Highest Percentage Yield Research Articles

Extraction, isolation and characterization of secondary metabolites in the leaves of Morinda lucida from Oshiegbe in Ebonyi State

Abstract This research work assessed the extraction, isolation and characterization of secondary metabolites in the leaves of Morinda lucida. The leaves of the plant were collected from Oshiegbe in Ebonyi state. They were air-dried and pulverized for extraction. The extraction was done using petroleum ether, ethyl acetate and ethanol through sequential extraction method at room temperature. The extracts were concentrated and subjected to phytochemical analysis. The concentrated fraction was subjected to thin layer chromatography (TLC) and column chromatography to obtain the pure compounds. The isolated compounds were characterized using ultraviolet/visible spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gas chromatography-mass spectroscopy (GC-MS) for their structural elucidation. The result of the work showed that the ethanol extract recorded the highest percentage yield of 5.36 while the petroleum ether extract recorded the least percentage yield of 0.61. The preliminary phytochemical screening of the extracts revealed the presence of alkaloids, saponins, tannins, terpenoids, flavonoids, steroids and glycosides in the leaves of the plants. The ethanol extract yielded four pure isolates (compounds) of R f values: 0.93, 0.80, 0.86 and 0.72. The compounds were characterized as N-ethyl-N-nitroso-ethylmethanoate (1) bicyclo-[3,1,1]-2,6,6-trimethyl heptane-2,3-diol (2) dibutylphthalate (3) and 1,2-benzenedicarboxylic acid-butyl-2-methylpropyl ester (4) The spectral results and GC-MS fragmentation pattern agreed with the structures of the isolated compounds.

Economical and Environmentally Friendly Track of Biowaste Recycling of Scallop Shells to Calcium Lactate.

The scallop shell waste (Pectinidae, one of saltwater clams) was used as a raw material (precursor) to prepare calcium lactate (Ca(C2H4OHCOO)2), and the physicochemical properties of scallop-derived calcium lactate were then investigated. The scallop waste was first ground to obtain calcium carbonate (CaCO3) powder, and the calcium lactate compounds were successfully synthesized by the reactions between shell-derived CaCO3 and lactic acid (C2H4OHCOOH). The short preparation time, high percentage yield, and low-cost production are the preferred manners, and, in this research, it was the reaction of 70 wt % lactic acid and scallop-derived CaCO3. The thermal decompositions of both CaCO3 precursor and all prepared calcium lactates resulted in the formation of calcium oxide (CaO), which is widely used as a catalyst for biodiesel production. By comparing with the literature, the results obtained from the characterization instruments (infrared spectrophotometer, X-ray diffractometer, thermogravimetric analyzer, and scanning electron microscope) confirmed the formation and crystal structure of both CaCO3 and its calcium lactate product. The morphologies of calcium lactate show different sizes depending on the acid concentration used in the reaction process. Consequently, this work reports an easy, uncomplicated, low-cost technique to change the cheap calcium compound product (scallop CaCO3) derived from shellfish waste to the valuable compound (calcium lactate), which can be used in many industries.

DESIGN OF CITRONELLA LEAF DISTILLERS USING THE STEAM HYDRODISTILLATION METHOD

This study aims to design and test the citronella leaf distillation tool by conducting experiments and testing the tools and test results. The parameters observed were heat transfer in the citronella leaf distillery produced by the tool, the results of the conduction heat transfer research in the distillation tank were 1,032.61 J/s (Joules per second) and heat transfer by natural convection in the distillation tank was 3,761.16 J/s (Joules per second) with an initial water temperature of 28°C to a specified temperature of 98°C. The distillation time of more than 5 hours will reduce the quality of the yield which is not up to standard. The effect of the part of lemongrass which produces a high yield percentage is on the leaves, while the high quality of citronella oil is on the leaves. % citronella citronella on fresh leaves was 67.36%, withered leaves were 44.92%.

