By Sahana Ghosh
Kolkata, Feb 21 (IANS): Abundant in the lush hills of northeast India, a variety of plant-like organisms called lichens may hold the key to a potential drug against breast cancer that affects one in 28 women in India, according to a discovery by scientists here.
Attached to rocks and tree trunks and seen on the ground, these dual organisms are made up of a symbiotic association of fungus and alga and are known reservoirs of dyes and drugs.
India is home to more than 2,400 species of lichens - also included in the lower plants category along with mosses and ferns - or almost 16 percent of its global distribution.
Now, a team of five scientists at the Kolkata-based Bose Institute's Division of Molecular Medicine have shown that an extract of the tropical lichen species Parmotrema reticulatum (PRME) can "specifically" halt duplication of cancerous cells and trigger their death without harming normal cells.
Their medicinal properties have been attributed to the active compounds generated as a result of their mutually beneficial relationship, said Nripendranath Mandal, Associate Professor of the Division and leader of the research group involved in the study.
"The 70 percent methanolic extract PRME which we used possesses significant anti-cancer activity against breast cancer cells in the laboratory, that is, in vitro. We have also demonstrated the mechanism through which it acts. Further studies need to be carried out in vivo (biological systems) to develop it as a drug," Mandal told IANS.
The study was done in collaboration with Jayashree Rout of the Department of Ecology and Environmental Science at Silchar's Assam University.
The group was also able to point out the extract's targeted effect.
"At a dose of 300 micro-grams per millilitre, in 48 hours it exhibited 87 percent killing effect on cancer cells. However, it did not damage the normal cells," Mandal said.
What is more intriguing is the fact that this selective destruction of cancer cells (a crucial requirement to minimise the side effects of chemotherapy) stems from a synergy of the constituents in the PRME. Used individually, the active components lost their specificity.
"When the components of the extract were applied individually, the specificity towards cancer cells was lost and the constituents attacked normal cells as well," elaborated research scholar Nikhil Baban Ghate, who was a part of the research group.
Additionally, it also scavenged degenerative elements (an action termed antioxidant) called free radicals that are produced in the body during cancer and other diseases.
These outcomes reflect the involvement of different pathways in PRME's mechanism of action as an anti-cancer agent, along with its ability to interfere in disease progress - a critical find.
"Since the onset of cancer is multi-faceted, such multi-pronged approach of natural products could be the best way to tackle the disease," said Mandal, whose group has screened as many as 35 plants and herbs for anti-cancer and chemo-preventive effects.
Welcoming the discovery, Gopal Prasad Sinha, an authority on lichens in the country, said bio-prospecting or the search and screening of plants for novel drugs should be boosted.
"We keep discovering new species in India but there aren't many people trained to work in this field. Since the organisms are a combination of fungi and algae, myriad varieties of bioactive compounds are produced by them. This variety is found abundantly in the northeast and many other species are waiting to be tapped.
"Studies like these are necessary to obtain valuable products for human welfare," Sinha, a senior scientist at Allahabad's Botanical Survey of India, told IANS over the phone.