Cancer is one of the most dangerous diseases in the world today. The International Agency for Research on Cancer (IARC) estimated 14.1 million new cases of cancer worldwide in 2012 alone, out of which, eight million cases were from the developing countries. Approximately 8.2 million cancer deaths occurred in the same year, which means 22,000 cancer deaths every day. The World Health Organization has estimated that the cancer cases would increase by 70% over the next two decades. The most common causes of cancer deaths are lung, liver, stomach, colorectal, breast and oesophageal cancer. It is normally treated using radiation, chemotherapy and surgery. However, all these methods of treatment carry considerable side effects and thus, treating with naturally occurring compounds is the most desirable way. A research group at the Indian Institute of Science, Bangalore, led by Dr. S.C. Raghavan, has recently reported some natural anticancerous compounds in two independent studies.
The first study was conducted using quercetin, which is a naturally occurring compound abundantly seen in several fruits and vegetables. Quercetin was known to posses anticancer and anti-inflammatory activity, but the mechanism by which it works against cancer was not known until now. The researchers at the lab studied the antitumor potential of quercetin, both on mice models of cancer and cells in culture in the laboratory. The anticancerous potential of quercetin was very high in comparison to other naturally occurring compound like ellagic acid. Treatment with quercetin showed five fold increase in the life span of Swiss albino mice having cancer.
Quercetin induces apoptosis, a process by which cells commit suicide, in a controlled manner in high stress conditions. It also prevents multiplication of cancerous cells by blocking the process of cell division. Quercetin treatment significantly reduced the size of the cancerous tumor in experimental animals used in the study. They also found that quercetin interacts with DNA, the genetic material in organisms. Binding to DNA is one of the mechanisms by which anticancerous drugs cause DNA damage, which eventually leads to destruction of cancerous cells.
Quercetin is so active against cancer that it can even kill the highly aggressive leukemia cell line K562, which is resistant to most of the anticancerous drugs. One of the most interesting findings is that quercetin kills the cancerous cells without having significant adverse effects on non-cancerous cells of the body. Quercetin treatment had no side effect on the experimental animals, which justifies its use as a potential anticancer drug.
The second study was done using extract prepared from the medicinal plant Vernonia condensata. Vernonia condensatais a traditional medicine, which is used for treatment of cough, pneumonia, stomachache, digestive problems, muscular pain, liver problems, snakebite and diarrhea. The genus is distributed worldwide and mostly found in the tropical regions including India. Extract prepared from Vernonia condensata causeddeath of cancerous cells while sparing the normal cells. The researchers found that the Vernonia condensata extract functions by causing an imbalance in mitochondrial membrane potential (the charges on the membrane of cellular organelles called mitochondria). This imbalance eventually leads to destruction of the cancerous cells. The plant extract was successful in preventing growth of cancerous cells and increased the survival of mice with cancer by 60%. Treatment with Vernonia condensata extract also helped in the recovery of normal morphological features of tissues, which were damaged by tumor growth.
When asked about the potential use of their discoveries, Dr. S C Raghavan says, “Most of the chemicals used for cancer therapy suffer from significant side effects. Since it is a plant extract, we expect there are limited or no side effects. Quercetin is a good chemotherapeutic agent and it might show even better effect when used in combination with other chemotherapeutic agent.” Finally, some hope to treat the most dangerous disease, naturally.
About the authors
Sathees C. Raghavan is an Associate Professor at Department of Biochemistry, Indian Institute of Science, Bangalore Karnataka, India. Elizabeth Thomas, Shikha Srivastava, Ranganatha R. Somasagara, Mahesh Hegde, Mayilaadumveettil Nishana, Satish Kumar Tadi and Mrinal Srivastava are research scholars at Department of Biochemistry, IISc. Vidya Gopalakrishnan and Bibha Choudhary are from Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore 560 100, India.
About the study
The papers appeared online in the journal “Scientific Reports”
Quercetin: Scientific Reports | 6:24049 | DOI: 10.1038/srep24049
Vernonia condensata: Scientific Reports | 6:23255 | DOI: 10.1038/srep23255