Don’t help them to bury the light. The interplay between intersystem crossing and hydrogen transfer in photoexcited curcumin revealed by state-hopping dynamics

2021 ◽  
Author(s):  
Raúl Losantos ◽  
Andreea Pasc ◽  
Antonio Monari
Keyword(s):  
Natural Compound ◽  
Hydrogen Transfer ◽  
Curcuma Longa ◽  
Intersystem Crossing ◽  
Intense Absorption

Curcumin is a natural compound extracted from turmeric (curcuma longa), which has shown remarkable antiinflammatory, antibacterial, and possibly anticancert properties. The intense absorption in the visible domain, and the possibility...

scholarly journals Curcuma Longa, the “Golden Spice” to Counteract Neuroinflammaging and Cognitive Decline—What Have We Learned and What Needs to Be Done

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1519
Author(s):  
Alessandra Berry ◽  
Barbara Collacchi ◽  
Roberta Masella ◽  
Rosaria Varì ◽  
Francesca Cirulli
Keyword(s):  
Molecular Structure ◽  
Cognitive Decline ◽  
Neurodegenerative Disorders ◽  
Natural Compound ◽  
Water Solubility ◽  
Current Knowledge ◽  
Curcuma Longa ◽  
Biomedical Literature ◽  
Global Increase ◽  
New Strategies

Due to the global increase in lifespan, the proportion of people showing cognitive impairment is expected to grow exponentially. As target-specific drugs capable of tackling dementia are lagging behind, the focus of preclinical and clinical research has recently shifted towards natural products. Curcumin, one of the best investigated botanical constituents in the biomedical literature, has been receiving increased interest due to its unique molecular structure, which targets inflammatory and antioxidant pathways. These pathways have been shown to be critical for neurodegenerative disorders such as Alzheimer’s disease and more in general for cognitive decline. Despite the substantial preclinical literature on the potential biomedical effects of curcumin, its relatively low bioavailability, poor water solubility and rapid metabolism/excretion have hampered clinical trials, resulting in mixed and inconclusive findings. In this review, we highlight current knowledge on the potential effects of this natural compound on cognition. Furthermore, we focus on new strategies to overcome current limitations in its use and improve its efficacy, with attention also on gender-driven differences.

scholarly journals Curcumin: Modern Applications for a Versatile Additive

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 519
Author(s):  
Florentina Monica Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Violeta Purcar
Keyword(s):  
Bacterial Infections ◽  
Natural Compound ◽  
Review Paper ◽  
Curcuma Longa ◽  
Antibacterial Properties ◽  
Point Of View ◽  
Nano Particles ◽  
Synergistic Activity ◽  
Quality Of Food

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.

scholarly journals The Multifaced Actions of Curcumin in Pregnancy Outcome

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 126
Author(s):  
Giovanni Tossetta ◽  
Sonia Fantone ◽  
Stefano Raffaele Giannubilo ◽  
Daniela Marzioni
Keyword(s):  
Natural Compound ◽  
Curcuma Longa ◽  
Human Diet ◽  
Beneficial Effects ◽  
Toxic Agents ◽  
Anti Oxidant ◽  
Ancient Times ◽  
Anti Inflammatory ◽  
Pleiotropic Functions

Curcumin, also known as diferuloylmethane, is the main polyphenolic substance present in the rhizomes of Curcuma longa L. This plant showed many beneficial effects and has been used since ancient times for both food and pharmaceutical purposes. Due to its pleiotropic functions, curcumin consumption in the human diet has become very common thanks also to the fact that this natural compound is considered quite safe as it does not have serious side effects. Its functions as an anti-inflammatory, anti-oxidant, neuroprotective, immunomodulatory, anti-toxicant, anti-apoptotic, and anti-diabetic compound are already known and widely demonstrated. There are numerous studies concerning its effects on various human pathologies including cancer, diabetes and arthritis while the studies on curcumin during pregnancy have been performed only in animal models. Data concerning the role of curcumin as anti-inflammatory compound suggest a possible use of curcumin in managing pregnancy complications such as Preeclampsia (PE), Gestational Diabetes Mellitus (GDM), Fetal Growth Restriction (FGR), PreTerm Birth (PTB), and exposure to toxic agents and pathogens. The aim of this review is to present data to support the possible use of curcumin in clinical trials on human gestation complications.

