Education, Outreach & Diversity

The Ever-increasing Role that Sunflowers Play in Society

By Andrew F. Galloway

sunflower 2

Many cultures around the world personify sunflowers with happiness and harvest. They have been used as a crop for thousands of years, having been first domesticated in parts of Northern America by Native Americans. With growing concerns over the Climate Crisis and food security, much research has been undertaken on crops to increase their yield, reduce emissions, and to protect the viability of fertile land. Research related to sunflowers is having real-world impacts, including the creation of biofuels and eco-products using previously discarded harvest waste, and uses in pharmaceutical development.  

Sunflower harvest waste helps to reduce our reliance on fossil fuels  

Traditional harvesting practices only use a small portion of the total plant, in the case of sunflowers seeds are only used for consumption. The rest of the harvested material such as leaves, stalks and hulls (seed shells) are considered ‘by-product’, and are either ground up and ploughed back into the ground or added to livestock feed [1]. This traditional harvesting can cause the release of carbon dioxide whilst the soil micro-organisms breakdown the components of this by-product [1]. Research examining these practices has demonstrated how the majority of this by-product can be better used in creating biofuels [2]. The use of such material as biofuel is known as second-generation biofuels [3]. Their precursor, first-generation biofuels, used the same material that would have been used as food [4]. This type of biofuel caused debates on their ethicality due to their competition with food production. There are examples where biofuel derived from sunflowers has been blended to diesel for cars in parts of the US to reduce emissions [2; 5]. By using sunflower by-product in a more efficient manner, these new developments are reducing carbon dioxide emissions both by eliminating the discarded breakdown of unused by-product and by acting as a greener alternative to fossil fuels.

Sunflower by-product can also be used to manufacture eco-products. Some companies have developed a hardboard biomaterial by compressing the fibres from sunflower stalks under extreme heat to produce alternatives to many kinds of hard plastics [6;7]. A similar process can also produce bolts, furniture, insulation panels and smartphone cases. A key protein found within the hulls of sunflower seeds can create a natural superglue, which can be used to adhere various biomaterials together [7; 8]. This by-product could also have an impact on reducing single use plastics and non-recyclable packaging, such as the marrow-like spongey material contained within the stalks of the sunflowers that has been used to produce a biodegradable polystyrene [9]. Biodegradable films can also be made from the protein found in hulls as a natural alternative to plastic food wrap [10]. However, more investment is required to develop and refine the infrastructure so that growers and producers of biomaterials can further commercialise these new eco-products.

Sunflower products benefit animals

Another major issue facing our world is the decline of pollinating insects that help plants reproduce and to grow fruit, making them an essential player in agriculture. Research has shown that pollen from the common annual sunflower contains an anti-parasitic substance that reduces a bee’s infection and susceptibility to two devastating protozoan (microscopic lifeforms) and fungi parasites [11]. Planting sunflowers around fields is a simple solution to help improve the health of these economically important insects. Sunflowers can have an impact on larger economically important animals, as supplementing livestock feed with sunflower oil (5%/dry weight) can reduce a dairy cow’s methane emissions by up to 23% as well as enhancing the nutrition of feed [12; 13]. Methane being a more potent greenhouse gas compared to carbon dioxide. More research is required to determine if adding sunflower oil is economical when scaling up.

Use of sunflowers in medicine

Contained within sunflower oil is a fat molecule called lecithin, also found in other plants and animals. Lecithin is an amphiphilic molecule, meaning that it can attract both water soluble and other fat molecules. This unique property allows sunflower oil to envelop substances into a bubble-like structure (called micelle) when added to water [14]. Sunflowers produce large amounts of micelle making it of interest to industry. Research has demonstrated that the amphiphilic properties of sunflower lecithin can aid the absorption of medicines that have poor solubility, therefore increasing the effectiveness of such medicines. [15]. Another interesting pharmaceutical property of sunflowers is a protein called SFTI-1 (Sunflower Trypsin Inhibitor-1) that has been shown to inhibit some cancer-causing enzymes [16; 17]. However, to date this protein has not been adopted by industry due to the expense of producing synthetic versions of it on a commercial scale.

A recent concept emerging from plant science are pharmaceutical crops or pharma crops, which are genetically modified (having higher amounts of a targeted molecule) to produce therapeutic substances used in drugs and vaccines [16]. Developing pharma crops would enable a cheaper and more natural source of medicines. An area of concern when growing these crops is the potential for cross-contamination with non-genetically modified plants. However, this should not affect pharma crops, as they are required to be grown in biosecure greenhouses due to strict sterile measures needed for their licence. An example of a successful pharma crop is the Artemisia, which produces a molecule called artemisinin that is used to treat malaria [18]. It is thought that sunflowers could soon be used as a pharma crop to produce a drug for cancer treatment [16].

Conclusion

Sunflowers have been cultivated for thousands of years. With the Climate Crisis and pressure to refine agricultural practices, their usage has become more versatile. Sunflower by-product can be converted into a range of eco-products that help detached us from fossil fuels. Sunflowers have also been demonstrated to have an anti-parasitic substance that can protect bee populations from devastating infections. Supplementing cattle’s diet with sunflower oil can reduce their methane emissions by almost a quarter. Sunflowers also contain a compound that inhibits enzymes involved in the growth of some cancers. In the future this crop may become a pharmaceutical plant factory. 

 

Sources

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Andrew Galloway

Andrew Fife Galloway

Research Coordinator, Wellcome Centre for Integrative Neuroimaging, 
University of Oxford