases (sPPases) gene showed that, allelochemicals of U. lactuca extract reflected the highest genetic variation in C. salina and D. salina while causing a significant variation in different biochemical parameters.

Biological activity of plant extracts on the small tomato borer Neoleucinodes elegantalis, an important pest in the Neotropical region

The small tomato borer Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae), is the most harmful tomato pest in the Neotropical region. Control of this insect is a complex task that relies heavily on the use of chemical products and the correct timing to target the initial developmental stages (eggs and larvae) before they penetrate the tomato fruits. Given the potential of plant-derived compounds for controlling pests, the first step of this study was to assess the insecticide activity of the aqueous extracts of Capsicum annuum L. (bell pepper), Allium sativum L. (garlic), Nicotiana tabacum L. (commercial rope tobacco), and the crude oil of Ricinus communis L. (castor bean) against N. elegantalis larvae. Here, it was reported that the commercial rope tobacco extract was promising against N. elegantalis larvae (up to 100% control), and the extracts of C. annuum, A. sativum, and R. communis presented very low insecticide activity (< 50% mortality). The rope tobacco extract was then selected to assess its effectiveness not only on eggs and the prepupal stage, but also on female oviposition behavior. Finally, the components of rope tobacco were assessed through phytochemical analysis. Our toxicological bioassays revealed ovicidal (LC50 = 2.69 g/L) and larvicidal (LC50 = 1.64 g/L) activity of tobacco extract. Furthermore, exposure to low tobacco extract concentrations (0.2 g/L) caused significantly decreased survival abilities of the prepupal stage, similar to indoxacarb insecticide (positive control). Tomato fruits previously treated with low concentrations (0.2 and 3.1 g/L) reduced the egg-laying performance of N. elegantalis in short-and long-term exposure. Chemical analysis of the tobacco rope extract revealed not only nicotine as the major component, but also the presence of phenolics, terpenoids, steroids, and other alkaloids. Collectively, our findings indicate that aqueous extract of rope tobacco shows biological activities in different developmental stages, including deterrent effects on N. elegantalis oviposition, which may position it as a promising tool to prevent pest attacks on tomato fruits.

Cytotoxic effect of define concentration of Yarrow (Achillea millefolium) extract used in Iranian traditional medicine on AGS human gastric cancer cell-line

Gastric cancer is one of the main cancer-related death causes in the world threatening almost 12 million human lives by 2020. Achillea millefolium L. (yarrow) with domestic Iranian name of Bumadaran, has been as a curative plant for several medical conditions for a long time. Its antimicrobial and wound healing effects have been reported and in this study we aimed to survey the in-vitro cytotoxic and anti-cancer effects of this plant. After taxonomically identification of Achillea millefolium L., its hydroalcoholic extract was extracted and the AGS gastric cancer and L-929 normal fibroblastic cell-lines with treated by the different concentrations of extract in 3 time periods (24, 48, and 72 h). MTT assay was performed for the evaluation of cytotoxic effects. The 24 h treatment did not affect cell survival notably, while the concentrations of 64 and 16 µg/ml were determined as IC50 concentrations at 48 and 72 h incubation times respectively. The 72 h incubation time with 16 µg/ml showed the best effectiveness on cancerous cell-line while being safe for normal cell-line. The long-term treatment of AGS cancer cell-line by low concentrations of yarrow extract could be useful for the cytotoxicity upon this type of cancerous cells.

Evaluation of the cytotoxic and genotoxic effects of Sida planicaulis Cav extract using human neuroblastoma cell line SH-SY5Y

ABSTRACT Sida planicaulis is a weed thought to have originated in Brazil, where it is present in abundant quantities, but also this plant is also found in south-central Florida, Indian Ocean Islands, and the Pacific Islands. Sida planicaulis produces neurotoxicity that adversely affects livestock breeding with heavy animal losses and consequent negative impact on Brazil’s economy. The aim of this study was to determine the chemical profile, cytotoxic and genotoxic effects of ethanolic extracts of S. planicaulis collected in winter (leaf extract) and summer (leaf extract and leaf + flower extract) using an in vitro model of human neuroblastoma cell line SH-SY5Y. Phytochemical screening demonstrated the presence of alkaloids, flavonoids, and apolar compounds. Rutin, quercetin, and swainsonine were detected by HPLC and GC/MS, respectively. Phosphorus, potassium, iron, and zinc were the inorganic elements found. Extracts produced cytotoxicity at all concentrations tested (7–4,000 μg/ml) as evidenced by the colorimetric assay [3-(4,5-dimethyl-thiazol-2-yl) −2,5-diphenyl-tetrazolium bromide (MTT)]. Based upon the alkaline comet assay extracts were found to induce genotoxicity at concentrations ranging from 0.437 to 7 μg/ml. DNA damage produced by extracts was affirmed using a modified comet assay with the enzymes Endo III and FPG in a concentration dependent manner. Further, enzyme-modified comet assay showed both oxidized purines and pyrimidines, and consequently oxidative stress was related to genomic instability and cell death. Data suggest that low concentrations of ethanolic extracts of S. planicaulis (different seasons) induced increased DNA damage related to oxidative stress and chemical composition.

