International Journal of Chemistry

International Journal of Chemistry | Vol. 4, No. 5, May 2013 | pp. 33–40

DOI: 10.46882/2013/IJC/000056

Article Type: Original Research Paper

Title: Assessing the Hydrocarbon Tolerance and Phytoremediation Trait of Ricinus communis L. in Polycyclic Aromatic Hydrocarbon Spiked Soils

Names of Authors: O. F. Olawal¹, G. de Metru²*

Authors’ Affiliations:
¹Department of Plant Biology, University of Ilorin, Ilorin, Nigeria.
²Department of Plant Sciences, Wageningen University, Wageningen, Netherlands.

Abstract: Persistent organic pollutants like polycyclic aromatic hydrocarbons (PAHs) accumulate inside industrial soil sub-surfaces, requiring cost-effective vegetative extraction strategies. This controlled study investigates the growth kinetics and remediation efficiency of Ricinus communis L. (Castor bean) cultivated in soils artificially spiked with varying concentrations of phenanthrene (100 to 500 mg/kg) and pyrene (50 to 250 mg/kg). Plant structural indices, remaining soil PAH concentrations, and root zone microbial populations were quantified over a 90-day developmental period. R. communis demonstrated strong physiological tolerance, maintaining high root-to-shoot biomass ratios across all phenanthrene loading levels. High-Performance Liquid Chromatography (HPLC) profiling showed a 78.4% reduction in soil phenanthrene and a 62.5% reduction in pyrene concentrations within the rhizosphere of cultivated systems, compared to minimal attenuation in unplanted controls. Soil microbiological testing revealed a five-fold expansion of heterotrophic degradation bacteria within the castor root matrix. This confirms that root exudates actively stimulate microbial proliferation, accelerating the degradation of complex polycyclic aromatic structures in contaminated industrial terrains.

Keywords: Ricinus communis; Phenanthrene; Pyrene; Soil phytoremediation; Rhizosphere effect; Microbial degradation

Manuscript Timeline: Received: September 02, 2012; Revised: October 12, 2012; Accepted: November 05, 2012; Published: May 02, 2013.

Citation: Olawal, O. F., & de Metru, G. (2013). Assessing the Hydrocarbon Tolerance and Phytoremediation Trait of Ricinus communis L. in Polycyclic Aromatic Hydrocarbon Spiked Soils. International Journal of Chemistry, 4(5), 33–40.

International Journal of Chemistry | Vol. 4, No. 12, December 2013 | pp. 89–96

DOI: 10.46882/2013/IJC/000063

Article Type: Original Research Paper

Title: Phytochemical Fingerprinting, Essential Oil Chemical Profiling, and In Vitro Cytotoxicity of Ocimum gratissimum Leaves

Names of Authors: S. A. Abdulrahman¹, C. A. Rossi²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Minna, Nigeria.
²Department of Pharmacy, University of Genoa, Genoa, Italy.

Abstract: Ocimum gratissimum is heavily utilized in traditional medicine across developing countries to manage metabolic diseases, yet its volatile profile requires deep chemical mapping to clarify its therapeutic potential. This investigation reports the qualitative phytochemical screening, essential oil analysis via Gas Chromatography-Mass Spectrometry (GC-MS), and in vitro cytotoxicity profiling of hexane, ethyl acetate, and methanol leaf extracts. Qualitative tests revealed an abundance of terpenoids, flavonoids, and saponins concentrated majorly within the semi-polar ethyl acetate fraction. Essential oils gathered via hydro-distillation in a Clevenger apparatus were separated into 18 distinct peaks through GC-MS, with eugenol (42.5%), thymol (18.2%), and cis-ocimene (12.4%) emerging as the primary bioactive constituents. The cytotoxic potential was evaluated in vitro against human breast cancer (MCF-7) cell lines using the MTT assay, benchmarked against cisplatin. The ethyl acetate extract displayed significant cytotoxic activity with an IC50 value of 28.4 μg/mL, compared to 5.2 μg/mL achieved by the standard control. A linear correlation was observed between total phenolic content and cancer cell mortality, validating that eugenol and related plant phenolics drive free radical scavenging and apoptotic inductions, supporting further clinical investigation.

Keywords: Ocimum gratissimum; Essential oils; GC-MS analysis; Eugenol; Cytotoxicity; MTT assay

Manuscript Timeline: Received: February 12, 2013; Revised: March 24, 2013; Accepted: May 11, 2013; Published: December 02, 2013.

Citation: Abdulrahman, S. A., & Rossi, C. A. (2013). Phytochemical Fingerprinting, Essential Oil Chemical Profiling, and In Vitro Cytotoxicity of Ocimum gratissimum Leaves. International Journal of Chemistry, 4(12), 89–96.

