Geir Bjrklund  Amin Gasmi  Larysa Lenchyk  Mariia Shanaida  Saba Zafar  Pavan Kumar Mujawdiya  Roman Lysiuk  Halyna Antonyak  Sadaf Noor  Muhammad Akram  Kateryna Smetanina  Salva Piscopo  Taras Upyr  Massimiliano Peana 《Molecules (Basel, Switzerland)》2022,27(21)

The current review provides an up-to-date analysis of scientific data on astaxanthin (ASX) sources and experimental studies on its health benefits as a potent antioxidant in the aging process. ASX is a liposoluble carotenoid nutrient and reddish-orange pigment, naturally synthesized by numerous microalgae, yeasts, and bacteria as secondary metabolites. Provides a reddish hue to redfish and shellfish flesh that feed on ASX-producing microorganisms. The microalga Haematococcus pluvialis is the most important source for its industrial bioproduction. Due to its strong antioxidant properties, numerous investigations reported that natural ASX is a more significant antioxidant agent than other antioxidants, such as vitamin C, vitamin E, and β-carotene. Furthermore, several data show that ASX possesses important nutraceutical applications and health benefits, especially in healthy aging processes. However, further studies are needed for a deeper understanding of the potential mechanisms through which ASX could lead to its effective role in the healthy aging process, such as supporting brain health and skin homeostasis. This review highlights the current investigations on the effective role of ASX in oxidative stress, aging mechanisms, skin physiology, and central nervous system functioning, and shows the potential clinical implications related to its consumption.  相似文献   

    

Massimo Delle Piane  Luca Pesce  Matteo Cioni  Giovanni M. Pavan 《Chemical science》2022,13(37):11232

Spatial confinement is widely employed by nature to attain unique efficiency in controlling chemical reactions. Notable examples are enzymes, which selectively bind reactants and exquisitely regulate their conversion into products. In an attempt to mimic natural catalytic systems, supramolecular metal–organic cages capable of encapsulating guests in their cavity and of controlling/accelerating chemical reactions under confinement are attracting increasing interest. However, the complex nature of these systems, where reactants/products continuously exchange in-and-out of the host, makes it often difficult to elucidate the factors controlling the reactivity in dynamic regimes. As a case study, here we focus on a coordination cage that can encapsulate amide guests and enhance their hydrolysis by favoring their mechanical twisting towards reactive molecular configurations under confinement. We designed an advanced multiscale simulation approach that allows us to reconstruct the reactivity in such host–guest systems in dynamic regimes. In this way, we can characterize amide encapsulation/expulsion in/out of the cage cavity (thermodynamics and kinetics), coupling such host–guest dynamic equilibrium with characteristic hydrolysis reaction constants. All computed kinetic/thermodynamic data are then combined, obtaining a statistical estimation of reaction acceleration in the host–guest system that is found in optimal agreement with the available experimental trends. This shows how, to understand the key factors controlling accelerations/variations in the reaction under confinement, it is necessary to take into account all dynamic processes that occur as intimately entangled in such host–guest systems. This also provides us with a flexible computational framework, useful to build structure–dynamics–property relationships for a variety of reactive host–guest systems.

Encapsulation of guests in metal–organic cages allows control over chemical reactivity. Focusing on the hydrolysis of amides, here we show an effective molecular simulation approach to reconstruct reactivity in host–guest systems in dynamic regimes.  相似文献   

    

Chiguru Srinivas  Chebolu Naga Sesha Sai Pavan Kumar  Bhimapaka China Raju  Vaidya Jayathirtha Rao 《Helvetica chimica acta》2011,94(4):669-674

An efficient stereoselective total synthesis of (+)‐(4S,5S)‐muricatacin was accomplished in good yields from inexpensive, commercially available chemicals ((+)‐diethyl tartrate (DET) and undecan‐1‐ol) by utilizing Mitsunobu and Julia? Kocienski reactions, Wittig homologation, Swern oxidation, and lactonization.  相似文献   

    

Chebolu Naga Sesha Sai Pavan Kumar  Ejjirothu Srihari  Mettu Ravinder  Koochana Pranay Kumar  U. S. N. Murthy  Vaidya Jayathirtha Rao 《Journal of heterocyclic chemistry》2013,50(Z1):E131-E135

Several new thieno[2,3‐b]pyridine and thieno[2,3‐b]quinoline derivatives are synthesized in an efficient manner catalyzed by DBU as a base. Simple workup procedure, good yields, and mild reaction conditions are the salient features of this method. All the synthesized compounds are screened for antimicrobial activity against several organisms.  相似文献   

