Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 15, Issue 8, 2015

The implementation of computational tools in pharmaceutics has proven an effectual strategy in creating harmony between the physical and chemical aspects of proteins and potential inhibitors. This is achieved by bringing to life the three dimensional retrospect of biological systems, which takes into consideration computational approaches such as quantum mechanics and molecular dynamics to facilitate drug design and discovery. In this work, we aim to provide a summary of the computational aspects of naturally derived anti-cancer inhibitors targeting the enzyme family of glycosidases. Our study offers insight into the evolution of drug discovery, molecular modelling and molecular binding modes of natural product inhibitors associated with glycosidase enzymes.

There is an ever-increasing need for the development of new drugs with safe and improved profile for the treatment of cancer. From time immemorial, nature has been considered as an abundant source of medicinal compounds having therapeutic properties. An enormous chemical diversity is present in thousands and millions of species of microorganisms, marine organisms, plants and animals that can act as potential therapeutic agents against various types of human cancer. Literature survey revealed that many alkaloids isolated from marine cyanobacteria, fungi, algae, sponges and tunicates displayed a wide range of anticancer properties like antiproliferative, antiangiogenic, induction of apoptosis, promoting cytotoxicity by inhibition of topoisomerase activities and tubulin polymerization. In this context, bastadins derived from tyrosine-based alkaloids have been reported as one the important class of anticancer agents. In particular bastadin 6 (24), seems to be a promising natural lead compound for the development of marine natural product-based anticancer therapeutic agents. This review mainly highlights the pharmacologically active scaffolds like purine, tyrosine and tryptophan containing marine alkaloids that exhibit biological activity, including anti-angiogenesis, cytotoxicity and anticancer activity.

The natural stilbenoids combretastatin A-4 (CA4) and combretastatin A-1 (CA1) are potent antitubulin agents demonstrating antimitotic activity as well as tumor vascular disruption property. Due to structural simplicity and potent cytotoxicity of CA4 and CA1, they are considered as promising leads for the development of potent anticancer agents. In fact, scientific fraternity is motivated to synthesize several derivatives of CA4 and CA1 as novel therapeutic agents. In the literature, several studies have been carried out to evaluate the medicinal chemistry, pharmacology and structure–activity relationships (SAR) of a variety of modified combretastatin derivatives. The present report aimed at comprehensively revising the recent advancements (2006-2014) in the medicinal chemistry and SAR of diversified combretastatin analogues. The published data concerning new combretastatin A-4 analogues as antimitotic anticancer agents are presented and SAR is reviewed and discussed.

In this research work, a series of eighteen novel coumarinyl substituted thiazolidin-2,4-dione analogs (4a-4r) have been designed by molecular hybridization approach, synthesized and their structures were established on the basis of FTIR, 1H NMR, 13C NMR and elemental (CHN) analysis. These title compounds were screened for their cytotoxicity using MTT assay methodology against five different mammalian cancer cell lines viz. hormone dependant breast adenocarcinoma (MCF7), cervical carcinoma (HeLa), colorectal carcinoma (HT29), lung cancer (A549) and prostate adeno carcinoma (PC3). The cytotoxicity screening studies revealed that MCF-7, HeLa and A549 cancer cell lines were sensitive to all the tested compounds. Though the compounds showed varying degrees of cytotoxicity in the tested cell lines, most significant effect was observed for compounds 4i (1.06, 2.4 and 3.06 μM) and 4o (0.95, 3.2 and 2.38 μM) against MCF7, HeLa and A549 cell lines respectively. In conclusion, the anticancer results of these promising leads strongly encouraged us for additional lead optimization with the aim of developing more potential anticancer agents.

Cancer is the most dangerous disease that causes deaths all over the world. Natural products have afforded a rich source of drugs in a number of therapeutic fields including anticancer agents. Many significant drugs have been derived from natural sources by structural optimization of natural products. Cinnamic acid has gained great interest due to its antiproliferative, antioxidant, antiangiogenic and antitumorigenic potency. Currently it has been observed that cinnamic acid and its analogs such as caffeic acid, sinapic acid, ferulic acid, and isoferulic acid display various pharmacological activities, such as immunomodulation, anti-inflammation, anticancer and antioxidant. They have served to be the major sources of potential leading anticancer compounds. In this review, we focus on the anticancer potency of cinnamic acid derivatives and novel strategies to design these derivatives. We hope this review will be useful for researchers who are interested in developing anticancer agents.

Overexpression of epidermal growth factor receptor (EGFR) is seen in a number of human tumors like prostate, colon, breast and ovarian. Their expression is correlated with vascularity and often difficult to diagnose. Though a number of active inhibitors and anticancer drugs against EGFR-tyrosine kinase are known, increase in resistance together with many side effects designate the need for new and improved treatments. Natural products and their analoges have significant contribution in the cancer drug discovery and development process. Therefore in the current review we mainly discuss design, synthesis and structural activity relationship of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors from the natural origin.

