Parkinson’s disease (PD) is a neurological disorder associated with severe loss of dopaminergic neurons in
the substantia nigra. These neurons are particularly vulnerable due to increased iron and decreased
antioxidant levels with aging, constant exposure to reactive oxygen species (ROS), and the presence of
neurotoxic compounds. A literature review was compiled and published, in which we postulate that ROS,
iron, alpha-synuclein protein (α-syn), and neuromelanin form a toxic feedback loop in individuals with PD.
This feedback loop is theorised to be an early trigger culminating in neuronal death and subsequent spread
of the disease to neighbouring neurons. Consequently, antioxidants and iron-chelators may be important
therapeutic agents to target the accumulated ROS and iron in these neurons. Turmeric is an attractive
therapeutic candidate since it has well-established antioxidant properties and may chelate iron. This study
aimed to determine which components of turmeric have strong antioxidant and iron-chelating properties that
could potentially protect against dopaminergic neuronal degeneration in PD. A crude extract was obtained
from purchased turmeric using Soxhlet extraction. Subsequently, the crude extract was separated into
different compounds using thin-layer chromatography (TLC). Mass spectrometry (MS) was used to identify
the eluted compounds and a selected number of compounds were further analysed with liquid
chromatography-mass spectrometry (LCMS). After identifying the compounds, four were chosen to test their
total antioxidant capacity and iron chelation ability by comparing these compounds to Trolox (a known
antioxidant) and ethylenediaminetetraacetic acid (EDTA) (a strong iron chelator), respectively. Finally, a
human neuronal cell line, SH-SY5Y, was used to evaluate the effect of the extracted compounds on cell
viability, through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. We
successfully obtained a crude extract from turmeric powder after Soxhlet extraction. A total of 34 bands
were initially eluted from the TLC plate, with the experiment performed in duplicate. After MS, only 15 of
the 34 samples had identifiable compounds. Through LCMS, four compounds were identified with
confidence namely bis-demethoxycurcumin, demethoxycurcumin, curcumin, and aromatic (ar)-turmerone.
The antioxidant assays showed that curcumin had the strongest antioxidant activity while ar-turmerone had
the weakest. Analysis of the iron-chelating activity of these compounds found contradictory results.
However, with spectrophotometric observation and a commercially validated kit, the curcuminoids were
shown to have strong iron-chelation potential. Unexpectedly, ar-turmerone also showed iron-chelation
potential albeit to a lesser extent compared to the curcuminoids. The exploratory analysis with the SH-SY5Y
cells showed that bis-demethoxycurcumin increased cell viability by 152%, while ar-turmerone decreased it
by 73.5%, versus the vehicle control. These promising findings warrant further study using more targeted
techniques. Identifying new therapies for PD is of utmost importance since the current treatments only treat
the symptoms and do not address the pathobiology of neuronal loss. Natural compounds extracted from
plants may be particularly useful for the design of new treatment modalities since they may be more costeffective and have fewer side effects than synthetic medicines. CLICK TO REVIEW