# Fungal Pigments and Their Roles Associated with Human Health
## 5 Medical Relevance of Fungal Pigments
### Medical Roles of Other Pigments
#### 5.2.8 Others  
Aside from the above-described roles of fungal pigments in human health, other human health related roles have also been reported. Those included antioxidative, cytotoxic, and immunosuppressive roles. Below are brief descriptions of those studies.  
Anti-oxidative properties are commonly found among fungal pigments. The conjugated polyene chain in the carotenoids provides chemical reactivity against oxidizing compounds and free radicals that may otherwise result in damage to cellular functions. Apart from the anti-oxidative actions of carotenoids previously reviewed elsewhere [15], investigation of the Chinese medicinal fungus _Phellinus ignarius_ has led to the isolation and identification of three fungal pigments derived from pyrano[4,3-c]isochrom-4-one, phelligridins H, I, and J [198]. These orange or yellow pigments all showed antioxidant activity, as evidenced by inhibiting rat liver microsomal lipid peroxidation with IC\({}_{50}\) values of 4.8, 3.7, and 6.5\(\upmu\)M, respectively, for phelligridins H, I, and J. In addition, phelligridins H and I inhibited protein tyrosine phosphatase 1B (PTP1B), while phelligridin J exhibited cytotoxic activity against four human cancer cell lines, A2708 (ovary cancer), A549 (lung cancer), Bel-7402 (hepatoma) and HCT-8 (colon cancer) [198]. As PTP1B is an important player in cell proliferation, differentiation, and malignancy, being involved, for instance, in the development of breast cancer, lung cancer, and esophageal squamous cell carcinoma [199,200]. The above findings highlight the potential of these novel pigments as antitumor agents.  
The macula of human eye contains two carotenoids, lutein and zeaxanthin. Based on the NIH Eye Disease Case-Control Study [208], the dietary intake of antioxidants such as carotenoids is highly correlated to the incidence of age-related macular degeneration (AMD), demonstrating a statistically significant linear trend associating the reduction of risk with increasing consumption of carotenoids. It is widely recognized that these carotenoids may protect the macula from light-induced damage and scavenge free radicals generated in the photoreceptors [8].  
Four new azaphilones, namely longirostrerones A\(-\)D, along with three known sterols, have been isolated from extracts of the Thai soil fungus _Chatonium longirostre_[209]. Longirostrerones A\(-\)D exhibited potent cytotoxicity against KB (human epidermoid carcinoma of the mouth) cell lines with IC\({}_{50}\) of 1.04, 1.52, 0.23, and 6.38 uM, respectively. Among these azaphilones under study, longirostreone C showed significant cytotoxicity against KB (IC\({}_{50}\) = 0.23 uM), close to the control drugs doxorubicin and ellipticine. Moreover, longirostrerones A showed strong inhibitory effects on human breast adenocarcinoma MCF7 and small-cell lung cancer NCI-H187 cancer cell lines with IC\({}_{50}\) values of 0.24 and 3.08 uM, respectively. Apart from the antitumor activities shown above, longirostrerones A\(-\)C also displayed antimalarial activity against _Plasmodium falciparum_ with the IC\({}_{50}\) values ranging from 0.62 to 3.73 uM.  
An early report revealed the pronounced immunosuppressive activities of monascin and anakfalavin, two yellow oligoketide pigments isolated from the mycelium of _Monascus purpureus_[210]. By inhibiting murine T-splenocyte proliferation, monascin and anakfalavin could interact with regulatory mechanisms of the immune system and thus suppress its function, indicating that the two _Monascus_ pigments might serve as promising immunosuppressants.