Homoleptic Co(II), Cu(II) and Ni(II) complexes of a hydrazone derived from 3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one (dehydroacetic acid) and 2‐furoic acid hydrazide, and their heteroleptic analogues with 2,2′‐bipyridine were synthesized. The complexes were characterized by spectroscopic methods (ESI‐MS, IR and NMR), elemental analysis, magnetic susceptibility and molar conductance measurements. The homoleptic complexes adopted octahedral geometry, while the heteroleptic analogous had four‐coordinate tetrahedral (Co and Cu complexes) and square‐planar (Ni complex) geometries. The homoleptic complexes were non‐electrolytes, while the heteroleptic complexes were 1:1 electrolytes in DMSO. Antimicrobial experiments indicated that [Cu(L)2] and [Cu(L)(bipy)](CH3COO) had the best antibacterial activities, with MIC of 31.2 and 61.5 μg/ml against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212, respectively. Molecular docking determined that [Cu(L)(bipy)]⋅CH3COO had the highest binding energy and hydrogen bonding interactions with one of the active sites of amino acid residue (LEU73). Density functional theory (DFT) calculations of the complexes revealed that [Cu(L)(bipy)]⋅CH3COO possessed low energy gap, suggesting a higher activity and ability to donate electrons to electron‐accepting species of biological targets.

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A novel hydrazone ligand derived from condensation reaction of 3-hydroxy-2naphthoic hydrazide with dehydroacetic acid, and its Ni(II), Cu(II) and Co(II) complexes were synthesized, characterized by spectroscopic, elemental analyses, magnetic susceptibility and conductivity methods, and screened for antimicrobial, DNA binding and cleavage properties. Spectroscopic analysis and elemental analyses indicated the formula, [MLCl 2 ], for the complexes; square planar geometry for the nickel, and tetrahedral geometry for copper and cobalt complexes. The non-electrolytic natures of the complexes in Dimethyl Sulphoxide (DMSO) were confirmed by their molar conductance values in the range of 6.11-14.01 Ω −1 cm 2 mol −1 . The copper complex had the best antibacterial activity against Staphylococcus aureus (ATCC 29213). DNA cleavage activities of the compounds, evaluated on pBR322 DNA, by agarose gel electrophoresis, in the presence and absence of oxidant (H 2 O 2 ) and free radical scavenger (DMSO), indicated no activity for the ligand, and moderate activity for the complexes, with the copper complex cleaving pBR322 DNA more efficiently in the presence of H 2 O 2 . When the complexes were evaluated for antibacterial and A-DNA activity using Molecular docking technique, the copper complex was found to be most effective against Gram-positive (S. aureus) bacteria. [CuLCl 2 ] showed good hydrogen bonding interaction with the major-groove (C 2 . G 13 base pair) of A-DNA. Density functional theory (DFT) calculations of the structural and electronic properties of the complexes revealed that [CuLCl 2 ] had a smaller HOMO-LUMO gap, suggesting a higher tendency to donate electrons to electron-accepting species of biological targets.

Aim: To compare the phytochemicals and anti bacterial activities of leaf, stem and root extracts of Spathodea companulata. Methodology: The leaf, stem and root of Spathodea companulata were collected, washed, air-dried, ground and each extracted with water, methanol, ethyl acetate and n-hexane. The extracts were analysed for the presence of phytochemicals. Antimicrobial analysis was also carried out on the extracts. Results: Glycosides were present in all the extracts except stem aqueous extract. Steroids were found absent in most of the extracts except methanol stem and n-hexane root extracts. Saponins were found in methanol, aqueous and ethyl acetate extracts of the root and stem, and in methanol and aqueous leaf extracts. Alkaloids were present in methanol and aqueous extracts of the leaf and root, and in ethyl acetate and n- hexane extracts of the stem. Quantity of Alkaloids and tannins were higher in leaf, while flavonoids and glycosides were higher in the stem and the roots contained higher amount of saponins. The extraction solvent polarities played important role in the type of metabolites extracted. The stem extracts were found to be most active against the seven test organisms used. Conclusion: More work should be done on the isolation and identification of compounds responsible for some of the pharmacological effects of the plant parts and the subsequent development of the compounds in formulation of drugs.

Aim: To study the phytochemical, proximate, antimicrobial and anti-malarial activities of leaf extracts of Justicia carnea Methods: The leaf sample of Justicia carnea which has been used in Nigeria folklore in treating malaria, cancer and many other diseases was extracted with methanol, ethyl acetate and n-hexane. The extracts were subjected to qualitative and quantitative phytochemical screening, proximate, anti-malarial and antimicrobial screening. Results: The results showed that alkaloids, flavonoids, glycosides, phenolic compounds were present. Ethy acetate extract also exhibited the highest suppression against malaria parasite in-vitro, more than chloroquine. This inhibition and high abundance of alkaloids and glycosides gave credence to the therapeutic use of the plant as anti-malaria drug. The three extracts showed a concentration-dependent inhibition against S. aureus, Aspergillus spp and Bacillus spp. S. typhi, K. pneumonia, P. aerogenosa and C. albicans were resistant in all concentrations of the extracts. Conclusion: The therapeutic use of the leaves of J. carnea in treatment of malaria was validated. Its antimicrobial activity was also affirmed in some of the tested organisms.