Amifostine aminothiols and protection of keratinocyte apoptosis and DNA damage

Radioprotective Effects of Plants from the Lamiaceae Family

BACKGROUND

Edible and medicinal plants are still an interesting source of promising biologically active substances to drug discovery and development. At a time of increasing cancer incidence in the world, alleviating the bothersome side effects of radiotherapy in debilitated cancer patients is becoming an important challenge.

OBJECTIVE

The aim of the study was to overview the literature data concerning the radioprotective activity of extracts, essential oils, and some chemical compounds obtained from 12 species belonging to the Lamiaceae family, gathering of numerous spice and medicinal plants rich in valuable phytochemicals.

RESULTS AND CONCLUSION

The analysis of available publications showed radioprotective effectiveness of essential oils and complex extracts containing phenolic acids and flavonoids in various in vitro and in vivo models. Relatively welldocumented preventive properties exhibited the following species: Mentha × piperita, Ocimum tenuiflorum, Origanum vulgare, and Rosmarinus officinalis. However, few plants such as Lavandula angustifolia, Mentha arvensis, M. spicata, Plectranthus amboinicus, Salvia miltiorrhiza, S. officinalis, Scutellaria baicalensis, and Zataria multiflora should be more investigated in the future. Among the mechanisms of radioprotective effects of well-studied extracts and phytochemicals, it can be mentioned mainly the protection against chromosomal damage, scavenging free radicals, decreasing of lipid peroxidation and elevating of glutathione, superoxide dismutase, catalase, and alkaline phosphatase enzyme levels as well as the reduction the cell death. The plant substances protected the gastrointestinal tract, bone marrow and lung fibroblasts. In conclusion, studied species of Lamiaceae family and their active chemical compounds are potent in alleviating the side effects of radiotherapy and should be considered as a complementary therapy.

N-acetylcysteine protects melanocytes against oxidative stress/damage and delays onset of ultraviolet-induced melanoma in mice

PURPOSE

UV radiation is the major environmental risk factor for melanoma and a potent inducer of oxidative stress, which is implicated in the pathogenesis of several malignancies. We evaluated whether the thiol antioxidant N-acetylcysteine (NAC) could protect melanocytes from UV-induced oxidative stress/damage in vitro and from UV-induced melanoma in vivo.

EXPERIMENTAL DESIGN

In vitro experiments used the mouse melanocyte line melan-a. For in vivo experiments, mice transgenic for hepatocyte growth factor and survivin, shown previously to develop melanoma following a single neonatal dose of UV irradiation, were given NAC (7 mg/mL; mother's drinking water) transplacentally and through nursing until 2 weeks after birth.

RESULTS

NAC (1-10 mmol/L) protected melan-a cells from several UV-induced oxidative sequelae, including production of intracellular peroxide, formation of the signature oxidative DNA lesion 8-oxoguanine, and depletion of free reduced thiols (primarily glutathione). Delivery of NAC reduced thiol depletion and blocked formation of 8-oxoguanine in mouse skin following neonatal UV treatment. Mean onset of UV-induced melanocytic tumors was significantly delayed in NAC-treated compared with control mice (21 versus 14 weeks; P = 0.0003).

CONCLUSIONS

Our data highlight the potential importance of oxidative stress in the pathogenesis of melanoma and suggest that NAC may be useful as a chemopreventive agent.