HPLC-Based Activity Profiling for GABAA Receptor Modulators in Searsia pyroides Using a Larval Zebrafish Locomotor Assay

Fahimeh Moradi-Afrapoli, Hannes van der Merwe, Maria De Mieri, Anke Wilhelm, Marco Stadler, Pieter Zietsman, Steffen Hering, Kenneth Swart, Matthias Hamburger
2017 Planta Medica  
AbstractA dichloromethane extract from leaves of Searsia pyroides potentiated gamma aminobutyric acid-induced chloride currents by 171.8 ± 54% when tested at 100 µg/mL in Xenopus oocytes transiently expressing gamma aminobutyric acid type A receptors composed of α 1 β 2 γ 2s subunits. In zebrafish larvae, the extract significantly lowered pentylenetetrazol-provoked locomotion when tested at 4 µg/mL. Active compounds of the extract were tracked with the aid of HPLC-based activity profiling
more » ... ing a previously validated zebrafish larval locomotor activity assay. From two active HPLC fractions, compounds 1 – 3 were isolated. Structurally related compounds 4 – 6 were purified from a later eluting inactive HPLC fraction. With the aid of 1H and 13C NMR and high-resolution mass spectrometry, compounds 1 – 6 were identified as analogues of anacardic acid. Compounds 1 – 3 led to a concentration-dependent decrease of pentylenetetrazol-provoked locomotion in the zebrafish larvae model, while 4 – 6 were inactive. Compounds 1 – 3 enhanced gamma aminobutyric acid-induced chloride currents in Xenopus oocytes in a concentration-dependent manner, while 4 – 6 only showed marginal enhancements of gamma aminobutyric acid-induced chloride currents. Compounds 2, 3, and 5 have not been reported previously.
doi:10.1055/s-0043-110768 pmid:28511229 fatcat:xe5etwqthzfndabszbvjqjrxwy