A comparative analysis of metabolites from different parts of Curcuma aeruginosa, i.e. leaves, stems, adventitious
roots and rhizomes was performed by GC-MS/MS coupled with multivariate statistical analysis. The GC-MS/MS analysis
confirmed the occurrence of 26 metabolites belonged to terpenoids in almost all the samples. The Principal Component
Analysis (PCA) indicated that there was a clear distinction between rhizomes and other plant parts, i.e. stems, leaves,
and adventitious roots that could be explained by relatively higher contents of terpenoids including curzerene, alphafarnesen, furanocoumarin, velleral, germacrone cineole, borneol, beta- and gamma- elemene and methenolone. The
results of Hierarchical Clustering Analyses (HCA) corresponded with the PCA results where many terpenoids found
abundantly high in rhizome were clustered together. This was supported by the Pearson correlation analysis that
showed a significantly good relationship between those terpenoids. The adventitious roots demonstrated the strongest
antioxidant activity as compared to the other plant parts which could be attributed to its highest Total Phenolic
Contents (TPC). Total phenolic contents of all the plant parts were positively correlated with their antioxidant activities
which indicate that phenolic compounds may play a role in the overall antioxidant activities of the plants. The results
of the study highlighted the potential of this underexploited Curcuma species which could serve as a new source of
important phytochemicals and natural antioxidant that could be incorporated in functional foods and nutraceuticals.
In addition, chemical and biological evidence shown in the present work has rationalised the different uses of various
plant parts of C. aeruginosa.
Curcuma aeruginosa or temu hitam is herbaceous plant with high therapeutic values in its rhizome that is widely used in
traditional medicine. However, molecular studies on the secondary metabolite biosynthetic pathway of C. aeruginosa is
still limited. Hence, the aim of this study was to explore and reconstruct the secondary metabolite biosynthetic pathway
of C. aeruginosa rhizome by integrating the metabolite profiling and transcriptomic data. A total of 81 metabolites were
identified in the rhizome of C. aeruginosa; amongst others are curzerene and β-Cubebene which are potent antioxidants.
A total of 28,225 unigene were obtained from the transcriptomic sequencing of C. aeruginosa rhizome and analysed
to identify potential genes associated with the biosynthesis of its metabolites. Of these, 43 unigenes were identified and
mapped onto five sub-pathways; i.e. carotenoid biosynthetic pathway, diterpenoid biosynthetic pathway, monoterpenoid
biosynthetic pathway, terpenoid and steroid biosynthetic pathway, and sesquiterpenoid and triterpenoid biosynthetic
pathway. This study demonstrated a systematic bioinformatic approach to reconstruct a metabolic pathway in the rhizome
of C. aeruginosa using bioinformatic approach.