A peroxidase/phenolics/ascorbate system can scavenge hydrogen peroxide in plant cells

Abstract

The function of a peroxidase/phenolics/ascorbic acid system in plant vacuoles has not yet been well elucidated. We wished to study the redox reactions among hydrogen peroxide, phenolics and ascorbic acid (AA) in the presence of horseradish peroxidase. Horseradish peroxidase oxidized rutin and chlorogenic acid (CGA), compounds present in many kinds of plant. The oxidation was inhibited by AA. As a result of the inhibition. AA was oxidized and when almost all of it had been oxidized, oxidation of the phenolics commenced. Monodehydroascorbic acid (MDA) radical was detected during the oxidation of AA, suggesting that the inhibition of oxidation of rutin and CGA was due to reduction of phenoxyl radicals by AA. By comparison of time courses of changes in levels of AA and MDA radicals, and by kinetic calculation, it is suggested that in addition to AA, MDA radicals may also reduce phenoxyl radicals. It is proposed that the peroxidase/phenolics/AA system can function as a hydrogen peroxide scavenging system.

Exogenously applied polyamines increase drought tolerance of rice by improving leaf water status, photosynthesis and membrane properties

“…As evident from close correlations of growth and net photosynthesis with water relations attributes (Table 6), it is believed that PAs have the ability to improve the cell water status thereby allowing rice to grow better under limited moisture supply conditions. Foliar applied PAs due to their ability to act as growth regulator is able to modulate the plant metabolism and the production of metabolites involved in stress tolerance (Takahama and Oniki 1997). In this study, PAs application led to accumulation of high levels of free proline, soluble phenolics and anthocyanins, whilst curtailing the production of H 2 O 2 and MDA and reducing the relative membrane permeability (Table 4).…”

Transcription profile of soybean-root-knot nematode interaction reveals a key role of phythormones in the resistance reaction

“…Although it is widely recognized that PCs are involved in the H 2 O 2 scavenging cascade in plant cells [57], it was only recently that their accumulation was postulated to form part of an integrated redox system, quenching ROS and contributing to stress tolerance [45,58]. The model proposed to integrate PCs into a redox system is supposed to largely depend on cellular nucleotide sugar concentrations.…”

Environmental trends in the variation of biologically active phenolic compounds in Labrador tea, Rhododendron groenlandicum, from northern Quebec, Canada

“…But when plants suffer from photoinhibition, photosynthetically active photon flux density may be in excess of what is necessary for CO 2 assimilation and can generate an increase in reactive oxygen species (Carvalho and Amâncio 2002;Bhattacharjee 2011). Free or cell-wall-bound phenolic compounds act as antioxidants because of their capacity to efficiently inactivate reactive oxygen species (Rice-Evans et al 1997;Takahama and Oniki 1997;Nara et al 2006), therefore preventing photodamage in periods of high oxidative stress. Such activity may not only be beneficial to the plant, but may have a favourable impact on chronic diseases in humans such as type 2 diabetes (T2D) (McCune and Johns 2007;Sancho and Pastore 2012).…”