Green Tea Attenuates methomyl-Induced Cardiac Toxicity Through Modulating Oxidative Stress and Nuclear Factor kappa B Up- Regulation in Mice

ABSTRACT Methomyl (ME) is a carbamate insecticide that is causes a change in biochemical parameters and affects the oxidative state in the body through the production of free radicals. Herbal medicines derived from plant extracts are useful in treating many diseases, as they are considered natural antioxidants that have a protective role against toxins. This study aimed to evaluate the ability of green tea extract (GTE) to treat ME-induced cardiac toxicity in experimental animals. The experimental animals were divided into five groups. Blood and tissue were collected to estimate the biochemical parameters. ME caused significantly elevated levels of AST, LDH, NF-κB, and malondialdehyde. While a significant decrease was observed in levels of superoxide dismutase, a decrease in glutathione and glutathione-S-transferase was observed. Alterations in these biochemical markers were referred to oxidative stress-induced cardiac damage. The administration of GTE at a concentration (1.5%) to the ME treated group caused the tested biochemical parameters to appear close to those of the control group. GTE alleviates ME-induced oxidative stress in female albino mice. A higher concentration of GTE {1.5%} appears to have a better therapeutic effect than a lower concentration of extract {0.75%} in cardiac toxicity ME.

Comparison of Phytochemical Composition, Free Radical Scavenging Activity, and Antimicrobial Activity of Selected Herbs Against Two Foodborne Pathogenic Bacteria

Spices and herbs, owing to their natural benefits to human health, are gaining momentum as food preservatives in recent years. Due to their antioxidant activity, their extracts with bioactive principles form the basis of pharmaceutical and food processing applications. Two of such crops, mountain mint (<i>Pycnanthemum virginianum</i>) and red turmeric (<i>Curcuma longa</i>), were compared for their phytochemical composition, the antioxidant activity of methanolic extracts, and their antimicrobial activity against foodborne pathogenic bacteria, Listeria monocytogenes, Salmonella enteritidis in this study. Our results showed that the mountain mint had higher total phenolic content and total tannin content: 614.41±3.96 and 529.74±4.39 mg gallic acid equivalents/gram dry weight extract. In comparison, red turmeric had higher total flavonoid content: 1250.51±8.10 mg catechin equivalents/gram dry weight extract. A lower IC₅₀ value (21.39±0.86 μg/mL) of red turmeric reflected its higher antioxidant activity. A lower concentration of methanolic extract of red turmeric rhizome was needed for both MIC (62.5 and 125 μg/mL) and MBC (125 and 250 μg/mL) assay against <i>L. monocytogenes</i> and <i>S. enteritidis</i>, respectively. In conclusion, these findings showed the red turmeric methanolic extract as a source of potential phytochemicals and antioxidants exhibited relative efficiency with antimicrobial activity against two common foodborne pathogens. The results have implications for use in processed food preservation and protection against food spoilage pathogens.

Low concentrations of a polyphenolic extract from pine bark in high–concentrate diets decrease in vitro rumen ammonia nitrogen but not methane production

ABSTRACT This study was conducted to assess the effects of small supplemental doses of a polyphenolic extract from pine bark (PBE) on CH4 output and ruminal fermentation parameters when incubated in batch culture with a high–concentrate diet for 24–h. The data from the dietary substrates supplemented with 0.0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8% of PBE were evaluated in a randomized complete block design, and compared using ANOVA followed by Tukey's test and polynomial contrasts. Increasing doses of the PBE caused a linear decrease of the NH3–N concentration (p < 0.001), the potentially degradable dry matter (DM) fraction (p = 0.002), the partitioning factor (p = 0.001), CH4 production and proportion (p = 0.001 and p = 0.029, respectively), although only at 6–h, achieving the lowest productions (p = 0.016) with 1.5 and 1.8% PBE. In contrast, the PBE linearly increased asymptotic gas production (p = 0.007), gas yield (p = 0.004), pH (p = 0.002) and the short–chain fatty acid concentration (p < 0.001) at 24–h. Addition of least 1.5% PBE to high–concentrate diets reduces CH4 production by 31% at 6–h, whereas NH3–N concentration is reduced by 31% at 24–h incubations.

