Phytochemical Profiling, Antioxidant Activity, and Antimicrobial Potential of Curcuma aromatica Rhizomes from Central India

Abstract

Curcuma aromatica Salisb. (Zingiberaceae) is a medicinal plant native to the forests of Amarkantak, Central India. The present study aims to investigate the polyphenol content, as well as the antimicrobial and antioxidant properties of Curcuma aromatica Rhizomes. The qualitative analysis revealed the presence of pharmaceutically important phytochemicals such as tannins, flavonoids, phenols, quinones, terpenoids, coumarins, steroids, cardiac glycosides, phlobatannins, and alkaloids in both methanol (ME) and aqueous extracts (AE) which may contribute to their observed pharmacological properties. However, saponins were absent in the ME but present in the AE. Similarly, anthraquinones were detected only in the ME, whereas glycosides were absent in both ME and AE. Quantitative assessment of total phenols and flavonoids showed significantly higher content in ME. The in vitro antioxidant activity was assessed using total antioxidant activity (TAA), DPPH, and ABTS assays, revealing markedly higher activity in the ME. It showed significantly greater TAA (39.70 ± 0.13 mg AAE g⁻¹ dw; p < 0.0001), strong DPPH scavenging (66.01% at 220 µg/mL), and lower IC₅₀ values for DPPH and ABTS. Further, FTIR examination of ME identified functional groups such as OH, CH, C=C, N-O, C-O, and C-F, indicating the presence of distinct metabolites. The GC–MS analysis confirmed the presence of 48 volatile metabolites in the ME, with the predominant compounds being tumerone, curlone (β-turmerone), hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester, (E)-atlantone, and benzene, (1,1,4,6,6-pentamethylheptyl). The antimicrobial activity of the ME was evaluated using the agar well diffusion method, wherein strong antibacterial effects against X. oryzae (21.33 ± 0.57 mm at 15 mg/mL), B. cereus (16.33 ± 0.57 mm), and Microbacterium sp. (12 ± 0 mm) were noted. However, only partial activity against Alternaria alternata and Fusarium oxysporum were observed, while the AE showed no activity. The rhizomes of Curcuma aromatica contain a variety of bioactive compounds that show notable antioxidant and antimicrobial properties. However, detailed studies focusing on the isolation and characterization of these active constituents are necessary to confirm and better understand their biological effects