Viadent-related leukoplakia--the tip of the iceberg?

Carcinogenic potential of sanguinarine, a phytochemical used in 'therapeutic' black salve and mouthwash

Black salves are escharotic skin cancer therapies in clinical use since the mid 19th century. Sanguinaria canadensis, a major ingredient of black salve formulations, contains a number of bioactive phytochemicals including the alkaloid sanguinarine. Despite its prolonged history of clinical use, conflicting experimental results have prevented the carcinogenic potential of sanguinarine from being definitively determined. Sanguinarine has a molecular structure similar to known polyaromatic hydrocarbon carcinogens and is a DNA intercalator. Sanguinarine also generates oxidative and endoplasmic reticulum stress resulting in the unfolded protein response and the formation of 8-hydroxyguanine genetic lesions. Sanguinarine has been the subject of contradictory in vitro and in vivo genotoxicity and murine carcinogenesis test results that have delayed its carcinogenic classification. Despite this, epidemiological studies have linked mouthwash that contains sanguinarine with the development of oral leukoplakia. Sanguinarine is also proposed as an aetiological agent in gallbladder carcinoma. This literature review investigates the carcinogenic potential of sanguinarine. Reasons for contradictory genotoxicity and carcinogenesis results are explored, knowledge gaps identified and a strategy for determining the carcinogenic potential of sanguinarine especialy relating to black salve are discussed. As patients continue to apply black salve, especially to skin regions suffering from field cancerization and skin malignancies, an understanding of the genotoxic and carcinogenic potential of sanguinarine is of urgent clinical relevance.

Rise and fall of oral health products with Canadian bloodroot extract

The rhizome of Sanguinaria canadensis (SC, bloodroot) contains an active principle with antimicrobial, antiinflammatory, antioxidative and immunomodulatory effects. For this reason SC extract has been added to toothpastes and mouthwashes in various concentrations. When tested separately, neither the toothpastes nor the mouthwashes with SC extract had any demonstrable clinical effectiveness against dental plaque and gingivitis. Although using them together twice a day seemed more effective than using placebo, more recent studies have shown conflicting results. Preclinical safety studies up to 2000, which did not include studies longer than 6 months, were thought not to indicate any appreciable potential for harm - to the oral mucosa in particular. In 2003, the FDA Subcommittee on Oral Health Care Drug Products for Over-the-Counter Human Use concluded from a review that using SC-containing products is safe. However, for reasons unknown, the review failed to consider publications between 1999 and 2001 that suggested a possible link between the use of SC-containing products and the pre-neoplastic lesion, leukoplakia. As it happened, bloodroot had already been removed (in 2001) from the formula of one of the most widely used products in question and the brand has since then disappeared altogether from the worldwide market.

Sanguinarine cytotoxicity on mouse melanoma K1735-M2 cells--nuclear vs. mitochondrial effects

Sanguinarine (SANG) is an alkaloid recognized to have anti-proliferative activity against various human tumour cell lines. No data is available on the susceptibility of advanced malignant melanoma to SANG, although this disease has a very poor prognosis if not detected in time due to the resistance to conventional chemotherapy. The present work was designed to study the nuclear and mitochondrial involvement in the pro-apoptotic effect of SANG in an invasive mouse melanoma cell line. The results obtained show that SANG is primarily accumulated by the cell nuclei, causing inhibition of cell proliferation and inducing cell death, as confirmed by an increase in sub-G1 peaks. At low concentrations, SANG induces mitochondrial depolarization in a sub-population of melanoma cells, which also generally displayed strong nuclear labelling of phosphorylated histone H2AX. Western blotting revealed an increase in p53, but not Bax protein, in both whole-cell extracts and in mitochondrial fractions. Isolated hepatic mitochondrial fractions revealed that SANG affects the mitochondrial respiratory chain, and has dual effects on mitochondrial calcium loading capacity. We suggest that SANG is able to induce apoptosis in metastatic melanoma cells. The knowledge of mitochondrial vs. nuclear effects of SANG is important in the development of this promising compound for clinical use against aggressive melanoma.

Advances in oral medicine

This paper reviews some of the more important areas of oral medicine where significant advances have been made in the past decade. There have been developments in the definition of new entities causing orofacial pain, and new therapies. Oral cancer has been recognised as increasing in incidence and the genetic basis is becoming clearer, along with improvements in early diagnostic techniques and treatment. The basis of aphthae is being unravelled and new therapies are appearing. There is greater understanding of the aetiopathogenesis and treatment of various dermatoses that present in the mouth. Treatment and prevention of leukoplakias is improving and the importance of candidosis has become evident.