Green synthesis,characterization, and biological activities of saffron leaf extract-mediated zinc oxide nanoparticles: A sustainable approach to reuse an agricultural waste

To increase the profitability and sustainability of agricultural waste, a facile green approach was established to synthesize zinc oxide nanoparticles (ZnO NPs) using saffron leaf extract as a reducing and stabilizing agent. Structural characteristics of NPs were investigated by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and UV–Visible (UV–Vis) spectroscopy. Characterization results revealed that ZnO NPs is highly crystalline with a hexagonal wurtzite structure and spherical particles with diameter less than 50 nm, as confirmed by XRD and FESEM techniques. UV–Vis absorption spectra depicted an absorption peak at 370 nm, which confirms the formation of ZnO NPs. FTIR spectral analysis confirmed the presence of functional groups and metal oxygen groups. The biological activities of ZnO NPs were also investigated. The antibacterial effect of ZnO NPs was investigated against selected food pathogens (Salmonella Typhimurium, Listeria monocytogenes, and Enterococcus faecalis). The study results prove that the green synthesized ZnO NPs show enhanced antibacterial activity against S. Typhimurium when compared with other strains. A dose-dependent free radical scavenging activity was observed for ZnO NPs in both 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and fluorescence recovery after photobleaching (FRAP) assays. The ZnO NPs were evaluated for their photocatalytic activity during the degradation of methylene blue (MB) dye in aqueous solutions. The maximum removal of MB achieved was 64% with an initial ZnO NP concentration of 12 mg/mL under UV light. The present study revealed that the agricultural waste (saffron leaf) provides a simple and eco-friendly option to sustainably synthesize ZnO NPs for use as a photocatalyst. In addition, this is the first report on saffron leaf-mediated synthesis of ZnO NPs.     

片段化森林中檵木幼苗种内叶经济性状变异及其驱动因子

在异质性生境中，种内功能性状变异有助于植物对环境的适应，进而影响种群更新、群落构建和生态系统过程。探讨了种内叶经济性状的变异及受生境异质性的塑造情况。以千岛湖片段化生境中的常见种檵木（Loropetalum chinense）的幼苗为研究对象，测定了200株檵木幼苗个体水平的7个叶经济性状（比叶面积SLA、叶全碳量C、叶全氮量N等）及其对应的生境因子（郁闭度、土壤全碳量、土壤全氮量等），采用相关性检验、主成分分析和线性混合效应模型等方法探讨片段化森林中檵木幼苗的种内叶经济性状变异及生境异质性对该变异的驱动作用。结果显示：（1） 在7个叶经济性状所构成的21对相关性分析中，有12对显著相关。经主成分分析降维后，主成分1（PC1）占性状总变异的43.02%，主要与比叶面积、叶绿素浓度、叶全氮量呈正相关，与叶干物质质量分数和叶碳氮比呈负相关，体现了檵木的种内叶经济谱，可反映叶片的最大光合效率。（2）片段化对生境条件和叶经济性状均有影响。岛屿森林群落的郁闭度显著低于大陆。相对于大陆，岛屿中的檵木幼苗趋向于更小的PC1值（缓慢投资-收益策略）；大岛边缘较大岛内部偏向于更小的PC1值。（3）生境因子中，郁闭度对PC1具有显著正效应。研究表明，片段化生境中的檵木在幼苗阶段存在叶经济谱，生境片段化可通过影响生境条件进而改变檵木幼苗的叶经济性状。随着生境片段化程度的加剧，檵木幼苗的叶经济性状逐渐向缓慢投资-收益策略靠拢。     

Evaluation of green and efficient deep eutectic solvents as media for extracting alkaloids from lotus leaf

Deep eutectic solvents (DESs) were applied as eco-friendly solvents in this study for the extraction of alkaloids from lotus leaf, including O-nornuciferine, N-nornuciferine, nuciferine and roemerine. A series of hydrophilic and hydrophobic DESs with different hydrogen bond donors and a acceptors were synthesized and screened for a suitable DESs for extraction of alkaloids from lotus leaf. The study results showed that the hydrophilic DES with choline chloride and propanediol had the highest extraction yield. The main factors affecting the extraction efficiency—choline chloride–propanediol ratio, water content in deep eutectic solvents, solid–liquid ratio and extraction time—were investigated via a single-factor experiment. The optimized extraction conditions were 30% of water in choline chloride–propanediol (1:4) for heated extraction for 30 min and solid–liquid ratio 1:100 g/ml. Under optimum conditions, the extraction yields of O-nornuciferine, N-nornuciferine, nuciferine and roemerine were 0.069, 0.152, 0.334 and 0.041 g/100 g respectively, which were higher than those of methanol in acidified aqueous solution. This study suggests considerable potential for DESs as promising materials for the green and efficient extraction solvents for bioactive alkaloids from natural sources.     

