International Research Journal of Pure and Applied Chemistry

Recent Advances in Physicochemical Properties and Applications of Schiff Bases and Heterocyclic Drug Systems

2026-07-03T07:52:06+00:00

Schiff bases and heterocyclic drug systems are becoming increasingly important in medicinal and materials chemistry because of their remarkable physicochemical and biological properties. Schiff bases containing azomethine (>C=N–) functionality possess excellent chelating ability, structural flexibility, electronic tunability, and broad-spectrum biological activity. Similarly, heterocyclic drug systems containing nitrogen, oxygen, or sulfur heteroatoms are of substantial pharmaceutical importance because of their therapeutic efficacy and molecular interaction behaviour. Recent years have seen increasing research interest in understanding the physicochemical behaviour of Schiff bases and heterocyclic drug molecules in different solvent systems using acoustical, refractometric, spectroscopic, and fluorescence techniques.

Physicochemical investigations involving ultrasonic velocity, density, viscosity, refractive index, adiabatic compressibility, molar refraction, and polarizability provide valuable insights into intermolecular interactions, solvation effects, molecular aggregation, and structural organisation in solution systems. Such investigations are highly relevant to pharmaceutical formulation, molecular recognition, and sensor development. In addition to physicochemical characterisation, Schiff bases and their metal complexes exhibit diverse antimicrobial, antioxidant, anticancer, catalytic, and fluorescence-sensing applications.

This review provides a concise overview of the physicochemical characteristics and diverse applications of Schiff bases and heterocyclic drug systems, thereby offering valuable insights for medicinal chemists, synthetic researchers, and pharmaceutical scientists involved in the development of advanced therapeutic and functional materials. In particular, the review summarises recent advances in the physicochemical properties and applications of Schiff bases and heterocyclic drug systems, with emphasis on acoustical studies, solvent effects, refractometric analysis, molecular interactions, biological applications, coordination chemistry, and fluorescence-sensing behaviour. Special attention has been devoted to recent developments in Schiff base-derived fluorescent chemosensors and physicochemical investigations of heterocyclic drugs in various solvent systems. Furthermore, the article highlights the importance of integrating physicochemical characterisation with biological and analytical applications for the development of advanced functional materials and pharmaceutical systems.

Phytochemical Profiling and Organ-Specific Metabolite Distribution in Sudanese Petroselinum crispum (Parsley): Implications for Gastroprotective and Therapeutic Applications

2026-06-09T12:15:42+00:00

Petroselinum crispum (parsley), an essential member of the Apiaceae family, is a globally distributed biennial herb esteemed for its culinary versatility and multi-faceted pharmacological profile. In the Sudanese ethnobotany, it is utilized for its potent antioxidant, anti-inflammatory, and gastroprotective properties. This investigation aimed to quantify the extractive yield and characterize the organ-specific distribution of bioactive secondary metabolites across the roots, stems, and leaves of Sudanese P. crispum. Botanical samples were partitioned and subjected to a 72-hour maceration in a hydro-methanolic solvent system (70% MeOH). Crude extracts were concentrated under reduced pressure using rotary evaporation. Comprehensive qualitative phytochemical screening was performed to identify major metabolite classes, including alkaloids, phenolics, and terpenoids. Gravimetric analysis revealed a superior extractive yield in the roots (45.26%), followed by the stems (13.62%) and leaves (10.00%). The phytochemical matrix showed high complexity, with the leaves and roots exhibiting the greatest metabolite diversity. Screening confirmed the presence of flavonoids and phenolic compounds (highly concentrated in leaves), alkaloids (exclusive from roots and stems), tannins, phlobatannins, saponins, phytosterols, terpenoids, quinones, coumarins, and resins. Notably, anthraquinones were consistently absent across all anatomical parts. The high extractive yield and robust phytochemical profile, particularly within the root system, emphasize Sudanese P. crispum 's potential as a high-value raw material for the pharmaceutical and nutraceutical industries. Future research should prioritize HPLC-DAD and GC-MS profiling to achieve absolute quantification of marker compounds such as apigenin and myristicin. Furthermore, in vivo clinical evaluations are warranted to standardize Sudanese P. crispum extracts for evidence-based therapeutic applications.

