Background: Many studies have suggested the benefits of garlic oil extracts against Leishmania parasites. Recent research has proved that these derivatives (such as allicin) are cytotoxic and therapeutic effects of garlic are in fact due to an odorless compound (S-allyl-CYSTEINE). Considering the small number of studies in this field, we evaluated the effectiveness of S-allyl-CYSTEINE on survival, apoptosis, and proliferation of Leishmania major promastigotes in vitro.Methods: In this study Leishmania major promastigotes (MRHO/IR/75/ER) were used. The parasites were first cultured and then treated with S-allyl-CYSTEINE at end concentrations of 2.5, 5.0, 10.0, 20.0, 40.0, and 50.0 mM. Their survival, apoptosis, and proliferation was assessed after 72 hours.Findings: None of the concentrations of S-allyl-CYSTEINE could induce apoptosis in parasite promastigotes. Lower concentrations (5.0 and 10.0 mM) of S-allyl-CYSTEINE had greatest effect on proliferation. On the other hand, direct observation showed that cultures comprising S-allyl-CYSTEINE at end concentration of 20.0, 40.0, and 50.0 mM formed more rosettes.Conclusion: The antioxidant effects of S-allyl-CYSTEINE have been previously proved. Similarly, this study showed that some concentrations of S-allyl-CYSTEINE could affect the survival and growth of promastigotes in culture medium. Therefore, this substance seems to be a good stimulating factor for growth of parasite promastigotes in culture media.

N-acetyl CYSTEINE (NAC), as a nutritional supplement, is a greatly applied antioxidantin vivoand in vitro. NAC is a precursor of L-CYSTEINE that results in glutathione elevation biosynthesis. It acts directly as a scavenger of free radicals, especially oxygen radicals.NAC is a powerful antioxidant. It is also recommended as a potential treatment option for different disorders resulted from generation of free oxygen radicals. Additionally, it is a protected and endured mucolytic drug that mellows tenacious mucous discharges. It has been used for treatment of various diseases in a direct action or in a combination with some other medications. This paper presents a review on various applications of NAC in treatment of several diseases.

Background: Cathepsin B comprises a group of lysosomal CYSTEINE proteases belonging to the Papain family; it has an intracellular function in the process of protein catabolism, antigen processing in the immune response, and Alzheimer’ s disease. In cancers, cathepsin B interferes with autophagy and intracellular catabolism, and breaks down extracellular matrix, decreases protease inhibitors expression, and ultimately helps to accelerate metastasis, tumor malignancy, and reduce immune resistance. Methods: In this study, the 3D structure of cathepsin B was constructed using modeler and Iterative Threading ASSEmbly Refinement (I-TASSER), based on similarity to the crystallographic model of procathepsin B (1PBH). Then, the predicted cathepsin B model was evaluated using PROCHECK and PROSA for quality and reliability. Molecular studies suggested that the amino acids CYSTEINE 108, histidine 189, and histidine 190 form the envelope of the active site of cathepsin B. The docking studies of cathepsin B was performed with protease inhibitors cystatin C, E-64 and leupeptin. Results: The lowest binding energy was related to the cathepsin B-E-64 complex. Accordingly, it was found that E64 interacts with the amino acid CYSTEINE 108 of the active site of cathepsin B. Leupeptin made 2 hydrogen bonds with cathepsin B, but none with the active site of cathepsin amino acids. Cystatin C established a hydrogen bond with the arginine 18 of cathepsin B and made electrostatic bonds with aspartate 148 of cathepsin B. Conclusion: Therefore, the bioinformatics and docking studies of cathepsin B with its inhibitors could be used as reliable identification, treatment, and alternative methods for selecting the inhibitors and controllers of cancer progression.