Human Gene Expression as a Tool To Determine Horticultural Maturity in a Bioactive Plant (Echinacea purpurea L. Moench) ERNESTO ANTONIO BROVELLI* Nutrilite Health Institute, 19600 6th Street, Lakeview, California 92567 DIEGO RUA,HAERI ROH-SCHMIDT, AND AMITABH CHANDRA Access Business Group, LLC, 7575 Fulton Street East, Ada, Michigan 49355 ERIN LAMONT Chemical Ecology, Phytochemistry Faculty of Science, 30 Marie Curie, Ottawa, Ontario K1Y 6N5, Canada GIULIANA DORIS NORATTO Department of Horticultural Sciences, Texas A&M University, College Station, Texas 77843 A phenological study was conducted to determine the impact of harvest maturity on the immune- modulating properties of Echinacea purpurea. The aerial parts of this plant were collected during seven stages of development and were assayed for a common botanical marker for this species, cichoric acid. Plants of selected development stages were also assayed for total polysaccharides and compared for their immune-modulating effects on the THP-1 monocyte/macrophage cell line by means of a gene expression study. Although the concentration of cichoric acid did not change significantly during the course of the study, stage 1 (advanced vegetative) had the highest concentration of total polysaccharides and exhibited the most potent induction activity on immune- modulating cytokines such as interferon-γ and tumor necrosis factor-R. These findings suggest that the use of gene expression may be an effective tool not only to standardize botanical extracts but also to optimize harvest time. KEYWORDS: Harvest maturity; Echinacea; botanical marker; cichoric acid; polysaccharides; immune- modulating effects; gene expression INTRODUCTION By definition, “horticultural maturity is the stage of develop- ment when a plant or plant part possesses the prerequisites for utilization by the consumer for a particular purpose.” It is typically at this stage when plants are harvested (1). Depending on the plant, this purpose ranges from fresh consumption, to processing, to medicinal use, and therefore maturity or harvest- ing indices should be set according to the final use of the commodity. For fresh-market commodities, maturity indices focus on sensory characteristics, such as texture, color, or aroma (2). For bioactive or medicinal plants, harvest maturity has centered around the level of specific phytochemicals (3-5), but it has failed to address medicinal or functional considerations. The functional properties of Echinacea (also known as the American coneflower) have been broadly recognized given this plant’s property to modulate the immune system. Three species within the genus Echinacea have been assigned medicinal value: E. purpurea, E. angustifolia, and E. pallida (6). Recent clinical work has substantiated the functional activity of this plant (7-9), and although no report has conclusively identified the active fraction, cichoric acid, alkylamides, and polysaccha- rides have all been ascribed activity (10). Cichoric acid is one of the major constituents of E. pur- purea’s aerial parts and is often used as a botanical marker (11). A few studies have reported changes in the concentra- tion of cichoric acid as the plant develops. Wang et al. (12) observed that the maximum concentration of cichoric acid in the plant occurred at the blooming stage. According to Letchamo et al. (13), the concentration of cichoric acid in plants at the flower bud stage is more than double that in the developed flower stage. Stuart and Wills (14), on the other hand, reported steady levels in the concentration of this acid from preflower * Author to whom correspondence should be addressed [telephone (951) 928-6859; fax (951) 928-6835; e-mail ernesto.brovelli@nutrilite.com].