Sunflower Extract Can Protect Blueberries From Mold

Is your fridge beset with moldy blueberries? Well, a simple sunflower extract may just keep that spoilage at bay, according to scientists.

Researchers from the University of Chinese Academy of Sciences, Beijing, demonstrated that several compounds extracted from sunflower stems can fight against Botrytis cinerea, a mold that often grows over picked berries.

The researchers say the sunflower extracts could form the basis of new commercial biocontrol agents.

The findings were published in the Journal of Agricultural and Food Chemistry.

Don’t chuck the berries just yet; sunflower extracts can fight mold

After harvesting the seeds of flowers for their oil, most sunflower farmers discard the rest of the crop or use the stems for cattle fodder.

This process is wasteful in more ways than one as many chemicals found in sunflowers (such as diterpenoids) have been shown to have useful anti-tumor and disease-resistant properties.

Motivated to repurpose these compounds, the Chinese Academy of Sciences researchers set out to study if any sunflower compounds could prevent the spread of the fungal mold and help preserve perishable foods.

They extracted 17 diterpenoids – 4 of which were previously unknown and untested – from sunflower stems using methanol and ethyl acetate (EtOAc). They then studied how each compound interacted with fungal molds in vitro (in petri dishes) and in vivo (on blueberries inoculated with fungal spores).

“In this study, 4 new compounds with 13 diterpenoids were isolated from the receptacle of sunflower, and compounds 1, 3, 5 and 15 could inhibit the spore germination of gray mold by destroying the plasma membrane integrity,” Dr. Yun Zhao, a researcher at the Kunming Institute of Botany at the Chinese Academy of Sciences and first author of the study, said.

Commenting on their in vivo experiment, Yun Zhao noted that, over a period of six days, the sunflower extracts protected almost half the berries from mold growth: “The EtOAc extract of sunflower receptacle prevented blueberry rotting area development caused by gray mold effectively.”  

The sunflower compounds were so effective at preventing mold growth that Yun Zhao and their colleagues believe the chemicals could have a commercial future in the world of agriculture and biocontrol: “The EtOAc extract of sunflower receptacle has the potential to develop into a commercial biocontrol agent as it can effectively control blueberry rot caused by grey mold,” Yun Zhao said.

But, before this future can be guaranteed, the researchers want to probe the sunflower compounds a little further, to truly test their mettle.

“In the future, we will divide the study into two parts,” Yun Zhao said. “On the one hand, [we will] continue to study the mechanism by which extracts can control the development of diseases. On the other hand, drug dosage forms [will be] studied in order to reduce the amount of drug used and effectively control the disease.”

Dr. Yun Zhao was speaking to Leo Bear McGuinness, Science Writer for Technology Networks. 

Reference: Yun Z, Zi-Jiao W, Chang-Bin W, et al. New and antifungal diterpenoids of sunflower against gray Moll. Journ. of Agri. 2023. doi: 10.1021/acs.jafc.3c05553