Solubility enhancement of some poorly soluble drugs by solid dispersion using Ziziphus spina-christi gum polymer

A high percentage of marketed drugs suffer from poor water solubility and require an appropriate technique to increase their solubility. This study aims to compare physically modified and unmodified gum polymers extracted from Ziziphus spina-christi fruits as solid dispersion carriers for some drugs. Taguchi Orthogonal Design (L9) was chosen for the screening and optimization of the solid dispersions. The design has four factors: type of drug, type of polymer, type of solid dispersion process, and drug to polymer ratio. Each factor was varied in three stages and the total number of runs was 9 in triplicate. The polymer was physically modified by heating (M1ZG) or freeze-drying (M2ZG). The drugs were selected according to the biopharmaceutical classification system, namely loratadine and glimepiride (class II) and furosemide (class IV). Drugs were dispersed in the polymer in three different ratios 1: 1, 1: 2, and 1: 3. Solid dispersions were made by co-grinding, solvent evaporation, and kneading methods. Modified and unmodified polymers were characterized in terms of their organoleptic properties, solubility, powder flowability, density, viscosity, swelling index, and water retention capacity. Solid dispersions were characterized in terms of percentage practical yield, solubility improvement, and drug compatibility. The results showed that the organoleptic properties of polymers were not changed by the gum modification. The swelling index of the polymer was doubled in M1ZG. The viscosity and water retention capacity of the polymer was increased in both modified polymers. All solid dispersions showed a high practical percentage yield of more than 93%, the higher values ​​being more associated with loratadine and furosemide than with glimepiride. The improvement in solubility was observed in all solid dispersions prepared, the values ​​varying with the pH of the medium and the method of modification. The FTIR results indicated that there was no chemical interaction between these drugs and the polymer used. Analysis of the results according to the Taguchi orthogonal design indicated 51 folds aqueous solubility enhancement for loratadine using M2ZG polymer at a ratio of 1: 3 of Drug: polymer. This study showed the possibility of improving the solubility of other poorly soluble drugs.

In vitro antioxidant and anti-inflammatory activities of Costus igneus leaf fractions

Costus igneus Nak is an ethnobotanical plant used in the management of several inflammatory and oxidative stress-related disorders. There is a need to scientifically validate its use in ethnomedicine. This study investigated the antioxidant and anti-inflammatory activities of fractions from ethanol extract of C. igneus leaf using in vitro methods. Crude ethanol extract of C. igneus leaf was successively partitioned to obtain hexane, ethyl acetate, butanol and aqueous fractions. The fractions were screened for in vitro anti-inflammatory activity using erythrocyte membrane stabilization and inhibition of protein denaturation assays. In vitro antioxidant activity was carried out using 1-1-diphenyl, 2-picryl hydrazyl (DPPH), nitric oxide and hydrogen peroxide radical scavenging assays. Data were analyzed using GraphPad Prism 6.0 and p value was set at 0.05. The percentage yield of the crude ethanol extract of C. igneus leaf was 25.40%. The aqueous fraction (37.05%) had the highest percentage yield, followed by butanol fraction (34.33%), hexane fraction (16.58%) and the ethyl acetate fraction (12.04%). Anti-inflammatory studies showed that C. igneus butanol fraction (CIBF) had the highest erythrocyte membrane stabilizing effect (IC50 = 140.61 µg/mL) and highest percentage inhibition of protein denaturation (IC50 = 20.40 µg/mL) when compared to the hexane, ethyl acetate and aqueous fractions. Antioxidant study also showed that CIBF had the highest percentage inhibition of DPPH radicals (IC50 = 18.36 µg/mL), highest nitric oxide radical scavenging activity (IC50 = 67.26 µg/mL) and highest hydrogen peroxide radical scavenging activity (IC50 = 160.50 µg/mL) when compared to the hexane, ethyl acetate and aqueous fractions. The findings showed that CIBF demonstrated remarkable anti-inflammatory and antioxidant activities in vitro. Key words: Costus igneus, Antioxidant, Anti-inflammatory, In vitro, Butanol fraction.