Advanced Microtexture Evaluation of Dextran Biofilms Obtained from Low Cost Substrate Loaded with Maytenus rigida Extract

We have obtained kefir biofilms loaded with Maytenus rigida extract. The main goal was to evaluate the influence of the addition of the extract on the biofilms microtexture using stereometric and fractal parameters. Atomic force microscopy, Fourier transform infrared spectroscopy, and contact angle tecniques were used to evaluate the topography, chemical interation and wettability of the biofilms. Chemical evaluation showed that the extract interacts with the polymeric matrix of the biofilms, changing their structure. This behavior affected the surface energy because the wettability decreased when the Maytenus content increased. The surface morphology was also affected and suggested the prevalence of bacteria and yeast at lower and higher extract concentrations, respectively. The surface roughness increased according to the increase in the extract concentration. Texture parameters revealed that the biofilm with lowest concentration had deeper furrows than for higher concentration. Advanced fractal parameters revealed that topographic uniformity, percolation and texture homogeneity were more suitable for the biofilm with 0.25 g.L-1 of extract. These results indicate that this biofilm have promising 3D micromorphology for regenerative medicine application. Furthermore, the physics tools used revealed to be very useful for characterizing of the microtexture of polymeric-based biological materials.

Effect of Aqueous and Ethanol Extract of Acacia nilotica L. Leaves on Seed Germination of Vigna radiata L.

&lt;p&gt;This research aimed to tested the effect of extract on Vigna radiata L. germination. Tested the effect of crude extract of A. nilotica leaves on germination was conducted experimentally using Factorial Completely Randomized Design (FCRD). The first fact or was the type of crude extract and the second factor was levels of extract concentration. The result showed that the application of aqueous and ethanol extract enhanced all parameters of V. radiata L. germination (percentage of seed germination, rate of seed germination, radicle length, seedling fresh weight). Application of lower concentration (0,25%) of aqueous and ethanol extract increased speed of germination, radicle length, and fresh weight of seed. The application of 75% aqueous extract increased the percentage of germination to 100% than control and another treatment. However, further research is needed to confirm the effect of this plant extract on the vegetative growth of Vigna radiata L.&lt;/p&gt;&lt;p&gt;Keyword: Acacia nilotica, aqueous extract, ethanol extract, seed germinatio&lt;/p&gt;

Investigating the Effects of Salvia chorassanica Bunge and Shoot Extracts on Gastric Cancer Cells: Evidence of Different Behavior on Various Tumor Grades

Background: Different Salvia species have demonstrated anti-proliferative effects on various cancer cells. Owing to the poor literature on the anti-proliferative effects of Salvia species on gastric cancer cells, present study was conducted to determine the anticancer effects of a local Iranian Salvia, Salvia chorassanica, on two different gastric cell lines. Methods: Root, stem and leaf extract of Salvia chorassanica were prepared through maceration method and were then used to treat the AGS and MKN-45 cell lines in different concentrations. MTT assay was employed to determine the toxicity of all the types of extracts on the two studied cell lines. The expression of Bax, Bcl-2, Caspase3, MMP2 and MMP9 genes were determined through reverse transcription Real time PCR (RT-PCR). Results: Bunge and shoot extracts demonstrated toxicity in both cell lines which were more considerable in AGS cells treated with root extract. In contrary to AGS cells, Caspase3 gene was up-regulated in all types of treatment while the MMP2 and MMP9 genes were down-regulated (p-value&lt;0.001). Except of the MKN-45 cells treated with leaf extract, Bax/Bcl-2 expression ratio was decreased in the treatment with all types of Salvia chorassanica extracts (p-value&lt;0.001). Conclusion: Remarkable low IC50 concentration of root extract in MKN-45 cell line is indicating the significant cytotoxicity of Salvia chorassanica against gastric cancer cells. Moreover, gene expression analysis in MKN-45 needs further confirmation on the potential anti-metastatic roles of leaf and root extracts in higher grades of gastric cancer.

