Green light radiation effects on free radicals inhibition in cellular and chemical systems

https://doi.org/10.1016/j.jphotobiol.2010.09.003Get rights and content

Abstract

Free radicals generation is inhibited through green light (GL) irradiation in cellular systems and in chemical reactions. Standard melanocyte cultures were UV-irradiated and the induced cellular reactive oxygen species (ROS) were quantified by the fluorescence technique. The same cell cultures, previously protected by a 24 h GL exposure, displayed a significantly lower ROS production.

A simple chemical reaction is subsequently chosen, in which the production of free radicals is well defined. Paraffin wax and mineral oil were GL irradiated during thermal degradation and the oxidation products checked by chemiluminescence [CL] and Fourier transform infrared spectra [FT-IR].

The same clear inhibition of the radical oxidation of alkanes is recorded. A quantum chemistry modeling of these results is performed and a mechanism involving a new type of Rydberg macromolecular systems with implications for biology and medicine is suggested.

Introduction

This paper presents a novel experimental result: green light (GL) irradiation inhibits free radicals generation, during the process of ultraviolet (UV) denaturation in cellular systems and inhibits the free radicals generation in chemical systems. Effects of visible light on biological and chemical systems have been frequently reported in the literature. Stimulatory effects of the red light on Escherichia coli and Saccharomycodes ludwigii have been reported [1], [2]. Protective effects of visible light on Salmonella cultures against fullerenes mutagenic effects have been reported [3]. During the last decades this field was rather active. The mechanisms of these effects were accounted for through photochemical reactions induced by the red and UV part of the spectrum, generated by conventional photon absorptions on cellular or chemical chromophores. The series of light effects obtained on protective enzymes (Deoxyribonucleic acid lyases, glutathione S-transferase, superoxide dismutase, etc.) or on the therapy of cancers [4] are due to this type of photodynamic processes. As far as cellular systems are concerned, chromophores for green photons were not reported. These types of chromophores have been observed at some exotic birds used in their flight orientation [5] and are present in retinal components. Accordingly, no photodynamic effects could be induced by low density green light (as in sunlight or white light). This is the physical bases for the specificity of the GL-effects. Since the green photons are not conventionally absorbed, the green light was practically ignored. The first observation concerning green light effects was reported by Coe in 1935, that oil-bearing foods are protected from rancidity by packing in green wrappers which absorb all light except the green delimited by λ = 490–580 nm [6]. Since 1970s a number of papers reported effects of visible light on biological systems from a different perspective. Fröhlich, in a pioneering paper, introduced the concept of long-range interaction in biology [7]. Comorosan published experimental results performing experiments on enzymes and revealing kinetics changes through visible light irradiations of their substrate [8], [9]. Comorosan has investigated the dependence of these effects on the wavelengths of the irradiation sources between 400 and 600 nm, reporting a maximum yield for the green light, about 540 nm [10]. The same type of results, using the green light irradiation technique on biological systems, has been reported [11], [12], [13], [14].

Recently an antioxidant effect of GL on cellular cultures, subjected to lethal doses of UV, has been reported [15]. The purpose of this paper is to investigate in depth the GL-antioxidant effects.

In this respect two types of experimental models have been designed:

  • (a)

    the cellular experimental model, in which the antioxidant effect of GL irradiation is recorded on the inhibition of free radicals generation;

  • (b)

    the chemical experimental model, in which the inhibition of free radicals generation with green light irradiation is recorded in a rigorously determined reaction.

For the cellular system, the melanocytes cultures were subjected to UV-irradiation and the resulted free radicals were determined by the modern fluorescence techniques. For the chemical system, we used long chain alkanes subjected to thermal degradation, and the resulted free radicals checked by chemiluminescence and Fourier transform infrared spectroscopy (FTIR). This reaction was chosen since it is well studied and a detailed mechanism for it is available [16]. This provides a rigorous basis for a quantum computation at the free radicals reaction step. In both experimental models, the green light irradiations inhibited the free radicals generation.

Section snippets

Materials and methods

  • The cells: a line of standardized mouse melanocyte (ECACC-85011438), available from CAMR Center for Research (Salisbury, Wiltshire) is used in Promo Cell Growth Medium Kit for melanocytes (Heidelberg, Germany).

