Suppression of growth of cultured malignant cells by allomelanins, plant-produced melanins.
Allomelanins, which belong to the melanins produced by higher plants and fungi, were studied with respect to their growth suppressive effects on cultured HCT-15 cells derived from human intestinal carcinoma and Meth/A cells derived from a Balb/C mouse lymphoma. Allomelanins were extracted from black soy beans and black sesame seeds with 0.2% NaOH in water. Proteins bonded to the allomelanins were removed by boiling the extracts for 20 hours in 30% NaOH. Although native allomelanins conjugated with protein did not suppress the growth of the cells, protein-free allomelanins did suppress it. That is, 50% suppression of HCT- 15 cell growth was found at a concentration between 100 and 200 micrograms/ml of the melanin prepared from the black soy beans, and between 25 and 100 micrograms/ml of that from the sesame seeds. For Meth/A cells, 50% suppression by allomelanin from the black beans was approximately 100 micrograms/ml; and that by the allomelanin preparation from sesame seeds, between 25 and 100 micrograms/ml. Thus, protein-free allomelanins seemingly suppress cultured mammalian and animal tumor cells.
Kamei
H
H
Department of Surgery, Aichi-Gakuin University Hospital, Nagoya, Japan. kamei@dpc aichi-gakuin.ac.jp
Koide
T
T
Kojima
T
T
Hasegawa
M
M
Umeda
T
T
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D006801:Humans; D008543:Melanins / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D008543:Melanins