Changes in immunomodulatory properties of Echinacea spp. root infusions and tinctures stored at 4 degrees C for four days.
BACKGROUND
Phytomedicinal preparations from members of the genus Echinacea are popular worldwide and frequently used to treat upper respiratory infections. With the increasing popularity of herbal medicines, many people are making their own Echinacea extracts at home and storing them at refrigerator (4 degrees C) temperatures. We tested the hypothesis that Echinacea extracts made using homemade methods change in immunomodulatory efficacy with storage at 4 degrees C over a 4-day period.


METHODS
Three extract types (50% ethanol tincture, cold water infusion, hot water infusion) from 5 different species (Echinacea angustifolia, E. pallida, E. purpurea, E. sanguinea, E. tennesseensis) were prepared. Four in vitro immune assays (monocyte secretion of TNF-alpha, IL-10, and IL-12; and peripheral blood mononuclear cell proliferation) using human blood were used to test extract efficacy at Days 1 and 4 post-extraction. Two statistical analyses, traditional ANOVA and several statistical models that account for endotoxin effects, were used.


RESULTS
Endotoxin was found to significantly impact immune outcomes only in 4-day old cold water infusions and not in all assays. Extracts showed the greatest stimulation in TNF-alpha assays. By extract type, 50% ethanol tinctures produced the most immune stimulation. By species, extracts from E. angustifolia extracts were the most efficacious in our assays; extracts from E. sanguinea showed the least activity overall.


CONCLUSIONS
Taken together, these results suggest that: (1) homemade Echinacea extracts are efficacious in modulating immune cell activity in vitro but that their properties change with time during storage at 4 degrees C; and (2) endotoxin effects from extracts may be important considerations in the analysis of immunobiological data.
Senchina
David S
DS
Immunobiology Program, Iowa State University, Ames, IA 50011, USA.
McCann
Dustin A
DA
Asp
Jessica M
JM
Johnson
Jack A
JA
Cunnick
Joan E
JE
Kaiser
Mark S
MS
Kohut
Marian L
ML
D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D004356:Drug Storage; D020900:Echinacea / Q000737:chemistry*; D006801:Humans; D007155:Immunologic Factors / Q000737:chemistry* / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D013696:Temperature
D016207:Cytokines; D007155:Immunologic Factors; D010936:Plant Extracts