Hypericin-loaded lipid nanocapsules for photodynamic cancer therapy in vitro.
Hypericin (Hy), a naturally occurring photosensitizer (PS), is extracted from Hypericum perforatum plants, commonly known as St. John's wort. The discovery of the in vitro and in vivo photodynamic activities of hypericin as a photosensitizer generated great interest, mainly to induce a very potent antitumoral effect. However, this compound belongs to the family of naphthodianthrones which are known to be poorly soluble in physiological solutions and produce non-fluorescent aggregates (A. Wirz et al., Pharmazie, 2002, 57, 543; A. Kubin et al., Pharmazie, 2008, 63, 263). These phenomena can reduce its efficiency as a photosensitizer for the clinical application. In the present contribution, we have prepared, characterized, and studied the photochemical properties of Hy-loaded lipid nanocapsule (LNC) formulations. The amount of singlet oxygen ((1)O2) generated was measured by the use of p-nitroso-dimethylaniline (RNO) as a selective scavenger under visible light irradiation. Our results showed that Hy-loaded LNCs suppressed aggregation of Hy in aqueous media, increased its apparent solubility, and enhanced the production of singlet oxygen in comparison with free drug. Indeed, encapsulation of Hy in LNCs led to an increase of (1)O2 quantum yield to 0.29-0.44, as compared to 0.02 reported for free Hy in water. Additionally, we studied the photodynamic activity of Hy-loaded LNCs on human cervical carcinoma (HeLa) and Human Embryonic Kidney (HEK) cells. The cell viability decreased radically to 10-20% at 1 μM, reflecting Hy-loaded LNC25 phototoxicity.
Institut de Recherche Interdisciplinaire (IRI), USR CNRS 3078, Université Lille 1, Parc de la Haute Borne, 50 Avenue de Halley, BP 70478, 59658 Villeneuve d'Ascq, France. rabah.boukherroub@iri.univ-lille1.fr.
Alexandre
A
Barras
Luc
L
Boussekey
Emmanuel
E
Courtade
Rabah
R
Boukherroub
D000873:Anthracenes; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D020902:Hypericum / Q000737:chemistry / Q000378:metabolism; D008027:Light; D008055:Lipids / Q000737:chemistry*; D018715:Microscopy, Video; D053769:Nanocapsules / Q000737:chemistry*; D009369:Neoplasms / Q000188:drug therapy; D010316:Particle Size; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology* / Q000627:therapeutic use; D026082:Singlet Oxygen / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
D000873:Anthracenes; D004337:Drug Carriers; D008055:Lipids; D053769:Nanocapsules; D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D010569:Perylene; C004965:hypericin