Old garlic bulbs that have grown ‘sprouts’ are often considered past their prime, however new research suggests these aging bulbs have higher levels of heart-healthy antioxidants than their fresh counterparts.
The Korean research team behind the study investigated whether sprouting enhanced the antioxidant activity of garlic after noting that the sprouting of plant seeds generally promotes the new synthesis of bioactive compounds such as phytoalexins – which protect the plant from external stressors.
Writing in the Journal of Agricultural and Food Chemistry, team reasoned that the same thing may be happening when green shoots grow from old heads of garlic – adding that previous studies have shown that sprouted beans and grains have increased antioxidant activity.
“Although garlic (Allium sativum) has been extensively studied for its health benefits, sprouted garlic has received little attention,” wrote the researcher, who were led by Jong-Sang Kim from Kyungpook National University in South Korea. “We hypothesized that sprouting garlic would stimulate the production of various phytochemicals that improve health.”
They found that garlic sprouted for five days had higher antioxidant activity than fresher, younger bulbs, adding that several different metabolites that were present suggest that it also makes different substances.
"Therefore, sprouting may be a useful way to improve the antioxidant potential of garlic," said Kim and his colleagues.
The team investigated whether sprouting enhanced the antioxidant activity of garlic – finding that sprouting enhanced the DPPH radical scavenging activity and ORAC of garlic.
“Sprouting also increased the capacity of garlic to suppress intracellular ROS induced by hydrogen peroxide in HT22 cells,” noted the team – who compared sprouted garlic extract and fresh garlic extracts for their ability to protect against glutamate-induced neural damage using the HT22 cell lines.
Although this increased neuroprotective effect could be suggested to be due to enhanced antioxidant capacity of sprouted garlic, Kim and his team said it is not clear which components in sprouted garlic are primarily responsible for the increased antioxidant capacity.
They also noted that sprouting did not increase the total phenolic content of garlic, suggesting that phenolics are not associated with the increased antioxidant activity and neuroprotective effect of the sprouted garlic extract.
“In addition, we identified metabolites whose concentrations were significantly altered during sprouting that might contribute to the bioactivity of sprouted garlic,” added Kim and colleagues.
Source: Journal of Agricultural and Food Chemistry
Volume 62, Issue 8, Pages 1875–1880, doi: 10.1021/jf500603v
“Garlic Sprouting Is Associated with Increased Antioxidant Activity and Concomitant Changes in the Metabolite Profile”
Authors: Alexandra Zakarova, Ji Yeon Seo, et al