Blooming problem for jasmine — it smells bad

Ever wondered why women who love to deck up their hair with jasmine choose just-opened buds over the fully-bloomed flowers? A team of researchers from a lab in Lucknow may have some answers.

Scientists from the Central Institute of Medicinal and Aromatic Plants (CIMAP) in Lucknow have found that buds of jasmine emanate a sweeter smell.

But this fragrance turns more pungent because of chemical changes that a volatile chemical compound — predominantly responsible for the fragrance — undergo.

In a work published early this week in the journal Phytochemistry , CIMAP scientists led by Ajit Shasany and Chandan Chanotiya, painstakingly recorded chemical changes that take place as these buds bloom.

To their surprise, they found that linalool, an aromatic compound responsible for the sweet smell not just in jasmine but in many other flowers, makes a switch from one form to another during flowering.

Linalool, an industrially important aroma molecule used in flavour and fragrance compositions, is naturally found in two forms — R-linalool and S-linalool. While they have same chemical composition, there is a subtle change in the way different molecules are stacked in them. “Structurally, they are mirror image of the each other,” said Pragadheesh V Shanmugam, who was the first author of the paper. Shanmugam, who completed his doctorate under Chanotiya, hails from a village in Erode district. While R-linalool has the fragrance of lavender, S-linalool smells like coriander, said Shanmugam.

“What was interesting to note was that there was a switch happening from R-linalool to S-linalool as the bud transforms into a fully-bloomed flower. As the flower blooms the levels of R-linalool go down, while that of S-linalool increase,” said Chanotiya. The relatively higher presence of S-linalool in the bloomed flower explains why people do not like it so much, he said.

“We have been able to isolate the gene responsible for the production of R-linalool in jasmine plant and are in the process of identifying the one that expresses S-linalool,” said Shasany.

The scientists hope that once this gene is isolated, they might be able to silence this gene, helping them to develop better-smelling jasmine varieties. Besides, this can also aid in producing better quality natural fragrant products, said Chanotiya.

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