Photosensitizing Toxicity of Alizarin with or without γ Radiation Against Spodoptera littoralis (Lepidoptera: Noctuidae) and the Impact on Elemental Composition

Photodynamic therapy uses photosensitizers that are activated by absorption of certain light wavelength resulting in generation of singlet oxygen (free radical) which are toxic to tissues and cells. The present study was performed to compare the efficacy of photodynamic action of alizarin against Spodoptera littoralis unirradiated and F1 irradiated larvae. Alizarin dye affected S. littoralis unirradiated larvae and F1 irradiated larvae but the effect was more pronounced in F1 irradiated larvae. Mortality exhibited a positive correlation to the concentration of photoactive dye. Carbon was the most abundant element in body tissue of untreated larvae and F1 larvae (both untreated and treated with LC50 alizarin). The least abundant element in the controls, larvae treated with LC50 and F1 larvae+LC50 alizarin was silicon, while in F1 larvae it was chloride (Cl). Therefore, it could be concluded that the combination of alizarin and gamma radiation caused lethal physiological disturbance in the larvae.