Evaluation of the bioactive compounds of Vernonia amygdalina Delile extracts and their antibacterial potentials on water-related bacteria

BackgroundThis study focused on the evaluation of the bioactive compounds of Vernonia amygdalina Del. leaf extracts and their antibacterial potential on some water-related bacterial isolates. The bacterial isolates were confirmed using standard microbiological test. The leaves of V. amygdalina were subjected to extraction using the Maceration method with water and ethanol as the extraction solvents. Gas chromatography–mass spectroscopy (GC–MS) was carried out on extracts. Antibacterial susceptibility test of V. amygdalina extracts on isolates was carried out.ResultsAqueous extract of V. amygdalina had a higher percentage yield (11.89%) than the ethanol extract (5.37%). The GC–MS carried out revealed the presence of butanoic acid, squalene, palmitaldehyde, octadecanoic acid, Z-hexadecanoic acid ethyl ester, oxirane, tetradecyl, 3- methyl-2-phenylindole, n-heneicosane, phytol, methyl-2-O-benzyl-d-arabinofuranoside, cholest-5-en-3-ol acetate; with hexadecanoic acid ethyl ester and 1,1-diethoxy-3methylbutane having the highest percentage composition of 24.37% and 13.42% in aqueous and ethanol extract, respectively, aqueous extract highly inhibited Escherichia coli with an inhibition zone of 10.333 ± 0.882 and 36.667 ± 0.882 for 25 mg/ml and 100 mg/ml, respectively, while the ethanol extracts inhibited most of the isolates with an inhibition range of 7.000 ± 1.155 to 30.333 ± 0.882. The minimum inhibitory concentration for both extracts on the isolates varies from 25 to 50 mg/ml.ConclusionsThe ethanol extract of V. amygdalina had a higher inhibitory activity on the bacterial isolates than water. These findings indicate the potential of ethanol extract of V. amygdalina leaf in the treatment of water borne infections.

Preparation and evaluation of sustained release dosage forms for posttransplant care

Aim: The purpose of the study was to prepare and characterize microbeads for oral sustained release of tacrolimus. Design, methodology, and approach: Tacrolimus-based microbeads were developed by ionic gelation method. Xanthan gum, chitosan, and sodium alginate were used as polymers for aqueous internal phase using calcium chloride as a cross-linking agent. The microbeads were evaluated for morphologic features by scanning electron microscopy, percentage yield, drug entrapment, and in vitro drug release. Findings and implications: Microbeads were examined for the effects of various variables in formulation process. The cross-linking reaction between sodium alginate and calcium chloride for being converted into calcium alginate in the formulation process was used in the microencapsulation of tacrolimus core material. The results showed the compatibility of the drug with the polymers in the formulation as observed in Fourier-transform infrared spectroscopy studies. The formulated microbeads showed high percentage yield and drug entrapment efficacy and the optimized formulation showed a delayed release effect following zero-order mechanism of release. Conclusion: Ionotropic gelation method was found to be a suitable method for preparing tacrolimus microbead-sustained-release drug delivery system. Chitosan and xanthan gum polymers showed potential in aiding the formulation of sustained release tacrolimus microbeads. Xanthan gum is soluble in water and confers high viscosity at low concentrations. The molecular weight of xanthan gum is more than the chitosan polymer which leads to better sustained release of microbeads prepared with xanthan gum compared to chitosan microbeads. Both chitosan and xanthan gum microbeads followed zero-order-release kinetic models.

Evaluation of Antimicrobial and Antioxidant Activities of Latex and Extracts of Euphorbia monostyla

Objective:: Euphorbia is a plant from the Euphorbiaceae family, and it has traditionally been used to treat gonorrheal, respiratory tract infections, skin infections and malaria. The aim of the present study was to evaluate antibacterial, antifungal and antioxidant activities of latex and extracts of Euphorbia monostyla. Materials and Methods:: Antimicrobial activity was studied by Disc-well diffusion and MIC-MBC methods.Also, its antioxidant activity was evaluated by DPPH and FRAP methods. Total phenolic content was evaluated by Folin-Ciocalteu reagent. Results:: It is displayed as a result of the work that solvent polarity will play a key role in increasing phenolic solubility. Methanol extract gave the highest percentage yield, and ethyl acetate resulted in the lowest percentage yield. The antimicrobial test showed that whole extracts had no beneficial uses on microorganisms in comparison to antibiotics types. Analysis of antioxidant assays revealed that aqueous and methanol extracts had the highest antioxidant properties. Conclusion:: Whole extracts had no beneficial uses on microorganisms compared to antibiotics types, but the aqueous extract of E. monostyla had moderate antioxidant activity and may contain valuable active compounds. This work is the first study that discusses E. monostyla, and further study is suggested to isolate its active compounds.

