Quinones were studied for their growth inhibitory effect on cultured malignant cells. HCT-15 cells derived from human colon carcinoma were used for these experiments. Quinones used were arbutin in the benzoquinone group, juglone and lawsone in the naphthaquinone group, alizarin, emodin, 1,8-dihydroxyanthraquinone, and anthraquinone in the anthraquinone group, and xanthone. Cultured cells were incubated with various concentrations of the quinones for four days in a 5% CO2 incubator, after which cell numbers were counted and significance of differences was analyzed by Student's t test. Anthraquinones and naphthaquinones used in these experiments were more effective than the monocyclic quinone. The 50% suppression dose was less than 12.5 micrograms/ml for them. The number of OH groups seemed to play an important role in the degree of the cell growth inhibition: anthraquinones with 2 or 3 OH groups were more effective than those with no OH group like, 9,10-dioxoanthracene and xanthone. In fact, anthraquinones with no OH group and xanthone were not significantly effective. Flow cytometric histograms revealed a specific pattern; that is, lawsone and juglone in the naphthaquinone group and alizarin and 1,8-dihydroxy-anthraquinone in the anthraquinone group blocked mainly the S phase, and emodin in the anthraquinone group blocked the G1 to S phase of the cell cycle.

When Balb/C mice that were fed with red glutinous rice, white ordinary rice, or commercially available standard food were inoculated with syngeneic Meth/A lymphoma cells i.p., the group fed the red rice survived longer than the other two groups. In order to determine if the anthocyanins contained in red-coloured seeds and fruit rinds were responsible for the tumor suppressive effect, we added anthocyanins extracted from grape rinds and glutinous red rice to petri dishes that had been seeded with HCT-15 cells. After 4 days of culture, cell counts were made. These anthocyanins were not effective in suppressing the tumor growth. However, anthocyanidins, which were generated by keeping anthocyanins in 5 to 6% HC1 methanol for 5 to 6 hours, were effective in the suppression of tumor growth. Flowcytometric histograms were made after 2 days of culture with these bioflavonoids. The histogram of cells treated with crude anthocyanin was similar to that of the control. Hydrolyzed anthocyanidins gave the elevation of S phase, suggesting a block in the step from S-phase to G2-phase. It seemed that the anthocyanidins contained in the grape rinds and red rice were effective on the suppression of cell growth as observed previously for anthocyanins extracted from the petals of higher plants.

Crude methanol extracts of red and white wines were added to diethyl ether in order to divide them into the anthocyanin fraction (insoluble in diethyl ether) and fractions containing other flavonoids and their derivatives (soluble in diethyl ether). However, the white wine did not contain anthocyanins (all of the methanol extract was soluble in diethyl ether). When HCT-15 cells, derived from human colon cancer or AGS cells, derived from human gastric cancer, were cultured with these fractions, the anthocyanin fraction from the red wine and the non-anthocyanic substances extracted from red and white wines suppressed the growth of the cells, and the suppression rate by the anthocyanin fraction was significantly higher than that of the other fractions. Thin-layer chromatographic analysis revealed mostly delphinidin in the anthocyanin fraction. The other fractions contained mostly flavonoids and their derivatives. The sugars in all fractions were mainly glucose, fucose, and fructose. Flow cytometric study suggested that the anthocyanin fraction blocked mostly S, G2, and M phase, and the non-anthocyanic flavonoids also blocked these phases, although the histographic pattern varied depending on the fractions. Methanol insoluble but water soluble fractions (mostly free sugars) of red and white wines did not show such suppressive effects.

Many bioflavonoids extracted from petals of higher plants and from fruit rinds, as well as purified flavonoids, have been reported to have antitumor effects in vitro and in vivo. Bioflavonoids extracted from red soybeans are mostly cyanin conjugated with glucose and rhamnose, whereas bioflavonoids of red beans are cyanin conjugated with rhamnose as revealed by thin-layer chromatogram. Flavonoids extracted from red soybeans were effective in inhibiting the growth of HCT-15 cells in vitro. On the other hand, flavonoids from red beans were not effective, although their hydrolyzed sugar-free forms were growth inhibitory. Sugar-bonded bioflavonoids extracted from both red soybeans and red beans were effective in prolonging the survival of Balb/C mice bearing syngeneic tumor-Meth/A cells, when they were dissolved in drinking water and given at a dose of approximately 500 micrograms/mouse/day.

Some PUFA as well as SFA were positively correlated with HOMA-R. These results indicate that the intake of diet fatty acid must be well balanced in diabetic patients and it is not always true to refrain from taking SFA and increase the unsaturated fatty acids in their diets.