Solvent-Dependent Excited-State Hydrogen Transfer and Intersystem Crossing in 2-(2′-Hydroxyphenyl)-Benzothiazole

2014 ◽  
Vol 119 (6) ◽  
pp. 2596-2603 ◽  
Author(s):  
Shawkat M. Aly ◽  
Anwar Usman ◽  
Maytham AlZayer ◽  
Ghada A. Hamdi ◽  
Erkki Alarousu ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Intersystem Crossing

Excited state hydrogen transfer dynamics in phenol–(NH3)2 studied by picosecond UV-near IR-UV time-resolved spectroscopy

2020 ◽  
Vol 22 (10) ◽  
pp. 5740-5748
Author(s):  
Shun-ichi Ishiuchi ◽  
Junko Kamizori ◽  
Norihiro Tsuji ◽  
Makoto Sakai ◽  
Mitsuhiko Miyazaki ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Bound State ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Hydrogen Transfer Reaction ◽  
Near Ir

Intersystem crossing from 1πσ* to 3πσ* states traps excited state hydrogen transfer reaction in a bound state formed by 3ππ* and 3πσ* states.

scholarly journals Probing Competing Relaxation Pathways in Malonaldehyde with Transient X-Ray Absorption Spectroscopy

2020 ◽  
Author(s):  
Nanna Holmgaard List ◽  
Adrian L. Dempwolff ◽  
Andreas Dreuw ◽  
Patrick Norman ◽  
Todd J. Martínez
Keyword(s):  
Excited State ◽  
Absorption Spectroscopy ◽  
Hydrogen Transfer ◽  
Intersystem Crossing ◽  
Light Sources ◽  
X Ray ◽  
Valence States ◽  
Specific Mapping ◽  
Intramolecular Hydrogen ◽  
X Ray Absorption

<p>Excited-state intramolecular hydrogen transfer (ESIHT) is a fundamental reaction relevant to chemistry and biology. Malonaldehyde is the simplest example of ESIHT, yet only little is known experimentally about its excited-state dynamics. Several competing relaxation pathways have been proposed, including internal conversion mediated by ESIHT and C=C torsional motion as well as intersystem crossing. We perform an in silico transient X-ray absorption spectroscopy (TRXAS) experiment at the oxygen K-edge to investigate its potential to monitor the proposed ultrafast decay pathways in malonaldehyde upon photoexcitation to its bright S2(pp*) state. We employ both restricted active space perturbation theory and algebraic diagrammatic construction for the polarization propagator along interpolated reaction coordinates as well as representative trajectories from ab initio multiple spawning simulations to compute the TRXAS signals from the lowest valence states. Our study suggests that oxygen K-edge TRXAS can distinctly fingerprint the passage through the H-transfer intersection and the concomitant population transfer to the S1(np*) state. Potential intersystem crossing to T1(pp*) is detectable from reappearance of the double pre-edge signature and reversed intensities. Moreover, the torsional deactivation pathway induces transient charge redistribution from the enol side towards the central C-atom and manifests itself as substantial shifts of the pre-edge features. Given the continuous advances in X-ray light sources, our study proposes an experimental route to disentangle ultrafast excited-state decay channels in this prototypical ESIHT system and provides a pathway-specific mapping of the TRXAS signal to facilitate the interpretation of future experiments.</p>

scholarly journals Probing Competing Relaxation Pathways in Malonaldehyde with Transient X-Ray Absorption Spectroscopy

2020 ◽  
Author(s):  
Nanna Holmgaard List ◽  
Adrian L. Dempwolff ◽  
Andreas Dreuw ◽  
Patrick Norman ◽  
Todd J. Martínez
Keyword(s):  
Excited State ◽  
Absorption Spectroscopy ◽  
Hydrogen Transfer ◽  
Intersystem Crossing ◽  
Light Sources ◽  
X Ray ◽  
Valence States ◽  
Specific Mapping ◽  
Intramolecular Hydrogen ◽  
X Ray Absorption