Dioxovanadium(V) Complex Incorporating Tridentate ONO Donor Aminobenzohydrazone Ligand: Synthesis, Spectral Characterization and Application as a Homogeneous Lewis Acid Catalyst in the Friedländer Synthesis of Substituted Quinolines

A dioxovanadium complex has been successfully prepared by the reaction of an ONO-donor Schiff base, derived by condensing aminobenzohydrazide and 3-ethoxysalicylaldehyde, with VO2(acac)2. The structures of synthesized products were explored spectroscopically through FT-IR, 1H & 13C NMR, and by elemental composition (CHN) through combustion analysis. The catalytic potential of the complex was explored for the synthesis of substituted quinolines by adapting the Friedländer method. In this method, a cyclocondensation reaction of ortho aminoaryl aldehydes or ketones was carried out with another ketone having an alpha methylene group under solvent-free conditions. The main advantages of the present catalytic work are less time required for the completion of the reaction, high percentage yield, and easy work out procedure.

Bioethanol Production from Cassava Peels Inoculated with Saccharomyces cerevisiae and Zymomonas mobilis

Aim: This study was designed to determine the bioethanol production from fermented cassava peel using Saccharomyces cerevisiae and Zymomonas mobilis.
 Methodology: Cassava peels were collected from cassava processing sites, washed, surface sterilized, dried, milled into flour, pretreated, and fermented. Saccharomyces cerevisiae and Z. mobilis suspensions were aseptically inoculated into the fermenting medium and allowed to stand for seven days. The pH, total reducing sugar, chemical composition, and bioethanol composition of the fermenting substrates were determined.
 Results: A pH decrease from 5.2 to 4.1 was recorded in the sample fermented with S. cerevisiae while the least pH value of 3.8 was obtained from the sample fermented with Z. mobilis, respectively. The total reducing sugar (glucose) of fermented samples decreased from 3.4% to 1.5% (Z. mobilis) and 3.4% to 1.88% (S. cerevisiae) compared with the control sample. The chemical composition showed high protein and fat contents in the fermented samples. High percentage yield of 30% with ethanol volume of 45 mL was recovered from cassava peel inoculated with S. cerevisiae while flash point, i.e. the lowest temperature at which fuel produces enough vapor to cause ignition leading to flame generation of 24oC, was recorded for both fermented samples inoculated with S. cerevisiae and Z. mobilis.
 Conclusion: The ability of the bacterium and the yeast isolates exhibiting high potential for bioethanol production could be promising in various industrial processes as an alternative to fossil transportation fuel.

Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of a dioxidomolybdenum complex with aminosalicyl-hydrazone Schiff base ligand: An experimental and theoretical approach

A new dioxidomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-methoxysalicylaldehyde, with MoO2(acac)2. The structures of synthesized products were explored spectroscopically through FT-IR, 1H &13C NMR and by elemental composition (CHN) through combustion analysis. The structural investigations of the dioxidomolybdenum(VI) complex were accomplished by taking its diffraction data through X-ray crystallography. The tridentate Schiff base ligand is bonded to the central metal through its deprotonated enolic and phenolic oxygen atoms and by the nitrogen of the azomethine group. The interpretation of the data obtained through diffraction analysis validates the distorted octahedral geometry of the prepared metal complex. QTAIM, MEP and NCI calculations and Hirshfeld surface analysis were performed to investigate the nature and types of non-covalent linkages present among the sample molecules. The theoretical calculations, performed by DFT using the B3LYP/Def2-TZVP level of theory, direct that the intended outcomes are in compliance with the actual consequences. Furthermore, the catalytic potential of the molybdenum complex was explored for the selective oxidation of benzylic alcohols to the desirable aryl aldehydes at room temperature in the presence of 70% aqueous tert-butyl hydroperoxide (TBHP) under solvent-free conditions. The main advantage of the present catalytic work is the accomplishment of reaction in a short period of time, high percentage yield and easy work-out procedure.

