The present study was designed to investigate the effects of linalool, a monoterpene alcohol found in essential oils of aromatic plants such as basil, on the growth of human breast cancer cells, both as a single agent and in combination with doxorubicin (Adriamycin). Essential oils derived from various aromatic plants have been reported to have chemopreventive and antitumor effects. A number of studies have also demonstrated the ability of some chemopreventive phytochemicals to increase the sensitivity of cancer cells to conventional chemotherapy drugs. The success of chemotherapy is often limited by the development of resistance to the treatment. Multidrug resistant phenotypes, which have been reported in a number of tumors, generally involve reduced intracellular drug accumulation as a result of increased drug efflux by membrane transporters. In the present study, two human breast adenocarcinoma cell lines, MCF7 WT and multidrug resistant MCF7 AdrR, were used. Linalool alone only moderately inhibited cell proliferation. However, subtoxic concentrations of linalool increased doxorubicin-induced cytotoxicity and pro-apoptotic effects in both chemotherapy-resistant cell lines. A significant synergism between linalool and doxorubicin was observed in MCF7 AdrR cells, which may have been due, at least in part, to the ability of linalool to increase doxorubicin accumulation and to cause a decline in Bcl-xL levels. The authors conclude that linalool may improve the therapeutic index of anthracyclines in the management of breast cancer, especially in multidrug resistant tumors.

The present study investigated the anti-proliferative activity of essential oils from 17 Thai medicinal plants on human mouth epidermal carcinoma and mouse leukemia cell lines. Each line of cancer cells was treated with the oil samples at various concentrations. Guava leaf oil showed the highest anti-proliferative activity in the human mouth epidermal carcinoma cell line. Sweet basil oil had the highest anti-proliferative activity in the murine leukemia cell line. The authors conclude that essential oils of Thai medicinal plants have the potential for use as cancer treatment.

The present study was designed to evaluate the anticancer effects of basil polysaccharide in vivo. 150 mice were divided into five groups to observe the effect on tumor growth after H22 liver cancer cells had been transplanted into their right armpit region and treated with different dosages of basil polysaccharide for 14 days. Mitomycin, a chemotherapy drug, used as control. An additional 150 mice were divided into three groups and models of tumor metastasis in the lung by various paths (lymphatic, blood circulatory and spontaneous) were established. These mice were treated with basil polysaccharide or mitomycin to observe the influence of treatments on tumor metastasis by various paths. Basil polysaccharide of various dosages showed no effect on tumor growth. However, in high and middle dosages, it was found to significantly reduce the number of metastasis nodules. The authors conclude that basil polysaccharide has a tumor metastasis inhibitory effect, which might be effected by blocking the function of platelets in the tumor metastasis progress.

Basil or sweet basil (Ocimum basilicum) is cultivated throughout India. The effects of doses of 200 mg/kg and 400 mg/kg body weight of an extract of the fresh leaves of Ocimum basilicum on various liver enzymes and other factors were evaluated in the liver of 8-9 week old Swiss albino mice. In addition, the anticancer potential of basil leaf extract was studied, using carcinin-induced forestomach and skin lesions. Basil leaf extract was found to be very effective in elevating antioxidant enzyme response by significantly increasing the hepatic glutathione reductase, superoxide dismutase, and catalase activities. Reduced glutathione, the major intracellular antioxidant, showed a significant elevation in the liver and also in all the other organs. In the forestomach, kidney and lung, glutathione S-transferase and DT-diaphorase levels were augmented significantly. Significant declines in lipid peroxidation and lactate dehydrogenase activity were also observed. Chemopreventive response was evident from reduced tumor burden as well as from a reduced percentage of tumor bearing mice. The authors conclude that basil leaf augmented the Phase II enzyme activity that is associated with detoxification of xenobiotics, while inhibiting the Phase I enzyme activity. In addition, basil leaf extract was found to be highly effective in inhibiting carcinogen-induced tumor incidence in both the tumor models.

The levels of the following chemicals were assessed carefully in certain food products: 4-allylanisole (estragole), 4-allyl-1,3-benzodioxole (safrole) and 4-allyl-1,2-dimetoxybenzene (eugenol methyl ether). The detection limits, as found in both standard solutions and in foods, were 10, 5 and 8 ng/ml for estragole, safrole and eugenol methyl ether, respectively. The estragole, safrole and eugenol methyl ether levels were measured in 42 samples, for a total of six product types, including “Pesto” sauce, tomato sauce containing basil, “Cola tasting” beverages, Bologna sausage, Vienna sausage and fresh basil. The levels ranged from below the detection limit up to 19.30 mg/kg for estragole in “Pesto” sauce.

Rosmarinic acid is a phenolic compound found in herbs such as rosemary, sweet basil and perilla. The present study investigated the effects of rosmarinic acid on cultured mouse mesangial (kidney) cell proliferation. Cultured murine mesangial cells were stimulated by growth factors with or without rosmarinic acid. [3H]thymidine incorporation was measured both for signal transduction and cell cycle dependency and mRNA extracted from the cells was analyzed. Rosmarinic acid was found to inhibit cell proliferation induced by platelet-derived growth factor or tumor necrosis factor, and these effects involved several phases of the cell cycle. The authors concluded that rosmarinic acid inhibits cytokine-induced mesangial cell proliferation and suppresses platelet-derived growth factor and c-myc mRNA expression in platelet-derived growth factor-stimulated mesangial cells.

Extracts of 15 kinds of commonly consumed Thai vegetables were tested for antimutagenic activities against direct-acting and indirect-acting mutagens using Salmonella typhimurium TA100 as the test strain. It was found that Thai bitter gourd fruits, but not sweet basil leaves, partially inhibited DMBA-induced mammary gland carcinogenesis in female Sprague-Dawley rats when fed to the animals two weeks before the DMBA treatment. The authors noted that sweet basil leaves may not contain any anticarcinogen against DMBA-induced mammary gland carcinogenesis.