Isolation and identification of alkaloids and non-alkaloidal compounds from pandanus pygmaeus, pandanus conoideus and pandanus leram / Ummu Amirah Armayni

A phytochemical investigation in order to isolate alkaloids was performed on the middle polar extract of three non-aromatic Pandanus species which are Pandanus pygmaeus (P. pygmaeus), Pandanus conoideus (P. conoideus) and Pandanus leram {P. leram). All of these plants were subjected to neutral extraction and were successively macerated with hexane, dichloromethane (CH2CI2) and methanol (MeOH). Dragendorff s reagent was used in a preliminary test to detect the presence of alkaloids in plant extracts. The crude extracts of these three Pandanus species produced positive results with Dragendorff s reagent. The crude extracts were then further fractionated and purified using various chromatographic techniques including flash column chromatography, open column chromatography, centrifugal thin-layer chromatography (Chromatotron™) and preparative thin layer chromatography (prep TLC). The structural "elucidation of compounds was established based on spectroscopic evidence of ID and 2D nuclear magnetic resonance (NMR) and mass spectroscopy (MS), and comparison with literature values. A total of three alkaloids were isolated from the extracts of two Pandanus species, P. pygmaeus and P. conoideus. Phytochemical studies on CH2CI2 extract of P. pygmaeus leaves resulted in the isolation of two alkaloids, and one of which is new. The isolation of known indolizidine alkaloid, pygmaeusamine and its isomer, pygmaeusamine-B was a major success and therefore, the hypothesis of this study is accepted. In addition, the structure of pygmaeusamine-B showed C9-N-C9 skeleton and consists of two lactone moieties. Thus, it supported the suggested nomenclature of Pandanus alkaloids. Further investigation on CH2CI2 extract of P. conoideus roots yielded one steroidal type of alkaloid. All of the alkaloids isolated from these two Pandanus species are from non-acid base extraction and suggested that these alkaloids are natural products and not the experimental artifacts. In short, this is the first documented occurrence of novel Pandanus isomer, and the steroid alkaloid from P. pygmaeus and P. conoid EUs, respectively. Along the investigation on these three Pandanus species, one aromatic compound, biphenyl was isolated from P. pygmaeus and two terpenes, stigmastenone and P-sitostenone were isolated from CH2CI2 extract of P. conoideus roots and chloroform fractions of P. leram leaves which are also believed to be the first report related to the plant species.