Experimental and theoretical studies of new dioxomolybdenum complex: Synthesis, characterization and application as an efficient homogeneous catalyst for the selective sulfoxidation

A new dioxomolybdenum(VI) complex with tridentate ONO-donor Schiff base ligand derived from isoniazid has been synthesized and characterized by elemental analyses, FT-IR and 1H NMR, and its solid state structure was confirmed by single crystal X-ray diffraction (SC-XRD) technique. In the complex, the molybdenum center adopts a slightly distorted octahedral geometry, by using three O,N,O-donor atoms of the tridentate ligand, an oxo group makes the equatorial plane, while a methanol and another oxo group employ the axial positions. QTAIM, MEP, NCI calculations and Hirshfeld surface analysis were performed to investigate the nature and types of non-covalent linkages present among the sample molecules. The theoretical calculations, performed by DFT using the B3LYP/Def2-TZVP level of theory, direct that the intended outcomes are in compliance with the actual consequences. In addition, the catalytic performance of the complex was studied in oxidizing the different sulfides with H2O2 as an oxidizing agent in ethanol as a solvent under refluxed conditions. The main edge of the present catalytic work is the accomplishment of reaction in a short period of time, high percentage yield and full selectivity to sulfoxides without any formation of sulfones.

Synthesis, spectra (FT-IR, NMR) investigations, DFT, FMO, MEP, NBO analysis and catalytic activity of MoO2(VI) complex with ONO tridentate hydrazone Schiff base ligand

A new dioxomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-ethoxysalicylaldehyde, with MoO2(acac)2. The structures of synthesized products were explored spectroscopically through FT-IR, 1H & 13C NMR and by elemental composition (CHN) through combustion analysis. The tridentate Schiff base ligand is bonded to the central metal through its deprotonated enolic and phenolic oxygen atoms and by the nitrogen of the azomethine group. The interpretation of the data obtained through diffraction analysis validates the distorted octahedral geometry for the prepared metal complex. Furthermore, the catalytic potential of the molybdenum complex was explored for the selective oxidation of the aryl and alkyl sulfides to the corresponding sulfones in the presence of 30% aqueous H2O2 in ethanol. The main edge of the present catalytic work is the accomplishment of reaction in a short period of time, high percentage yield and easy work-up procedure.

Synthesis of a carboxylic acid-based ruthenium sensitizer and its applicability towards Dye-Sensitized Solar Cells

This work reports the synthesis of ruthenium based Ru(bpy)2(dcbpy)(ClO4)2[(bpy)2,2′-bipyridine;dcbpy = 4,4′-dicarboxy-2,2′-bipyridine] (RuC) dye and its application in solid and liquid state Dye-Sensitized Solar Cells (DSSCs). Synthesis resulted with high-pure orange coloured dye with a high yield percentage of 45%. The dye was characterized via Nuclear Magnetic Resonance (NMR) spectroscopy, Mass spectroscopy, Cyclic Voltammetry (CV) and UV–vis spectroscopy. The calculated bandgap (Eg) of 2.38 eV from absorbance spectra of pure RuC in ethanol solution showed best proximity with the data obtained from CV measurements. The RuC showed strong absorption in near UV region with the highest molar extinction coefficient (MEC) of 14,746 M−1cm−1 at 463 nm. Plateau of over 80% of External Quantum Efficiency (EQE) spectra reveals the efficient carrier generation of RuC in near UV region. Carboxylic acid groups of RuC provide the potential for enhanced electron transfer from TiO2 surface, and an increased electron density at the interface leads to higher current density. The RuC sensitized solid and liquid state DSSCs exhibited a short circuit current density (JSC) over 3.04 mA/cm2 and 5.82 mA/cm2, and power conversion efficiency (PCE) of 1.2% and 1.8% respectively under simulated Air Mass 1.5 irradiation (100 mWcm−2).