From Agricultural Waste to Health-promoting Salts: Peanut Shells and Corn Cobs as Alternatives to Table Salt

2026-06-11T08:02:38+00:00

Background: Excessive consumption of sodium chloride is associated with hypertension and cardiovascular diseases, while large amounts of agricultural residues such as peanut shells and corn cobs remain underutilized and contribute to environmental pollution. Valorizing these biomasses into mineral-rich plant-based salts may provide a sustainable and healthier alternative to conventional table salt.

Aims : This study proposes an innovative approach for producing plant-based mineral salts from peanut shells and corn cobs, aiming to partially replace sodium chloride (NaCl) while addressing environmental and health concerns associated with agricultural residues.

Study design.

The study focused on the transformation of agricultural residues into mineral salts and the physicochemical characterization of the obtained products.

Place and Duration of Study: The biomasses were processed under laboratory conditions through drying, incineration, leaching, and evaporation procedures.

Methodology : The biomasses were oven-dried at 105 °C and incinerated at 550 °C. The resulting ashes were leached with distilled water and the filtrates were evaporated at 105 °C to obtain crystalline salts, with average extraction yields of 19.13% and 48.11% for peanut shells and corn cobs, respectively. ICP-OES analysis revealed a high potassium content in both salts : peanut shells K (468.10 mg/g), Na (5.60 mg/g), Ca (1.22 mg/g), Mg (0.07 mg/g); corn cobs K (411.20 mg/g), Na (3.63 mg/g), Ca (2.13 mg/g), Mg (0.04 mg/g).

Results : The Na/K ratio was extremely low (0.01) in both cases. Anion analysis indicated significant chloride contents (44.37 mg/L and 49.70 mg/L), while iodide was not detected. The predominance of potassium suggests a strong potential for these salts as healthier alternatives to NaCl.

Conclusion : These findings indicate that plant-based salts derived from peanut shells and corn cobs could serve as promising alternatives to conventional table salt. However, iodine fortification is required prior to consumption to prevent iodine deficiency disorders.

Natural and Human-Induced Impacts on the Origins and Distributions of Fatty Alcohols in Sediment Cores from Cross River System, Nigeria

2026-06-26T06:46:29+00:00

Tropical rivers are important pathways for transporting organic carbon to the ocean, yet the use of molecular markers to distinguish natural inputs from human-induced effects in these dynamic systems remains limited. This study evaluated the distribution and possible sources of fatty alcohols in two 50 cm sediment cores collected from the upper and lower sections of the Cross River system, south-eastern Nigeria. The sediment cores were sectioned at 5 cm intervals and analysed for fatty alcohol biomarkers using gas chromatography-mass spectrometry. Seventeen fatty alcohol compounds, ranging from n-C12ol to n-C28ol, together with phytol, were identified. The upper system was characterised by comparatively higher average abundances of middle-chain fatty alcohols, particularly n-C18ol (1283 +- 2.1 ng/g TOC), n-C20ol (683 +- 2.2 ng/g TOC), n-C22ol (3486 +- 3.1 ng/g TOC) and n-C24ol (2923 +- 3.0 ng/g TOC), suggesting a substantial contribution from submerged macrophytes under relatively favourable light conditions. Long-chain fatty alcohols, represented mainly by n-C26ol (2961 +- 2.6 ng/g TOC) and n-C28ol (2897 +- 2.2 ng/g TOC), were also more abundant in the upper system, indicating stronger terrestrial organic matter input. In contrast, the lower system showed relatively greater influence of short-chain fatty alcohols in selected core intervals, which may reflect enhanced aquatic biological inputs. Down-core variations in fatty alcohol ratios indicate that sedimentary fatty alcohol origins and distributions were controlled by aquatic productivity, terrestrial organic matter supply and post-depositional alteration. The findings suggest that fatty alcohols can provide useful information on organic matter sources in tropical riverine and estuarine sediments when site-specific environmental controls and anthropogenic disturbances are carefully considered.

