Chemical Composition, Biological Activities and Acute Toxicity of Essential Oils, Extracts, and Isolated Compounds of Curcuma zedoaria (Christm.) Roscoe

Abstract

Curcuma zedoaria (Christm.) Roscoe (Zingiberaceae), commonly called white turmeric or zedoary, is a chemically complex rhizomatous species used in Asian traditional medicines and increasingly investigated as a source of volatile and non-volatile bioactive constituents. This critical narrative review evaluates the chemical composition, biological activities and acute-toxicity evidence for essential oils, solvent extracts, fractions and isolated compounds of C. zedoaria. Literature published from 1968 to 6 August 2026 was examined through accessible scholarly databases and citation searching, with emphasis on studies in which botanical identity, preparation, chemical characterisation and experimental design could be appraised. The evidence shows pronounced compositional heterogeneity. Rhizome oils have been reported as curzerenone-, epicurzerenone-, zerumbone-, camphor-, 1,8-cineole-, beta-curcumene- or mixed sesquiterpene-rich, while leaf oil and non-volatile fractions show distinct profiles. Geographic provenance, accession, plant organ, processing, extraction and analytical procedures therefore limit the validity of treating “zedoary oil” as a single reproducible intervention. Preclinical studies support antimicrobial, antiparasitic, insecticidal, anti-inflammatory, analgesic, antiproliferative, antiangiogenic, hepatoprotective, antimutagenic and wound-related activities, and several isolated sesquiterpenes and diarylheptanoids have plausible molecular targets. Nevertheless, most efficacy evidence derives from in vitro assays or small animal models, often without cross-study chemical standardisation, pharmacokinetic information, exposure matching or independent replication. Safety evidence is substantially thinner than efficacy evidence. Preparation-specific acute and subchronic findings range from tolerability at selected doses to marked toxicity of inadequately processed rhizome material, an intraperitoneal essential-oil median lethal dose in mice, haematological and reproductive effects after repeated extract exposure, and developmental toxicity of essential oil in pregnant rats. These data do not support a single species-wide safe dose. Future work should prioritise voucher-confirmed material, chemotype-defined preparations, validated quantitative chemistry, exposure-based toxicology, reproductive-safety assessment and human studies designed around standardised products. Overall, C. zedoaria is pharmacologically promising but translational confidence remains constrained by chemical variability and an underdeveloped safety evidence base.