# Physiological Effects of Green-Colored Food-Derived Bioactive Compounds on Cancer
## 2 Physiological Effects and Mode of Actions (MoA)
### Indole Derivatives  
Indole has also known as benzypyrrole, is an aromatic organic compound composed of benzyl and a pyrrole ring [77]. The aromatic properties of indole originate from the mobilization of its 10 \(\pi\) electrons throughout the indole structure [77]. Although the presence of indole has been confirmed in various plant species, the primary natural source of this compound has been identified as cruciferous vegetables, such as cabbage, cauliflower, and broccoli [78]. The biosynthesis of this compound begins with the attachment of tryptophan and other amino acids or through microbial activities [79]. Indol-3 carbinol (I3C) is the most popular indole derivative that has been widely investigated for its strong anti-cancer benefits [80]. ISC is highly bioavailable, and upon the actions of the acidic gastric juice, I3C is converted into its principal metabolite, known as diindolylmethane (DIM) [81]. It has been reported that the anti-carcinogenic activities of I3C could largely be attributed to its oligomeric products [82]. According to earlier reports, I3C demonstrates anti-cancer effects by targeting multiple signaling pathways and receptors, such as estrogen receptor signaling, Akt-Nfkb signaling, endoplasmic reticulum stress, BRCA gene expression, and caspase activation (Table 1) [82].  
Although anti-carcinogenic effects of I3C have been shown against various forms of cancer, including breast, cervical, prostate, and endometrial cancers, the therapeutic effects of I3C against breast and prostate cancers have been noteworthy, and hence drew remarkable research attention over the last decade [83]. Epidemiological studies have found a clear association between the consumption of cruciferous vegetables and the lower incidence of breast and prostate cancers [81]. A clinical study conducted in 2018 reported that women with stage III-IV breast cancers treated with combined therapy of I3C and catechin experienced a lower recurrence of the disease [84]. This study suggested I3C and catechin as maintenance therapy for breast cancer. [PERSON] et al. reported that I3C showed anti-tumor activity by regulating estrogen activity and metabolism in human tumor cells [78]. The same group of researchers later found that I3C exerted anti-carcinogenic effects by modulating the BRCA genes in human breast and prostate cancer cells [85]. Remarkably, I3C suppressed the prostate cancer cells by inhibiting the telomerase activity and the gene expression [86]. Positive effects of I3C in several in vivo cancer models, including breast, lung, liver, and stomach cancers, have also been reported [81]. Based on these studies, it is worth suggesting that I3C has all the potential to be among the forefront of the natural medicinal agents in anti-cancer therapy. Even though the food applications of indole and its derivatives have yet to begun, the pharmaceutical applications of them are now a commonplace. However, for their safe and effective food and pharmaceutical applications, green synthesis technologies, such as microwave- or ultrasound-assisted synthesis are being proposed [87].