Physicochemical profiling, phytochemical analysis, and antibacterial activity of the methanolic leaf extract of Curcuma caesia Roxb

Abstract

Curcuma caesia Roxb. (Black turmeric), a member of the family Zingiberaceae, is an important medicinal plant widely used in traditional medicine. While the rhizome of Curcuma caesia has been extensively investigated for its pharmacological properties, the leaves remain comparatively less explored despite their ethnomedicinal importance. Therefore, the present study was undertaken to evaluate the phytochemical composition and antibacterial potential of the methanolic leaf extract of Curcuma caesia. Fresh leaves were collected from the Hiranagar region of Kathua district, Jammu and Kashmir, India, and subjected to methanolic extraction. Preliminary organoleptic evaluation of the leaf powder and extract revealed characteristic green color, aromatic odor, and fine texture. Physicochemical analysis showed a percentage extractive yield of 18%, total ash content of 4%, and moisture content of 14%, indicating the basic quality parameters of the plant material. Qualitative phytochemical screening of the methanolic extract revealed the presence of several bioactive constituents, including alkaloids, saponins, glycosides, phenols, flavonoids, steroids, tannins, terpenoids, carbohydrates, proteins, and amino acids. The antibacterial activity of the extract was evaluated against six bacterial pathogens using the agar well diffusion method. The extract exhibited moderate antibacterial activity with zones of inhibition ranging from 6.15±0.10 mm to 9.00±0.55 mm, whereas the standard antibiotic streptomycin sulphate showed comparatively higher inhibitory activity. The results indicate that Curcuma caesia leaves contain diverse phytochemicals that may contribute to their antibacterial potential and support their possible use as a natural source of bioactive compounds.