Apigenin

Dulbecco’s modified Eagle’s medium (DMEM) and fetal bovine serum (FBS) were purchased from HyClone Laboratories, Inc. (Logan, UT, USA). 1% penicillin/streptomycin was obtained from GE Healthcare (Chicago, IL, USA). Dimethyl sulfoxide (DMSO), ethanol, lipopolysaccharides (LPS), nitrite assay kit, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), spermidine, histidine, serine, asparagine, glucose, citrulline, glutamate, glucose-6-phosphate, methionine, itaconate, tryptophan and FMOC-glycine were purchased from Sigma-Aldrich (St. Louis, MO, USA). Lysine, arginine, aspartate, threonine, glutamine, proline, creatine and tyrosine were purchased from Alfa Aesar (Ward Hill, MA, USA). Apigenin, apigetrin, apiin, bergapten and xanthotoxin were purchased from Toronto Research Chemicals (North York, ON, Canada).

Five differentially prepared Chamomilla recutita extracts were provided by WALA Heilmittel GmbH (Aqueous total fermented- CT and aqueous root fermented- CR), Weleda AG (86% ethanolic flower- CF, and 30% ethanolic root- CRE) and DHU-Arzneimittel GmbH & Co. KG (63% ethanolic mother tincture- CU). Both the aqueous fermented extracts were manufactured following the German Homeopathic Pharmacopoeia (GHP 33c), while the ethanolic extracts were produced according to European Pharmacopoeia (Ph.Eur.) 1.1.3 (GHP 2a) (flower), 1.2.12 (GHP 19f) (root), and 1.1.5 (GHP 3a) (mother tincture). Comminuted fresh whole plant or fresh flowers or fresh roots were used to manufacture the extracts. The aqueous extracts were subjected to 7-days fermentation followed by 6-months maturation at 15°C. The ethanolic extracts were pressed and filtered at the end of the extraction process. Apigenin (HPLC, >95% purity) was purchased from Toronto Research Chemicals, while chamazulene (GC, >95% purity) and α-Bisabolol (GC, >93% purity) were purchased from Sigma-Aldrich. All pure compounds were dissolved in DMSO at the indicated concentrations. A maximum threshold of 0.1% was set for the final solvent concentrations in the treatment conditions.