For centuries, a herb native to southeastern China and Korea has been used to treat various disorders like bacterial infections, inflammation, hepatitis and cancer. Traditional Chinese medicine has long regarded this member of the mint family to be an anti-inflammatory, diuretic, and anti-tumoral agent. It is only in recent years that Western researchers have been taking a closer look at the cytotoxic effects of this herb.

Scutellaria Barbata or the Baikal Skullcap is known by many synonyms, such as apigenin, baicalin, ban-ji-ryun (Korean), banjiryun (Korean), ban-zhi-lian (Chinese), barbatin A, barbatin B, barbatin C, benzyaldehyde, berberine, carthamidin, flavonoidglycoside, flavonoids, Herba Scutellariae Barbatae, hexahydrofarnesylacetone, isocarthamidin, Lamiaceae (family), luteolin, menthol, neo-clerodane diterpenoids, PC-SPES, pheophorbide A, resveratrol, SBJ, scutebarbatine B, scutellarein, Scutelleria baicalensis, Scutellaria baicalensis Georgi, Scutellaria bardata, Scutellaria barbata D. Don, Scutellaria rivularis Wall., scutellarin, wogonin.

The National Cancer Institute thesaurus describes Scutellaria Barbata D. Don (Lamiaceae) as having potential antineoplastic activity. Containing the antioxidant flavone scutellarin, herba Scutellaria barbata has been shown to induce apoptosis of ovarian and breast tumor cells in vitro.

A research article from the Sept. 17, 2004, issue of the journal Life Science concluded that Scutellaria Barbata significantly inhibited growth of a human lung cancer cell line. A study in the August 2009 issue of the European Journal of Cancer Prevention found that an extract of Scutellaria Barbata induced apoptosis, or programmed cell death, in a mouse liver cancer cell line. Many more studies support these findings.

In vitro studies have shown that Scutellaria Barbata exerts anticancer effects via caspase-dependent apoptosis (1,2,3), and by downregulating Bcl-2 protein that is expressed by tumor cells (4). Scutellaria Barbata also increased macrophage function in a murine carcinoma cell line that resulted in inhibition of tumor growth (5). It was shown to affect the metabolism of mutagenic compounds such as benzopyrene, thereby reducing their ability to bind DNA (6).

According to a study published in the January 2009 issue of Planta Medica which researched 13 different Scutellaria species, Scutellaria contains a combination of plant chemicals that together can significantly slow the growth of several different cancers. “On the basis of our preliminary results, we expect maximum benefit from Scutellaria…in combination with standard therapy such as surgery, chemotherapy, and immunotherapy,” says Prahlad Parajuli, PhD, assistant professor in the Department of Neurosurgery at Wayne State University and Karmanos Cancer Institute in Detroit, Michigan.

Past studies have shown that Scutellaria has potent antibacterial, anti-inflammatory, and anti-cancer properties, which come primarily from natural plant chemicals (phytochemicals) called flavonoids. Most of the research conducted on Scutellaria so far has focused on the roots of the herb, which are rich in the flavonoid wogonin. However, the leaves and stems are also thought to be high in cancer-fighting phytochemicals, according to study co-author Nirmal Joshee, PhD, assistant professor of Plant Science at Fort Valley State University in Georgia.

After analyzing leaf, stem, and root extracts from 13 different Scutellaria species, the researchers found that each extract contained different combinations of six flavonoids: apigenin, baicalein, baicalin, chrysin, scutellarein, and wogonin. Most extracts contained three or four different flavonoids. Two extracts contained all six flavonoids.

Human breast, prostate, and brain cancer cells, as well as non-cancerous cells, were then treated with the Scutellaria extracts. Nine of the extracts significantly halted the spread of cancer cells. The higher the dose and longer the duration of treatment, the more effectively the extracts killed cancer cells. Four extracts—all from the Scutellaria leaf—were particularly effective at triggering the death (apoptosis) of brain cancer cells.

The researchers also looked at how the flavonoids in Scutellaria—both individually and in combination—affected cancer cells. A combination of four flavonoids, each at a low dose, blocked the growth of brain cancer cells by almost 50 percent. However, when those same flavonoids were given individually at the same dose, they had no effect on the cancer, which suggests that each one possesses a different anti-cancer mechanism and the effects are amplified when the different flavonoids work together.

Certain flavonoids in Scutellaria also appeared to target specific types of cancer. For example, baicalein significantly slowed the growth of brain cancer cells. This may be because individual flavonoids affect mechanisms that are unique to each cancer, said the authors in their report “In vitro antitumor mechanisms of various Scutellaria extracts and constituent flavonoids” in Planta Medica. 2009;75:41-48.

