title: Antiviral C-25 epimers of 26-acetoxy steroids from the South China Sea gorgonian Echinogorgia rebekka.
abstract: Four new steroids with an acetoxy linked at the end of the side chain, echrebsteroids A-D (1-4) were obtained from the South China Sea gorgonian Echinogorgia rebekka. The absolute configurations of 1-3 were determined using the modified Mosher's method on the hydrolysis products. The isolation of the pair of epimers (2 and 3) represents the first reported separation of C-25 epimers of 26-acetoxy steroids. The (25R)-epimer (3) exhibited promising antiviral activity against respiratory syncytial virus with an IC50 value of 0.19 μM and a comparatively higher therapeutic ratio (TC50/IC50 = 128).
authors.affiliation: Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China , Qingdao 266003, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Cao
authors.forename: Chang-Lun
authors.initials: CL
authors.lastname: Shao
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Meng-Qi
authors.initials: MQ
authors.lastname: Zhang
authors.forename: Kai-Xia
authors.initials: KX
authors.lastname: Xu
authors.forename: Hong
authors.initials: H
authors.lastname: Meng
authors.forename: Chang-Yun
authors.initials: CY
authors.lastname: Wang
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000737:chemistry*; D000998:Antiviral Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002681:China; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009792:Oceans and Seas; D012136:Respiratory Syncytial Viruses / Q000187:drug effects; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D013256:Steroids