Essential oils for all

Distilling knowledge, (re)discovering plants

The consumer craze for fragrances and aromas shows no sign of letting up - the market for essential oils continues to grow. Beyond the advantages they represent for the export sector, these plant extracts are also useful for ACP countries that want to protect the health of their inhabitants and harvests. A number of ACP research efforts are under way to identify the most promising plants.

Detergent infused with citrus essence, citronella candles that repel mosquitoes, eucalyptus-based treatments to alleviate respiratory problems and - wait for it - socks impregnated with essential oils. Nature is a strong selling point right now and the agrifood, chemical, pharmaceutical and cosmetic industries are constantly on the lookout for natural substances that are just as effective as synthetic products but are also beneficial to health and the environment. The trend helps explain the massive upsurge in interest in essential oils (EOs), volatile fragrant substances produced by wild or cultivated plants. The most common method of extraction is steam distillation (see box) or, in the case of citrus fruits, cold pressing of the zest. EOs are not to be confused with the fatty oils extracted from oleaginous plants such as shea or jojoba.

The price of these precious oils depends on the parts and quantities of plants used, as well as on the difficulty of harvesting them, a process mainly done by hand. One of the most costly EOs is Neroli oil, extracted from the blossoms of the bitter orange tree (Citrus aurantium), grown in many ACP countries. A tiny 2 ml bottle sells for around €13 on the Internet while the essence extracted from the skin of the fruits is between 10 and 15 times less expensive.

New clients

According to the report Indian Oil Industry 2005, global output of EOs and citrus essences hovers between 100,000 and 110,000 t. Some 55% of production is accounted for by the South, led by Brazil, China, India and Indonesia, which are also major consumers. The international aroma and perfume market (worth US$6.3 billion in 2006, according to BCC Research) is expected to grow by an annual 4.5% in the coming years. The EU, Japan and USA are traditionally the biggest importers of EOs, but demand from Asian countries, especially South Korea and China, is growing rapidly. The boom in aromatherapy, a treatment involving the absorption, massage or inhalation of often organic EOs, is helping to create niche markets for high value-added products.

ACP countries are well placed to profit from these trends. Their climate, the richness of their flora and plentiful supply of labour are clear advantages when it comes to growing and harvesting aromatic plants. Some countries have a virtual monopoly on plants with unique properties: Amyris balsamifera or West Indian sandalwood in Haiti, muhuhu (Brachylaena hutchinsii) in Kenya and Tanzania, buchu (Agathosma betulina) in South Africa, to mention those that are most widely marketed.

The Caribbean has a long tradition of EO production. Despite strong competition, Grenada remains the world's second largest exporter of nutmeg oil (Myristica fragrans) after Indonesia. Haiti is the world's leading producer of amyris oil (Amyris balsamifera) and the second biggest producer of vetiver - see our field report - and produces citrus essences for liqueurs. Jamaica is known for its EO made from the leaves and berries of the pimento (Pimenta dioica and P. racemosa), while Dominica produces significant quantities of bay essence (Laurus nobilis). The search for new aromatic plants to develop in the region may help in the push for agricultural diversification and job creation.

In the Pacific region, the Centre for the Development of Enterprise (CDE) is encouraging farmers to start producing EOs to help them penetrate the world market by offering quality products which, it says, are in growing demand. Two species of sandalwood have traditionally been an important source of revenue for the region: Santalum austrocaledonicum in Vanuatu and S. yasi in Fiji and Tonga. Three medicinal plants have been identified as holding out significant promise for the local EO industry: a variety of basil (Ocimum gratissimum), a type of mint (Plectranthus amboinicus) and a tree (Pandanus tectorius).

Despite the rich diversity of its flora, sub-Saharan Africa still only plays a marginal role in the EO market. Notable exceptions are South Africa, which has a sizeable output of different oils (eucalyptus, geranium, camomile, lavender), Côte d'Ivoire (citrus essence) and Madagascar, a major producer of EOs extracted from ylang-ylang and cloves. Other countries, including Ghana, Malawi and Nigeria, have recently joined their ranks.

In 2004, PAHE, the pan-African network for aromatic plants and essential oils, launched a campaign to encourage African countries to draw up SME development strategies for the production of essential and edible oils. The initiative was aimed at creating jobs and increasing earnings from traditional knowledge and non-timber forest products. South Africa has successfully created various support programmes for small-scale farmers producing EOs. In the Northern Cape, the country's Department of Science and Technology is encouraging the cultivation and distillation of geranium as a way of creating jobs and reducing poverty.