International Journal of Chemistry | Vol. 4, No. 2, February 2013 | pp. 9–16

DOI: 10.46882/2013/IJC/000053

Article Type: Original Research Paper

Title: Isolation, Screening, and Kinetic Optimization of Cellulase Complexes Sourced from Thermophilic Fungal Strains

Names of Authors: C. N. Nwosu¹, H. A. Tanaka²*

Authors’ Affiliations:
¹Department of Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Biotechnology, Tokyo Institute of Technology, Tokyo, Japan.

Abstract: Industrial saccharification of tough lignocellulosic biomass requires robust cellulolytic enzymes that can resist thermal denaturation under operational refinery configurations. This study focuses on the selective isolation, biochemical screening, and thermal kinetic optimization of high-yielding cellulolytic fungal strains sourced from geothermal hot spring soils. Soil suspensions underwent enrichment culturing in Mandels' mineral media containing microcrystalline cellulose at elevated temperatures. Two distinct fungal strains displaying large hydrolysis zones via Gram's iodine clearing tests were isolated. The highest-yielding strain was identified morphologically and via genetic sequencing as Aspergillus fumigatus. Optimization experiments under solid-state fermentation showed that maximum endoglucanase and exoglucanase production occurred at a temperature of 45°C and a medium pH of 5.0 after 96 hours of incubation. Utilizing agricultural cotton residues as alternative substrates induced a high enzyme yield (6.2 U/mL) compared to wood sawdust (2.1 U/mL). The crude cellulase complex retained over 85% of its initial catalytic activity across a temperature stability range of 40 to 60°C for 24 hours, establishing an exceptionally stable enzyme framework for economic bioethanol manufacturing tracks.

Keywords: Thermophilic fungi; Aspergillus fumigatus; Solid-state fermentation; Cellulase; Thermal stability; Bioethanol production

Manuscript Timeline: Received: July 11, 2012; Revised: August 20, 2012; Accepted: September 15, 2012; Published: February 06, 2013.

Citation: Nwosu, C. N., & Tanaka, H. A. (2013). Isolation, Screening, and Kinetic Optimization of Cellulase Complexes Sourced from Thermophilic Fungal Strains. International Journal of Chemistry, 4(2), 9–16.

International Journal of Chemistry | Vol. 4, No. 1, January 2013 | pp. 1–8

DOI: 10.46882/2013/IJC/000052

Article Type: Original Research Paper

Title: Phytochemical Screening, Volatile Fingerprinting, and Antiprotozoal Capacity of Crude Extracts from Carica papaya Seeds

Names of Authors: A. E. Ogunkoya¹, J. M. S. Cabral²*

Authors’ Affiliations:
¹Department of Chemistry, Ekiti State University, Ado-Ekiti, Nigeria.
²Department of Bioengineering, Instituto Superior Técnico, Lisbon, Portugal.

Abstract: Carica papaya seeds are frequently utilized in traditional tropical medicine as an anthelmintic agent, yet their volatile bioactive profiles require deep chromatographic mapping to clarify structural efficacy. This investigation reports the qualitative phytochemical screening, volatile constituent identification via Gas Chromatography-Mass Spectrometry (GC-MS), and in vitro antiprotozoal capacity of hexane, ethyl acetate, and methanol seed extracts. Qualitative testing revealed a heavy presence of alkaloids, benzyl glucosinolates, phenolics, and flavonoids concentrated within the semi-polar ethyl acetate fraction. GC-MS profiling of the ethyl acetate extract identified 15 prominent peaks, with benzyl isothiocyanate (38.42%), oleic acid (22.15%), and palmitic acid methyl ester (12.30%) emerging as the primary bioactive components. The antiprotozoal potential was evaluated in vitro utilizing susceptibility assays against Giardia lamblia trophozoites, benchmarked against metronidazole. The ethyl acetate extract displayed the highest antiprotozoal activity, yielding an IC50 value of 15.8 μg/mL, compared to 2.4 μg/mL achieved by the standard drug. A linear correlation was observed between the concentration of benzyl isothiocyanate and protozoal cell mortality, validating that thiocyanate derivatives act as the driving contributors to structural cellular disruption, lending scientific validation to traditional medical usage.

Keywords: Carica papaya; Seed extract; Gas Chromatography-Mass Spectrometry; Benzyl isothiocyanate; Antiprotozoal activity; Giardia lamblia

Manuscript Timeline: Received: July 02, 2012; Revised: August 14, 2012; Accepted: September 10, 2012; Published: January 03, 2013.