  • Fluorescence probe: Dichlorofluorescin diacetate (DCFDA-Sigma–Aldrich, Germany, D.6883 min 97%).

  • Paraffin wax: white (Aldrich, Germany) and mineral oil, Sigma M3516 (Aldrich, Germany).

  • The fluorescence spectroscopy was performed with F900 Edinburgh Instruments at 90° angle. Measurements were

Theory/calculation

In order to detail the mechanism that takes place in complex cellular molecules, we have performed a quantum mechanical modeling on a well defined chemical structure, using the Gaussian 02 software. As starting molecule we have used the isopropyl compound, one of the paraffin wax main components. For computation we selected n-butane, which results by thermal degradation of the paraffin wax and mineral oil. The molecular geometry of the n-butane was optimized using Kohn-Sharm theory [20]. The

Results

The cellular system: two types of techniques are used in biology to detect production of ROS in cells: spin traps and fluorescence probes. Spin traps have the disadvantage that the electron spin resonance signal may be blocked by antioxidants and cellular enzymatic reducing systems in the medium. The fluorescence probes do not distinguish between intracellular and extracellular fluorescence from chemical reactions in culture medium, Halliwell and Whiteman [23]. They actually measure a total

Discussion

All our experiments, on cellular ROS and on the alkans thermal oxidation show a clear GL-antioxidant effect. The results in Fig. 1 clearly show that the cells grown under GL exposure acquire a protective effect and generate a lower ROS level. As far as a possible interpretation of the GL effect on the cells, we refer to our previous results on a common cellular albumin which includes carbonyl groups through its peptide structure [24]. In this study, through physical techniques (circular

Conclusions

The GL irradiation may generate a series of Rydberg states for the alkanes conformation, which may in turn induce a cooperative effect of quantum macroscopic type. As a result, the Rydberg states may be GL-created, forming a new type of long lived GL-induced metastable/macromolecular system. A detailed physical mechanism for these new results has recently been reported [24].

Within this scientific evidence we suggest a possible interpretation of our results and advance a Rydberg conjecture: due

Acknowledgement

We acknowledge the skilful technical assistance of Mrs. Mariana Muresan from our Dept. of Biochemistry.

References (29)

  • S. Comorosan et al.

    The effect of electromagnetic field on enzymic substrates

    Biochim. Biophys. Acta

    (1972)
  • T.I. Karu et al.

    Biostimulating action of low intensity monochromatic visible light: is it possible?

    Laser Chem.

    (1984)
  • S.F. Kolyakov et al.

    Changes in the circular dichroism spectra of a suspension of live cells exposed to low-intensity laser radiation (λ = 820 nm)

    Dokl. Biochem. Biophys.

    (2001)
  • E.V. Babynin et al.

    Study of Mutagenic Activity of fullerene and some of its derivatives using His+ reversions of salmonella typhimurium as an example

    Russ. J. Genet.

    (2002)
  • M. Triessheijn et al.

    Photodynamic therapy in oncology

    Oncologist

    (2006)
  • S. Johensen et al.

    Light-dependent magnetoreception: quantum catches and opponency mechanisms of possible photosensitive molecules

    J. Exp. Biol.

    (2007)
  • M.R. Coe et al.

    J. Am. Oil Chem. Soc.

    (1935)
  • H. Fröhlich et al.

    Nature

    (1970)
  • S. Comorosan

    The measurement problem in biology

    Int. J. Quantum Chem.: Quantum Biol. Symp.

    (1974)
  • S. Comorosan

    Progess in Theoretical Biology, Biological Observables

    (1976)
  • R. Sherman et al.

    Effect of penicillin irradiation on bacterial growth and penicillin resistance

    Chemotherapy

    (1974)
  • G.E. Bass

    The comorosan effect: toward a perspective

    Int. Symp. Quantum Biol. Quantum Pharmacol.

    (1975)
  • B.C. Goodwin et al.

    Low energy electromagnetic perturbation of an enzyme substrate

    Physiol. Chem. Phys.

    (1975)
  • F.M. Etzler et al.

    Modulation of reaction kinetics via an apparently novel interaction of light and matter

    Physiol. Chem. Phys. Med. NMR

    (1986)
  • Cited by (5)

    View full text