In the past decades, tricyclic acridone ring system has become one of the major research interests of the medicinal chemists due to the biological significance of this moiety in drug design and drug discovery. Acridone scaffold has substantial bio-potential since it possess crucial activities such as antibacterial, antimalarial, antiviral and anti-neoplastic. The diverse biological activity of acridone and its prospective in reversal of multi-drug resistance has attracted attention of medicinal chemists to explore this scaffold especially to treat multi-drug resistance in cancer. Considering this potential in this review we have summarized the synthesis and the antitumor activities of different acridone derived compounds reported from 2000 to 2014.

The use of specific compounds to suppress the growth of tumors or reverse carcinogenesis is defined as chemoprevention. Natural products have been known as one of the most important resources of anticancer agents. Among them, carotenoids are lipophilic molecules accumulating in lipophilic compartments including lipoproteins and/or membranes. Various carotenoids were used as major phytonutrients to inhibit the development of tumors in vitro and in vivo. They have shown different functions such as scavenging free radicals, inhibition of angiogenesis, prevention of cell propagation, and apoptosis induction in lung, colon, breast and prostate. Regarding these roles, most carotenoids possess anti-oxidant properties. However, their therapeutic use is problematic due to the lack of solubility of carotenoids in water. Hence, recent studies have been focused on uncommon carotenoids soluble in water because of their glycosylated form, such as crocin(s) extracted from saffron. These structures with their cytotoxicity effects on human cancer cells are suggested as the most suitable compounds for cancer treatment. Herein, we summarize different functions of carotenoids for suppressing tumor growth.

Coumarin enjoys an important place in drug discovery process due to its presence in diversity of biologically active compounds. Many compounds of plant origin are derivatives of coumarin. Taking these natural products as lead, research groups across the globe have designed and synthesized numerous coumarin analogues for treatment of varied diseases. Cancer is one of the dreadful chronic diseases, and many drugs are available for its treatment. However, due to heterogeneity of cancer, the search is still on to develop drugs for specific types of cancers. The present review is an attempt to study various coumarin derivatives of natural as well as synthetic origins, which are identified or developed for the treatment of different types of cancers. Herein, we have classified various anticancer coumarin derivatives on the basis of their origin as well as substitution around it. These are discussed under the headings of natural, semi-synthetic and synthetic coumarin derivatives. The synthetic coumarin derivatives are further classified as mono-, di- and poly-substituted and fused coumarin derivatives. Of the six positions available for substituents on coumarin nucleus, only three positions (C-3, C-4 and C-7) are exploited for the selection of functional groups appropriate for anticancer activity. The other positions (C-5, C-6 and C-8) are either unexplored or very less exploited. The present review is expected to provide the medicinal chemists a guide to choose new functional groups for substitution at different positions of coumarin nucleus for development of novel compounds for the treatment of a specific type of cancer.

Throughout our evolution, the importance of natural products for medicine and health has been increasing and it continues to be a key source of novel anticancer drugs, leads and new chemical entities. Among natural products, tricyclic heteroaromatic alkaloids such as carbazoles are an important class of natural and semi-synthetic organic compounds. In the last few decades medicinal role of natural and semi-synthetic carbazoles has expanded significantly, especially as a vital heterocyclic class of antitumor agents. Some of the carbazoles that displayed potential anticancer activity have undergone clinical trials. However, complications arising due to multidrug resistance in clinical trials led to very few of the selected carbazoles being approved for cancer therapy. Planar, polycyclic and aromatic carbazoles exhibit anticancer activity via DNA intercalation. Further many carbazoles can be cytotoxic by inhibiting DNA-dependent enzymes such as telomerase and topoisomerase I/II.

Phospholipase A2 (PLA2), Cyclooxygenase (COX) and 5-Lipoxygenase (5-LOX) are arachidonic acid metabolizing enzymes and their inhibitors have been developed as therapeutic molecules for cancer and inflammation related disorders. In the present study, PLA2, COX 1&2 and 5-LOX inhibitory studies of Borassus flabellifer seed coat extract were carried out and substantial 5-LOX inhibitory activity was found. Dammarane triterpenoid 1 (Dammara-20,23-diene-3,25-diol) was isolated according to 5-LOX activity guided isolation, and screened for COX (1 & 2) inhibitory activities. Dammarane triterpenoid 1 inhibited carrageenan-induced rat paw edema and TNF-α; secretion levels in lipopolysaccharide (LPS)-induced THP-1 human monocytes. Anticancer activity studies demonstrated the antiproliferative effect of dammarane triterpenoid 1 on various cancer cell lines including MIA PaCa-2 pancreatic, DU145 prostate, HL-60 leukemia and Caco-2 colon cancers. Dammarane triterpenoid 1 showed good antiproliferative activity on MIA PaCa-2 pancreatic cancer cell line with IC50 of 12.36±0.33 μM, among other tested cell lines. Apoptosis inducing activity of dammarane triterpenoid 1 was confirmed based on increased sub-G0 phase cell population in cell cycle analysis, loss of mitochondrian membrane potential, elevated levels of cytochrome c, nuclear morphological changes and DNA fragmentation in MIA PaCa-2 pancreatic cancer cells. Therefore, dammarane triterpenoid skeleton may raise the hope of developing novel anti-inflammatory and anticancer drugs in the future.