Combination of extracts from Aristolochia cymbifera with streptomycin as a potential antibacterial drug.

The appearance of new antibiotic-resistant bacteria is a societal problem that requires the development of new alternative treatments. Therefore, this work evaluated the antibacterial activity of ethanolic (EHI), dichloromethanic (EDI) and hexanic (EHE) extracts from Aristolochia cymbifera stems and the combination of these extracts with an antimicrobial drug to develop a new antibacterial therapy. The EDI, EHE and EHI extracts were obtained by maceration using three different solvents. The minimal inhibitory concentrations (MIC) of these extracts were determined using the microdilution test to determine the antibacterial potential of these extracts and their combination with streptomycin against Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae and Shigella flexneri. The extract dose leading to the cytotoxicity of 50% of the cells (CC50) was evaluated using mammalian cells MA104 and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The extracts had a MIC under 500 mg/L and a CC50 lower than 50 mg/L. The antibiotic/extract proportion influenced the antibacterial activity of the mixtures, and the proportion that optimized the antibacterial activity of streptomycin was a mixture that contained 75 percent of extract. This composition included less than 6.5 mg/L of extract and 2.5 mg/L of streptomycin and has potential as a new antibacterial therapy.

Search for the antiprostatic principle of stinging nettle (Urtica dioica) roots.

While searching for the antiprostatic active principle of the roots of Urtica dioica we ethanol-precipitated a polysaccharide mixture from an aqueous root extract and obtained chemically defined acidic polysaccharides with molecular masses of 15-210kDa. The chemical structures of these compounds have been determined. Some polysaccharides stimulated T lymphocytes in vitro while others influenced the complement system or triggered the release of TNF-α. The crude polysaccharide extract showed a prolonged antiinflammatory activity in the rat paw edema test for 22 hr, which is comparable to the pharmacological efficacy of indometacin. We have reisolated the isolectin mixture (UDA) originally detected in Urtica roots by Peumans et al. (1984). This mixture displayed immunomodulatory effects on T lymphocytes in a dose-dependent manner. In addition, UDA also directly inhibited cell proliferation and blocked binding of epidermal growth factor to its receptor on a tumor cell line, as determined by a [(125)I]-EGF binding assay. These investigations suggest that Urtica polysaccharides and also the N-acetyl-glucosamine specific lectin UDA play a major role in the antiprostatic activity of the drug and phytopreparations containing it.

Antiasthmatic effects of onions: inhibition of 5-lipoxygenase and cyclooxygenase in vitro by thiosulfinates and "Cepaenes".

Nine thiosulfinates (TS) and four "Cepaenes" (CS) isolated from onions and/or synthetized by us showed dose dependent (0.25 to 100 microM) marked inhibitory effects on both cyclooxygenase (CA, tested on sheep seminal vesicle microsomes) and 5-lipoxygenase activity (LO, tested on porcine leukocytes). The following rank order of activity was observed: saturated aliphatic TS less than aromatic TS approximately alpha, beta-unsaturated TS less than CS. CS inhibited both CA and LO by more than 75% at 10 and 1 microM concentrations respectively. Most likely, these in vitro effects are responsible for antiinflammatory and antiasthmatic properties of onion extracts observed in vivo, at least in part.

[Biologically active compounds from the aqueous extract of Urtica dioica]. / Biologisch aktive Verbindungen aus dem Wasserextrakt von Urtica dioica.

From the water extract of the roots of Urtica dioica (stinging nettle) a polysaccharide fraction was isolated which revealed activity in the carrageenan rat paw edema model and lymphocyte transformation test. Ion exchange chromatography and gel filtration of this fraction afforded 4 different polysaccharides, one of which reduced dose dependent hemolysis in the classical pathway of the complement test. The Urtica dioica lectin (UDA) was reisolated and found to stimulate the proliferation of human lymphocytes.