A drug based on the extract of Scutellaria barbata is also being developed to destroy the blood vessels supplying tumours. Professor Alan McGown and colleagues at the University of Salford have so far tested the drug in the laboratory on human cancer cells from tumors such as breast and lung cancers. In an anti-angiogenic approach, the drug works by attacking the tumor’s blood vessels, starving the cancer to death by blocking its supply of oxygen and nutrients. Co-researcher Dr Sylvie Ducki said: “If you target the vessels you are stopping the ‘food’ getting to the tumour and the tumour from spreading.” The drug is selective – targeting only tumour vessels and leaving blood vessels supplying healthy tissues alone. This is unlike conventional treatments which usually target tumour cells but also the normal cells, causing a lot of side effects.

A company called Bionovo has developed and is working to patent an extract of Scutellaria Barbata which it calls BZL101. The company’s researchers believe the herb’s main agent has the ability to specifically identify and target malignant cells, leaving normal cells intact and healthy. The oral anti-cancer drug BZL101 works by eliciting a cancer cell’s innate mechanism of self-suicide, or apoptosis. The drug selectively releases Apoptosis Inducing Factor-1 (AIF1) from a cancer cell’s mitochondrial membrane. AIF then moves to the cell’s nucleus, disintegrating the DNA structure, and fragmenting and killing the cancer cell. Bionovo’s scientists say that although AIF exists in all cells, this protein-translocation process can be elicited exclusively in cancer cells while avoiding normal cells.

Researchers from the Department of Molecular and Cell Biology and The Cancer Research Laboratory, University of California at Berkeley, recently reported that BZL101 disrupts proliferation of human breast and prostate cancer cells through distinct mechanisms dependent on the cancer cell phenotype.

After completing a phase I study on BZL101, researchers at The University of California at San Francisco and the Komen/UT Southwestern Breast Cancer Research Program at University of Texas Southwestern Medical Center
presented encouraging data at the 28th Annual San Antonio Breast Cancer Symposium. Some 16 patients has been evaluated in the clinical trial, receiving 350 ml (12 grams dry solubles) per day of the Scutellaria Barbata extract in tea form. Details of their findings are given in their report “Herba Scutellaria Barbatae for Metastatic Breast Cancer”.

Clinical trials are tedious affairs and it takes a long time to get a drug to market. Meanwhile, I’ll continue to enjoy the benefits of Scutellaria Barbata the old-fashioned way, brewed together with another ancient Chinese anti-cancer herb Oldenlandia Diffusa. This cancer-fighting combo makes a delicious, slightly bitter, smoky-flavored herbal tea, which I like to sweeten with another traditional Chinese herbal remedy, Lo Han Kuo, a dried fruit favored for its immune-system boosting properties. All these ingredients are easily available from any traditional Chinese medicine shop in Chinatown. Just ask for “Ban Zhi Lian” (Scutellaria Barbata), “Bai Hua She She Cao” (Oldenlandia Diffusa) and “Lo Han Kuo” (Momordica Grosvenor).

Incidentally, the fact that at least two known natural aromatase inhibitors – apigenin and chrysin – are flavonoids commonly found in the Scutellaria family of herbs, should make this herb even more appealing to people with hormone-sensitive cancers, such as estrogen receptor positive breast cancer. I just had my second cup of this cancer-fighting herbal tea for the day and I must say it’s a delicious way to take my medicine. Cheers to herbs!

References:
(1) Kim DI, et al. Regulation of IGF-I production and proliferation of human leiomyomal smooth muscle cells by Scutellaria barbata D. Don in vitro: isolation of flavonoids of apigenin and luteolin as acting compounds. Toxicol Appl Pharmacol 2005; 205(3):213-224.
(2) Yin X, et al. Anticancer activity and mechanism of Scutellaria barbata extract on human lung cancer cell line A549. Life Sci 2004; 75(18):2233-2244.
(3) Powell CB, et al. Aqueous extract of herba Scutellaria barbatae, a chinese herb used for ovarian cancer, induces apoptosis of ovarian cancer cell lines. Gynecol Oncol 2003; 91(2):332-340.
(4) Kim KW, Jin UH, Kim DI, et al. Antiproliferative effect of Scutellaria barbata D. Don. on cultured human uterine leiomyoma cells by down-regulation of the expression of Bcl-2 protein. Phytother Res. 2008 May;22(5):583-90.
(5) Wong BY, et al. Oldenlandia diffusa and Scutellaria barbata augment macrophage oxidative burst and inhibit tumor growth. Cancer Biother Radiopharm 1996; 11(1):51-56.
(6) Wong BY, Lau BH, Teel RW. Chinese medicinal herbs modulate mutagenesis, DNA binding and metabolism of benzo[a]pyrene 7,8-dihydrodiol and benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide. Cancer Lett 1992; 62(2):123-131.