Diversity and Utilization of Marine Cyanobacteria
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
Cyanobacteria in general and marine forms in particular are the richest sources of known and novel bioactive compounds including toxins with wide pharmaceutical applications (Carmichael, 1992; Becker, 1994; Patterson, 1996). Gustafson et al. (1989) reported anti-HIV activity of some marine cyanobacterial compounds from Lyngbyalager heimii and Phormidium tenue. A massive program of screening the extracts from the large culture collection of marine cyanobacteria in NFMC for anti-viral, anti-bacterial, anti-fungal and immuno-modulatory activities has been going on with great success. A compound has been purified from marine Oscillatoria laete-virians BDU20801 showing anti-candidal activity (Deth, 1999). A compound with immunopotentiating and male anti-fertility properties, without being toxic to other systems in a mice model, was reported to occur in the crude and partially purified extracts of Oscillatoria willei BDU130511 (Raghavan et al., 2002). Medically important gamma linolenic acid (GLA) is relatively rich in the cyanobacteria Spirulina platensis and Arthrospira sp. (Watenabe and Yamamoto, 1972; Cohen et al., 1987). This is converted into arachidionic acid and into prostaglandin E2 in the human body (Euler and Eliassen, 1967). `Prostoglandin E2 has a lowering action on blood pressure and the contracting function of smooth muscles. It plays a very important role in lipid metabolism.
Introduction to Infection, Resistance, and Immunity
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
The "weal and flare" that results from a minor skin scratch illustrates the speed, potency, and features of an infiammatory response. This reaction is characterized by redness, swelling, heat, and pain. Redness and heat are due to an increase in blood flow to the site of infiammation and result from local vasodila tion caused by chemical mediators produced in response to tissue damage. Swelling is due to leakage of blood fluids into the site of infiammation as a result of mediator- induced changes in the permeability of endothelial cells lining local blood vessels. Pain is due to tissue destruction exacerbated by proteolytic enzymes, lipolytic enzymes, and reactive oxygen intermediates released from cells (neutrophils, macrophages) that are recruited from the blood circulation into the inflammatory site. Prostaglandin E2 that is produced at the site of inflammation enhances sensitivity of local nerve cells also contributing to pain associated with inflammation. Pain itself is a defense mechanism. It calls attention to the damaged site and induces behavioral responses aimed at limiting damage and inducing avoidance of damaging behavior.
Micronutrients in Healthy Aging and Age-Related Decline in Organ Functions
Kedar N. Prasad in Micronutrients in Health and Disease, 2019
The activity of glutathione peroxidase in the brain and Cu/Zn SOD in the heart showed no significant changes in enzyme activity in rats as a function of aging.89 However, in other organs such as the liver, brain, and heart, a decrease in catalase activity was reported.89 Prostaglandin E2 (PGE2) is one of the toxic products released during chronic inflammation. PGA1, which is formed during extraction of PGE2, is stable and used in experimental systems. We have reported that PGA1-induced degeneration of murine differentiated neuroblastoma cells increased the expression of catalase gene, decreased the expression of glutathione peroxidase and Mn-SOD genes without changing the expression of Cu/Zn-SOD as determined by gene array and confirmed by real time PCR.90 The protein levels of glutathione peroxidase increased, whereas the protein level of Mn-SOD decreased and the levels of catalase and Cu/Zn-SOD did not change as determined by the Western blot.90
Pharmacological effects of protocatechuic acid and its therapeutic potential in neurodegenerative diseases: Review on the basis of in vitro and in vivo studies in rodents and humans
Published in Nutritional Neuroscience, 2019
Kinga Krzysztoforska, Dagmara Mirowska-Guzel, Ewa Widy-Tyszkiewicz
Enzymes commonly associated with inflammatory processes include cyclooxygenases, which are molecular targets for NSAIDs. Cyclooxygenases (COXs) exist in two major isoforms, namely COX-1 and COX-2, and are the central enzymes in the synthetic pathway of prostanoids (prostaglandins, prostacyclins and thromboxanes) and leukotrienes from arachidonic acid. Whereas COX-1 is constitutively expressed in almost all tissues, COX-2 is an inducible enzyme produced in certain conditions (elevated levels are observed i.a. in inflammation) and unexpressed in normal conditions in most cells. COX-2-dependent production of prostaglandin E2 (PGE2) takes place in injured and inflammatory cells and is increased in many diseases.15,44 Another enzyme linked with propagation of inflammatory response is inducible nitric oxide synthase – iNOS since excess of iNOS-produced nitric oxide (NO) participates in provoking inflammatory processes.39 Inhibition of NO via iNOS overproduction seems to be an interesting target for the novel anti-inflammatory therapies.
Investigational drugs targeting prostaglandin receptors for the treatment of glaucoma
Published in Expert Opinion on Investigational Drugs, 2018
Artemis Matsou, Eleftherios Anastasopoulos
Prostaglandin E2 (PGE2) is a classic potent inflammatory mediator, that is also associated with significant side effects, particularly the risk of blood-aqueous barrier disruption making this prostaglandin less attractive than PGF2 [25]. It has high affinity for all four EP receptor subtypes. Each receptor subtype has distinct tissue localization and activates different downstream signaling pathways. EP receptor binding has demonstrated efficacy in reducing IOP by increasing uveoscleral outflow and inducing morphological alterations in the conventional pathway, thus offering encouraging results for the use of EP agonists as IOP lowering agents [26]. The EP2 receptor has been found widely distributed in several ocular structures, including tissues closely associated with aqueous humor regulation, such as the cells lining the Schlemm’s canal, ciliary muscle and trabecular meshwork, as well as more superficial structures such as the corneal epithelium [27]. EP3 and EP4 receptors are also localized throughout the entire trabecular meshwork, the corneal endothelium and conjunctival cells. EP1 is predominantly expressed in TM cells, Sclemm’s canal and corneal epithelium. While EP receptor agonists, particularly EP2, had been associated with greater hypotensive effect in early preclinical studies, their heavy proinflammatory ability established F2α agonists as the preferred agents. Subtype-selective EP receptor agonists are an interesting and promising option in the arena of PG analogs for IOP control, achieving good IOP control while overcoming the unwanted inflammatory effects of native PGE2.
Pro-resolving lipid mediators as therapeutic leads for cardiovascular diseases
Published in Expert Opinion on Therapeutic Targets, 2019
Two cycooxygenases (COXs), COX-1 (a constitutive form) and COX-2 (an inducible form), respectively, catalyze the conversion of AA to PGs. PGs is a class of an unsaturated fatty acid with 20 carbon atoms, and the basic framework of PG is alkyl acid with a cyclopentane core and two side chains. Based on the five-membered ring or the entire molecular structure, PGs are divided into 10 subclasses. Of these subclasses of PGs, prostaglandin D, E, F, G, H and I are known to play an important role in the process of inflammation [7]. Specifically, prostaglandin E2 (PGE2) is well-known pro-inflammatory lipid mediator produced by prostaglandin E synthase in leukocytes. Thromboxanes are derived from prostaglandin H2 (PGH2) by thromboxane synthase (TXS) in platelets. Thromboxanes regulate thrombus formation platelet aggregation and vascular constriction in acute myocardial infarction [12,13].
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