“The … CP was strongly reduced by alpha- and beta-carotene, canthaxanthin, and retinol (ID50-values: 67-112 nmol ml-…, 50-63% maximum inhibition at 1 micromol ml-1 top agar), moderately by beta-cryptoxanthin, and lutein (45% and 28%, respectively), and only marginally … at all, by all remaining carotenoids.”