## 3 Bioactivity of Pigments and Lipids from Plastids of Marine Phytoplankton
### Pigments
#### 3.1.1.2 Anti-Cancer  
Chlin has been reported to have potent anti-mutagenic and anti-carcinogenic effects in short-term tests _in vitro_ and _in vivo_[45, 46]. There is an abundant literature about the interest of food molecules to preserve health, for reviews see [76]. However, it may happen that food, for instance stored in poor conditions, gets infected by molds such as _Aspergillus flavus_ and _A. parasitic_. These fungi secrete mycotoxin aflatoxin B1 (AFB), one of the most known human carcinogenesis linked to diet. The action mechanism of AFB is pretty well known. However, it is out of the scope of this contribution to present the details of these mechanisms and it is sufficient to known the following facts to understand the interest of tetrapyroles in thwarting AFB action. Briefly, AFB is metabolized by cytochrome P450 (CYP) enzymes to the exo-AFB-8,9-epoxide (AFBO), which constitutes the main metabolites of the reaction. (for details, see recent reviews, e.g., [77]). AFBO is highly reactive, and can further bind covalently to cellular macromolecules such DNA forming AFB-N7-guanine adducts. These adducts are chemically unstable and rapidly excreted but they are stabilized through rearranging to a ring-opened formamidopyrimidine structure. The AFB-DNA-adducts can trigger somatic alterations at transcriptionally active DNA regions when not removed by DNA repair enzymes [78]. The ability of Chlin to form complex with carcinogens is not restricted to AFB (for a review, see [79]) as AFB could also bind heterocyclic amines that favour the development of colorectal adenoma [80]. Heterocyclic amines are for instance produced when meat is cooked at high temperature [80]. Thus, Chlin exhibits the property to chelate AFB yielding to the formation of chemically stable Chlin-AFB complexes, and those complexes are no longer absorbed by intestine and excreted with feces [81]. Moreover, inhibitory effects of Chlin on human CYP have been reported [82]. Based on these effects, Chlin was used recently in a chemointervention trial in China, resulting in a 55% reduction of the urinary AFB-N7-guanine adduct [83]. [PERSON] _et al._[84] proposed arguments for a protective action of Chl on DNA damages. The efficiency of dephytylated compounds is less than the phytylated ones [85]. In addition, Chlin has been reported to exhibit an anti-proliferative effect on various cancer cell lines [86, 87, 88]. [PERSON] _et al._[70]) reported that Chlin alterates the expression of genes coding for proteins involved in the transformation of normal to malignant phenotype of buccal pouch cells.  
However, [PERSON] [89] reported that commercially available Chlin can have a tumor promoting effect and at present the Chlin content in food is regulated [55].  
Microalgae pigments may have interest to restore drug sensitivity or reverse multi-drug resistance (MDR) in cancer cells, as some of them inhibit or down-regulate drug efflux pumps. For instance, a significant reduction of P-glycoprotein expression in drug-resistant hepatocellular carcinoma (R-HepG2) cells, at both transcriptional and translational levels, was observed when cells were treated with pheophorbide _a_[90]. Recently, a natural Chl of the Phaeophyceae, Chl c2, was found to trigger the degranulation of a rat basophilic leukemia cell line (RBL-2H3), whereas Chl \(a\) and b were unable to do it [91]. In addition, Chl c2 has an anti-allergic power.