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Influence of Light on Essential Oil Constituents
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Marie-Christine Cudlik, Gerhard Buchbauer
Khayyat and Roselin, 2018). The main chemical components of most EOs are terpenoids (like monoterpenes and sesquiterpenes) as well as phenolic compounds, all of them characterized by low molecular weight (Dhifi et al., 2016). In case of oxygen availability, photooxidation is the most important possible photochemical reaction. Furthermore, double-bond isomerization, photopolymerization, Diels-Alder photocycloaddition and photoepoxidation are prevalent transformation pathways for EO constituents under influence of light. Often, neither light nor oxygen alone can trigger chemical reactions in EOs; they work synergistically (Li et al., 2016). Some transformations occur only when energy is provided in the form of radiation, and oxygen can be taken from the air surrounding. This close relationship between these two factors renders it difficult to differentiate between them and to draw a line as to which is more important in triggering reactions.
Mucocutaneous Side Effects
Published in Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish, Retinoids in Dermatology, 2019
Tugba Kevser Uzuncakmak, Ayse Serap Karadag
Retinoid associated photochemical reactions are an issue of concern in several research fields including photochemistry, spectroscopy, and photobiology (35). Such reactions may be classified as photoisomerization, photopolymerization, photooxidation, or photodegradation and may present as photoallergic, photoirritant, and phototoxic clinical responses. The knowledge about the exact mechanism is very limited; however, many patients complain about a decreased tolerance to UV radiation shortly after sun exposure during treatment with retinoids (36). Such photosensitivity is more common with isotretinoin and etretinate and probably is related to the reduction in the thickness of the stratum corneum. Also, the incidence and severity of these reactions are dependent on different factors, including the type of product, vehicle, retinoid concentration, dosage and wavelength of the light, and photoirradiation time (35,36).
Marine-Algal Bioactive Compounds
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Iahtisham Ul-Haq, Masood Sadiq Butt, Natasha Amjad, Iqra Yasmin, Hafiz Ansar Rasul Suleria
Marine organisms are vital in the production of cosmeceutical and pharmaceutical compounds. Certain compounds from marine organisms are of significant importance to protect against the harmful effects of ultraviolet (UV) radiations and photoaging complications (Pallela et al. 2010). Photo-oxidation of living fragments particularly in skin cells is a prominent phenomenon involved in oxidative stress that primarily involves interaction of ultraviolet radiations which have strong oxidative properties (Cardozo et al. 2011). In this context, phlorotannins including dieckol and eckol from E. cava have exhibited strong protective effects to reduce the damages caused by exposure to a spectrum of light. The compounds can lower the intracellular ROS arising from γ-rays exposure. Furthermore, DNA damage and lipid peroxidation in membranes due to exposure to radiations is curtailed by eckol administration. Based on scientific evidences, it can be stated that phlorotannins possess consequential competencies to reduce skin damage arising from oxidative stress induced by radiations. Further, these compounds can profoundly be utilized in pharmaceutical, functional foods and cosmetic industries to alleviate skin damages (Li et al. 2011a).
Trends in research on corneal cross linking from 2001 to 2020: a bibliometric analysis
Published in Clinical and Experimental Optometry, 2023
Shaopei Wang, Kaili Yang, Yawen Wang, Liyan Xu, Yuwei Gu, Qi Fan, Meng Zhu, Qing Wang, Kai Guo, Shengwei Ren, Dongqing Zhao
Cluster # 5 (purple) represents keywords related to CXL in the treatment of infectious keratitis, such as ‘ultraviolet-a’, ‘infectious keratitis’, ‘therapy’, ‘bacterial keratitis’, and ‘fungal keratitis’. Infectious keratitis is a serious vision-threatening disease that can be caused by bacterial, viral, fungal or protozoal infections.34,35 CXL hardens the stroma of the cornea, increasing its resistance to enzymatic degradation caused by microorganisms and thus arresting the progression of corneal melting.36,37 Furthermore, the Reactive Oxygen Species produced by the cross-linked photooxidation react with the intracellular components of the microorganism, resulting in cell inactivation and death.38 Clinical studies revealed that CXL combined with an antimicrobial treatment is effective in the treatment of bacterial, fungal and acanthamoeba keratitis compared with the effect of the standard antimicrobial therapy alone. However, it may aggravate or activate the infection by herpes simplex virus and should not be used to treat viral keratitis.39,40
In silico prediction of post-translational modifications in therapeutic antibodies
Published in mAbs, 2022
Studies on the impact of pKa on the risk of His oxidation have yielded inconsistent results. For example, Amano et al. reported no correlation between pKa of His residues and His oxidation,82 whereas Miyahara et al. reported His residues with lower pKa values were more prone to photooxidation.88 The discrepancy in the reported role of pKa on His oxidation could be due to the different stress conditions (i.e., MCO versus UVC light exposure) used in these studies and the different by-products formed after the stress condition (i.e., oxo-His versus Asn and Asp residues). Compared to Met and Trp oxidation, in silico prediction of His oxidation is understudied.49 Future studies could investigate the impact of pKa on His oxidation for different types of oxidative stress (e.g., photooxidation versus MCO).
Topical delivery of l -ascorbic acid spanlastics for stability enhancement and treatment of UVB induced damaged skin
Published in Drug Delivery, 2021
Mona Elhabak, Samar Ibrahim, Samar M. Abouelatta
No change in color was reported after 6 months. Mean and standard deviation comparison was carried out using one-way ANOVA followed by the Post-hoc test using graph pad software. Spanlastics did not show any significant change (p > .05) in PS, PDI or zeta potential excluding aggregation (Table 2). Furthermore, no significant change (p > .05) in %EE was determined confirming LAA stability. Vitamin C in topical formulations undergoes photooxidation as well as chemical oxidation in dark. The entrapment of LAA inside the hydrophilic core of nanovesicles protected the vitamin from surrounding aqueous media and hence prevented its oxidation and subsequent degradation. Farahmand et al., showed the highest protection of LAA when formulated in W/O/W multiple emulsions. It also demonstrated that the formation of mixed micelles and the entrapment of LAA in the hydrophilic head of surfactant might have a crucial role for LAA stability (Farahmand et al. 2006).