Antimicrobial peptides (AMPs) are gaining attention as substitutes for antibiotics in order to combat the risk posed by multi-drug resistant pathogens. Several research groups are engaged in design of potent anti-infective agents using natural AMPs as templates. In this study, a library of peptides with high sequence similarity to Myeloid Antimicrobial Peptide (MAP) family were screened using popular online prediction algorithms. These peptide variants were designed in a manner to retain the conserved residues within the MAP family. The prediction algorithms were found to effectively classify peptides based on their antimicrobial nature. In order to improve the activity of the identified peptides, molecular dynamics (MD) simulations, using bilayer and micellar systems could be used to design and predict effect of residue substitution on membranes of microbial and mammalian cells. The inference from MD simulation studies well corroborated with the wet-lab observations indicating that MD-guided rational design could lead to discovery of potent AMPs. The effect of the residue substitution on membrane activity was studied in greater detail using killing kinetic analysis. Killing kinetics studies on Gram-positive, negative and human erythrocytes indicated that a single residue change has a drastic effect on the potency of AMPs. An interesting outcome was a switch from monophasic to biphasic death rate constant of Staphylococcus aureus due to a single residue mutation in the peptide.
Background and aim
Chrysin is a flavonoid found in plant extracts from
Passiflora
species, honey and propolis. It has demonstrated anti-adipogenic activity
in vitro
but there are no studies substantiating the anti-obesity activity of chrysin
in vivo
.
Experimental procedure
The pancreatic lipase (PL) inhibitory potential of chrysin was determined by preliminary
in silico
screening and further confirmed by
in vitro
PL inhibitory assay and oral fat tolerance test (OFTT). The effect of chrysin on acute feed intake and sucrose preference test was determined in normal rats. Obesity was induced by feeding of high fructose diet (HFD) to the rats. The rats were divided into six groups: normal control, HFD control, orlistat and three doses of chrysin (25, 50 and 100 mg/kg body weight). Body weight, body mass index (BMI), abdominal circumference/thoracic circumference (AC/TC) ratio, calorie intake, adiposity index, fecal cholesterol, locomotor activity and histopathology of the adipose tissue of the rats were evaluated.
Results
Chrysin showed good affinity to PL with competitive type of inhibition. It significantly reduced serum triglycerides in OFTT. Chrysin also significantly reduced acute feed intake and sucrose preference in rats. Chrysin significantly decreased the body weight, BMI, AC/TC ratio, adiposity index, calorie intake while it significantly increased the fecal cholesterol and locomotor activity of the rats. Chrysin was found to reduce the size of the adipocytes when compared to the HFD control group.
Conclusion
Thus, chrysin exerted anti-obesity effect by inhibiting PL, reducing sucrose preference, reducing calorie intake and increasing the locomotor activity of rats.
N10-alkylated 2-bromoacridones are a novel series of potent antitumor compounds. DNA binding studies of these compounds were carried out using spectrophotometric titrations, Circular dichroism (CD) measurements using Calf Thymus DNA (CT DNA). The binding constants were identified at a range of K=0.3 to 3.9×10(5) M(-1) and the percentage of hypochromism from the spectral titrations at 28-54%. This study has identified a compound 9 with the good binding affinity of K=0.39768×10(5) M(-1) with CT DNA. Molecular dynamics (MD) simulations have investigated the changes in structural and dynamic features of native DNA on binding to the active compound 9. All the synthesized compounds have increased the uptake of Vinblastine in MDR KBChR-8-5 cells to an extent of 1.25- to1.9-fold than standard modulator Verapamil of similar concentration. These findings allowed us to draw preliminary conclusions about the structural features of 2-bromoacridones and further chemical enhancement will improve the binding affinity of the acridone derivatives to CT-DNA for better drug-DNA interaction. The molecular modeling studies have shown mechanism of action and the binding modes of the acridones to DNA.
68 "Nanotechnology" was first defined by Tokyo Science University, Norio Taniguchi in 1974. [8] Although the application of nanotechnology to medicine appears to be a relatively recent trend, the basic nanotechnology approaches for medical application dates back to several decades. [9] Lipid vesicles which were named as liposomes, were described in 1965, [10] in 1976 the description about the first controlled release polymer system of macromolecules was given, [11] Nanotechnology based devices and applications in medicine: An overview Abstract Nanotechnology has been the most explored and extensively studied area in recent times. Many devices which were earlier impossible to imagine, are being developed at a lightning speed with the application of nanotechnology. To overcome the challenges offered by the most dreaded diseases, such as cancer or any disease involving the central nervous system or other inaccessible areas of the human body, nanotechnology has been proved to be a boon in making the treatment more target specific and minimizing the toxicities. This review describes a handful of important devices and applications based on nanotechnology in medicine made in recent times. This article also describes in brief the regulatory concerns and the ethical issues pertaining to nanomedical devices.
We conclude that non-competitive type of inhibition, as shown in this study, can serve as an effective method to block NA and evade the currently seen drug resistance.
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