Karen Hecht’s research while affiliated with Moses Lake Industries and other places

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Publications (9)


S2.pdf
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October 2023

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Supporting information for "Marine Drugs 21(10):514, DOI: 10.3390/md21100514". We summarized the singlet oxygen scavenging activity of carotenoids and other compounds in a more extended from Table 1.

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Astaxanthin: Past, Present, and Future

September 2023

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563 Reads

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34 Citations

Marine Drugs

Astaxanthin (AX), a lipid-soluble pigment belonging to the xanthophyll carotenoids family, has recently garnered significant attention due to its unique physical properties, biochemical attributes, and physiological effects. Originally recognized primarily for its role in imparting the characteristic red-pink color to various organisms, AX is currently experiencing a surge in interest and research. The growing body of literature in this field predominantly focuses on AXs distinctive bioactivities and properties. However, the potential of algae-derived AX as a solution to various global environmental and societal challenges that threaten life on our planet has not received extensive attention. Furthermore, the historical context and the role of AX in nature, as well as its significance in diverse cultures and traditional health practices, have not been comprehensively explored in previous works. This review article embarks on a comprehensive journey through the history leading up to the present, offering insights into the discovery of AX, its chemical and physical attributes, distribution in organisms, and biosynthesis. Additionally, it delves into the intricate realm of health benefits, biofunctional characteristics, and the current market status of AX. By encompassing these multifaceted aspects, this review aims to provide readers with a more profound understanding and a robust foundation for future scientific endeavors directed at addressing societal needs for sustainable nutritional and medicinal solutions. An updated summary of AXs health benefits, its present market status, and potential future applications are also included for a well-rounded perspective



Structure of astaxanthin (AX) and related carotenoids.
AX performs its antioxidant activity both inside and on the surface of the plasma membrane. Due to its strongly hydrophobic conjugated polyene structure and terminal polar groups, AX can exist both inside and on the surface of the phospholipid membrane. Therefore, AX is able to exert its effects against ROS both at the surface and inside of phospholipid membranes. On the other hand, β-carotene exerts its antioxidant activity only inside the phospholipid membrane. As for other antioxidants, ascorbic acid cannot exert its effect inside the phospholipid membrane, due to its high hydrophilicity, whereas tocopherols are relatively effective at the surface of the phospholipid membrane. This figure excludes the detailed structure of the cell membrane, including localization of different levels of lipids lipid rafts and proteins to avoid complications.
AX partially induces the antioxidant defense system while inhibiting the ROS-mediated inflammatory signaling pathway. AX inhibits ROS-mediated activation of canonical NFκB signaling and related signals such as JAK/STAT3. Consequently, the induction of pro-inflammatory cytokine gene expression is suppressed, resulting in attenuation of inflammatory signals. On the other hand, AX produces partial activation of Nrf2 via dissociation of Nrf2/Keap-1 by electrophiles, and/or other pathways. Consequently, antioxidant enzymes are induced and act in an anti-inflammatory function in vivo. Thus, AX suppresses the exacerbation cycle of chronic inflammation and shifts the cycle toward improvement. The regulation of these inflammation-related signaling pathways by AX involve a mixture of acute-phase responses to AX that result from ROS scavenging, modulation of phosphorylation and protein modifications related to the regulation of intracellular Redox balance, modulation of adaptor protein association with receptors, and the more chronic induction of gene expression mediated by these results. In this figure, lipid rafts and precise and detailed signal pathways are not shown to avoid complications. In particular, it has been reported that AX affects the points indicated by the orange arrows. This figure was adapted from the reference [70,71].
AX regulates various mitochondria-associated metabolic pathways, mitochondrial biogenesis and its quality control via AMPK activation. (A) AMPK is activated by exercise, energy depletion, or certain active drugs (e.g., AICAR, adiponectin, metformin and imeglimin) by (1) increased Ca2+ influx; (2) direct modification by ROS and activation of MAPKs; and (3) increased AMP/ATP ratio. Activated AMPK induces activation of PGC-1α and related gene expression, leading to enhanced energy metabolisms, adapted metabolic switching, and increased mitochondria biogenesis. Furthermore, AMPK regulates gene expression of Nampt and promotes de novo synthesis of NAD+ in the cell. As a result, it enhances the activity of Sirtuins and further enhances the activity of PGC-1α. Thus, AMPK/Sirtuins/PGC-1α forms a positive feedback loop in their actions. (B) AMPK contributes to mitochondrial quality control; AMPK not only enhances mitochondrial biogenesis, but also regulates mitochondrial fission and fusion via phosphorylation of Mef, and induces mitophagy in autophagosomes via the phosphorylation of Ulk-1 for the impaired mitochondria. AX activates AMPK. In particular, it has been reported that AX affects the points indicated by the orange arrows. In this figure, precise and detailed signal pathways are not shown, to avoid complications. This figure was adapted from the reference [116,133,134].
Human clinical studies with astaxanthin (AX) that examined oxidative stress markers.