Analysis on microstructure and properties evolution and life prediction of P92 steel in high temperature service

P92 steel (10Cr9MoW2VNbBN) is widely used in high-temperature steam piping and high-temperature header fabrications of ultra-supercritical units. In this paper, a follow-up study on the microstructure, mechanical properties and life of P92 steel steam pipes which are virgin, 31,000 h in service, 49,000 h in service and 71,000 h in service was carried out. The results show that the mechanical properties of the P92 steel drop significantly after 31,000 h of service, then decrease slowly with the increase of the service time. When the service time reaches 71,000 h, the high temperature yield strength, percentage elongation, and impact absorbed energy are all close to the lower limit regulated by the ASME standard. Moreover, the morphology of lath martensite becomes fragmentary, the width of the martensitic lath increases and carbide particles cluster and grow at the grain boundary. M23C6 phase coarsens and local Laves phase precipitates. Meanwhile, the dislocation density decreases to some degree. Furthermore, there is a good corresponding relationship between the room temperature hardness and the high temperature tensile strength of the P92 steel after a long period of service. The prediction model of the remaining endurance life of P92 components is proposed on the basis of the room temperature hardness.

Formulation and In-Vitro Evaluation of Meloxicam Solid Dispersion using Natural Polymers.

Meloxicam (MLX) is non-steroidal anti -inflammatory, poorly water soluble, highly permeable drug and the rate of its oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. Solid dispersion (SD) is an effective technique for enhancing the solubility and dissolution rate of such drug.
 The present study aims to enhance the solubility and the dissolution rate of MLX by SD technique by solvent evaporation method using sodium alginate (SA), hyaluronic acid (HA), collagen and xyloglucan (XG) as gastro-protective hydrophilic natural polymers.
 Twelve formulas were prepared in different drug: polymer ratios and evaluated for their, percentage yield, drug content, water solubility, dissolution, crystal lattice using powder X-ray diffraction (PXRD) and studies and Fourier Transform Infrared Spectroscopy (FTIR) for determination the drug-polymer interaction.
 All the prepared showed improvement of drug solubility except that prepared with HA. The best result was obtained with formula SD1 (MLX: SA 1:1) that showed a high percentage yield (97), high drug content (97.4±0.05) and increase in solubility compared to solubility of pure MLX with improved dissolution rate. the PXRD study revealed the conversion of the drug to amorphous form without chemical interaction according to FTIR results

Solubility and Dissolution Enhancement of Ebastine by Surface Solid Dispersion Technique

Ebastine (EBS) is a non-sedating antihistamine with a long duration of action. This drug has predominantly hydrophobic property causing a low solubility and low bioavailability. Surface solid dispersions (SSD) is an effective technique for improving the solubility and dissolution rate of poorly soluble drugs by using hydrophilic water insoluble carriers.
 The present study aims to enhance the solubility and dissolution rate of EBS by using surface solid dispersion technique. Avicel® PH101, Avicel® PH 102, croscarmellose sodium(CCS) and sodium starch glycolate(SSG) were used as water insoluble hydrophilic carriers.
 The SSD formulations of EBS were prepared by the solvent evaporation method in different drug: carrier weight ratios and evaluated for their percentage yield, drug content , water solubility, dissolution study in 0.1 N HCl, crystal lattice using powder X-ray diffraction (PXRD) and Fourier Transform Infrared Spectroscopy (FTIR) for determination the drug-carrier interaction.
 Most of the prepared SSD formulas showed improvement of drug solubility. The best result was obtained with formula SSD16 (EBS:CCS 1:15) that showed high percentage yield (98.5%), high drug content (98.39%) and 8.2 fold increase in solubility compared to solubility of pure drug with improved dissolution rate. The drug was converted to amorphous form without chemical interaction with the carrier.

