Low-level chemiluminescence is produced in a hydrogen peroxide (H(2)O(2))/gallic acid/haemoprotein system with single broad peaks around 520 nm, regardless of the biological role of the haemoprotein. The free haem iron systems (haemin and haematin systems) gave a higher photon intensity (1.5 x 10(4) and 2.0 x 10(4) cps) than that of the H(2)O(2)/gallic acid/haematoporphyrin system. These results indicated that haem iron plays a significant role in the photon emission of haemoprotein systems. A free radical with a g value of 2. 0058 was detected through a direct electron spin resonance (ESR) method. The photon intensity of the H(2)O(2)/gallic acid/haemoprotein system decreased in the order: HRP > cytochrome c > myoglobin > haemoglobin, and this corresponded to the decrease in radical intensity. These results indicated that the formation of the free radical with a g value of 2.0058 may be the key step for chemiluminescence in the H(2)O(2)/gallic acid/haemoprotein system. A quartet line similar to DMPO-OH adducts and uncomplexed free radicals (g = 2.0058) was detected using the ESR spin-trapping method in the H(2)O(2)/gallic acid/cytochrome c system.

Electron Spin Resonance Spectroscopy↗

PubMedDate not supplied

Chemiluminescence of adzuki bean and soybean seedlings.

The chemiluminescence of extracts from leguminous seedlings (adzuki bean and soybean) was investigated. In an H(2)O(2)/gallic acid/water extract system, the photon intensities of adzuki bean seedlings were increased after germination and in the hypocotyls it reached a maximum level during the first 4 days of germination. On day 4 after germination, chemiluminescence in the primary leaf part exhibited the strongest intensity. Emission spectra showed a main peak at 510 nm, with shoulders at 660 nm. Mechanical injuries to the stems and cotyledons resulted in about a 1.5- and 6.8-fold increase of chemiluminescence, respectively. In an H(2)O(2)/70% EtOH extract/HRP system, photon intensities increased after germination and reached a maximum level during the first 2 days of germination. On day 4 after germination, chemiluminescence in the root and leaf area was stronger than in any other area. Emission spectra showed a main peak at around 570 nm, with shoulders at around 660 nm. The photon intensities of stems and cotyledons after mechanical injuries resulted in about an 0.72-fold decrease and an 8.8-fold increase in the presence of H(2)O(2) and acetaldehyde (MeCHO), respectively.

Fabaceae↗

PubMedDate not supplied

Screening of chemiluminescence constituents of cereals and DPPH radical scavenging activity of gamma-oryzanol.

The chemiluminescence (CL) constituents of cereals were detected by CL using the H(2)O(2)-acetaldehyde system. The cereals tested, such as rice, millet and sorghum, exhibited various levels of CL activity. The gamma-oryzanol fraction was extracted from brown rice and separated into four constituents by HPLC. The four constituents were identified as cycloartenyl ferulate, 24-methylenecycroartanyl ferulate, campesteryl ferulate and beta-sitosteryl ferulate. Free radical scavenging activities with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and CL intensities of four constituents (gamma-oryzanol components) were measured and compared with that of gallic acid, which is a typical free radical scavenger. Four constituents scavenged DPPH radicals and scavenging activities were proportional to CL intensities. Concentrations of four CL constituents required to quench 50% (IC(50)) of the free radicals ranged from 0.9 to 1.1 mmol/L. We demonstrated that measurement of CL intensities was a rapid and convenient method for screening DPPH radical scavenging activities of rice.

Bepridil↗