There are 350 types of olfactory receptor (OR) in the human nose – each specifically evolved to perceive just one odour.
But did you know that ORs are also present in other organs of the human body? Indeed, some of these ORs are present in every single organ of the human body. Moreover, all are present in the human brain.
The exciting cosmetic and therapeutic possibilities involving these extranasal OR was the topic of 'Smelling beyond the nose', a presentation by Dr Hanns Hatt at the SEPAWA Congress, taking place from 10-12 October in Berlin.
Dr Hatt, from Ruhr-Universitat Bochum, cited human sperm – which are have ORs stimulated by 15 odours in vaginal secretion – as a prime example of the usefulness of extranasal ORs.
"Sperm swim in a cloud of odours that trigger responses. They're totally blind but can swim towards the ovum," Hatt said.
With potential for the nutraceuticals industry, Hatt told delegates that OR in the intestines respond to the odour of spices like cumin, which trigger the secretion of serotonin, boosting intestinal motility and facilitating better digestion.
In cosmetics, Hatt said there were odours that had been found to act on melanocytes – meaning the future could include fragrances that may be used to acquire a tan.
Meanwhile, Sandalor scent was found to stimulate ORs to increase the proliferation and movement of keratinocytes to promote better wound healing and, of course, younger looking skin.
Extranasal scents, said Hatt, have also been linked to blood pressure regulation, hair follicle activation and heart function, as well as reducing the proliferation of certain carcinoma cells, and facilitating cancer diagnosis – OR2B6, for example, is an OR very specific to breast cancer, which can be used as a diagnostic marker.
Hatt stressed that, for such efficacy, odours must be applied directly to the site via topical application, ingestion or addition to the blood stream, rather than inhaled.
He also stressed that of these 350 human ORs there are only 50 types of receptor for which the scientific community knows the appropriate 'key' – meaning there are 300 for us yet to activate.
"We will hear a lot more with view to the application of human extranasal olfactory receptors in cosmetics and in therapeutics, but there are still lots of olfactory receptors where we don't know what activates them," Hatt concluded.
