Holy basil (Ocimum tenuiflorum) contains ursolic acid and other compounds with powerful antioxidant, anti-inflammatory, antimicrobial, and antifungal properties. Holy basil has radioprotective properties, having been shown to protect against radiation-induced sickness and prevent radiation-induced DNA damage.

Breast cancer-related effects of holy basil

Holy basil has been shown to inhibit breast cancer (including DCIS) growth and progression by affecting cell proliferation and angiogenesis in a mouse experimental model. A 2023 study reported that holy basil extract inhibited the proliferation of ER+/PR+ breast cancer cells.
Ursolic acid has been shown to reverse multidrug resistance in breast cancer cells. One study found that ursolic acid reversed resistance to Taxol (paclitaxel) in Taxol-resistant triple negative breast cancer. Another study reported that ursolic acid resensitized multidrug resistant ER+/PR+ breast cancer cells to Adriamycin chemotherapy. Still another 2021 study demonstrated that ursolic acid also increased the sensitivity of triple negative breast cancer cells to Adriamycin.
Holy basil should not be used during radiation treatment since its radioprotective properties could interfere with the effectiveness of radiotherapy.

Additional comments

Holy basil, which is not typically consumed as food in the U.S., is available as tea (Tulsi tea). Holy basil should be purchased organic.
While they are closely related, basil (Ocimum basilicum), otherwise known as sweet basil, is not exactly the same plant as holy basil (Ocimum sanctum). Fresh or dried basil typically is used as a food ingredient, whereas holy basil normally is consumed as a herb in the U.S.

Sources of information provided in this webpage

The information above, which is updated continually as new research becomes available, has been developed based solely on the results of academic studies. Clicking on any of the underlined terms will take you to its tag or webpage, which contain more extensive information.
Below are links to 20 relevant studies concerning this food and its components. For a more complete list of studies, please click on holy basil.