High performance hybrid reinforcement of nitrile rubber using short pineapple leaf fiber and carbon black

Rubber composites with very high moduli at low elongation, high elongation at break and high ultimate breaking strength have been developed. The matrix was acrylonitrile butadiene rubber (NBR) and the hybrid (fibrous and particulate) reinforcements were short, fine pineapple leaf fiber (PALF) and carbon black. The amount of PALF was fixed at 10 parts (by weight) per hundred of rubber (phr) while that of carbon black was varied from 0 to 30 phr. Uniaxial NBR composites were prepared. Tensile strength, elongation at break, modulus and tear strength of the hybrid composites were characterized in both longitudinal (parallel to the fiber axis) and transverse (perpendicular to the fiber axis) directions. The addition of carbon black causes the slope of the early part of the stress–strain curve to increase and also extends breaking to greater strains. At carbon black contents of 20 phr and above, the stress–strain relation displays an upturn at high elongations, providing greater ultimate strength. Comparison with the usual carbon black filled rubber shows that the composite behavior at low strains is determined by the PALF, and at high strains by the carbon black. This high performance PALF-carbon black reinforced NBR shows great promise for engineering applications.     

Multiconstituent identification in root,branch, and leaf extracts of Juglans mandshurica using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

As a traditional medicinal plant, Juglans mandshurica has been used for the treatment of cancer. Different organs of this plant showed anti‐tumor activity in clinic and laboratory. Comparative identification of constituents in different plant organs is essential for investigation of the relationship between chemical constituents and pharmacological activities. For this aim, the roots, branches, and leaves of J. mandshurica were extracted with 50% v/v methanol and then subjected to ultra‐high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry analysis conducted under low and high energy. As a result, we have to date identified 111 compounds consisting of 56 tannins, 29 flavonoids, 13 organic acids, 8 naphthalene derivatives, and 5 anthracenes. Five compounds, namely, diquercetin trihydroxy‐truxinoyl‐glucoside, two quercetin kaempferol dihydroxy‐truxinoyl‐glucosides, syringoyl‐tri‐galloyl‐O‐glucose, and dihydroxy‐naphthalene syringoyl‐glucoside, were tentatively identified as new compounds. Of the compounds identified, 76 were found in the root extract, 67 in the branch extract, and 37 in the leaf extract. Only six compounds including four organic acids and two tannins were found in all three extracts. We developed a rapid and sensitive ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry approach to identify multiple constituents of complex extracts without separation and ion selection. The results presented provide useful information on further research of the bioactive compounds of J. mandshurica .     

Preparation of Catechin Nanoemulsion from Oolong Tea Leaf Waste and Its Inhibition of Prostate Cancer Cells DU-145 and Tumors in Mice

Anti-cancer activity of catechin nanoemulsions prepared from Oolong tea leaf waste was studied on prostate cancer cells DU-145 and DU-145-induced tumors in mice. Catechin nanoemulsions composed of lecithin, Tween-80 and water in an appropriate proportion was prepared with high stability, particle size of 11.3 nm, zeta potential of −67.2 mV and encapsulation efficiency of 83.4%. Catechin nanoemulsions were more effective than extracts in inhibiting DU-145 cell growth, with the IC₅₀ being 13.52 and 214.6 μg/mL, respectively, after 48 h incubation. Furthermore, both catechin nanoemulsions and extracts could raise caspase-8, caspase-9 and caspase-3 activities for DU-145 cell apoptosis, arresting the cell cycle at S and G2/M phases. Compared to control, catechin nanoemulsion at 20 μg/mL and paclitaxel at 10 μg/mL were the most effective in reducing tumor volume by 41.3% and 52.5% and tumor weight by 77.5% and 90.6% in mice, respectively, through a decrease in EGF and VEGF levels in serum.     

Chemical Composition,Antioxidant and Antimicrobial Activity of Raspberry,Blackberry and Raspberry-Blackberry Hybrid Leaf Buds

In our investigation, the chemical composition and bioactive potential of leaf buds of raspberry, blackberry, and a raspberry-blackberry hybrid were determined. Antioxidant and antimicrobial properties were tested in water (W), ethanol-water (EW), and glycerol-water (GW) extracts from the buds. These plant organs contain relatively large amounts of minerals, especially Fe. The total antioxidant capacity (TAC) measured by the ABTS and DPPH methods ranged from 2.86 to 12.19 and 6.75 to 24.26 mmol per 100 g fresh weight (FW) of buds, respectively. TAC values were generally higher in the raspberry than in the case of blackberry and raspberry-blackberry hybrid extracts. The antioxidant properties of the extracts were strongly positively correlated with their content of total phenolic (TP). No such relationship was noted for ascorbic acid (AA), whose concentration in all extracts was at a similarly low level. Antioxidant properties determined in vitro were confirmed for the GW extract from raspberry leaf buds in biological test based on the growth parameters of Δsod1 Saccharomyces cerevisiae mutant cells in hypertonic medium. The extracts also exhibited strong antibacterial properties against Staphylococcus aureus and Enterococcus faecalis and weaker against Enterobacter aerogenes. The studied leaf buds could be therefore an unconventional source of minerals, natural antioxidants and antibacterial compounds with potential applications in the food, pharmaceutical, and cosmetics industries.     

