COMPARATIVE STUDY IN ANTIOXIDANT ACTIVITIES OF THE DIFFERENT RIPENESS STAGES OF ARTOCARPUS HETEROPHYLLUS LAM. FRUIT

The ethyl acetate extracts obtained from under-ripe (Young Stage), mature (Mature Stage) and ripe fruit (Ripe Stage) fruit pulp of Artocarpus heterophyllus Lam. were evaluated for their Total Phenolic Content, Total Flavonoid Content and antioxidant property. Total Moisture Content and the Total Ash Content of pulp were determined by subjecting to heat treatment. Total Phenolic Content was evaluated using Folin-Ciocalteu method and Total Flavonoid Content by Aluminium Chloride Colorimetric Assay. Antioxidant activity was determined by DPPH Radical Scavenging, ABTS Radical Scavenging and FRAP Assays. The highest moisture content varies as Young Stage>Mature Stage>Ripe Stage in 84.71% to 70.38% range and Total Ash Content of the Ripe Stage pulp was the highest (6.86 %) and the least was observed for the Young Stage with a value of 5.40 %. For the Total Phenolic Content, crude extracts isolated from Mature Stage showed highest value (434.04 mg GAE/g) and Total Flavonoid Content was highest in crude extract of the Young Stage (446.79 mg QE/g). Ripe Stage Crude extract gave lowest value for both Total Phenolic Content and Total Flavonoid Content. For DPPH Radical Scavenging, ABTS Radical Scavenging and FRAP Assays, highest activity was reported by crude extract of Young Stage followed by crude extract of Mature Stage and least activity was given by crude extract of Ripe Stage. A correlation between Total Phenolic Content and Total Flavonoid Content with antioxidant activity was noticeable. A declination of the antioxidant activity was observed as the fruit reaches its maturity

Double deboronation and homometalation of 1,1'-bis(ortho-carborane)

Diastereomeric diruthenium and dicobalt species derived from double deboronation and metalation of 1,1′-bis(ortho-carborane) have been prepared and characterised.</p

Icosahedral metallacarborane/carborane species derived from 1,1′-bis(o-carborane)

We thank ORSAS (GS) and the EPSRC (DE and DMcK supported by project EP/E02971X/1, WYM supported by project EP/I031545/1) for funding.Examples of singly-metallated derivatives of 1,1[prime or minute]-bis(o-carborane) have been prepared and spectroscopically and structurally characterised. Metallation of [7-(1[prime or minute]-1[prime or minute],2[prime or minute]-closo-C2B10H11)-7,8-nido-C2B9H10]2- with a {Ru(p-cymene)}2+ fragment affords both the unisomerised species [1-(1[prime or minute]-1[prime or minute],2[prime or minute]-closo-C2B10H11)-3-(p-cymene)-3,1,2-closo-RuC2B9H10] (2) and the isomerised [8-(1[prime or minute]-1[prime or minute],2[prime or minute]-closo-C2B10H11)-2-(p-cymene)-2,1,8-closo-RuC2B9H10] (3), and 2 is easily transformed into 3 with mild heating. Metallation with a preformed {CoCp}2+ fragment also affords a 3,1,2-MC2B9-1[prime or minute],2[prime or minute]-C2B10 product [1-(1[prime or minute]-1[prime or minute],2[prime or minute]-closo-C2B10H11)-3-Cp-3,1,2-closo-CoC2B9H10] (4), but if CoCl2/NaCp is used followed by oxidation the result is the 2,1,8-CoC2B9-1[prime or minute],2[prime or minute]-C2B10 species [8-(1[prime or minute]-1[prime or minute],2[prime or minute]-closo-C2B10H11)-2-Cp-2,1,8-closo-CoC2B9H10] (5). Compound 4 does not convert into 5 in refluxing toluene, but does do so if it is reduced and then reoxidised, perhaps highlighting the importance of the basicity of the metal fragment in the isomerisation of metallacarboranes. A computational study of 1,1[prime or minute]-bis(o-carborane) is in excellent agreement with a recently-determined precise crystallographic study and establishes that the {1[prime or minute],2[prime or minute]-closo-C2B10H11} fragment is electron-withdrawing compared to H.Publisher PDFPeer reviewe

Biomimetic Synthesis, Characterization, and Evaluation of Fluorescence Resonance Energy Transfer, Photoluminescence, and Photocatalytic Activity of Zinc Oxide Nanoparticles