Novel synthesis of porous Si-TiO2 composite as a high-capacity anode material for Li secondary batteries

Porous Si materials can be considered as a candidate for and an alternative to commercial graphite anodes for Li-ion batteries. In this study, we propose a modified magnesiothermic method to increase the materials’ yield and a design strategy to improve their electrochemical properties. For magnesiothermic solid-state reactions, Mg2Si was used instead of metallic Mg and amorphous nanoscale SiO2 was adopted. The two starting materials were converted into Si and MgO via a high-temperature solid-state reaction, resulting in a high-yield percentage of Si. Then, amorphous TiO2 layers were formed and the MgO was removed by chemical etching, forming a porous structure. The materials at each step were thoroughly characterized by using various analytical tools. Electrochemical test results demonstrated that the amorphous TiO2 coated porous Si composite electrode exhibited a high reversible capacity of 1965 mA h g−1 after 100 cycles and a greatly improved initial Coulombic efficiency of 90.1%. These results can be attributed to the controlled porous structure of the composite and amorphous TiO2 coating layer. The modified magnesiothermic method and porous material design could attract commercial use of Si-based materials as Li-ion battery anodes.

Identification and Quantification of Secondary Metabolites and The Antimicrobial Efficacy of Leaves Extracts of Some Medicinal Plants

Azadirachta indica, Calotropis procera, Carica papaya, and Vernonia amygdalina are among the most frequently used plants with proven ethnomedicinal applications in Ilorin, Nigeria. This study investigated the active constituents and antimicrobial efficacy of acetone and aqueous extracts of these plants against Candida albicans, Escherichia coli ATCC 259220, and Staphylococcus aureus ATCC 25923 by the disc diffusion technique. High-Performance Liquid Chromatography (HPLC) fingerprint of the constituents of acetone extracts of C. papaya, A. indica, and V. amygdalina was further investigated. Highest percentage yield (10.20 %) was obtained for acetone extract of A. indica while the lowest yield (10.20 %) was obtained for aqueous extract of C. papaya. Varying constituents viz. coumarins, glycosides, protein, saponin, anthraquinone, flavonoid, tannin and terpenoid were detected. Different levels of antimicrobial efficacy were exhibited by each of the plants while a synergistic effect was observed at 100 mg/mL concentration of acetone extract of the combination of all the plants. An array of compounds was separated at different peak heights corresponding to concentration of the compounds. Creptolepinone was detected in highest percentage (47.0 %) in acetone extracts of C. papaya while phorbolester was detected in lowest percentage (1.2 %). Myricetin was detected in highest percentage (39.6 %) in acetone extracts of A. indica while alpha funebren was detected in lowest percentage (1.5 %).  Vernodalin was detected in highest peak height (48.8 %) in V. amygdalina and andrographoside was detected in lowest peak height (0.6 %). This study depicts that the plants may be promising pharmaceutical candidates that can be used in the development of new therapeutic agents.

Optimised transesterification of used frying oils: production and characterisation of biodiesel

ABSTRACT To compete with the growing energy demands, it is necessary to explore some new alternative sources of energy. Presently, biodiesel is being acknowledged for its environmentally friendly and renewable nature. In order to avoid fuel versus fuel problem, biodiesel can be made by using low-cost feedstocks such as non-conventional seed oils (Jatropha, Karanja and Castor), discarded and repeated fried/used frying oils. This work is targeted towards production of biodiesel from used frying oils collected from local frying outlets. Alkali-catalysed transesterification reaction was applied to make biodiesel through optimisation of different reaction variables with glycerine as the byproduct. Optimised conditions/reaction variables such as catalyst type and concentration, methanol/oil molar ratio, reaction temperature and agitation intensity yielded good quality and high percentage yield of biodiesel. The optimum parameters for biodiesel production were observed as 9:1 molar ratio of methanol/used frying oil, 1.5% KOH by wt. of oil, 60°C reaction temperature and 600 rpm agitation intensity. GC-MS and FTIR analysis of the produced used frying oil methyl esters (UFOMEs) confirmed the complete conversion of oil into biodiesel. The biodiesel fuel properties like density, flash point, kinematic viscosity, cloud point, pour point were determined and found comparable with American (ASTM D6751) and European (EN 14214) standard methods. From the results, it can be concluded that low cost of used frying oil as raw material was observed to be the most important aspect for economic viability of biodiesel production using such feedstocks.