An Insight into Kiwiberry Leaf Valorization: Phenolic Composition,Bioactivity and Health Benefits

During kiwiberry production, different by-products are generated, including leaves that are removed to increase the fruit’s solar exposure. The aim of this work was to extract bioactive compounds from kiwiberry leaf by employing microwave-assisted extraction (MAE). Compatible food solvents (water and ethanol) were employed. The alcoholic extract contained the highest phenolic and flavonoid contents (629.48 mg of gallic acid equivalents (GAE) per gram of plant material on dry weight (dw) (GAE/g dw) and 136.81 mg of catechin equivalents per gram of plant material on dw (CAE/g dw), respectively). Oppositely, the hydroalcoholic extract achieved the highest antioxidant activity and scavenging activity against reactive oxygen and nitrogen species (IC₅₀ = 29.10 μg/mL for O₂^•−, IC₅₀ = 1.87 μg/mL for HOCl and IC₅₀ = 1.18 μg/mL for ^•NO). The phenolic profile showed the presence of caffeoylquinic acids, proanthocyanidin, and quercetin in all samples. However, caffeoylquinic acids and quercetin were detected in higher amounts in the alcoholic extract, while proanthocyanidins were prevalent in the hydroalcoholic extract. No adverse effects were observed on Caco-2 viability, while the highest concentration (1000 µg/mL) of hydroalcoholic and alcoholic extracts conducted to a decrease of HT29-MTX viability. These results highlight the MAE potentialities to extract bioactive compounds from kiwiberry leaf.     

Preparation and characterization of a novel green tea essential oil nanoemulsion and its antifungal mechanism of action against Magnaporthae oryzae

Blast is one of the most devastating fungal diseases of rice caused by Magnaporthe oryzae. Plant essential oil (EO) can function as antifungal agents and are regarded as a safe and acceptable method for plant disease control. However, EOs are unstable and hydrophobic, which limits its use. In the present study, we aimed for the preparation and characterization of a nanoemulsion (NE) from green tea essential oil (GTO) by ultrasonication method and determined the antifungal activity of NE on M. oryzae. The particle size and zeta potential of the NE were 86.98 nm and −15.1 mV, respectively. The chemical composition and functional groups of GTO and NE were studied by using GC–MS analysis, portable Raman spectroscopy, and FTIR coupled with chemometric analysis. GC–MS analysis showed the major components in GTO and NE were n-Hexyl cinnamaldehyde and L-α-Terpineol. Both GTO and NE showed good antioxidant activity and total phenol content. Moreover, the NE showed good antifungal activity against M. oryzae which was further confirmed by scanning electron microscopy (SEM) examination. Also, confocal Raman micro-spectroscopy (CRM) revealed the antifungal mechanism of GTO and NE on M. oryzae which proves the cell damage. To the best of our knowledge, this is the first study on the antifungal activity of GTO and NE against M. oryzae and also the use of CRM for the evaluation of the chemical changes in single fungal hyphae in a holistic approach. This study suggests that the prepared NE could be a potential candidate for use as a substitute for synthetic fungicides.     

Straightforward Preparation of (2E,4Z)-2,4-Heptadien-1-ol and (2E,4Z)-2,4-Heptadienal

Abstract

A concise synthesis of (2E,4Z)-2,4-heptadien-1-ol and (2E,4Z)-2,4-heptadienal is presented. Commercially available (Z)-2-penten-1-ol was converted to ethyl-(2E,4Z)-2,4-heptadienoate by reaction with activated MnO₂ and (carboethoxymethylene)triphenylphosphorane in the presence of benzoic acid as a catalyst. Ethyl-(2E,4Z)-2,4-heptadienoate was converted to (2E,4Z)-2,4-heptadien-1-ol with LiAlH₄. The alcohol was partially oxidized to (2E,4Z)-2,4-heptadienal with MnO₂. The title compounds are male-specific, antennally active volatile compounds from the Saltcedar leaf beetle, Diorhabda elongata Brulle (Coleoptera: Chrysomelidae) and have potential use in the biological control of the invasive weed saltcedar (Tamarix spp).