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A Fungal solution to Cancer

Nature is the mother to all solutions! And this has been proven time and again. In early 1960’s National Cancer Institute, United States, funded researchers to find a natural compound to treat one of the most dreadful diseases of all times- cancer. After screening through thousands of trees, scientists finally found a remarkable chemical compound from the bark of a Pacific Yew tree (Taxus brevifolia). They named this biomolecule with anti-cancer properties as Paclitaxel (marketed as Taxol).

While the unique structural properties of paclitaxel captivated scientists, its extraction posed a major challenge. Just to harvest a gram of this compound from the bark, an entire yew tree had to be cut down. Because of the rare existence and its slow growing nature, loss or possible extinction of this tree started becoming a major concern both for the ecologists and the nature-lovers across the globe. Consequently, while scientists were grappling with the issue of the continued supply of yew plants, a semi-synthetic way to make Taxol on a large scale was soon invented. For this, scientists would obtain some chemicals from the yew tree and manufacture some in the lab. The undeterred scientists didn’t want to stop here. They further explored the possibility of finding a potential source of this remarkable drug, in the woods again!

Two decades later into the quest, a group of scientists stumbled upon an endophytic fungus- a type of friendly, harmless fungus - living inside this yew plant species. And this seemingly shy fungus, which didn’t show any external symptoms of its presence within the plant, was soon declared a Taxol producer! With great optimism and euphoria, this discovery had been heralded as an alternative to plant-based Taxol production, reducing the impact on nature. It was argued to intensify efforts of cancer research teams and the drug industries alike. It also opened the doors for the scientists to look for more of such chemical compounds of therapeutic value, in plants. That said, even today, the full potential of such an approach is still a keenly pursued topic in several scientific and industrial labs of the world

In our backyard, a team from biochemistry lab at the Indian Institute of Science, Bangalore, led by Prof. C. Jayabaskaran, has been, for over a decade working on identification and extraction of natural compounds of pharmaceutical value found in well-known medicinal plants and their endophytic fungi. Not long ago, while working on mass cultivation of an evergreen shrub, Chinese yew (Taxus celebica) of the Yew family, Prof. Jayabaskaran accidently came across a fungus growing from the aseptic cuttings of this shrub. It was later identified as Fusarium solani, a Taxol-producing endophytic fungus. This finding changed the course of his lab research and now, much of his important work focuses on carrying out various studies on the same.

The need to identify and mine such natural compounds before we destroy the existing biodiversity concerns Prof. Jayabaskaran, and this apparently is the driving force of his research. His enthusiastic team of researchers at the lab is consistently working on finding more such pharmaceutically valued substances or molecules from other endophytic fungi showing potential of being developed into an anticancer drug. Recently, the team reported the finding of a unique chemical compound (Cholestanol glucoside), an anticancer compound. It was isolated from an endophytic fungus (Lasiodiploidiat heobromeae) residing in the Ashoka tree (Saraca asoca).

One of the major challenges in extraction of these medicinal compounds is their occurrence in extremely small amounts. It obviously becomes difficult for the scientists to isolate and purify them. For over two decades since the discovery of nearly 200 different Taxol producing endophytic fungi, scientists around the world have been working to translate this discovery to industrial level production. But, none has seen any success. Despite this, using various approaches Prof. Jayabaskaran’s team is working with zeal to come up with a reasonable chance of success - scaling up the microbial cultures to industrial levels, like the antibiotic Penicillin. Recently, in a joint venture with a Kolkata based biotech company- Phytobiotech, they had even done a collaborative project to study such a feasibility. However, owing to several less understood factors and the enigmatic nature of this organism, the results remained far from what had been anticipated.

 “A well known or any novel drug, even a single one, getting closer to market potential would be great to see before retiring”, says the undeterred Professor with a spark of hope in his eyes, keeping the trail of his scientific explorations alive. “To make the availability of affordable drugs to common man a reality” is what drives us, he further adds. Research in endophytic fungi opens a scope for the future generations of students and teachers to explore options beyond mainstream areas, opines Prof. Jayabaskaran.

About the scientist: Dr. C. Jayabaskaran is a Professor at the Department of Biochemistry. Currently he works in his lab with a team of 8 Phd students and an equal number of Postdoctorol fellows. The Taxol group comprises his students Satpal Singh and Balendra Sah as well postdocs Dr. Subban Kamalraj and Dr. Venkatesh.

Contact: Tel: +91-80-22932482, +91-80-23600118

 Email: cjb@biochem.iisc.ernet.in

Labwebpage: http://biochem.iisc.ernet.in/cjayabaskaran.php#