Owing to the development of nanotechnology, biosynthesis of nanoparticles (NPs) is gaining considerable attention as a cost-effective and eco-friendly approach that minimizes the effects of toxic chemicals used in NP fabrication. The present work reports low-cost phytofabrication of zinc oxide (ZnO) NPs employing aqueous extracts of various parts (leaves, stems, and inflorescences) of Tephrosia purpurea (T. purpurea). The formation, structure, morphology, and other physicochemical properties of ZnO NPs were characterized by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). UV–Vis spectral analysis revealed sharp surface plasmon resonance (SPR) at around 250–280 nm, while the XRD patterns confirmed distinctive peaks indices to the crystalline planes of hexagonal wurtzite ZnO NPs. TEM analysis confirmed the presence of spherical-shaped ZnO NPs with average particle sizes (PS) between 25–35 nm, which was in agreement with the XRD results. FTIR analysis revealed that phenolics, flavonoids, amides, alkaloids, and amines present in the plant extract are responsible for the stabilization of the ZnO NPs. Further, the hydrodynamic diameter in the range of 85–150 nm was measured using the DLS technique. The fluorescence resonance energy transfer (FRET) ability of biogenic ZnO NPs was evaluated, and the highest efficiency was found in ZnO NPs synthesized via T. purpurea inflorescences extract. Photoluminescence (PL) spectra of biogenic ZnO NPs showed three emission peaks consisting of a UV–Vis region with high-intensity compared to that of chemically synthesized ZnO NPs. The biosynthesized ZnO NPs showed photocatalytic activity under solar irradiation by enhancing the degradation rate of methylene blue (MB). Among the prepared biogenic ZnO NPs, T. purpurea leaves mediated with NPs acted as the most effective photocatalyst, with a maximum degradation efficiency of 98.86% and a half-life of 84.7 min. This is the first report related to the synthesis of multifunctional ZnO NPs using T. purpurea, with interesting characteristics for various potential applications in the future

Natural Antibrowning Agents against Polyphenol Oxidase Activity in Annona muricata and Musa acuminata

Fresh-cut fruits and vegetables emerge as popular food for consumers in retail markets. However, a loss of millions of dollars yearly to the food industry has been due to discoloration of fruits and vegetables caused by a pronounced reaction called enzymatic browning, which is caused by the activity of the polyphenol oxidase enzyme present in most of the fruits and vegetables. The main objective of this study was to investigate the natural antibrowning effects of the aqueous extract of ginger and essential oil of cinnamon bark on PPO enzymatic activity in Annona muricata (katu anoda) and Musa acuminata (ash plantains), which are considered to be widely consumable by Sri Lankans due to its respective health benefits. The antibrowning activity analyzed using a UV-visible spectrophotometer at a wavelength of 525 nm showed that cinnamon bark oil of 0.0035 g/mL had a % inhibitory activity of 51.97 percent on PPO activity in Annona muricata and 49.51 percent on PPO activity in Musa acuminata, while the aqueous extract of ginger of 0.091 g/mL had a % inhibitory activity of 60.90 percent on PPO activity in Annona muricata and 48.10 percent on PPO activity in Musa acuminata, respectively. This study shows that cinnamon bark oil and ginger can be used as effective, natural, nontoxic antibrowning agents that can inhibit the activity of the PPO enzyme, thereby preventing the essence and nutritional benefits of fruits and vegetables

Green Synthesis, Structural Characterization and Photocatalytic Applications of ZnO Nanoconjugates Using Heliotropium indicum

In recent years, biosynthesized zinc oxide nanoparticles (ZnO NPs) have been gaining importance due to their unique properties and tremendous applications. This study aimed to fabricate ZnO NPs by using extracts from various parts of the traditional medicinal plant Heliotropium indicum (H. indicum) and evaluate their photocatalytic activity. Further, their potential in photoluminescence and fluorescence resonance energy transfer (FRET) was assessed. The Ultraviolet-Visible spectrum exhibited a hypsochromic shifted absorption band between 350–380 nm. Transmission electron microscopy (TEM) analysis revealed spherical NPs, while X-ray diffraction (XRD) data revealed wurtzite, hexagonal and crystalline nature. The TEM and XRD consistently determined an average particle size range from 19 to 53 nm. The photocatalytic degradation reaches a maximum of 95% for biogenic ZnO NPs by monitoring spectrophotometrically the degradation of methylene blue dye (λmax = 662.8 nm) under solar irradiation. Photoluminescence analysis revealed differentiated spectra with high-intensity emission peaks for biogenic ZnO NPs compared with chemically synthesized ZnO NPs. Eventually, the highest efficiency of FRET (80%) was found in ZnO NPs synthesized from the leaves. This remains the first report highlighting the multifunctional ZnO NPs capabilities mediated by using H. indicum, which could lead to important potential environmental and biomedical applications

Green and Cost-Effective Synthesis of Metallic Nanoparticles by Algae: Safe Methods for Translational Medicine

