Shrimp processing waste is the single largest industrial waste in Tunisia causing diverse environmental
problems. Extraction of astaxanthin from the shell waste of the deep-water pink shrimp (Parapenaeus longirostris) was
investigated. A hight astaxanthin yield was obtained using acetone (72.42 µg/g). Thin layer chromatographic separation of
carotenoid extracts from P. longirostris yielded three distinct bands. The Rf values for the three bands were respectively
0.33, 0.60, 0.80 which corresponded to astaxanthin, astaxanthin monoester and astaxanthin diester.
The antioxidant activities of astaxanthin at different concentrations were evaluated using various in vitro antioxidant
assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, β-carotene bleaching and
DNA nicking assays. Interestingly, astaxanthin extract showed strong antioxidant activity. The radical scavenging
activities and reducing powers of astaxanthin were close to and even better than those of the synthetic antioxidant BHA.
The astaxanthin extract from shrimp shell waste exhibited high inhibition of β-carotene bleaching and also showed a well
DNA protection against degradation by hydroxyl radicals. The anti-proliferative activity of the astaxanthin extract was
also investigated. The inhibition concentration (CI50) of proliferation of tumor cells of human laryngeal carcinoma (Hep 2
cells) was 300 µg astaxanthin /ml.