We have investigated the individual and combined effects of β-carotene (βC) and a crude polysaccharide extract of the red alga Porphyridium cruentum (PC) on Mitomycin C (Mit-C) sensitivity of peripheral blood lym­phocytes of humans occupationally exposed to low dose gamma radiation. Peripheral blood lymphocytes in vitro were treated with Mit-C and the chromosome abnormal­ities in the presence or absence of βC and/or PC were recorded. The incidence of chromosomal abnormalities increased from 1.9% in cell cultures without Mit-C to 7.8% in those with Mit-C with a significant increase in chromosomal aberrations (chromatid breaks, chromosome breaks, dicentrics and rings) (p <0.05). However, in Mit-C treated cultures that contained βC+PC the incidence was 1.3%. Mitomycin C-induced aberrations in the lympho­cytes decreased significantly with the addition of βC and PC to the culture. This suggests that mutagen sensitivity may be reduced by a βC+PC combination and that this combination may protect humans exposed to radiation.

      Key words: Lymphocyte; Mitomycin C (Mit-β); Porphyridium cruentum (PC); β-Carotene (βC); X-rays; Chromosome aberration(s).