(From left) Research team members Ajit Kumar Shasany, Shubra Rastogi and Anil Tripathi
New Delhi, June 1: Indian scientists have sequenced the full genome of tulsi in a research effort they say is intended to yield pathways to new medicines from this medicinal herb revered for centuries by several systems of medicine.
The researchers in a government laboratory in Lucknow and a private genome sequencing centre in Bangalore have generated a draft sequence of the 386 million genetic alphabets that make up the full genome of Ocimum sanctum, the botanical name for tulsi.
In their three-year-long research effort, the scientists have also identified over 53,480 protein-coding genes in the tulsi genome. Some of these genes are believed to play key roles in the biosynthesis of the myriad biochemicals in the plant promoted in traditional medicine as a herb that can fight infections and inflammation, protect people from diabetes and cardiovascular diseases, help wounds heal and ease painful and spasomodic conditions.
"Now, we can explore the plant's properties through its genetic make-up," Ajit Kumar Shasany, a molecular biologist at the Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, who led the genome sequencing effort, said.
Tulsi is the first medicinal herb from the family named Lamiaceae - whose members also include mint, oregano, and rosemary - to have its genome sequenced. Shasany and his colleagues from CIMAP - a laboratory under the Council of Scientific and Industrial Research - and Genotypic, the collaborating institution in Bangalore, have described their work in the journal BMC Genomics.
"It was exciting to work on the genome of tulsi. I've heard so much about this herb since childhood," said Shubra Rastogi, a post-doctoral research fellow at CIMAP and first author of the study. "We want to understand why this herb seems so important in ancient medicine."
The genome sequence will allow scientists to study the biochemical pathways involved in the synthesis of medicinal compounds such as phenylpropanoids and terpernoids found in tulsi as well as look for new pharmacologically-active compounds in the herb. Ancient Indian text Charak Samhita mentions tulsi as a remedy for common ailments.
Five years ago, a team of pharmacologists reviewed modern scientific studies on Tulsi and listed several leads -- extracts of the plant have been shown promise through anti-diabetic, anti-fungal, anti-microbial, cardioprotective, and analgesic [pain-relieving] properties.
The CIMAP researchers say the genome sequence will help decipher how modifications of the basic phenylpropanoids and terpenoids occur within the plant, leading to new knowledge about minor as yet unidentified pharmacological compounds and their therapeutic actions.
"Several compounds produced during the biosynthetic pathway may have their own medicinal properties which we hope to explore," Shasany said. "So the genes involved in these pathways will tell us about the nature of biochemical reactions and how the medicinal properties emerge."
The CIMAP team began their sequencing effort about three years ago and spent the past year analysing the sequence and annotating its genes.