Studies on extracts of Argentinean plants: cytotoxic tumoral activity per se and as photosensitizers in photodynamic therapy of cancer

BATLLE A; MAMONE L; CASAS A; RODRIGUEZ L; DI VENOSA G

Honolulu

Congreso; Pacifichem 2010; 2010

Pacific Basin Societies (Pacifichem)

Photodynamic Therapy(PDT) and Photodiagnosis(PD) can be used for the treatment and diagnosis of tumors and other non-tumoral diseases. PDT is based on combining the use ing a photosensitizer(PS), light irradiation and oxygen. There are a good number of PSs. Among them there exist some natural products, obtained from plants and synthesized, most of them not yet studied. Only 15% of plants have been searched for new PSs. Our aim has been to investigate extracts, obtained from autochthonous plants, looking for new PSs and to evaluate their cytotoxic properties per se. Next, we plan to purify the photoactive compound, determine its chemical structure and attempt its synthesis. Extracts from 40 plant species have been studied. Time exposure was 24hrs. It was found that exposure of the murine tumoral line LM2 to the methanolic extracts of 10 µg/ml of Combretum fruticosum and 50 µg/ml of Scutia buxifolia leaves and irradiation with light doses of 0.19J/cm2 and 0.073J/cm2,respectively,induced 50% death. Methanolic extracts from 10.0 µg/ml of Iochroma australis and 0.025µg/ml of Jacaranda mimosifalia flowers and 0.08 µg/ml of Colleae argentina leaves as well as acquous extracts from 1µg/ml of Solanium verbacifolium flowers, were inducing 50% death in LM2 cells. Treatment of human mammary tumoral cell line HB4a-Ras with 50 µg/ml of Iochroma australis and Solanium verbacifolium flowers, also induced 50% death. Exposure of the murine tumoral line LM3 to 0.05 mg/ml of crude methanolic extracts of Collea argentina and Macfadyena unguis cati, induced 50% death, irradiating with 0.43 J/cm2 for Collea and 0.53 J/cm2 for Macfadyena,respectively. Irradiations have been performed using a last generation 630nm Lumiia Laser, the first prototype developed in Argentina. Comparative studies with this Laser and others we had been using, were done, showed that Lumiia Laser, is very easy and friendly to use, portable, more powerful and far more economic than other similar equipments.