Isolation of Geissospermum laeve alkaloids by pH-zone refining centrifugal partition chromatography for metal corrosion studies

Control of metal corrosion is of technical, economical, environmental, and aesthetical importance. The use of corrosion inhibitors is one of the best options to protect metals and alloys from corrosion. The environmental toxicity of synthetic inhibitors has prompted the search for green compounds. Plant extracts have become important as an environmentally acceptable, readily available and renewable source for a wide range of biodegradable, heavy metals-free inhibitors. Among natural compounds, alkaloids have very high corrosion inhibition efficiency. An alkaloidic extract of Geissospermum laeve (Apocynaceae) has been fractionated by centrifugal partition chromatography using the pH-zone refining mode in order to investigate the effect of isolated alkaloids on C38 steel corrosion in HCl 1M. Indole alkaloids were identified by LC-MS, ¹H and ¹³C NMR.