Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the 9th leading cause of cancer-related deaths in the U.S. Since 1980, its incidence rates have increased more than three times and its death rates have more than doubled. This year, 41, 260 new cases and 30, 520 deaths related to this disease were estimated by the American Cancer Society.
As opposed to other prevalent cancers like breast and lung cancer, only a few medical interventions have been thoroughly tested for HCC. The three curative treatments currently available for patients with early-stage HCC include local destruction, surgical resection, and orthotopic liver transplantation. If the cancer is widespread, other treatment options like chemotherapy, immunotherapy, and targeted therapy are also available. Read more on liver cancer treatments through What You Need to Know About Liver Cancer Treatment.
With the limitations of the treatments available for HCC, there is then a need for alternative chemopreventive and therapeutic treatments to help patients with advanced HCC achieve a higher chance of survival and extend remission after curative treatments. Although more medical studies still need to be done and it still does not replace the conventional treatments mentioned above, the use of herbal medicines may complement these.
The use of herbal medicine for liver cancer treatment has been a long tradition practiced by herbalists and indigenous healers worldwide. According to herbalists, illnesses result from body imbalances, and the herbs may be used to neutralize these imbalances and keep the body’s overall balanced status.
For the past decades, herbal medicines have grown in popularity due to their safety, long-lasting curative effects, few adverse side effects, and cost-effectiveness. Studies on the prevention and treatment of HCC using herbal medicine have also accumulated. The compounds derived from herbs and their composites have captured the interest of many oncologists. In vivo and in vitro, they have studied certain compounds used as an anti-HCC agent. A review article by Vijayaalakshmi in 2015 states that clinical research in the current century has verified the efficacy of herbal plants in treating various liver diseases while basic scientific studies have revealed the therapeutic effects of the herbal plants.
Common anti-HCC herbal compounds
In general, herbal medicines are composed of a combination of herbs and other ingredients, also called “herbal composite formula. The use of different ingredients ensures efficacy on several target sites simultaneously. Some of the most common compounds include:
Curcumin is a compound extracted from Curcuma longa or turmeric, which is a tropical plant extensively cultivated in many countries in Asia and widely used as a spice and coloring agent in food. In addition to food application, this plant is also known for treating different liver diseases, digestive disorders, and skin problems due to its anti-inflammatory and antioxidant properties. It contains similar liver protectant compounds that artichoke leaves and milk thistle contain. Due to its shrinking effect on engorged hepatic ducts, it is used to treat hepatitis, jaundice, and cirrhosis.
In terms of cancer application, in vitro and in vivo studies of anticancer effects of curcumin have been studied. Studies found that this compound has the ability to control cancer cell proliferation, tumor growth, migration, and metastasis. For example, a recent study by Willenbacher, et al showed that curcumin can counteract cancer-inducing inflammation in humans and animals due to its efficient anti-inflammatory effects.
Resveratrol is a polyphenol found abundantly in grape skins and red wine. This compound is found to have potent inhibitory effects against cancer cells, including HCC as it can be efficiently absorbed in the liver. The study of Bishayee et al supports this by finding out that resveratrol inhibits cell proliferation and apoptosis induction in rat samples.
Resveratrol is also found to exhibit pharmacological activities for treating other liver diseases like liver steatosis, liver fibrosis, and fatty hepatitis due to its anti-inflammatory, antioxidative, and hepatoprotective properties.
Silibinin, a polyphenolic flavonoid, is one of the major components of silymarin extract from milk thistle seeds. This compound has a wide range of pharmacological activities, including antiproliferative, antioxidant, immunomodulatory, and antiviral, on different organs. Moreover, studies suggest that silibinin also has anticancer effects against liver cancer. With an appropriate dose, it can inhibit the growth of human hepatocellular cancer cells while elevating the apoptotic cell population.
Other studies find the compound effective in treating other liver diseases. A review conducted by Wellington and Jarvis also mentioned that daily administration of silymarin for several years can significantly reduce the mortality of patients with alcoholic liver cirrhosis.
- Tanshinone II-A
Tanshinone II-A is a lipophilic active compound derived from the roots and rhizomes of Salvia miltiorrhiza Bunge, a Chinese medicinal herb popular as Danshen in English. It is used in different provinces in China and other neighboring countries to treat a wide range of diseases, including liver disorders, diabetes, cardiovascular diseases, apoplexy, and arthritis. The compound has known effects to relieve pain, activate blood circulation, and remove blood stasis.
In the past few years, Tanshinone II-A was reported to have antitumor effects on various tumor cell lines of humans. It can inhibit tumor growth, regulate the cell cycle, induce apoptosis, and reverse multidrug resistance for cancer cells responsible for HCC, leukemia, lung cancer, colorectal cancer, breast cancer, and prostate cancer.
- Other reported compounds
In addition to the four, there are also other compounds investigated for their chemopreventive effect to treat HCC.
- Salvianolic acid B, a polyphenolic acid derived also from Danshen, has shown effects on improving acute and chronic liver diseases of injured rats.
- Baicalein, a flavonoid from Baikal skullcap root, was investigated by Matsuzaki et al for its anti-HCC effect. They found that this compound can inhibit the activity of topoisomerase II, an enzyme responsible for DNA replication and chromosome segregation. Moreover, they observed that baicalein suppresses HCC cell line proliferation.
Pheophorbide a (Pa) is an active compound extracted from Scutellaria barbata, a species of flowering plant in the mint family. A research by Tang et al studied the anti-proliferative effect of Pa on a multidru