The multipurpose Buchu

Likely discovered and certainly used extensively by one of humanity's most ancient of peoples, the Khoi and San, Buchu is a special plant type found on the damp lower slopes of the mountains and hills of the South Western Cape. Also known as boegoe (Afrikaans) or ibuchu (Xhosa), buchu belongs to the Rutaceae (citrus) family of fynbos.

Appearing in a bountiful 125 different varieties, buchu is a flowering plant. Some versions are richly and unmistakably fragrant: 'The volatile oils in the glands clotting the leaves and fruit' the website www.plantzafrica.com records, 'emit an easily recognizable buchu fragrance when touched or crushed'. It is evergreen and belongs to the class of mountain fynbos.

The Khoi and San apparently used buchu as one ingredient to make body lotions and chewed their leaves as a cure for stomach cramps. Medicinal applications are now well known, as a general health tonic, to treat mild cystitis and prostatitis, an appetite stimulant (in small doses) and to aid digestion, and these Khoi and San pioneered.

It can act as diuretic, a stimulant (apparently good for a hangover) and to treat colds, flu, coughs, rheumatism and gout. It has been used to wash and clean wounds. Buchu can be taken orally in the form of an infusion tea or as a tincture in brandy or vinegar. The leaves can also be chewed fresh or dried. As it has a mild laxative effect, the herb should not be taken in excess.

Two types of buchu are particularly important from a commercial point of view: Agathosma betulina and the other being Agasthosma crenulata (the species name Agasthosma derives from the Greek agathos meaning pleasant and osme meaning smell). These two are famous for their use as part of fragrances and as flavour enhancers.

Buchu is indigenous and is believed to have been our country's first export product. Currently, about 90 per cent of our buchu is exported. To be more precise, it is the oils from betulina and crenulata that are in high demand. The biochemical compounds of the two are pretty much the same, but they come in differing concentrations.

Betulinaís oil is used in the food industry to mainly enhance fruit flavours and particularly to make black currant products taste better. Specific applications are to enhance peach, mint berry, raspberry, grapefruit, apricot, strawberry, mango and guava flavours, and to give these strong herbal nuances.

Crenulata is used to give colognes their fruity notes. It is credited with smelling of sulfurous, minty, camphorous, sweet, fruity, musty, catty and fruity. One of the odd things in the biology of smell (olfaction) is that we do not, beyond stink or the soapy smells of Pritt, have the vocabulary to describe the nuances, which is why we always do so by analogy.

For example, the Pulegone oil extracted from Betulina is described as being golden in colour, with a strong-sweetish, mint like odour and catty note, all being largely references to sight, tastes and overwhelming smells of cat pee. Crenulata is decribed as paler in colour, with a sharper Pulegone note. (www.schickennaturals.co.za) Pulegone is naturally occurring organic compound obtained from a variety of plants including buchu, Nepta cataria (or catnip) and pennyroyal. It is an oily liquid and, as suggested earlier, has the sharp odour of camphor, peppermint and sulfur. The finer molecular components are now known.

Pulegone has become staple to the aromatherapy industry. You can well imagine why, given its range of wonderful properties. Like so many other fragrances, it has crept into our extraordinary world of smell. Of course, other fragrances like the smell of laundry detergents, shoe polish, cleansing materials, glues and others are not there by accident.

It sounds trivial, but laundry detergents are biochemically calibrated to smell of the flowers of spring, cleaning agents of forests and some stick glues of female pheromones. The is a massive industry out there busy making fragrances that appeals to the repertoire of smells that bring out our deepest emotions and powerful personal memories.

The world of industry and commerce exploits it to the full. There are apparently more biochemists working in the smell industry than found at universities. The perfume industry is a celebration of smell, and it is at the heart of the tough and sometimes bloody-minded world of branding, intellectual property rights and the molecular biology of olfaction.