Environmentally Benign Approach to the Synthesis and Biological Evaluation of Derivatives of Pyrrolo[2,3-b]pyridine

2026-06-29T04:58:27+00:00

A series of novel 7-(phenacyl)-1H-pyrrolo[2,3-b]pyridinium bromide analogues was synthesised using an environmentally benign and efficient protocol. The methodology involved the direct N-alkylation of 1H-pyrrolo[2,3-b]pyridine with substituted phenacyl bromides under mild conditions via a mechanochemical procedure, as an alternative to conventional synthetic methods. The compounds were characterised by FT-IR, UV-visible spectroscopy, ¹H NMR, HRMS, and elemental analysis. The biological potential of the synthesised analogues was evaluated using antimicrobial assays. The compounds exhibited poor to moderate biological activity, depending on the electronic nature of the substituents on the aromatic ring. Electron-withdrawing substituents, such as nitro, chloro, and bromo groups, enhanced biological activity relative to electron-donating substituents. The present study demonstrates an efficient green synthetic route to biologically important pyrrolopyridinium derivatives and indicates their potential as pharmacological scaffolds.

Eco-Friendly Fabrication of Biogenic Nanocomposites and their Application in Selective Removal of Heavy Metal Ions from Aqueous Systems

2026-06-29T10:10:00+00:00

The present study investigates the eco-friendly synthesis of a biogenic chitosan–Fe₃O₄ nanocomposite using Moringa oleifera leaf extract as a natural reducing and stabilising agent, and its application in the selective removal of heavy metal ions from aqueous systems. Magnetite nanoparticles were first synthesised via a green co-precipitation method and subsequently incorporated into a chitosan matrix to develop a magnetically separable adsorbent. The structural and functional properties of the prepared nanocomposite were confirmed through standard characterisation techniques, indicating successful integration of iron oxide nanoparticles within the biopolymer framework. Batch adsorption experiments were performed to evaluate the removal efficiency of Pb(II), Cd(II), Cu(II), Ni(II), and Cr(VI) under varying experimental conditions, including pH, contact time, initial concentration, and competitive multi-metal systems. The results indicated strong pH-dependent adsorption behaviour, in which divalent cations exhibited maximum uptake under near-neutral conditions, whereas Cr(VI) showed higher removal efficiency under acidic conditions. Among all tested ions, Pb(II) demonstrated the highest adsorption capacity and selectivity in both single- and mixed-metal systems. Kinetic analysis revealed that adsorption followed a pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Equilibrium data were well described by the Langmuir isotherm, indicating monolayer adsorption on a homogeneous surface. Regeneration studies confirmed that the nanocomposite retained significant adsorption efficiency over multiple cycles, demonstrating its stability and reusability. Overall, the findings suggest that biogenic chitosan–Fe₃O₄ nanocomposites offer a sustainable, efficient, and reusable approach for heavy metal remediation in contaminated water systems.

Study of the Effectiveness of Domestic Wastewater Treatment in the City of Brazzaville Using Vertical-Flow Artificial Marshes Planted with Cyperaceae (Cyperus alternifolius L.)

2026-06-29T13:07:54+00:00

Domestic wastewater can cause environmental pollution if it is discharged into the environment without prior treatment, particularly because of its high organic load. In this study, the experimental pilot consisted of two basins: the first was planted with Cyperus alternifolius L., and the second was unplanted and used as a control to monitor the effectiveness of phytoremediation. The system was regularly supplied with municipal wastewater from Brazzaville at a frequency of once every seven (7) days. Thirteen (13) physicochemical parameters were measured before and after treatment. The assessment of removal performance showed that the system achieved a marked decrease in the mean concentrations of several measured parameters from the feedwater, including TSS (372.2, 8.16 and 16.70 mg/L), turbidity (85, 6.5 and 11.41 NTU), and COD (291.37, 92.97 and 69.94 mg/L). \(NO_3^-\) (124.7, 26.01 and 20.32 mg/L), \(PO_4^3-\) (74, 17.41 and 12.06 mg/L), nickel (6.3, 0.71 and 0.16 mg/L), and copper (3.35, 0.10 and 0.13 mg/L) were measured in the feedwater, control filter and Cyperus alternifolius L. planted filter, respectively. Multivariate analysis of means and standard deviations revealed a statistically significant difference in more than twelve (12) parameters in the filtrates from the two filters, with p-value < 0.001. The Cyperus alternifolius L. planted filter contributed to the assimilation of pollutants present in wastewater, resulting in improved treatment performance under the experimental conditions.

