Antibacterial and anticandidal screening of Tunisian Citrullus colocynthis Schrad. from Medenine.

ETHNOPHARMACOLOGICAL RELEVANCE: Resistance to current antibacterial drugs and the rise of opportunistic fungal infections are growing global concerns. Traditional medicine is a potential source of new antibacterials and antifungals. Citrullus colocynthis Schrad. (Cucurbitaceae) endemic in Southern Tunisia, is used in folk medicine against dermatological, gynaecological and pulmonary infections. AIM OF STUDY: To assess in vitro antibacterial and anticandidal activity of aqueous and diluted acetone extracts of Citrullus colocynthis Schrad. MIC and MBC/MFC were determined for plant organs at different maturation stages. MATERIALS AND METHODS: Citrullus colocynthis Schrad. was harvested and its identification was verified. Aqueous and diluted acetone extracts (from the plant's roots, stems, leaves and three maturation stages of its fruit and seeds) were screened for activity against Gram-negative and Gram-positive bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis)-and various Candida spp. (Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei). RESULTS: All extracts showed activity against all strains. The highest MICs and MBCs/MFCs were obtained from the fruit aqueous extracts (MIC 0.10mg/ml against Candida albicans and Candida glabrata, 0.20mg/ml against Escherichia coli and Pseudomonas aeruginosa), lowest activity from the root extracts. CONCLUSIONS: Citrullus colocynthis Schrad. shows antibacterial and anticandidal properties. The folk medicinal use as a broad-spectrum antimicrobial agent is validated.

Preparation and evaluation of a new class of gene transfer reagents: poly(-alkylaminosiloxanes).

We report the evaluation of poly(-alkylaminosiloxane) as a novel class of polycationic DNA carriers. Controlled hydrolysis of mono- and di-aminoalkylmethyldimethoxysilane provided a wide range of defined oligomeric mixtures. Basic hydrolysis conditions yielded mixtures composed mainly of cyclic and long linear oligomers, while under acidic conditions mainly short-linear oligomers were derived. They all efficiently interacted with plasmid DNA as revealed by electron microscopy and DNA retardation assays. However, only diamine-based oligomers prepared under basic conditions were able to mediate substantial levels of DNA transfection in human HeLa cells. SiDA1b, prepared by basic hydrolysis of 3-(2-aminoethylamino)propyl-methyl-dimethoxysilane, was found to be at least as efficient as the frequently used cationic transfection agents DOTAP and polyethylenimine (PEI). The transfection activity was sensitive to bafilomycin A1, suggesting a mechanism that depends on proton capture during the acidification process associated with endocytosis.