23 epi 26 deoxyactein

LC-MS/MS analysis was performed using a Thermo Scientific LTQ XL mass spectrometer with an electrospray ionization (ESI) source (Thermo Fisher Scientific, Waltham, MA, USA) coupled to a Dionex Ultimate 3000 HPLC system equipped with a micro vacuum degasser, an autosampler, and diode-array detector (DAD) (Thermo Fisher Scientific, Waltham, MA, USA). All extractions were carried out with HPLC grade solvents. Sample preparation was performed using C18 SPE columns purchased from Agilent Technologies (Wilmington, DE, USA). Standard compounds aloin, echinacoside, and withaferin A were purchased from Sigma-Aldrich (St. Louis, MO, USA). 23-epi-26-deoxyactein was purchased from Cayman Chemical Company (Ann Arbor, MI, USA). The following botanical supplements were purchased by mail order from Amazon.com: Black cohosh-1 (540 mg, root), Black cohosh-2 (540 mg, root), Ashwagandha-1 Ksm-66 tablets (600 mg, root - standardized to contain 5% withanolides and 200 mg of L-theanine), Ashwagandha-2 Ksm-66 capsules (900 mg, root), Echinacea-1 (400 mg, Echinacea purpurea aerial components), and Echinacea-2 (400 mg, Echinacea purpurea aerial components).