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Astaxanthin as a Novel Mitochondrial Regulator: A New Aspect of Carotenoids, beyond Antioxidants

December 2021

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591 Reads

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65 Citations

Astaxanthin is a member of the carotenoid family that is found abundantly in marine organisms, and has been gaining attention in recent years due to its varied biological/physiological activities. It has been reported that astaxanthin functions both as a pigment, and as an antioxidant with superior free radical quenching capacity. We recently reported that astaxanthin modulated mitochondrial functions by a novel mechanism independent of its antioxidant function. In this paper, we review astaxanthin’s well-known antioxidant activity, and expand on astaxanthin’s lesser-known molecular targets, and its role in mitochondrial energy metabolism.


Astaxanthin for improved muscle function and enhanced physical performance

January 2021

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91 Reads

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5 Citations

This chapter describes the reported functions of natural astaxanthin on muscle physiology and performance. The first section discusses oxidative stress in skeletal muscle during exercise and how natural astaxanthin interacts with the endogenous antioxidant system. It further gives an insight into how astaxanthin is incorporated into cell membranes, particularly within the mitochondria, describing the effects seen on mitochondrial functions such as ATP production and fat metabolism. The following section describes the results seen in clinical trials on muscle endurance and muscle strength in populations ranging from well-trained young people to the elderly. This also includes the additional outcomes of natural astaxanthin on exercise in connection with sarcopenia. Finally, it covers the impact of astaxanthin on muscle recovery and the reduction in exercise-induced inflammation.

Citations (3)


... Reports have suggested that astaxanthin has the ability to cross the blood-brain barrier, thereby working to reduce free radical-induced neurotoxicity and memory loss, and its anti-inflammatory properties indicate it has cardioprotective benefits and has woundhealing, neuroprotective, hepatoprotective, and osteoprotective properties [18][19][20][21]. The natural form of astaxanthin is normally esterified and has been observed to exhibit higher bioactivity than synthetic astaxanthin [22][23][24][25][26]. Astaxanthin incorporated into omega-3rich products can provide synergistic antioxidative and anti-inflammatory benefits [27][28][29] and also improve omega-3 oil storage stability [30][31][32][33]. ...

Reference:

Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
Astaxanthin: Past, Present, and Future

Marine Drugs

... Accumulating evidence has underscored mitochondrial fission as a crucial process for maintaining metabolic homeostasis, with its dysregulation implicated in various metabolic disorders like obesity [67]. Nishida et al. reviewed the molecular targets of AST and indicated that AST improved mitochondrial stability and enhanced mitochondrial function through activation of the AMPK/Sirtuins (SIRTs)/PGC-1 pathway in mice [68]. In addition, AMPK controls mitochondrial quality by facilitating mitochondrial biogenesis, regulating mitochondrial fission and fusion via phosphorylation of Mef, and inducing mitophagy through phosphorylation of Ulk-1 in damaged mitochondria [69][70][71]. ...

Astaxanthin as a Novel Mitochondrial Regulator: A New Aspect of Carotenoids, beyond Antioxidants

... With regard to performance enhancement, it appears that individuals training for endurance events may benefit the most from AX supplementation. While a few well-written reviews on the benefits of AX supplementation and exercise performance exist [9,24], the purpose of this review is to briefly outline the training adaptations that follow from endurance exercise and then detail the role of AX in mitochondrial regulation, specifically as it relates to potentially improving endurance performance and enhancing mitochondrial training adaptations in the endurance athlete. After its discovery and approval as a dietary supplement, a series of animal studies followed demonstrating the biological and antioxidative properties of AX [18]. ...

Astaxanthin for improved muscle function and enhanced physical performance
  • Citing Chapter
  • January 2021