Phospholipase A2s (PLA2s) are group of enzymes, which cleave phospholipids specifically at sn-2 position to liberate free fatty acid, mostly arachidonic acid (AA) and lysophospholipids (LPLs). Inhibition of PLA2 prevents the liberation of AA and LPLs. Hence, researchers have been considering PLA2s could be a better therapeutic target than the downstream enzymes cyclooxygense and lipoxygenase. Several isoforms of PLA2s exist; they are mainly divided into secretory PLA2s (sPLA2), cytosolic PLA2s (cPLA2), and calcium independent PLA2s (iPLA2), platelet activating factor- acyl hydrolase (PAF-AH), lysosomal PLA2 (LPLA2), adipose-specific PLA2 (Ad- PLA). Each isoform of PLA2s is different in its chemical structure and physiological functions. sPLA2s (Groups IIA, V and X) are well characterized as proinflammatory mediating enzymes but their role in cancer is controversial. Groups IVA, IVB and IVC cPLA2s are present in humans but only Group IVA cPLA2 plays key role in pathophysiology of various cancers and inflammation. The role of iPLA2 in inflammation and cancer is limited. Lipoprotein associated PLA2 (Group VIIA PLA2), a PAF-AH isoform, has key role in atherosclerosis. Several isoform specific PLA2 inhibitors have been developed and some of the PLA2s inhibitors are currently under clinical trials for various inflammatory and oncologic diseases. This review focuses on the recent experimental evidences to support the notion that PLA2s are causally implicated in the pathobiology of cancer and inflammatory related disorders and discuss the potential utility of isoform specific PLA2 inhibitors as preventive and/or therapeutic agents.
Diabetes is a major chronic metabolic disorder globally and around of 285 million people are affected by the disease and the number is expected to double in the next two decades. The major focus of anti-diabetic therapies is to enhance insulin production, sensitivity and/or reduce the blood glucose level. Although several synthetic drugs have been developed as antidiabetic agents but their utility has been hampered due to their side effects and poor efficacy. In this scenario, research on natural products has been gained importance due their safety profile in toxicity studies. Terpenoids belong to an important class of natural products and several terpenoids have been reported as antidiabetic agents. Some of them are under various stages of pre-clinical and clinical evaluation to develop them as antidiabetic agents. These agents can inhibit enzymes responsible for the development of insulin resistance, normalization of plasma glucose and insulin levels and glucose metabolism. Triterpenes can act as promising agents in the treatment of diabetic retinopathy, neuropathy and nephropathy or in impaired wound healing by inhibiting several pathways involved in the diabetes and associated complications. However, efforts in understanding the biological actions and clinical studies involving the applications of triterpenes in treating diabetes are very limited. Hence, special attention is imperative to explore the therapeutic potential of these compounds and provide new information to the scientific community. This review aims to provide the recent advances in triterpenes chemistry, its derivatives, biological interventions and its therapeutic applications with special emphasis on diabetes and its associated disorders.
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