Several types of dyes are available in the market as colouring agents to food commodities. Some commonly used synthetic food dyes include: brilliant blue, indigo carmine, citrus red, fast green, erythrosine, allura red, tartrazine and sunset yellow. The main food biocolorants are carotenoids, flavanoids, anthocyanidins, chlorophyll, betalain and crocin. There has been a rising concern over the health implications of the use of food dyes in human diets. How safe are these food colourants? This has led to a lot of studies, both by individual researchers, corporate organization-sponsored and even government-sponsored researches, to authenticate the benefits or risks associated with the use of food colourants (synthetic and natural). This review critically evaluated scientific researches from various published journal articles and reports, with a view of clarifying the health implications of using these food dyes. Various studies have shown that synthetic food colourants have considerable toxicological effects, including but not limited to carcinogenicity, hypersensitivity reactions, and behavioral effects. However, natural food colourants have been found to be relatively safe to humans. Besides the colouring property, they have been found to possess a number of pharmacological properties like strong antioxidant, antimutagenic, anti-inflammatory, antineoplastic and antiartheritic effects.

Twelve new derivatives of benzothiazole bearing benzenesulphonamide and carboxamide were synthesised and investigated for their in vivo anti-inflammatory, analgesic and ulcerogenic activities. Molecular docking showed an excellent binding interaction of the synthesised compounds with the receptors, with 17c showing the highest binding energy (-12.50 kcal/mol). Compounds 17c and 17i inhibited carrageenan-induced rat paw oedema at 72, 76, and 80% and 64, 73, and 78% at 1 h, 2 h, and 3 h, respectively. In the analgesic activity experiment, compounds 17c, 17 g, and 17i had ED 50 (mM/kg) of 96, 127, and 84 after 0.5 h; 102, 134, and 72 after 1 h and 89, 156, and 69 mM/kg after 2 h, respectively, which were comparable with 156, 72, and 70 mM/kg for celecoxib. The ulcerogenic index of the most active derivatives 17c and 17i were 0.82 and 0.89, respectively, comparable to 0.92 for celecoxib. The physicochemical studies of the new derivatives showed that they will not have oral bioavailability problems. ARTICLE HISTORY

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Two novel heterocyclic ligands, 2-[(5-fluoro-1,3-benzothiazol-2-yl)amino]naphthalene-1,4-dione (HL 1 ) and 2-[(5-methyl-1,3-benzothiazol-2-yl)amino]naphthalene-1,4-dione (HL 2 ), and their Pd(II), Ni(II) and Co(II) complexes were prepared and characterized using 1 H NMR, 13 C NMR, infrared and UV-visible spectroscopic techniques, elemental analysis, magnetic susceptibility, thermogravimetry and molar conductance measurements. The infrared spectral data showed that the chelation behaviours of the ligands towards the transition metal ions were through one of the carbonyl oxygen and deprotonated nitrogen atom of the secondary amine group. Molar conductance results confirmed that the complexes are non-electrolytes in dimethylsulfoxide. The geometries of the complexes were deduced from magnetic susceptibility and UV-visible spectroscopic results. Second-order perturbation analysis using density functional theory calculation revealed a stronger intermolecular charge transfer between ligand and metal ion in [NiL 1 (H 2 O) 2 (CH 3 COO-)] and CoL 1 compared to the other complexes. The in vitro antibacterial activity of the compounds against some clinically isolated bacteria strains showed varied activities. [NiL 1 (H 2 O) 2 (CH 3 COO-)] exhibited the best antibacterial results with a minimum inhibitory concentration of 50 μg mL −1 . The molecular interactions of the compounds with various drug targets of some bacterial organisms were established in a bid to predict the possible mode of antibacterial action of the compounds. The ferrous ion chelating ability of the

Heteroleptic divalent metal complexes [M(L) (bipy)(Y)]•nH2O (where M = Mn, Co, Ni, and Zn; L = Schiff base; bipy = 2,2’-bipyridine; Y = OAc and n = 0, 1) have been synthesized from pyrimidine Schiff base ligand 3-{(E)-[(4,6-dimethylpyrimidin-2-yl)imino]methyl} naphthalen-2-ol, 2,2’-bipyridine and metal(II) acetate salts. The Schiff base and its complexes were characterized by analytical (CHN elemental analyses, solubility, melting point, conductivity) measurements, spectral (IR, UV-vis, 1H and 13C-NMR and MS) and magnetometry. The elemental analyses, Uv-vis spectra and room temperature magnetic moment data provide evidence of six coordinated octahedral geometry for the complexes. The metal complexes’ low molar conductivity values in dimethylsulphoxide suggested that they were non-ionic in nature. The compounds displayed moderate to good antimicrobial and antifungal activities against S. aureus, P. aeruginosa, E. coli, B. cereus, P. mirabilis, K. oxytoca, A. niger, A. flevus and R. Stolonifer. The compounds also exhibited good antioxidant potentials with ferrous ion chelation and, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assays. Molecular docking studies showed a good interaction with drug targets used. The structural and electronic properties of complexes were further confirmed by density functional theory calculations.