Mini Reviews in Medicinal Chemistry - Volume 19, Issue 10, 2019

Aptamers are single-stranded DNA or RNA oligonucleotides generated by a novel in vitro selection technique termed Systematic evolution of ligands by exponential enrichment (SELEX). During the past two decades, various aptamer drugs have been developed and many of them have entered into clinical trials. In the present review, we focus on aptamers as potential therapeutics for hematological diseases, including anemia of chronic inflammation (ACI) and anemia of chronic disease (ACD), hemophilia, thrombotic thrombocytopenic purpura (TTP) or VWD type-2B, and sickle cell disease (SCD), in particular, those that have entered into clinical trials.

Cutaneous pigmentation plays critical role in determining the color of skin along with photo protection of skin from dreadful effects of ultraviolet radiations. Conversely, abnormal accumulation of melanin is responsible for hyper pigmentary disorders such as melasma, senile lentigines and freckles. Because of the visible nature of dermatologic diseases, they have a considerable psychosomatic effect on affected patients. Tyrosinase inhibitors are molecules that interrelate in some way with the enzyme to prevent it from working in the normal manner. Past many decades witnessed the quest for the development of natural tyrosinase inhibitors due to imperative role played by tyrosinase in the process of melanogenesis and fungi or fruit enzymatic browning. Mechanism of pigmentation is characterized by the intact process of the synthesis of specialized black pigment within melanosomes. Melanin is synthesized by a cascade of enzymatic and chemical reactions. For this reason, melanin production is mainly controlled by the expression and activation of tyrosinase. In the current article, we discussed tyrosinase inhibitors from the natural sources, which can be an essential constituent of cosmetics products and depigmenting agents for the treatment of hyperpigmentory disorders.

Resveratrol is a non-flavonoid polyphenol containing a terpenoid backbone. It has been intensively studied because of its various promising biological properties, such as anticancer, antioxidant, antibacterial, neuroprotective and anti-inflammatory activities. However, the medicinal application of resveratrol is constrained by its poor bioavailability and stability. In the past decade, more attention has been focused on making resveratrol derivatives to improve its pharmacological activities and pharmacokinetics. This review covers the literature published over the past 15 years on synthetic analogues of resveratrol. The emphasis is on the chemistry of new compounds and relevant biological activities along with structure-activity relationship. This review aims to provide a scientific and reliable basis for the development of resveratrol-based clinical drugs.

Glycyrrhizic acid (GA), a triterpene isolated from the roots and rhizomes of licorice, named Glycyrrhiza glabra, is the principal bioactive ingredient of anti-viral, anti-inflammatory and hepatoprotective effects. GA has been used in the clinical treatment of hepatitis, bronchitis, gastric ulcer, AIDS (acquired immunodeficiency syndrome), certain cancers and skin diseases. It has a direct effect on anti-HBV (hepatitis B virus) via affecting the HBsAg (hepatitis B surface antigen) to extracellular secretion, improving liver dysfunction in patients with chronic hepatitis B, and ultimately improving the immune status of HBV. GA can significantly inhibit the proliferation of HIV, showing an immune activation. The clinical application of GA on the prevention and treatments of various diseases may derive from its numerous pharmacological properties. This review provides the summary of the antiviral effects of GA on research progress and mechanism in recent years.

Background & Objective: A series of novel derivatives possessing the thiophene moiety were synthesized using ethyl 5'-amino-2,3'-bithiophene-4'-carboxylate as the starting material. Methods: The new synthesized derivatives were screened as lactate dehydrogenase (LDH) inhibitors. LDH plays an important role in glucose metabolism in cancer cells and can affect tumor genesis and metastasis. Results: 3-Substituted p-tolylthieno[2,3-d]pyrimidin-4(3H)-ones 4 were the most potent inhibitors in this study compared to Galloflavin reference drug. Conclusion: Molecular docking studies on the Human Lactate Dehydrogenase active site were carried out on the synthesized compounds and the MolDock scores ranged between -127 to -171.

Background: In view of numerous biological activities of 3-substituted isocoumarins a number of analogues based on this scaffold were synthesized for their in vitro pharmacological evaluation. Methods: The syntheses of 3-substituted isocoumarins were carried out via a Pd/C-catalyzed Suzuki- Miyaura coupling of 3-chloroisochromen-1-one with a range of boronic acid derivatives. This C-C bond forming reaction was facilitated by ultrasound irradiation to afford the desired products in good yields. A number of 3-(het)aryl isocoumarin derivatives were prepared by using this methodology and subsequently tested for their TNF-α inhibitory properties in vitro followed by cytotoxicities via the MTT assay. Results: Several compounds showed inhibition of TNF-α with one compound showing an IC50 value of 9.01±1.25 μM. Three compounds also showed promising cytotoxic properties against two cancer cell lines with IC50 ~ 0.9-2.7 μM. Conclusion: The isocoumarin framework could be an effective template for the design and discovery of new inhibitor of TNF-α for the potential treatment of related diseases.

Background: A series of 5-(2-amino-6-(3/4-bromophenyl)pyrimidin-4-yl)benzene-1,3-diol scaffolds was synthesized by Claisen-Schmidt condensation and characterized by NMR, IR, Mass and elemental analyses. Methods: The synthesized pyrimidine scaffolds were screened for their antimicrobial activity by tube dilution method as well for antiproliferative activity (human colorectal (HCT116) cancer cell line) by SRB assay. Results: The antimicrobial screening results demonstrated that compounds, k6, k12, k14 and k20 were found to be the most potent ones against selected microbial species. The anticancer screening results indicated that compounds, k8 and k14 displayed potent anticancer activity against cancer cell line (HCT116). Conclusion: Further, the molecular docking study carried to find out the interaction between active pyrimidine compounds with CDK-8 protein indicated that compound k14 showed best dock score with better potency within the ATP binding pocket and may be used as a lead for rational drug designing of the anticancer molecule.