Metal nanoparticles (NPs) have received much attention for potential applications in medicine (mainly in oncology, radiology and infectiology), due to their intriguing chemical, electronical, catalytical, and optical properties such as surface plasmon resonance (SPR) effect. They also offer ease in controlled synthesis and surface modification (e.g., tailored properties conferred by capping/protecting agents including N-, P-, COOH-, SH-containing molecules and polymers such as thiol, disulfide, ammonium, amine, and multidentate carboxylate), which allows (i) tuning their size and shape (e.g., star-shaped and/or branched) (ii) improving their stability, monodispersity, chemical miscibility, and activity, (iii) avoiding their aggregation and oxidation over time, (iv) increasing their yield and purity. The bottom-up approach, where the metal ions are reduced in the NPs grown in the presence of capping ligands, has been widely used compared to the top-down approach. Besides the physical and chemical synthesis methods, the biological method is gaining much consideration. Indeed, several drawbacks have been reported for the synthesis of NPs via physical (e.g., irradiation, ultrasonication) and chemical (e.g., electrochemisty, reduction by chemicals such as trisodium citrate or ascorbic acid) methods (e.g., cost, and/ortoxicity due to use of hazardous solvents, low production rate, use of huge amount of energy). However, (organic or inorganic) eco-friendly NPs synthesis exhibits a sustainable, safe, and economical solution. Thereby, a relatively new trend for fast and valuable NPs synthesis from (live or dead) algae (i.e., microalgae, macroalgae and cyanobacteria) has been observed, especially because of its massive presence on the Earth&rsquo;s crust and their unique properties (e.g., capacity to accumulate and reduce metallic ions, fast propagation). This article discusses the algal-mediated synthesis methods (either intracellularly or extracellularly) of inorganic NPs with special emphasis on the noblest metals, i.e., silver (Ag)- and gold (Au)-derived NPs. The key factors (e.g., pH, temperature, reaction time) that affect their biosynthesis process, stability, size, and shape are highlighted. Eventually, underlying molecular mechanisms, nanotoxicity and examples of major biomedical applications of these algal-derived NPs are presented

Effect of pH Value on the Bandgap Energy and Particles Size for Biosynthesis of ZnO Nanoparticles: Efficiency for Photocatalytic Adsorption of Methyl Orange

In this paper, ZnO nanoparticles (NPs) were greenly synthesized at different pH values of 4, 6, 9.5, and 11 via Portulaca oleracea leaf extract, and the effect of pH on the optical and structural properties was studied. UV-Vis spectrophotometers and FTIR spectroscopy characterized the optical properties. Meanwhile, the structural properties were characterized via Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Furthermore, their photocatalytic dye degradation was examined against methyl orange dye. The characterization results have confirmed the successful biosynthesis of ZnO nanoparticles with a size ranging between 22.17 to 27.38 nm. The synthesis pH value significantly influenced ZnO NPs&rsquo; optical and morphological properties. The results have also indicated the high performance of the greenly synthesized ZnO NPs for dye degradation

Characterizations of Alpha-Cellulose and Microcrystalline Cellulose Isolated from Cocoa Pod Husk as a Potential Pharmaceutical Excipient

Cellulose is a non-toxic, bio-degradable, and renewable biopolymer which is abundantly available in nature. The most common source of commercial microcrystalline cellulose is fibrous wood pulp. Cellulose and its derivatives have found wide commercial applications in the pharmaceutical, cosmetic, food, paper, textile, and engineering industries. This study aims to isolate and characterize cellulose forms from cocoa pod husk (CPH) and to assess its mechanical and disintegration properties as a direct compression excipient in metronidazole tablets. Two isolated cellulose types (i.e., cocoa alpha-cellulose (CAC) and cocoa microcrystalline cellulose (C-MCC)) were compared with avicel (AV). CAC and C-MCC were characterized for their physicochemical properties using Scanning Electron Microscopy (SEM), FTIR spectroscopy, Differential Scanning Calorimetry (DSC), and X-Ray Powder Diffraction (XRD). Metronidazole tablets were produced by direct compression with cellulose. The mechanical and disintegration properties of the tablets were evaluated. CAC and C-MCC yield was 42.3% w/w and 38.25% w/w, respectively. Particle diameters were significantly different with CAC (282.22 &mu;m) &gt; C-MCC (161.32 &mu;m) &gt; AV (72.51 &mu;m). CAC and C-MCC had a better flow than AV. SEM revealed the fibrous nature of the cellulose. FTIR and XRD analysis confirmed the presence of cellulose with crystallinity index of 69.26%, 43.83%, and 26.32% for AV, C-MCC, and CAC, respectively. C-MCC and AV are more crystalline and thermally stable at high temperatures compared to CAC. The mechanical and disintegration properties of C-MCC and AV tablets complied with pharmacopeia specifications. Taken together, C-MCC isolated from CPH displayed some fundamental characteristics suitable for use as a pharmaceutical excipient and displayed better properties compared to that of AV