The Synergistic Effects for Apoptosis of Propolis Extracts and MG-132 on HeLa Ovarian Cancer Cell Line and Its Molecular Mechanism

In this study, we investigated the synergistic effect of apoptosis of propolis extract and MG-132 on HeLa ovarian cancer cells. The cytotoxicity of MG-132 and propolis was confirmed on dose-dependent manner. The LD<SUB>50</SUB> values of MG-132 and propolis showed at 10 μM and 100 μg/mL, respectively. Based on this concentration, in order to investigate the synergistic effect, the apoptosis effect of the mixture of low concentration of MG-132 and propolis extract was confirmed. The concentration of the mixture determined 0.5 μM MG-132 and 10 μg/mL and 25 μg/mL of propolis extracts. Cytotoxicity was measured after treating HeLa cells with a mixture of MG-132 and propolis extract. HeLa cells survived at least 90% in 0.5 μM of MG-132 and 25 μg/mL of propolis. However, it survived less than 80% when treated with a MG-132 and propolis extract. We investigated the level of expression of apoptosis-related proteins by Western blotting. When apoptosis stimulation occurred, apoptosis marker proteins PARP and caspase-3 produced 70 kDa and 19 kDa fragment, respectively. Treatment with a mixture of MG-132 and propolis extract produced PARP and caspase-3, but a single treatment did not. In the treatment of MG-132 and propolis extract, ubiquitination as another apoptosis molecule was expressed very strongly. In the mixture of MG-132 and propolis extract, the apoptosis molecule as well as proliferation protein expression level was changed. JAK showed digested fragments in mixture treatment group. Thus, the interaction of the mixture of MG-132 and propolis extract can induce apoptosis stimulation, and protein expression levels related to apoptosis and proliferation in cells are changed. Mixture of the two molecules could show potential as a cancer treatment.

Bitumen-stabilized earthen architecture: The case of the archaeological site of La Joya, on the Mexican Gulf Coast

The presence of fossil hydrocarbons in archaeological construction samples from a Mexican Gulf coast site, dated 100BC-AD600, led to the hypothesis that petroleum derivatives were used to stabilize earthen construction, a knowledge thought to originate in the early XX century. A two-step study first compared 10 construction and 6 paleosoil samples with previously profiled archaeological bitumen of the site of La Joya. This procedure required to adapt the standard bitumen protocol by Gas Chromatography coupled to Mass Spectrometry and δ13C Isotope Ratio Mass Spectrometry for low concentration of organic extract in earthen sediment samples, and allowed to infer that bitumen was added to the construction samples. A second step compared the La Joya results with 63 earthen architecture samples from 13 sites in Mesoamerica to evaluate whether the strategy was unique to the site or if it was shared and possibly exported. The results indicate that the use of bitumen as a stabilizer was opportunistic in sites on the Gulf coast located nearby surface seeps, but that the technology was not exported to sites in contact with the Gulf region.

The effect of ultrasonic on reducing anti-browning minimum effective concentration of purslane extract on fresh-cut potato slices during storage

Enzymatic browning is one of the major difficulties for the preservation and commercial value of fresh-cut products. To research more healthy and inexpensive anti-browning methods, we investigated the effect of ultrasonic coupling purslane extract on the browning resistance of fresh-cut potato during 8d storage at 4 °C. Firstly, the optimal ultrasonic time (10 min) was obtained. Then, the results showed that the combined application with lower purslane extract concentration (0.02%, w/w) could achieve a better anti-browning effect than the optimal concentration of alone purslane extract (0.05%, w/w). The combined application not only significantly inhibited the key enzyme activities of polyphenol oxidase (PPO) and peroxidase (POD), but also effectively reduced the damage to cell membrane, maintained its integrity and permeability. Meanwhile, it also improved antioxidant capacity during storage. Overall, the ultrasonic cavitation combined with purslane extract would be a promising method for fresh-cut industry.

Molluscicidal and parasiticidal activities of Eryngium triquetrum essential oil on Schistosoma mansoni and its intermediate snail host Biomphalaria glabrata, a double impact

