BMAP-27 is a cathelicidin-derived bovine antimicrobial peptide, which shows moderate cytotoxicity and potent antibacterial activity against a wide variety of microorganisms. Despite a number of studies, very little is known about the amino acid sequences of this peptide that controls its antibacterial and cytotoxic activities. Small stretches of phenylalanine and leucine zipper sequences were identified at the N- and C-termini of the molecule, respectively. To understand the structural and functional roles of these sequence elements, we synthesized and characterized several analogues of BMAP-27 after substituting leucine or phenylalanine residue(s) at a and/or d positions of the leucine and phenylalanine zipper sequences, respectively, with alanine. BMAP-27 analogues exhibited significantly reduced cytotoxicity against the human red blood (hRBC) and murine 3T3 cells as compared to that of the wild-type peptide. Interestingly, BMAP-27 and its analogues exhibited comparable antibacterial activity against the selected Gram-positive and Gram-negative bacteria. Moreover, BMAP-27 and its analogues exhibited similar localization and assembly onto the selected bacteria and induced comparable permeability in these cells. However, only BMAP-27, not its analogues, assembled and bound strongly onto the hRBCs and permeabilized them. The results indicated that not only a leucine zipper but also a phenylalanine zipper sequence plays an important role in maintaining the assembly of BMAP-27 on the mammalian cells examined here and cytotoxic activity against them. To the best of our knowledge, this is the first report of the evaluation of structural and functional roles of a phenylalanine zipper sequence in a naturally occurring antimicrobial peptide.
Elastin-like polypeptides (ELPs) are large molecular weight biopolymers. They have been widely studied as macromolecular carriers for targeted delivery of drugs. The aim of the present article is to review the available information on ELPs (including our recent investigations), their properties, drug delivery applications to tumor sites and future perspectives. This review also provides information on the use of short synthetic ELPs for making ELP-drug conjugates, for targeted delivery of anticancer drugs. In the present review we also focus on the point that short ELPs can also be used for targeting anticancer drugs to tumor sites as they behave similar to long ELPs regarding their capacity to undergo inverse temperature transition (ITT) behavior.
The antioxidant properties of four successive extracts of Ipomoea leari Paxton and the successive chloroform extract fraction, ILCF-28, were tested using standard in vitro and in vivo models. The amount of the total phenolic and flavonoid content was also determined. The successive chloroform extract, ILC and its fraction ILCF-28 exhibited strong scavenging effect on 2,2diphenyl-2-picryl hydrazyl (DPPH), Nitric oxide, 2,2-azino-bis (3ethylbenzo-thiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation, Reducing power, p-NDA and hydrogen peroxide methods. The free radical scavenging effect of ILC and ILCF-28 was comparable with that of reference antioxidants. The ILCF-28 having the highest content of phenolic compounds and strong free radical scavenging effect when administered orally to male albino rats at 100, 200 and 400mg/kg body weight for 7 days, prior to carbontetrachloride (CCl 4) treatment, caused a significant increase in the levels of catalase (CAT) and superoxide dismutase (SOD) and a significant decrease in the levels of lipidperoxidation (LPO) in serum, liver and kidney, in a dose dependent manner, when compared to CCl 4 treated control. These results clearly indicate the strong antioxidant property of the plant Ipomoea leari. The study provides a proof for the ethnomedical claims and reported biological activities. The plant has, therefore, very good therapeutic potential.
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