    

Boga Srinivas  Vydyula Pavan Kumar  Regati Sridhar  Vutukuri Prakash Reddy  Yadavalli Venkata Durga Nageswar  Kakulapati Rama Rao 《Helvetica chimica acta》2009,92(6):1080-1084

    

Harshad&#x;B. Ghodke  Ramya Krishnan  Kasinath Vignesh  G.&#x;V.&#x;Pavan Kumar  Chandrabhas Narayana  Yamuna Krishnan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2007,119(15):2700-2703

  相似文献   

    

Vydyula Pavan Kumar  Perepogu Arun Kumar  Iragavarapu Suryanarayana  Yadavalli Venkata Durga Nageswar  Kakulapati Rama Rao 《Helvetica chimica acta》2007,90(9):1697-1704

The two pyrrolidinylidenesulfamido‐modified β‐cyclodextrins (β‐CDs) 3 and 4 were prepared and studied for chiral discrimination of the enantiomers (R)‐ and (S)‐ 1 of zolmitriptan. The pyrrolidinylidenesulfamido spacer improved the chiral discrimination and binding abilities of these modified cyclodextrins. The hosts 3 and 4 showed higher selectivity for (S)‐ 1 . The association constants (Table) and enantioselectivity factors were calculated for the complexes of (R)‐ and (S)‐ 1 with the β‐CDs 2 – 4 . The formation of host?guest complexes was confirmed by ¹H‐NMR studies.  相似文献   

    

Pavan Kumar Prathipati  Subhra Mandal  Christopher J. Destache 《Biomedical chromatography : BMC》2019,33(2)

A sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for quantification of bictegravir in human plasma. A small volume of only 50 μL aliquot of plasma was precipitated with acetonitrile containing an internal standard (IS). Chromatographic separation was performed on a Kinetex EVO C₁₈ column, 50 × 3.0 mm, 5 μm using an isocratic mobile phase containing 80:20 acetonitrile–water with 0.1% formic acid. A mass spectrometer was operated in ESI positive multiple reaction monitoring mode using the m/z 450.1/289.1 for bictegravir and 420.1/277.1 for IS. The dynamic range of the method was 1–10,000 ng/mL with a correlation coefficient of ≥0.9991. The precision results of calibration standards were in the range of 0.05–4.57% and accuracies were 95.07–104.70%. The mean extraction recovery was 98.64% with a precision of 2.91%. The method was validated as per US Food and Drug Administration guidelines and was found to be accurate and precise. The method was successfully applied to in vitro cellular uptake study.  相似文献   

    

Dr. Ping Peng  Dr. Fang‐Fang Li  Venkata S. Pavan K. Neti  Dr. Alejandro J. Metta‐Magana  Prof. Dr. Luis Echegoyen 《Angewandte Chemie (International ed. in English)》2014,53(1):160-163

Given the unique structural and electronic properties of C₆₀, metal–organic frameworks (MOFs) containing C₆₀ linkers are expected to exhibit interesting characteristics. A new hexakisfullerene derivative possessing two pairs of phenyl pyridine groups attached to two methano‐carbon atoms located at the trans‐1 positions was designed and synthesized. The four pyridyl nitrogen atoms define a perfectly planar rectangle. This new C₆₀ derivative was used to assemble the first fullerene‐linked two‐dimensional MOF by coordination with Cd²⁺.  相似文献   

    

Aurélien Hameau  Séverine Fruchon  Christian Bijani  Alessandro Barducci  Muriel Blanzat  Rémy Poupot  Giovanni M. Pavan  Anne‐Marie Caminade  Cédric‐Olivier Turrin 《Journal of polymer science. Part A, Polymer chemistry》2015,53(6):761-774

The synthesis of new series of PPH (poly(phosphorhydrazone)) dendrimers with amino‐PEG phosphonates or the corresponding amino‐PEG phosphonic acids as terminal groups is presented, from generations 1–3. The size of PEG‐terminated dendrimers is experimentally measured by diffusional NMR, and by means of dynamic light scattering. Classical molecular dynamics and well‐tempered metadynamics simulations are used to assess or confirm the formation of aggregates in some cases. The influence of PEG capping on the cytotoxicity profiles of the dendrimers is evaluated on human peripheral blood mononuclear cells by means of LIVE/DEAD assays, and confirms the importance of PEG capping to ensure low cytotoxicity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 761–774  相似文献