China
Africa
Explore chapters and articles related to this topic
The Role of Plant-Based Natural Compounds in Inflammation
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Marcela Dvorakova, Premysl Landa, Lenka Langhansova
Twenty-three naturally occurring quinones were tested for their ability to inhibit COXs and 5-LOX. In the case of COXs, shikonin (a major constituent of the root extracts of Alkanna tinctoriaTausch., Lithospermum erythrorhizon Sieb. Et Zucc or Arnebia euchroma (Royle) Johnst.) and primin (found in Miconia sp.) exerted sub-micromolar inhibitory activity toward COX-2 (IC50 = 0.33 µM and 0.09 µM, respectively) and moderate inhibitory activity toward COX-1 (IC50 = 1.91 µM and 5.14 µM, respectively) (Landa et al., 2012). In addition, four other naturally occurring naphthoquinones (juglone, 7-methyljuglone, alkannin and diospyrin), all displayed good inhibitory activities toward COXs with IC50 values in the range of 1.39–2.50 µM for COX-1, and 0.55–1.58 µM for COX-2, with diospyrin (found in Diospyros sp, Figure 22.7D) giving the best values (Landa et al., 2012). In the case of 5-LOX, the lowest IC50 values in the cell-based assay (4.0 µM and 4.1 µM), corresponding to the IC50 value of the reference inhibitor Zileuton (IC50 = 4.1 µM), were obtained for benzoquinones primin and thymohydroquinone (found in Nigella sativa L. seeds), respectively. Thymoquinone, the unreduced form of thymohydroquinone, displayed only low inhibitory activity with IC50 = 18.2 µM. In addition, similarly, low inhibitory activity was observed for the naphthoquinone shikonin (IC50 = 24.3 µM) (Landa et al., 2013).
Ultraviolet and Light Absorption Spectrometry
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Zoltan M. Dinya, Ferenc J. Sztaricskai
The antibiotics of this family are structurally related to the quinones, such as polycyclic, naphtho- and benzoquinones, and quinonelike compounds. From a practical point of view the most important representatives are antibiotics with a naphthacene skeleton, or, as they are also called the tetracyclines.
Natural Products as Economical Agents for Antioxidant Activity
Published in Hafiz Ansar Rasul Suleria, Megh R. Goyal, Masood Sadiq Butt, Phytochemicals from Medicinal Plants, 2019
Nida Nazar, Abdullah Ijaz Hussain, Syed Makhdoom Hussain, Poonam Singh Nigam
Quinones are class of compounds having aromatic rings with ketone substitutions as shown in Figure 8.1b. These compounds are reactive and abundant in nature. Being colored in nature during cutting or damaging of food fruit and vegetables, these compounds are accountable for the browning reactions. For example, in human skin during melanin biosynthetic pathway it acts as an intermediate.130 It retains dyeing property due to presence in henna (tree).43
Potential of the natural products against leishmaniasis in Old World - a review of in-vitro studies
Published in Pathogens and Global Health, 2020
Sofia Cortes, Carolina Bruno de Sousa, Thiago Morais, João Lago, Lenea Campino
Plant extracts and their derivatives are well known as sources of compounds that could achieve high biological activities, including against Leishmania parasites [64]. In this review 86 isolated compounds exhibiting antileishmanial activity against one or both parasite life forms of different parasite species were listed (Table 1). This review shows that identified metabolites are chemically diverse, comprising different chemical families. These include alkaloids such a quinazoline derivative (1), terpenoids such as sesquiterpenes (2–8), diterpenes (9–11) and triterpenes (12–22). Lignoids have been described as lignans (23–27) and neolignans (28–30). Minor phenylpropanoids (31–36) and a phenylethanoid (37) were identified. Other aromatic compounds have also been described, as iridoids (38–41), a diarylheptanoid or curcumin (42) and its derivatives (43–45), hydrolyzable tannins (46–50). From the chemical family of quinones, several compounds were studied as benzoquinones (51–53), hydroquinones and derivatives (54–61), naphthoquinones (62–65) and isoflavanquinones (66–68). Flavonoids known as flavones (69–72), a coumarin (73), benzoic acid derivatives (74, 75), steroids (76–84) and triacylglycerols (85, 86) have also been described.
Bioactivation of herbal constituents: mechanisms and toxicological relevance
Published in Drug Metabolism Reviews, 2019
Quinone and precursors are naturally abundant in herbal and dietary products. There are three major pathways by which electrophilic quinone intermediates are formed from their precursors such as catechols, hydroquinones, phenols and alkoxy aromatics; direct two electron enzymatic oxidation or two successive one electron oxidations of the parent catechols or hydroquinones respectively, ortho- or para-hydroxylation of phenols followed by oxidation of formed catechols or hydroquinones, and O-dealkylation of alkoxy aromatics and oxidation of the resulting catechols or hydroquinones. Biological properties of quinone precursors are often mediated by their oxidative metabolism to quinones. Once formed, the quinone intermediates have a variety of biological targets in vivo capable of inducing cytotoxic and genotoxic responses as well as triggering cytoprotective and chemopreventive mechanisms via induction of detoxification enzymes and modulation of redox status (Bolton and Dunlap 2017).
Zinc-dependent and independent actions of hydroxyhydroquinone on rat thymic lymphocytes
Published in Drug and Chemical Toxicology, 2019
Honoka Wada, Keisuke Oyama, Risa Kamae, Toshiya Masuda, Kaori Kanemaru, Kumio Yokoigawa, Yasuo Oyama
Quinones exert various simple and complex actions on cells, inducing cytoprotective and cytotoxic actions (Bolton and Dunlap 2017). Therefore, it is not surprising that micromolar concentrations of HHQ seem to exert both beneficial and adverse actions on rat thymocytes. HHQ at 3–30 µM almost completely inhibited the H2O2-induced increase in cell lethality (Figure 4), although at 30 µM, it significantly decreased [GSH]i (Figure 3). One may argue the possibility that HHQ decomposes H2O2, resulting in reduced oxidative stress. However, this is unlikely because of the following reasons. H2O2 also exerts high nucleophilicity, and can attack olefins to produce oxidation products. Although this reaction requires conjugated electron-withdrawing groups, HHQ has no electron-withdrawing group in its structure. Therefore, the possibility of direct reaction between H2O2 and HHQ is very low.