New branched polypeptides were synthesized for a detailed study of the influence of the side-chain structure on the conformation and biological properties. The first subset of polypeptides were prepared by coupling of tetrapeptides to poly[L-Lys]. These polymers contain either DL-Ala3-X [poly[Lys-(X-DL-Ala3)n]] or X-DL-Ala3 [poly[Lys-(DL-Ala3-X)n] (n less than or equal to 1)] tetrapeptide side chains. Another group of branched polymers comprise a mixture of DL-Alam and of DL-Alam-X oligomeric branches in a random distribution [poly[Lys-(DL-Alam-Xi)] (i less than 1, m approximately 3)]. In each subset the X = Leu or Phe derivatives were prepared. The N-protected tetrapeptides were synthesized by conventional liquid phase methods and were coupled as active esters. The degree of racemization was found relatively high both for active esters and coupled derivatives, when optically active amino acids were in the C-terminal position of the tetrapeptides. In the case of the poly[Lys-(Leu-DL-Ala3)n] derivative, comparative experiments were carried out using various methodical alterations. The highest stereochemical homogeniety could be achieved when the tetrapeptide active ester was synthesized by the "backing off" method. CD spectra of poly[Lys-(Xi-DL-Alam)] (i less than 1, m approximately 3) and of poly[Lys-(X-DL-Ala3)n] were analyzed and compared to those of poly[Lys-(DL-Alam-Xi)] and of poly[Lys-(DL-Ala3-X)n]. All measurements were performed in water solutions of varying pH values and ionic strengths. The data obtained suggest that branched polypeptides containing a mixture of two different types of oligomeric side chains (DL-Alam and DL-Alam-Xi or Xi-DL-Alam) distributed randomly adopt an almost identical conformation to those that comprise only the respective tetrapeptide (DL-Ala3-X or X-DL-Ala3) branches. The results also indicate that the tendency to form an ordered structure is determined by the identity and the position of the chiral amino acid X (Phe or Leu) in the side chain.

This study provides a scientific information about the aqueous and methanol extracts of Rubia tinctorum based on its antimicrobial potential against gram positive and gram negative bacteria isolated from burns infection using the broth dilution and well diffusion method. Results of this study indicate the presence of many phytochemicals which have antimicrobial activity against broad spectrum of bacteria. The methanol extract of R.tinctorum showed highest activity than aqueous ones. The minimum inhibitory concentration (MIC) of the aqueous extract on the tested organisms was 25-100mg/ml while in the methanol extract ranged between 25-50mg/ml on the tested organisms and the minimum bacterial concentration (MBC) of the aqueous extract was 25-200 mg/ml while the methanol extract ranged between 25-100 mg/ml. The highest activity of methanol extract demonstrated at 100 C o , 121 C o agai nst S.aureus, K.spp, A.hydrophila, and S.marcescens, while there was low activity against S.dysenteria and E.coli. The activity of plant extract increased at acidic pH5-3 whearus, there are slightly increased of plant extract at alkaline pH 8. R.tinctorum contained. essential element (Pb, Na, K, Ca, Fe, Zn, P, Mn, Co and Cu) at different concertation. The high preformance liquid chromatograph (HPLC) analysis of R. tinctorum showed some chemical compounds that have antimicrobial activity against test isolates. The result of this study demonstrate that HPLC analysis of R.tinctorum constituent revealed that htis plant have antimicrobial activity against test organism and this may be suggest the use at this extract in treatment of infections disease.

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Isopeptides (ε-peptides) of lysine, with a given Mw and low polydispersity (10–400 units), were synthesized to study the relationship between their chemical structure and biological effect. The designed compounds were of high purity, low polydispersity and high stereochemical purity. The effect of the compounds was tested on a human erythroleukemia cell line (K-562) and on four transplantable mouse tumors (L1210 lymphoid leukemia, P38 macrophage derived tumor, Ehrlich ascites carcinoma, Lewis lung tumor /LLT/). In case of the L1210 and P388 tumors and the Ehrlich carcinoma, survival of the animals was used as an indicator of the effect. In case of the Lewis lung tumor, the number and size of metastases in the lung and/or liver of treated and untreated mice were used as indicators. The polymers of polymerisation degree 80–120 (Mw 10.2–15.4 KD) showed the strongest antiproliferative effect both on K562 cells and the tumors growing in vivo. This effect was manifest with a significantly higher survival rate as compared to the control (L1210, P38, Ehrlich ascites), furthermore, by a decrease in the number and size of liver and lung metastases (LLT).

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