Citation: Ogunkoya, A. E., & Cabral, J. M. S. (2013). Phytochemical Screening, Volatile Fingerprinting, and Antiprotozoal Capacity of Crude Extracts from Carica papaya Seeds. International Journal of Chemistry, 4(1), 1–8.

International Journal of Chemistry | Vol. 4, No. 10, October 2013 | pp. 73–80

DOI: 10.46882/2013/IJC/000061

Article Type: Original Research Paper

Title: Synthesis, Characterization, and Photoluminescence Profiles of Novel Europium(III) Complexes with Phenanthroline Derivatives

Names of Authors: A. O. Balogun¹, L. M. Martinez²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Physical Chemistry, National Autonomous University of Mexico, Mexico City, Mexico.

Abstract: Trivalent lanthanide coordination compounds possess intense monochromatic emissions that make them valuable components for light-emitting diodes, optical sensors, and biochemical assays. This study details the synthesis and characterization of novel europium(III) complexes using 1,10-phenanthroline and beta-diketone ligands. The newly synthesized rare-earth complexes were characterized using elemental analysis, molar conductance, Fourier-transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-Vis) absorption spectrophotometry. Analytical data confirmed a 1:1:3 metal-to-ligand stoichiometric configuration, corresponding to the general molecular formula [Eu(L)₃(phen)], where L represents the deprotonated beta-diketone fraction. Molar conductance measurements in acetonitrile established that the complexes are completely non-electrolytic. FT-IR spectra confirmed that both ligands coordinate to the central Eu(III) ion via the carbonyl oxygens and the azomethine nitrogen atoms. Room-temperature photoluminescence spectra exhibited highly intense, narrow emission lines characteristic of the Eu(III) ion, dominated by the electric dipole transition (⁵D₀ to ⁷F₂) at 612 nm. The high luminescence quantum yield (45.2%) and long emission lifetime (0.84 ms) indicate efficient energy transfer from the organic ligands to the central metal ion via an intramolecular antenna mechanism, presenting a robust framework for developing red-emitting materials.

Keywords: Europium complexes; Rare earth elements; Photoluminescence; Intramolecular energy transfer; Antenna effect; Coordination chemistry

Manuscript Timeline: Received: January 15, 2013; Revised: March 02, 2013; Accepted: April 10, 2013; Published: October 04, 2013.

Citation: Balogun, A. O., & Martinez, L. M. (2013). Synthesis, Characterization, and Photoluminescence Profiles of Novel Europium(III) Complexes with Phenanthroline Derivatives. International Journal of Chemistry, 4(10), 73–80.

International Journal of Chemistry | Vol. 4, No. 11, November 2013 | pp. 81–88

DOI: 10.46882/2013/IJC/000062

Article Type: Original Research Paper

Title: Adsorptive Sequestration of Nickel(II) Ions from Industrial Effluents Using Sulfonated Tea Waste Matrices

Names of Authors: E. N. Chidi¹, J. P. van der Berg²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Chemical Engineering, Delft University of Technology, Delft, Netherlands.

Abstract: The contamination of aquatic networks by toxic industrial nickel residues presents persistent public health and ecological hazards due to its bioaccumulative nature. This research examines the adsorptive performance of chemically modified black tea waste prepared via sulfonation with concentrated sulfuric acid for the removal of Ni(II) ions from aqueous systems. Structural configurations and morphology changes were monitored using scanning electron microscopy (SEM) and FT-IR spectroscopy, which confirmed the successful introduction of sulfonic acid (-SO₃H) active functional groups onto the biomass surface. Batch extraction experiments evaluated parameters of solution pH, contact time, adsorbent dosage, and initial metal concentrations. Maximum Ni(II) removal was achieved at an optimum pH of 6.0, with an equilibrium contact period of 90 minutes. Equilibrium data matched the Langmuir isotherm expressions perfectly, indicating a maximum monolayer adsorption capacity of 52.64 mg/g at 298 K. Sorption kinetics conformed to the pseudo-second-order model with high correlation coefficients (R² > 0.998), proving that chemical ion exchange reactions governed the phase transfer process. Thermodynamic parameters confirmed that the sorption mechanism was spontaneous (delta G° = -4.25 kJ/mol) and endothermic, establishing sulfonated tea waste as an affordable material for metal recovery.

Keywords: Tea waste; Chemical modification; Sulfonation; Nickel removal; Adsorption kinetics; Chemisorption

Manuscript Timeline: Received: February 02, 2013; Revised: March 18, 2013; Accepted: April 22, 2013; Published: November 08, 2013.

Citation: Chidi, E. N., & van der Berg., J. P. (2013). Adsorptive Sequestration of Nickel(II) Ions from Industrial Effluents Using Sulfonated Tea Waste Matrices. International Journal of Chemistry, 4(11), 81–88.