Open Access Original Research Article

Assessment of Heavy Metal Contamination in Red Seaweeds from the Coastal Areas of Zanzibar by Using EDXRF Technique

Suleiman A. Suleiman, Salum K. Salum, Miza A. Kombo, Atumaini A. Makoba, Fatma O. Khamis

Chemical Science International Journal, Page 1-9
DOI: 10.9734/CSJI/2021/v30i1030255

The content of Mn, Zn, Ni, Cu, Fe, and Pb in 10 samples of Kappaphycus alvarezii (cottonii) and 10 samples of Eucheuma denticulatum (spinosum) from 15 different sites in the intertidal coastal area of Zanzibar were determined by using EDXRF. The heavy metals assessed in both species decreased in the order of Fe >Mn > Zn >Pb> Cu > Ni. In general, the cottonii samples in Unguja had significantly higher (p ≤ 0.05) concentrations of Fe, Zn, Ni, Cu and Pb than the spinosum samples, but the latter had significantly higher levels of Mn. Similarly, the cottonii samples in Pemba had significantly higher (p ≤ 0.05) concentrations of Ni, Cu and Pb than the spinosum samples, but the latter had significantly higher levels of Fe and Zn. The concentrations of heavy metals in cottonii and spinosum in the present study were noticed lower compared to publish results. The results from this study revealed that, the heavy metals contaminations in cottonii and spinosum along the coastal area in Zanzibar were mainly caused by effluents that directly flow into marine environments. Hence, serious measures should be taken to reduce the flow of waste effluents into the marine ecosystem.

Open Access Original Research Article

Assessment of Occupational Risks in the Toxicology and Pharmacology Laboratory Using the FMECA Method

Khalid Laarej, Mohammed Jbilou, Mustapha Bouatia, Adil Elyadini, Rachid Alami

Chemical Science International Journal, Page 10-23
DOI: 10.9734/CSJI/2021/v30i1030256

The Toxicology and Pharmacology Laboratory is a high-risk work environment, especially the chemical risk that appears when people are exposed to reagents and chemicals. A corrective approach is required to identify and control these risks. The aim of this study is to determine how to manage the analytical risks at LTP designated for the dosage of drugs and poisons (narcotics, pesticides, mycotoxins, etc.). For this purpose, the risk analysis applying the FMECA method, a risk management tool that aims on the one hand, to qualitatively analyze the process, to analyze the failure modes, the causes and their effects, and to on the other hand, rate the criticality defined by the parameters of frequency of occurrence, severity and detection that will allow a quantitative analysis of each of the failure modes. Thus, the criticality calculation will help to determine the critical risks to be corrected, and to recommend corrective and preventive actions to be implemented within the service.

Open Access Original Research Article

A Comparative Assessment on Antioxidant and Phytochemical of Trichilia monadelpha (Thonn) J.J. De Wilde (Meliaceae) Plant Extracts

P. D. Clark, E. Omo-Udoyo

Chemical Science International Journal, Page 24-33
DOI: 10.9734/CSJI/2021/v30i1030257

This study was designed to evaluate the phytochemical screening and antioxidant activities of Trichilia monadelpha plant extracts. The leaves were extracted using two different solvents namely-(n-hexane and methanol).  The dry or wet yield of n-hexane extract was 1.3%, while methanolic extract exhibited a percentage yield of 3.7 %.  Phytochemical research revealed the presence of secondary plant metabolites such as; alkaloids, flavonoids, cardiac glycosides, terpenoids and saponins. In-vitro antioxidant activity was determined using three assays (DPPH free radical scavenging assay, reducing ability and hydroxy radical scavenging activity) with four concentrations (0.25, 5.0, 1.0 and 2.0 mg/L), vitamin C was also used as a standard antioxidant.

The percentage of inhibition was measured, and the results from all assay models showed a concentration-dependent percentage of inhibition by the methanol extract. However, the percentage values for the 2,2, -diphenyl-1-picrylhydrazyl (DPPH), reducing ability and hydroxy radical scavenging activity assays of T. monadelpha leaf was lower than that of standard vitamin C. The Pearson’s correlation coefficient was evaluated and the results showed that of the two extracts, the methanolic extract had the most antioxidant activity with the methanol extract exhibiting a better significant correlation that had a similar trend to that of the antioxidant compound (vitamin C). The results of this study have shown that the plant Trichilia monodelpha contains bioactive compounds which may have contributed to its antioxidant properties.

Open Access Original Research Article

3D Series Metal Complexes Containing Schiff Base Ligand with 2,2'-Bipyridine: Synthesis, Characterization and Assessment of Antifungal Activity

B. Kpomah, U. Ugbune, T. E. Idu

Chemical Science International Journal, Page 34-45
DOI: 10.9734/CSJI/2021/v30i1030258

The rapid increase in the number of multidrug-resistant of most pathogenic organisms is fast becoming a global concern, thus, the discovery of novel active pharmacological compounds against new targets is a matter of urgency. The incorporation of metal ions into organic ligands has introduced metal-organic drugs framework with synergistic effects for novel applications in the biological system. In this research work, metal(II) chloride complexes of copper, nickel and zinc containing methylphenylketone thiosemicarbazone (MPK-TSC) with 2,2’-bipyridine (bipy) were synthesized; they were further characterized by satisfactory microelemental analysis, Fourier Transform InfraRed (FTIR) spectra as well as electronic spectra study. The complexes are proposed to have the formulae [L1ML2(Cl2)] where M=metal ion, L1=methylphenylketone thiosemicarbazone   L2=2,2’-bipyridine. The complexes are of 1:2 (metal:ligand) stoichiometry and non-electrolytes in solution, the bidentate nature of the two ligands was evident from the FTIR spectra. The compounds were screened for their antifungal activity against four pathogenic fungi: Aspergillus niger, Penicillium Species, Rizopus and Candida albicans using disc diffusion method. The activities of the complexes have been found to be greater than those of the metal salts and the uncoordinated ligands.

Open Access Original Research Article

Synthesis and Preservation of Organic Molecules with Homochiral Excess by Adsorption on Carbon in Carbonaceous Chondrites

V. M. Zhmakin

Chemical Science International Journal, Page 46-53
DOI: 10.9734/CSJI/2021/v30i1030259

The nature of carbon, initial components, molecules of homochiral abiogenic synthesis and their preservation from decay and racemization for more than 4.5 billion years in carbonaceous chondrites has not been established. In the oxygen-free atmospheres of the nebula and early Earth, hydrogen and hydrogen-containing gases were oxidized with carbon monoxide and carbon dioxide to form carbon and water, as well as the intermediates of these reactions, formaldehyde and methane acid. Together with ammonia, they were the initial components of organic synthesis. According to the Rebinder rule, carbon adsorbs hydrogen well, including in organic molecules. In this connection, experiments with the assumed conditions of the early Earth were carried out by adsorption on carbon to obtain R-(rectus, Latin) ribose from formaldehyde, and S-(sinister) serine from formaldehyde, methane acid and ammonia. For other S-amino acids, a stereo chemical justification of their formation based on S-serine is given. For carbonaceous chondrites, the results of the above experiments were confirmed by the correlation of an increase in homochiral excess with an increase in the amount of hydrogen in aldonic acids and lactic acid with a coefficient of 0.94 and 0.85 in amino acids. The justification of the homochiral process will reduce the costs of searching for life on planets, for scientific research, for the production of medicines, perfumes, food, and so on. Doubts about the extraterrestrial origin of homochiral enantiomers in carbonaceous chondrites arise most often due to a lack of understanding of the reasons for their appearance. This work will significantly reduce such skepticism.