A demanding market

EOs belong to a group of products which, according to the CDE, have the advantage of requiring little investment and simple, tested technologies that are easy to use and install in rural settings. They can make a significant contribution to boosting revenues for rural communities, take up little space and can easily be despatched by plane at reasonable cost.

Production methods have to meet exacting quality standards to ensure that plants have adequate levels of active ingredients. Those that fail to do so command lower prices. Since EOs are complex substances, they require regular laboratory testing if they are to qualify for export. One important step is to determine their chemotype (see box) - their precise biochemical structure, which is strongly influenced by the ecological area in which a plant is harvested.

As Spore observed back in 2000 (Spore 86), "It is a rewarding, but exacting market to conquer, and one where quality counts." The EU imposes rigorous standards. The REACH system, which since 2006 has ensured control of 30,000 chemical substances, also applies to essential oils. It requires manufacturers to demonstrate that their products are not harmful in any way, a process that is beyond the means of most ACP SMEs, unless they have assistance.

Adding to their difficulties is the fact that small-scale producers must also take account of specific market constraints, which may change dramatically from one year to the next due to competition. Producers need to be well informed of market trends, build up contacts with potential clients and make sure they hold onto those clients by supplying adequate quantities of EOs regularly. Even though producers in the South now have more direct access to the markets of industrialised countries - mainly due to the Internet - these markets remain distant, sporadic and exclusively based on raw materials. It is hard to find export markets for plant-based products, unless they are part of a long tradition such as Bay Rum in the Caribbean, a blend of EOs, including one extracted from Pimenta racemosa. This has long been used in Europe as an eau de Cologne or hair lotion.

Most recent studies on EOs focus on the commercial opportunities that local and regional markets offer ACP countries. One example is a small-scale enterprise in Ghana which is seeking to tap the markets of neighbouring countries with an anti-mosquito lotion based on citronella EO (Cymbopogon nardus).

Research all round

EOs can be extremely useful in their country of origin where their antiviral, antibacterial and antifungal properties may help protect humans, livestock, crops and harvests. In Papua New Guinea, pharmacies sell waria waria oil distilled from Asteromyrtus symphyocarpa, whose antiseptic properties are similar to those of tea tree (Melaleuca alternifolia).

A number of research initiatives are under way in ACP countries to study the properties of EOs extracted from local flora, based on traditional knowledge. In South Africa, branches of Lippia javanica have long been used to repel insects. The EO from this shrub has been found to be effective in warding off Aedes aegypti mosquitoes, which are vectors of yellow fever. When added to candles, the EO repels 98% of these mosquitoes, compared with 40% using citronella. In Burkina Faso, Cameroon, Congo and Kenya, tests are being conducted to establish the capacity of various plants to repel malaria-carrying mosquitoes.

In Cameroon, several universities are working together to study the efficacy of EOs extracted from local plants to act as biopesticides. Some are looking at the potential of EOs to combat weevils and lesser grain borers, pests which cause serious damage to maize stocks. Others are comparing the ability of various citrus essences to fight Phaeoramularia angolensis, a fungal pathogen that causes spotting on citrus fruit and leaves, and hampers cultivation in many parts of Central Africa. At the heart of the network, the University of Ngaoundéré is focusing on the domestication of plants as sources of EOs and the dissemination of this information further afield.

In Burkina Faso, a team from the agricultural research institute INERA has demonstrated the efficacy of EOs extracted from Cymbopogon citratus, C. giganteus, Lippia multiflora and Ocimum basilicum against rice seed fungi. In Madagascar, the antibiotic properties of EO of Cinnamosma fragrans, one of the country's many traditional medicinal plants, have caught the attention of researchers from the national rural development research institute FOFIFA and CIRAD, who see it as a potential substitute to the antibiotics used on shrimp farms.

The success currently being enjoyed by EOs is fuelling a constant search for new plants with potentially beneficial ingredients. This can sometimes lead to over-harvesting of wild plant populations, especially in forests. Cultivation is the best option, as a way of avoiding serious damage to biodiversity while encouraging the creation of jobs and income for small-scale producers and distillers.