Strength of Onion-induced Human Antiplatelet Activity is Associated with Plant Development

• Published in: HortScience Vol. 32; no. 3; p. 524
• Main Author: Goldman, I.L
• Format: Journal Article
• Language: English
• Published: 01.06.1997
• ISSN: 0018-5345; 2327-9834
• DOI: 10.21273/HORTSCI.32.3.524A

Much of the medicinal activity induced by vegetable Alliums is derived from a suite of organosulfur compounds formed following hydrolysis of the S -alk(en)yl- l -cysteine sulfoxides (ACSOs). One of these medicinal activities is the inhibition of blood platelet aggregation; a factor that may influence cardiovascular health. Concentrations of ACSOs in the onion bulb ebb-and-fl ow during the vegetative phase, suggesting they act as storage forms of sulfur. To examine whether medicinal efficacy paralleled these changes, I tracked bulb, leaf, and inflorescence-induced antiplatelet activity during reproductive growth of four onion genotypes. Levels of bulb-induced antiplatelet activity dropped sharply for the first 8 weeks following the end of vernalization. Leaf-induced antiplatelet activity also dropped rapidly for the first 4 weeks, but rose precipitously by week 6. The rapid loss in leaf-induced antiplatelet efficacy between week 6 and week 8 suggests a recycling of these organosulfur compounds from the leaves to the developing flower stalk and inflorescence, which would be needed for protection against insect pests. Overall, I found a dramatic decrease in bulb-induced antiplatelet activity concomitant with an initially similar decrease and subsequent increase in leaf-induced antiplatelet activity. These were complemented by the presence of high levels of antiplatelet activity induced by the inflorescence. These data indicate development mediates the medicinal activity induced by onion plants. Furthermore, the flux of antiplatelet activity induced by various plant organs suggests that this medicinal trait is serendipitously associated with the storage and cycling of sulfur in onion plants; perhaps in response to insect predation.