Hydrochemical Assessment and Irrigation Suitability of Groundwater in the Grande Niaye of Pikine (Dakar): Contribution of Multivariate Analysis and Water Quality Indices

2026-07-02T10:31:19+00:00

Groundwater quality is a key concern for sustaining market gardening in peri-urban semi-arid settings where agricultural intensification, urban growth and inadequate sanitation may affect irrigation resources. This study assessed the hydrochemical characteristics and irrigation suitability of groundwater in the Grande Niaye of Pikine (Dakar) using four sampling stations (S1–S4). The investigation combined field and laboratory physicochemical measurements, hydrochemical diagrams, Principal Component Analysis (PCA) and irrigation water quality indices. The analysed waters showed near-neutral pH, with values ranging from 6.7 to 7.5 and a mean of 6.9. Electrical conductivity varied from 668.5 to 1016 µS/cm, with a mean of 840.7 µS/cm, indicating moderate mineralisation and compliance with irrigation guideline values. Major ion concentrations suggested variable enrichment in chloride, bicarbonate, sodium, calcium and magnesium, while nitrate concentrations ranged from 10.6 to 88.5 mg/L, indicating localised nitrogen inputs. PCA accounted for 89.0% of the total variance through the first two components (PC1 = 65.1%; PC2 = 23.9%). PC1 was associated mainly with mineralisation and ionic enrichment, whereas PC2 reflected nitrate-related influence. The irrigation indices indicated generally favourable sodicity conditions: SAR ranged from 2.42 to 3.43, KI from 0.61 to 0.83, SSP from 43.38 to 49.83% and MH from 28.26 to 47.31%. RSC values ranged from -5.74 to 1.85 meq/L, suggesting acceptable carbonate-related risk, whereas potential salinity values of 8.57–14.57 indicated a need for drainage and monitoring. Overall, the groundwater remains broadly suitable for irrigation, but nitrate enrichment, salinity potential and hardness require regular assessment to support sustainable use in this peri-urban agricultural area.

The Extraction of Some Water Bound Metal Ions using Palmitic Acid as a Green Extractant

2026-07-04T05:35:38+00:00

Background: Nickel (Ni²⁺) and iron (Fe²⁺) ions from industrial wastewater pose environmental risks because of their toxicity and persistence in water systems. Conventional extraction methods often use toxic organic reagents, which has increased interest in greener alternatives. Naturally occurring fatty acids, such as palmitic acid, have potential as biodegradable extractants for metal ion removal through solvent extraction techniques.

Aims: This study aimed to investigate the removal of Ni2+ and Fe2+ ions from aqueous solutions using palmitic acid and to determine the effects of selected extraction parameters on process efficiency.

Study Design / Methodology: A liquid-liquid extraction process was used. Specific parameters of the aqueous phase, including ion concentration and pH, as well as the concentration of palmitic acid in the organic phase, were regulated.

Results: The results showed that the removal of these ions from the aqueous solutions depended on the initial ion concentration, palmitic acid concentration and equilibrium pH. Based on the percentage removal efficiency and distribution coefficient, ion removal increased with increasing initial ion concentration, palmitic acid concentration and equilibrium pH. The highest percentage removal efficiency and distribution coefficient values were obtained at an initial ion concentration of 50 ppm, a palmitic acid concentration of 10 ppm and an equilibrium pH of 5.5. Using the slope analysis method, the oxidation state of the ions was validated and the nature of the extracted metal ion-organic complex was determined. The range of the standard Gibbs free energy for the extraction of Ni2+ and Fe2+ ions was between 62.88 and 70.24 KJ mol-1.

Conclusion: The results showed that palmitic acid had the capacity to remove Ni2+ and Fe2+ metal ions found in water. Its extraction capability depended on the initial concentrations of Ni2+ and Fe2+ ions in the aqueous phase and the concentration of palmitic acid. From the optimisation of the pH levels, most metal ions were removed from the aqueous phase at pH 5.5. From slope analysis, it was affirmed that a complexation reaction involving two acidic hydrogen atoms from two molecules of palmitic acid complexed with one ion of Ni2+ and Fe2+ during the extraction.