The use of TRH in the treatment of various CNS disorders has been proven clinically. However, TRH itself is a poor drug candidate due to its short plasma half-life (5 min), poor biopharmaceutical properties (low intestinal and CNS permeability) and endocrine side effect. Nevertheless, researchers have come up with metabolically stable, more potent and selective TRH analogs and prodrugs. Taltirelin, one of the TRH analogs, has been approved under the trade name of Ceredist(®) in Japan for the treatment of spinocerebellar degeneration. Several other TRH analogs are in various stages of preclinical or clinical development.

Thyrotropin-releasing hormone (TRH), a hypothalamic orally active neuropeptide, has been manifested in a wide range of biological responses. Besides its central role in regulating the pituitary-thyroid axis by simulating the release of thyrotropin, TRH has considerable influence on the activity of a number of neurobiological systems. Due to the therapeutic potential of TRH to treat several CNS maladies, the development of CNS-selective and metabolically stable TRH analogs is an area of interest. TRH is known to elicit its biological response through two G-protein coupled receptors for TRH (namely, TRH-R1 and TRH-R2). The distinct distribution of TRH receptors in tissues has provided opportunity to discover receptor subtype-specific analogs, which would demonstrate high CNS activities, and are completely free of hormonal activities. In this review, an in-depth analysis of the chemistry and biology of TRH and its analogs is provided. Recent discoveries of TRH-R2 selective analogs, TRH super agonists, metabolically stable TRH analogs, and targeted delivery of TRH analogs have been also discussed.

Thermosets composed of cross-linked polymers demonstrate enhanced thermal, solvent, chemical, and dimensional stability as compared to their non-cross-linked counterparts. However, these often-desirable material properties typically come at the expense of reprocessability, recyclability, and healability. One solution to this challenge comes from the construction of polymers that are reversibly cross-linked. We relied on lessons from Nature to present supramolecular polymer networks comprised of cooperative Janus-faced hydrogen bonded cross-links. A triazine-based guanine-cytosine base (GCB) with two complementary faces capable of self-assembly through three hydrogen bonding sites was incorporated into poly­(butyl acrylate) to create a reprocessable and recyclable network. Rheological experiments and dynamic mechanical analysis (DMA) were employed to investigate the flow behavior of copolymers with randomly distributed GCB units of varying incorporation. Our studies revealed that the cooperativity of multiple hydrogen bonding faces yields excellent network integrity evidenced by a rubbery plateau that spanned the widest temperature range yet reported for any supramolecular network. To verify that each Janus-faced motif engages in multiple cross-links, we studied the effects of local concentration of the incorporated GCB units within the polymer chain. Mechanical strength improved by colocalizing the GCB within a block copolymer morphology. This enhanced performance revealed that the number of effective cross-links in the network increased with the local concentration of hydrogen bonding units. Overall, this study demonstrates that cooperative noncovalent interactions introduced through Janus-faced hydrogen bonding moieties confers excellent network stability and predictable viscoelastic flow behavior in supramolecular networks.

Curcumin is an important nutraceutical that has enormous potential for a variety of diseases, but the medicinal properties of curcumin cannot be utilized due to its low in vivo bioavailability. Therefore, in view of the foregoing, there is an extensive need for combinatorial extract “curcumin with piperine and quercetin” which may enhance bioavailability of oral curcumin by inhibiting the enzymes responsible for the metabolism of curcumin. Thus, the present study investigated the effect of combinatorial extract of curcumin on obesity, glucose intolerance, and oxidative stress in high fat diet and low-dose streptozotocin-induced rats. Oral administration of combinatorial extract for 28 days significantly (P < 0.05) reduced PGL (64.84%), PTG (88.94%), LDL (26.38%) and PTC (50.23%) levels, respectively and improved glucose tolerance (P < 0.05) significantly to exogenously administered glucose (2 g/kg) at 60, 90, and 120 min interval on OGTT. The results for antioxidant potential indicate that at 100 mg/kg dose of combinatorial extract of curcumin significantly prevented the high-fat diet and low-dose streptozotocin-induced changes in the oxidative stress parameters (P < 0.01) which supports popular medicinal uses of this combinatorial extract as antihyperglycemic and hypolipidemic and is likely to bring this promising natural product to the forefront of therapeutic agents in the in the treatment of “metabolic syndrome”.