Biomaterial Database

The mechanisms of ROS-photogeneration by berberine, a natural isoquinoline alkaloid. 2010

Liang Shen, and Hong-Fang Ji

Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Center for Advanced Study, Shandong University of Technology, Zibo 255049, PR China.

The reactive oxygen species (ROS)-photogenerating mechanisms of berberine (BER) have been elucidated based on the time-dependent density functional theory calculated triplet excited (T(1)) state characters in explicit solvent models. The lowest triplet excitation energy of BER is obtained for the first time. Mechanistic analysis reveals the strong dependence of 1O2 and O2(.-) generation on the solvent polarity. Through direct energy transfer pathway from T(1) state BER to 3O2, 1O2 can be photogenerated both in benzene and ethanol. Nevertheless, O2(.-) can be given birth to only in ethanol through two pathways, i.e., direct electron transfer from T(1) state BER and electron transfer from BER(.-) (formed through autoionization reactions) to 3O2. The findings also provide clues to explaining the much higher 1O2-yield of BER in nonpolar than in polar solvents.

UI	MeSH Term	Description	Entries
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D011789	Quantum Theory	The theory that the radiation and absorption of energy take place in definite quantities called quanta (E) which vary in size and are defined by the equation E	Quantum Theories,Theories, Quantum,Theory, Quantum
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D001599	Berberine	An alkaloid from Hydrastis canadensis L., Berberidaceae. It is also found in many other plants. It is relatively toxic parenterally, but has been used orally for various parasitic and fungal infections and as antidiarrheal.	Umbellatine
D012997	Solvents	Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)	Solvent
D017319	Photosensitizing Agents	Drugs that are pharmacologically inactive but when exposed to ultraviolet radiation or sunlight are converted to their active metabolite to produce a beneficial reaction affecting the diseased tissue. These compounds can be administered topically or systemically and have been used therapeutically to treat psoriasis and various types of neoplasms.	Photosensitizer,Photosensitizers,Photosensitizing Agent,Photosensitizing Effect,Photosensitizing Effects,Agent, Photosensitizing,Agents, Photosensitizing,Effect, Photosensitizing,Effects, Photosensitizing
D017382	Reactive Oxygen Species	Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of SIGNAL TRANSDUCTION and GENE EXPRESSION, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.	Active Oxygen Species,Oxygen Radical,Oxygen Radicals,Pro-Oxidant,Reactive Oxygen Intermediates,Active Oxygen,Oxygen Species, Reactive,Pro-Oxidants,Oxygen, Active,Pro Oxidant,Pro Oxidants,Radical, Oxygen
D055668	Photochemical Processes	Chemical reactions effected by light.	Processes, Photochemical