Abstract: The oxidative damage to Spodoptera litura (SL) cells by hematoporphyrin monomethyl ether (HMME), the second generation photosensitizer for PDT, was investigated. IC₅₀ value, the output of MDA and the content of GSH, and the alteration of cell organelles were assayed or observed to explore the feasibility of applying HMME and its derivatives to control agricultural pest insects. IC₅₀ values obtained with MTT at 24 h and 48 h post HMME treatment with irradiation were 8.35 μg/mL and 7.66 μg/mL, respectively. The results obtained with TBA method showed that photoactivated HMME could induce MDA increasing in dose dependent manner. When the treatment concentration of HMME was 50.000 μg/mL, the output of MDA at 48 h post treatment was 173.08±3.51 nmol/L. The GSH level, however, exhibited a contrary tendency. When the treatment concentration of HMME was 50.000μg/mL, the GSH content decreased by 39.59% compared with the same concentration treatment without irradiation. The SEM photographs showed that distinct pores in SL cells treated with 6.250 μg/mL HMME and irradiation, and sunken and plicate membrane appeared in the treated SL cells. All the evidence indicated that HMME had induced oxidative damage to SL cells.

Key words: Hematoporphyrin monomethyl ether (HMME), Spodoptera litura SL cell, oxidative damage, malondialdehyde, glutathione, cell ultrastructure