In the design and development of therapeutic agents, macromolecules with restricted structures have stronger competitive edges than linear biological entities since cyclization can overcome the limitations of linear structures. The common issues of linear peptides include susceptibility to degradation of the peptidase enzyme, off-target effects, and necessity of routine dosing, leading to instability and ineffectiveness. The unique conformational constraint of cyclic peptides provides a larger surface area to interact with the target at the same time, improving the membrane permeability and in vivo stability compared to their linear counterparts. Currently, cyclic peptides have been reported to possess various activities, such as antifungal, antiviral and antimicrobial activities. To date, there is emerging interest in cyclic peptide therapeutics, and increasing numbers of clinically approved cyclic peptide drugs are available on the market. In this review, the medical significance of cyclic peptides in the defence against viral infections will be highlighted. Except for chikungunya virus, which lacks specific antiviral treatment, all the viral diseases targeted in this review are those with effective treatments yet with certain limitations to date. Thus, strategies and approaches to optimise the antiviral effect of cyclic peptides will be discussed along with their respective outcomes. Apart from isolated naturally occurring cyclic peptides, chemically synthesized or modified cyclic peptides with antiviral activities targeting coronavirus, herpes simplex viruses, human immunodeficiency virus, Ebola virus, influenza virus, dengue virus, five main hepatitis viruses, termed as type A, B, C, D and E and chikungunya virus will be reviewed herein.
A limited number of overexpressed transcription factors are associated with cancer progression in many types of cancer. BTB and CNC homology 1 (BACH1) is the first mammalian heme-binding transcription factor that belongs to the basic region leucine zipper (bZIP) family and a member of CNC (cap 'n' collar). It forms heterodimers with the small musculoaponeurotic fibrosarcoma (MAF) proteins and stimulates or suppresses the expression of target genes under a very low intracellular heme concentration. It possesses a significant regulatory role in heme homeostasis, oxidative stress, cell cycle, apoptosis, angiogenesis, and cancer metastasis progression. This review discusses the current knowledge about how BACH1 regulates cancer metastasis in various types of cancer and other carcinogenic associated factors such as oxidative stress, cell cycle regulation, apoptosis, and angiogenesis. Overall, from the reported studies and outcomes, it could be realized that BACH1 is a potential pharmacological target for discovering new therapeutic anticancer drugs.
Skin grafts are indicated when there is a major loss of skin. Full-thickness skin graft is an ideal choice to reconstruct defect of irregular surface that is difficult to immobilize. Full-thickness mesh grafts can be applied to patch large skin defect when there is less donor site in extensively traumatized and burned surgical patients. The concept of using natural biomaterials such as keratin, basic fibroblast growth factor is slowly gaining popularity in the field of medical research to achieve early healing. The main objective of this study is to evaluate the efficacy of gelatin conjoined with keratin processed from the poultry feather and commercially available basic fibroblast growth factor (bFGF) as a sandwich layer in promoting the viability of full-thickness skin mesh grafts. The efficacy was assessed from the observation of clinical, bacteriological, and histopathological findings in three groups of experimental dogs. The clinical observations such as color, appearance and discharge, and hair growth were selected as criteria which indicated good and early acceptance of graft in keratin-gelatin (group II). On bacteriological examination, Staphylococcus aureus and Proteus was identified in few animals. Histopathological study of the patched graft revealed early presences of hair follicles; sebaceous gland, and normal thickness of the epidermis in keratin-gelatin in group II treated animals compared with other group (group I-control, group III-bFGF-gelatin).