Possible anti-tumor-promoting activity of components in Japanese soybean fermented food, Natto: effect on gap junctional intercellular communication

Abstract

In order to detect any protective agent against tumor formation, we examined the anti-tumor-promoting effect of a Japanese traditional soybean fermented food, Natto. Dye transfer was employed as an assay method. When fluorescent dye was microinjected into cultured BALB/3T3 cells, the dye was transformed into the neighboring cells through the gap junction. This dye transfer was blocked by the treatment with the tumor promoters 12-O-tetra-decanoylphorbol-13-acetate (TPA), a high concentration of NaCl and lithocholic acid (LCA). This reduction of the dye transfer by TPA treatment was not observed when the cells were pretreated with retinoic acid, an anti-tumor promoter. Thus, the recovery of the dye transfer in TPA-treated BALB/3T3 cells was proven to ge a good indicator for detecting some possible anti-tumor promoters. After extraction and fractionation of Natto, we obtained an active fraction (H1) which showed recovery of the dye transfer in TPA-treated cells. The fraction contained straight-chain saturated hydrocarbons. A comparison of the fraction and the authentic samples by GC analysis suggests that the H1 fraction contained straight-chain saturated hydrocarbons from around C30 to C32. Among these hydrocarbons, hentriacontane (C31) was found at the highest concentrations, and was shown to have the highest activity. Hentriacontane at a very low concentration of 0.65 ng/ml was shown to recover the dye transfer inhibited by the treatment with TPA as well as with NaCl and LCA.

Recent Progress in Research and Technology on Soybeans

“…Natto also has anti-tumor-promoting activity, because the extract prevented the reduction of dye transfer caused by a typical tumor promoter of 12-O-tetradecanoylphorbol-13-acetate (Takahashi et al, 1995). Besides these, natto possesses the activities to inhibit angiotensin I-converting enzyme, as soy sauce does (Okamoto et al, 1995).…”

Characterization of Bacillus subtilis strains in Thua nao, a traditional fermented soybean food in northern Thailand

“…Natto extract exhibits antioxidative activity (Esaki et al. 1990), anti‐tumor activity (Takahashi et al. 1995), and angiotensin‐I converting enzyme inhibitory activity (Okamoto et al.…”

Pyrostegia venusta heptane extract containing saturated aliphatic hydrocarbons induces apoptosis on B16F10-Nex2 melanoma cells and displays antitumor activity in vivo

“…Takahashi et al ., (1995) have found that hentriacontane, the main component in their bioactive fraction, showed the highest antitumor activity. [55] This same compound predominates in the epicuticular wax in leaves from Kigelia pinnata , and is responsible for the plant protection against UV radiation and for its antitumour potential. [56] The saturated hydrocarbon gentriacontan (C 31 H 64 ), present in the chloroform extract of Clinopodium vulgare , was reported to inhibit the growth of Erlich ascites tumor in mice, and also possesses antitumor activity against CEM and K-562 human leukemia cell lines in vitro .…”