The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities.

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Six aromatic oligoazomethines were synthesized containing seven benzene rings each. The terminal rings were substituted with different groups, namely, H, Cl, NO2, OH, OCH3 and CH3. The synthesis was carried out by condensing the para‐substituted benzaldehydes with benzidine to give the three‐ring compound, which was then condensed with terephthaldehyde to give the respective seven‐benzene‐ring oligomers. The oligomers were characterized by elemental analysis, electronic spectra, Fourier‐transform infrared and thermal analysis. The oligomers were used to investigate the effects of their molecular structure on their electronic spectra, as well as their thermal, electronic and electrical properties. The different conformers were reported and compared. The DC electrical conductivity variation of oligoazomethines was studied in the temperature range 300–500 K after annealing for 24 h at 100 °C and after doping with 5% I2. An attempt was made to relate the DC electrical conductivity, electronic properties and thermal properties to the chain length, substituted groups and coplanarity. The fairly low conductivity obtained was attributed to the non‐linearity of the rings in the chain. The different groups (neutral, electron withdrawing or electron donating) attached at the ends of the oligomer showed no influence upon the conductivity of the different oligomers. The action of doping gave almost the same enhancement as that noticed in the case of a long‐chain polymer. The DC electrical conductivity was interpreted using the band energy model. The seven‐benzene‐ring oligomer gave the same DC electrical conductivity as the long‐chain polymer. Copyright © 2004 Society of Chemical Industry

A New Schiff base ligand and its Pt (II) complex were synthesized. The ligand was prepared by condensation of 2-(4-isobutylphenyl)propanehydrazide with 2,3,4-trihydroxy benzaldehyde this novel ligand and its functional group was carefully designed and selected from well-known biological drugs. The structure of the ligand and its Pt-complex have been confirmed by spectroscopic data, i.e. elemental (CHN) analysis, FT-IR, electronic spectra, NMR spectra. The ligand and its Pt-complex were investigated for their in vitro anticancer potential using HeLa and PC3 cells. The Pt-complex showed a higher cytotoxic activity than the ligand towards Hela cells and PC3 cells.