Portal de Periódicos da CAPES

Photosensitization of albino rats fed on lucerne-proetin concentrate

1974; Cambridge University Press; Volume: 31; Issue: 2 Linguagem: Inglês

10.1079/bjn19740021

1475-2662

Evelyn Lohrey, B.A. Tapper, E.L. Hove,

Saffron Plant Research Studies

1. The photosensitizing effect of leaf-protein concentrate (LPC) prepared from lucerne ( Medicago sativa ) was demonstrated when it was included in the diet of albino rats at concentrations between 40 and 480 g/kg diet. 2. Skin lesions of varying severity up to the sloughing of ears and tails occurred when such rats were illuminated with natural daylight through window-glass or with simulated daylight from a bank of lamps having emission maxima at 410, 437 and 660 nm and with approximately 4% of the energy of summer sunlight. 3. Protein concentrates prepared from ryegrass ( Lolium multiforum ) and a crude chlorophyll extract of spinach ( Spinacea oleracea ) did not cause these effects. 4. Extracts from blood plasma and livers of rats given lucerne LPC contained pheophorbide- a and two other unidentified green pigments, but no detectable phylloerythrin or chlorophyll. Extracts from the blood of rats given ryegrass LPC had no detectable pheophorbide or other chlorophyll-derived pigments. 5. The lucerne LPC given to the rats contained relatively large amounts of pheophorbide- a among a variety of pigments. The ryegrass LPC and the spinach extracts had only small amounts of this pigment relative to the other chlorophyll-type pigments. 6. These findings indicate that pheophorbide- a and related pigments are the agents responsible for the photosensitization of the rats. Possible explanations of their presence in lucerne LPC are discussed.