diacyloxy-p-terphenyls, thelephantin O was carried out very recently (Fujiwara et al.
2012). These bioactive compounds, thelephantin and vialinin A, have shown to be
potent cytotoxic agents against cancer cells, by decreased cell viability in human
hepatocellular carcinoma cells (HepG2) via iron chelation, and human colonic
carcinoma cells (Caco2) (Norikura et al. 2011, 2013). Grifolin is a secondary
metabolite isolated from fresh sporomes of the EEM A. confluens which has the
ability to inhibit tumor cell growth by inducing apoptosis (Ye et al. 2005). This
process regulates the cell death through a strictly controlled program playing an
important role in most human functions, from fetal development to adult homeostasis (Reed 2001). Defects in the regulation of apoptosis or programmed cell death
make important contributions to the pathogenesis and progression of most cancers
and leukemias (Reed 2004). For this reason, bioactive compounds, such as grifolin,
which inhibit the proliferation of tumor cells by inducing apoptosis, are considered to
have potential as antitumor agents. Ye et al. (2007) identified the novel targets of
grifolin by studying its effect on the human nasopharyngeal carcinoma (CNE1) cell
line, and Luo et al. (2011b) showed that grifolin inhibits the growth of cancer cell
lines by upregulating death-associated protein kinase 1DAPK1 via p53 in these
nasopharyngeal carcinoma cells. Jin et al. (2007) found that grifolin induces apoptosis via inhibition of PI3K/AKT signaling pathway in human osteosarcoma cells.
Therefore, grifolin might represent a promising candidate in the prevention and
intervention of cancer by targeting DAPK1 signaling to induce cell cycle G1 phase
arrest (Luo et al. 2011b). Ergone is a bioactive steroid found in different mushrooms
including the edible wild mushroom called ‘‘charcoal burner’’ (Russula cyanoxantha) (Gao et al. 2000). Zhao et al. (2011) found that ergone extracted from sporomes
of R. cyanoxantha has a potent antitumor activity against hepatocellular carcinoma
HepG2 cells by inducing G2/M phase arrest and apoptosis. They also found that
ergone-induced apoptosis by activating caspases via both intrinsic and extrinsic
pathways. In addition, the ratio of Bax/Bcl-2 markedly increased in cells treated with
ergone. Previously, a ceramide potentially involved in the apoptosis process was
extracted from this species by Gao et al. (2001). These results are significant as they
provide an insight into the molecular mechanism of ergone which might be a potent
chemotherapeutic agent for the treatment of liver cancer. This type of cancer is a
worldwide major health problem, with an estimated incidence ranging from 500,000
to 1 million new cases annually (Lau and Lai 2008). Additionally, it has been found
that ergones have other beneficial functions including cytotoxic (Lee et al. 2005)
diuretic (Zhao et al. 2009a, b) and immunosuppresive activities (Fujimoto et al.
2004). Zhang et al. (2010) isolated for the first time a lectin from the important
ectomycorrhizal genera Russula. As this novel lectin came from the edible mushroom, called in China ‘‘red mushroom’’ (Russula lepida) was named RLL. The
protein was characterized and showed a potent antitumor activity, having an antiproliferative activity toward the hepatoma HepG2 cells and human breast cancer
MCG-7. Daily intraperitoneal injections of RLL (5.0 mg/kg body weight/day for
20 days) brought about 67.6 % reduction in the weight of S-180 tumor. Similarly,
Zhao et al. (2010) isolated another novel dimeric lectin, from Russula delica, with a
molecular weight of 60 kDa and high hemagglutinating activity, which potently
6 Edible Ectomycorrhizal Mushrooms
175
2012). These bioactive compounds, thelephantin and vialinin A, have shown to be
potent cytotoxic agents against cancer cells, by decreased cell viability in human
hepatocellular carcinoma cells (HepG2) via iron chelation, and human colonic
carcinoma cells (Caco2) (Norikura et al. 2011, 2013). Grifolin is a secondary
metabolite isolated from fresh sporomes of the EEM A. confluens which has the
ability to inhibit tumor cell growth by inducing apoptosis (Ye et al. 2005). This
process regulates the cell death through a strictly controlled program playing an
important role in most human functions, from fetal development to adult homeostasis (Reed 2001). Defects in the regulation of apoptosis or programmed cell death
make important contributions to the pathogenesis and progression of most cancers
and leukemias (Reed 2004). For this reason, bioactive compounds, such as grifolin,
which inhibit the proliferation of tumor cells by inducing apoptosis, are considered to
have potential as antitumor agents. Ye et al. (2007) identified the novel targets of
grifolin by studying its effect on the human nasopharyngeal carcinoma (CNE1) cell
line, and Luo et al. (2011b) showed that grifolin inhibits the growth of cancer cell
lines by upregulating death-associated protein kinase 1DAPK1 via p53 in these
nasopharyngeal carcinoma cells. Jin et al. (2007) found that grifolin induces apoptosis via inhibition of PI3K/AKT signaling pathway in human osteosarcoma cells.
Therefore, grifolin might represent a promising candidate in the prevention and
intervention of cancer by targeting DAPK1 signaling to induce cell cycle G1 phase
arrest (Luo et al. 2011b). Ergone is a bioactive steroid found in different mushrooms
including the edible wild mushroom called ‘‘charcoal burner’’ (Russula cyanoxantha) (Gao et al. 2000). Zhao et al. (2011) found that ergone extracted from sporomes
of R. cyanoxantha has a potent antitumor activity against hepatocellular carcinoma
HepG2 cells by inducing G2/M phase arrest and apoptosis. They also found that
ergone-induced apoptosis by activating caspases via both intrinsic and extrinsic
pathways. In addition, the ratio of Bax/Bcl-2 markedly increased in cells treated with
ergone. Previously, a ceramide potentially involved in the apoptosis process was
extracted from this species by Gao et al. (2001). These results are significant as they
provide an insight into the molecular mechanism of ergone which might be a potent
chemotherapeutic agent for the treatment of liver cancer. This type of cancer is a
worldwide major health problem, with an estimated incidence ranging from 500,000
to 1 million new cases annually (Lau and Lai 2008). Additionally, it has been found
that ergones have other beneficial functions including cytotoxic (Lee et al. 2005)
diuretic (Zhao et al. 2009a, b) and immunosuppresive activities (Fujimoto et al.
2004). Zhang et al. (2010) isolated for the first time a lectin from the important
ectomycorrhizal genera Russula. As this novel lectin came from the edible mushroom, called in China ‘‘red mushroom’’ (Russula lepida) was named RLL. The
protein was characterized and showed a potent antitumor activity, having an antiproliferative activity toward the hepatoma HepG2 cells and human breast cancer
MCG-7. Daily intraperitoneal injections of RLL (5.0 mg/kg body weight/day for
20 days) brought about 67.6 % reduction in the weight of S-180 tumor. Similarly,
Zhao et al. (2010) isolated another novel dimeric lectin, from Russula delica, with a
molecular weight of 60 kDa and high hemagglutinating activity, which potently
6 Edible Ectomycorrhizal Mushrooms
175