China
Africa
Explore chapters and articles related to this topic
Pharmacological actions of chemical constituents
Published in C. P. Khare, Evidence-based Ayurveda, 2019
Cardiac glycosides are found in several plants, including foxglove (Digitalis purpurea), lily of the valley (Convallaria majalis), oleander (Nerium oleander), yellow oleander (Thevetia peruviana), Strophanthus kombe/gratis/gratus seeds, squill (Urginea maritima/sea onion/indica bulbs), Digitalis lanata, dogbane (Apocynum cannabinum) and Adonis vernalisare. Medical professions prefer foxglove, while most of the herbalists prefer lily of the valley. Due to structural differences, the glycosides in the lily of the valley have less potential for cumulative poisoning.
Apocynin protects retina cells from ultraviolet radiation damage via inducing sirtuin 1
Published in Journal of Drug Targeting, 2020
Feng Liu, Chen Lin, Jinsheng Hong, Chuanshu Cai, Weijian Zhang, Jianrong Zhang, Lihong Guo
Apocynin is one of the main bioactives found in the roots of Canadian hemp (Apocynum cannabinum), which was used to treat heart problems and dropsy. It is a naturally occurring methoxy-substituted catechol with a molecular weight of 166.17 Da (Figure 1(A)). It is wildly recognised as a specific inhibitor of nicotinamide-adenine dinucleotide phosphate (NADPH)-oxidase complex in many cell types including both non-phagocytic and phagocytic cells [7]. Though its inhibitory mechanism is not fully understood, Apocynin has been shown to reduce both the membrane translocation and the expression level of neutrophil cytosol factor 1 (p47phox), a cytosolic component of NADPH complex [8]. The membrane translocation of p47phox is required for the activation of NAPDH-oxidase, which functions as a transmembrane electrogenic enzyme that catalyses the production of reactive oxygen species (ROS) [9,10]. The inhibition of NADPH-oxidase activation by Apocynin leads to the decreased production of ROS in the cells. For example, Apocynin can reduce ROS production in activated neutrophils with a half maximal inhibitory concentration (IC50) of 10 µM, though it has no impact on phagocytosis or other intracellular defensive mechanisms [11].
Opportunities for future therapeutic interventions for hyperoxaluria: targeting oxidative stress
Published in Expert Opinion on Therapeutic Targets, 2019
We have recently reviewed inhibitors of NADPH oxidase and refer readers to the review [31]. List of a number of chemicals that inhibit ROS production by NADPH oxidases is provided here in Table 1. The table also describes their mode of action and pharmacologic effects. The two most studied NADPH oxidase inhibitors are apocynin and diphenyleneiodonium chloride (DPI). Apocynin, first extracted from the roots of Apocynum cannabinum was found to block the association of cytoplasmic p47phox with membrane-bound p22phox in leukocytes, monocytes, and endothelial cells. It is also a scavenger of hydrogen peroxide. Results of our studies have shown that apocynin can reverse hyperoxaluria induced activation of the NADPH oxidase system in rat kidneys indicating its general antioxidant properties [58]. DPI acts by taking electrons from electron transporter and creating a radical which blocks the appropriate transporter of electrons through a covalent binding. DPI action appears to be non-specific towards as far as various isoform concerned. It can partially or completely inhibit a variety of enzymes including iNOS, xanthine oxidase, and NADPH oxidase.
Pharmacology of apocynin: a natural acetophenone
Published in Drug Metabolism Reviews, 2021
Shreya R. Savla, Ankit P. Laddha, Yogesh A. Kulkarni
Apocynin is an acetophenone (Figure 1) having a molecular weight of 166.17 g, a melting point of 115 °C, and forms needle-shaped crystals in water, It has a faint odor similar to vanilla. It was isolated first from the roots of Canadian hemp (Apocynum cannabinum) by Horace Finnemore (Finnemore 1908). Its extracts found use in the official therapeutic preparations for cases of heart ailments and dropsy. The identification of apocynin took place during a study focusing on the isolation of constituents having immune-modulatory activity from Picrorhiza kurroa (family Scrophulariaceae). It was identified in roots of a native plant found growing in mountainous regions of India, Pakistan, Nepal, and Tibet (Hougee et al. 2006; Luchtefeld et al. 2008). An important discovery led to the idea of apocynin as a pro-drug. It has been proposed that apocynin gets converted to its dimer, diapocynin, in vivo, which is the active form (Johnson et al. 2002). Apocynin is primarily reported as a potent NOX 2 inhibitor. It prevents the translocation of cytosolic subunits of NOX 2 to the membrane and inhibits its activation (Peters et al. 2001; Barbieri et al. 2004). It has been noted that activation of apocynin by conversion into its dimer is required for NOX 2 inhibiting activity and this activation takes place by the action of enzymes known as myeloperoxidases (MPOs) (Simons et al. 1990). The process of activation involves the formation of apocynin free radicals, produced by the reaction with hydrogen peroxide and MPO. The radical causes oxidation of thiols present in the NOX enzyme (Clark et al. 1990; Johnson et al. 2002).