<p>Excited-state intramolecular hydrogen transfer (ESIHT) is a fundamental reaction relevant to chemistry and biology. Malonaldehyde is the simplest example of ESIHT, yet only little is known experimentally about its excited-state dynamics. Several competing relaxation pathways have been proposed, including internal conversion mediated by ESIHT and C=C torsional motion as well as intersystem crossing. We perform an in silico transient X-ray absorption spectroscopy (TRXAS) experiment at the oxygen K-edge to investigate its potential to monitor the proposed ultrafast decay pathways in malonaldehyde upon photoexcitation to its bright S2(pp*) state. We employ both restricted active space perturbation theory and algebraic diagrammatic construction for the polarization propagator along interpolated reaction coordinates as well as representative trajectories from ab initio multiple spawning simulations to compute the TRXAS signals from the lowest valence states. Our study suggests that oxygen K-edge TRXAS can distinctly fingerprint the passage through the H-transfer intersection and the concomitant population transfer to the S1(np*) state. Potential intersystem crossing to T1(pp*) is detectable from reappearance of the double pre-edge signature and reversed intensities. Moreover, the torsional deactivation pathway induces transient charge redistribution from the enol side towards the central C-atom and manifests itself as substantial shifts of the pre-edge features. Given the continuous advances in X-ray light sources, our study proposes an experimental route to disentangle ultrafast excited-state decay channels in this prototypical ESIHT system and provides a pathway-specific mapping of the TRXAS signal to facilitate the interpretation of future experiments.</p>

scholarly journals The Diarylheptanoid Curcumin Induces MYC Inhibition and Cross-Links This Oncoprotein to the Coactivator TRRAP

2021 ◽  
Vol 11 ◽  
Author(s):  
Alexander Mödlhammer ◽  
Sandra Pfurtscheller ◽  
Andreas Feichtner ◽  
Markus Hartl ◽  
Rainer Schneider
Keyword(s):  
Transcriptional Activation ◽  
Protein Modification ◽  
Natural Compound ◽  
Molecular Mechanisms ◽  
Curcuma Longa ◽  
Covalent Binding ◽  
Adaptor Protein ◽  
Protein Stabilization ◽  
Human Tumors ◽  
Interaction Partners

The c-Myc protein (MYC) is a transcription factor with strong oncogenic potential controlling fundamental cellular processes. In most human tumors, MYC is overexpressed by enhanced transcriptional activation, gene amplification, chromosomal rearrangements, or increased protein stabilization. To pharmacologically suppress oncogenic MYC functions, multiple approaches have been applied either to inhibit transcriptional activation of the endogenous MYC gene, or to interfere with biochemical functions of aberrantly activated MYC. Other critical points of attack are targeted protein modification, or destabilization leading to a non-functional MYC oncoprotein. It has been claimed that the natural compound curcumin representing the principal curcumoid of turmeric (Curcuma longa) has anticancer properties although its specificity, efficacy, and the underlying molecular mechanisms have been controversially discussed. Here, we have tested curcumin’s effect on MYC-dependent cell transformation and transcriptional activation, and found that this natural compound interferes with both of these MYC activities. Furthermore, in curcumin-treated cells, the endogenous 60-kDa MYC protein is covalently and specifically cross-linked to one of its transcriptional interaction partners, namely the 434-kDa transformation/transcription domain associated protein (TRRAP). Thereby, endogenous MYC levels are strongly reduced and cells stop to proliferate. TRRAP is a multidomain adaptor protein of the phosphoinositide 3-kinase-related kinases (PIKK) family and represents an important component of many histone acetyltransferase (HAT) complexes. TRRAP is important to mediate transcriptional activation executed by the MYC oncoprotein, but on the other hand TRRAP also negatively regulates protein stability of the tumor suppressor p53 (TP53). Curcumin-mediated covalent binding of MYC to TRRAP reduces the protein amounts of both interaction partners but does not downregulate TP53, so that the growth-arresting effect of wild type TP53 could prevail. Our results elucidate a molecular mechanism of curcumin action that specifically and irreversibly targets two crucial multifunctional cellular players. With regard to their broad impact in cancer, our findings contribute to explain the pleiotropic functions of curcumin, and suggest that this natural spice, or more bioavailable derivatives thereof, may constitute useful adjuvants in the therapy of MYC-dependent and TRRAP-associated human tumors.

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

1967 ◽  
Vol 25 ◽  
pp. 78-79
Author(s):  
M. Arif Hayat
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Hydrogen Transfer ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Root Tips ◽  
Root Cells ◽  
Transfer Processes ◽  
Standard Procedures ◽  
A Cell ◽  
Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

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