Antitumor-promotion activity

In 2004, Fumkawa and co-workers reported the isolation of glybomine B (60) and glybomine C (61), along with glybomine A (42) (see Scheme 2.9), from the stem of G. arborea (68). This group of carbazole alkaloids showed antitumor-promoting activity against (12-0-tetradecanoylphorbol-13-acetate) TPA-induced EBV-EA activation. 

Okuyama, T., M. Takata, H. Nishino, A. Nishino, J. Takayasu, and A. Iwashima. 1990. Studies on the antitumor-promoting activity of naturally occurring substances. . Inhibition of tumor-promoter-enhanced phospholipid metabolism by umbelliferous materials. Chem. Pharm. Bull. 38 1084-1086. 

On the other hand, EGCG and green tea extract are acknowledged cancer-preventive agents in Japan [75,76]. Natural products with antitumor promotion activity isolated from foodstuff and medicinal plants have been summarized by Konoshima and his co-worker and Akihisa and... 

For the highly inhibitive compounds in the TPA-induced inflammatory assay, we evaluated their antitumor-promoting activity by a standard initiation-promotion protocol [Fig. (3)] [37,40]. Initiation was achieved by a single application of 50 pg of DMBA (2), a well known tumor initiator, to the skin of backs of 8-week-old female ICR mice. From one week after initiation, 1 pg of TPA (1) was applied twice a week until week 20. The test compound (2.0 or 0.2 pM) dissolved in acetone-dimethyl sulfoxide (DMSO) (9 1, 100 pi) was applied 30 min before each TPA treatment. Groups of 15 mice were used. The number of tumors was counted weekly. 

As discussed in the previous sections, a number of triterpenoids with great structural diversity have antitumor-promoting activities. In contrast, 28-deacetylbelamcandal (288), a spiroiridal-type triterpenoid, has recently been reported to possess tumor promoting activity [92]. Compound 288, which stimulated differentiation of human promyelocytic leukemia (HL-60) cells (a fast method for screening TPA-type tumor promoters),... 

The concept that inflammation and carcinogenesis are related phenomena has been the subject of many studies that have attempted to link these two processes in a mechanistic fashion [94-99]. In connection with this, as is evident in some triterpenoids such as oleanolic acid (142), glycyrrhetic acid (147), and ursolic acid (210) in Table 2, those possessing anti-inflammatory activity in various experimental models exhibited antitumor-promoting activity as well. This suggests that most of the other anti-inflammatory triterpenoids and sterols listed in Table 2 might have antitumor-promoting properties which have not been evaluated, yet. 

Because of such extensive application in folk medicine, it is easy to understand the interest that the lapachol, the related naphthoquinones a-lapachone, P-lapachone and other naphthoquinones derivatives, have aroused as potential drugs. In fact, a broad variety of biological activities have been described for this kind of compounds. Some examples are antitumor promoting activities [11-12], inactivators of human cytomegalovirus protease [13], antiprotozoal activity [14], trypanocidal activity [15], anticancer activity [16], and antibacterial and antifungal activities [17]. 

Satomi, Y.,Tokuda, H., Fuji, H., Shimidzu, N.,Tanaka, Y., and Nishino, H. 1996. Antitumor promoting activity of fucoxanthin, natural carotenoids. J. Kyoto Pref. Univ. Med., 105,739-743. 

Yoshizawa, S., Horiuchi, T., Sugimura, T., et al.. Antitumor promoting activity of (-)-epigallocatechin-3-gallate the main constituent of tannin in green tea, Phytother. Res., 1, 44-47, 1987. 

The major pigment in Curcuma species (Zingiberaceae family) is the yellow phenolic diarylheptanoid curcumin (Jl). Curcumin and its analogs have potent antioxidant and antiinflammatory effects, cytotoxicity against tumor cells, and antitumor-promoting activity (96). The biologic effects and targets of curcumin, as well as its possible roles in cancer prevention and therapy, have been reviewed recently (97, 98). 

Ethanolic extract (50%) of M. oleifera (whole plant excluding roots) shows anti-cancer activity in mice (50). Evaluation of the anticancer potential of 11 plants used in Bangladeshi folk medicine has shown that, only three extracts, among which M oleifera, is considered as a potential source of anticancer compounds (56). Crude ethanol extract of M. oleifera dried seeds inhibits the formation of Epstein-Barr virus-early antigen (EBV-EA) induced by 12-0-tetradecanoylphorbol-13-acetate. At a dosage of 100 pg/mL, the extract inhibits EBV-EA formation by 100% suggesting its antitumor-promoting activity (99). 

Antitumor and antitumor promoting activities were also observed in SDB. 

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