BackgroundFreshwater snails are the intermediate hosts of a large variety of trematode flukes such as Schistosoma mansoni responsible for one of the most important parasitic diseases caused by helminths, affecting 67 million people worldwide. Recently, the WHO Global Vector Control Response 2017–2030 (GVCR) programme reinforced its message for safer molluscicides as part of required strategies to strengthen vector control worldwide. Here, we present the essential oil from Eryngium triquetrum as a powerful product with molluscicide and parasiticide effect against S. mansoni and the snail intermediate host Biomphalaria glabrata.MethodsIn the present study, we describe using several experimental approaches, the chemical composition of E. triquetrum essential oil extract and its biological effects against the snail B. glabrata and its parasite S. mansoni. Vector and the free-swimming larval stages of the parasite were exposed to different oil concentrations to determine the lethal concentration required to produce a mortality of 50% (LC50) and 90% (LC90). In addition, toxic activity of this essential oil was analyzed against embryos of B. glabrata snails by monitoring egg hatching and snail development. Also, short-time exposure to sublethal molluscicide concentrations on S. mansoni miracidia was performed to test a potential effect on parasite infectivity on snails. Mortality of miracidia and cercariae of S. mansoni is complete for 5, 1 and 0.5 ppm of oil extract after 1 and 4 h exposure.ResultsThe major chemical component found in E. triquetrum oil determined by GC-FID and GC/MS analyses is an aliphatic polyacetylene molecule, the falcarinol with 86.9–93.1% of the total composition. The LC50 and LC90 values for uninfected snails were 0.61 and 1.02 ppm respectively for 24 h exposure. At 0.5 ppm, the essential oil was two times more toxic to parasitized snails with a mortality rate of 88.8 ± 4.8%. Moderate embryonic lethal effects were observed at the concentration of 1 ppm. Severe surface damage in miracidia was observed with a general loss of cilia that probably cause their immobility. Miracidia exposed 30 min to low concentration of plant extract (0.1 ppm) were less infective with 3.3% of prevalence compare to untreated with a prevalence of 44%.ConclusionsEssential oil extracted from E. triquetrum and falcarinol must be considered as a promising product for the development of new interventions for schistosomiasis control and could proceed to be tested on Phase II according to the WHO requirements.

Ultrastructural response of wheat (Triticumaestivum L.) lines to potential allelopathy of Alstoniascholaris (L.) R. Br. leaf extract

An investigation was carried out to evaluate the impact of the allelopathic effect of Alstonia scholaris leaf extract on morphoanatomical and physiological characteristics of 5 wheat lines. Three extract dilutions were prepared, viz. 0 (control), 15 and 30% of the aqueous extract and sprayed on wheat lines (3094, 5066, M5082, 7076 and A2011) at 15-day intervals until maturity from November 2017 to May 2018. All wheat lines responded differently to an allelochemical extract of A. scholaris. Disintegration of root parenchyma and transformation of stem chlorenchyma to sclerenchyma in stems were noted in Line 3094. Increased sclerification in the root cortex (141.7-212.5 µm) and stem hypodermal region (212.5-354.2 µm) was recorded in Line 5066. Line M5082 showed intensive sclerification in the root cortex and vascular region, and around stem vascular bundles along with a significant decrease in leaf thickness. Line 7076 was the most sensitive genotype showing significant reduction in the stem (1402.8-821.8 µm) and root area (963.5- 791.9 µm) and leaf thickness (1346.2-396.8 µm). Line A2011 responded very differently by increasing proportion of parenchyma and sclerenchyma. A low concentration (15%) of allelochemical extract promoted growth and development and a high concentration (30%) was toxic, causing growth retardation and tissue damage.

Synthesis of Au, Ag, and Au-Ag Bimetallic Nanoparticles Using Pulicaria undulata Extract and Their Catalytic Activity for the Reduction of 4-Nitrophenol.

Plant extract of Pulicaria undulata (L.) was used as both reducing agent and stabilizing ligand for the rapid and green synthesis of gold (Au), silver (Ag), and gold–silver (Au–Ag) bimetallic (phase segregated/alloy) nanoparticles (NPs). These nanoparticles with different morphologies were prepared in two hours by stirring corresponding metal precursors in the aqueous solution of the plant extracts at ambient temperature. To infer the role of concentration of plant extract on the composition and morphology of NPs, we designed two different sets of experiments, namely (i) low concentration (LC) and (ii) high concentration (HC) of plant extract. In the case of using low concentration of the plant extract, irregular shaped Au, Ag, or phase segregated Au–Ag bimetallic NPs were obtained, whereas the use of higher concentrations of the plant extract resulted in the formation of spherical Au, Ag, and Au–Ag alloy NPs. The as-prepared Au, Ag, and Au–Ag bimetallic NPs showed morphology and composition dependent catalytic activity for the reduction of 4-nitrophenol (4-NPh) to 4-aminophenol (4-APh) in the presence of NaBH4. The bimetallic Au–Ag alloy NPs showed the highest catalytic activity compared to all other NPs.