Two New isoquinoline alkaloids from the bark of Alphonsea cylindrica King and their antioxidant activity

Publication date: February 2019Source: Phytochemistry Letters, Volume 29Author(s): Ahmed Kareem Obaid Aldulaimi, Saripah Salbiah Syed Abdul Azziz, Yuhanis Mhd Bakri, Mohd Azlan Nafiah, Saadon Abdulla Aowda, Khalijah Awang, Marc LitaudonAbstractTwo new isoquinoline alkaloids, iraqiine (1) and kareemine (2), along with five known alkaloids, muniranine (3), kinabaline (4), O-methylmoschatoline (5), atherospermidine (6) and N-methylouregidione (7), were purified from the dichloromethane crude extract of Alphonsea cylindrica bark. The structures of these compounds were elucidated through extensive 1D and 2D NMR, IR and LC–MS studies and comparison with previously reported data. Compounds (1–5 and 7) were tested for their antioxidant activity using in vitro DPPH radical scavenging assay, and 1, 3 and 4 showed the highest antioxidant activities with IC50 values of 48.77 ± 1.01, 44.51 ± 1.12 and 64.28 ± 0.93 μg/ml, respectively.Graphical abstract

Source: Phytochemistry Letters - December 2, 2018 Category: Chemistry Source Type: research