Chromatographic separation and detection methods of Aloe arborescens Miller constituents: A systematic review

Aloe arborescens Miller (Family Asphodelaceae) is a member of genus Aloe, which is used in traditional medicine to cure various diseases. The extracts of the plant have been reported to possess anticancer, immunomodulator, antidiabetic, anti-inflammatory and antioxidant activities. The phytochemical investigations have revealed diverse chemical constituents, including phenolics [anthraquinones, anthrones, pyrones, chromones and coumarins], polysaccharides [arborans [(1-4) linked glucomannans, polysaccharide (A, B and C): (A: a linear (1-6)-O-α-glucan, B: a branching (1-2)-O-l-arabinose with (1-2)-O-d-galactose linkages and C: (1-4)-O-β-mannan with 18% acetyl group)]], glycoproteins and carboxypeptidase enzyme. There are many reports, describing the different methodologies developed to perform chemical analysis as well as, separation, detection and identification of these constituents. Different chromatographic techniques were applied such as gas chromatography (GC), high-performance liquid chromatography (HPLC), liquid chromatography-electrospray ionization coupled with mass spectroscopy (LC-ESI/MS/MS) and gel filtration chromatography. Also the isolated compounds were identified based on the spectroscopic analysis; ultraviolet-visible spectroscopy (UV-vis), infra-red spectroscopy (IR), mass spectroscopy (MS) and nuclear-magnetic resonance (NMR). This study aims to pinpoint the active components besides finding out new structural leads for future drugs. Therefore, the review is targeted to provide evidence reported in the relevant literature on qualitative and quantitative research to assist scientists in isolation and characterization of bioactive compounds in A. arborescens.