Proposing monograph for the quality control of Curcuma longa L. in Cambodia

Turmeric (Curcuma longa L.) has been used for centuries in Khmer Traditional Medicine to treat various diseases especially gastrointestinal conditions. Due to its widespread use, this plant can be adultered with other plants mostly those of the same genus and the detection of adulterants are mainly based on experienced traditional healers and herbalists. Objectives: Establish a monograph of turmeric to assure its quality. Methods: Primary and secondary rhizomes were obtained from a local market in Phnom Penh and five provinces in Cambodia. Analytical methods were selected from literature review and previously published monographs. Macroscopic and microscopic characterisation and physicochemical assays including color reaction, Thin Layer Chromotography (TLC) (toluene : acetic acid 80:20 v/v) and UV-Visible spectrophotometry were proposed in this monograph development. Results: Macroscopic, microscopic study and colored reaction were rapid and practical methods for turmeric identification while TLC provided good selectivity in differentiating turmeric from similar species Curcuma zanthorrhiza Roxb. To measure the curcuminoids, the active ingredients in Cambodian turmeric, a quantification method was realised by UV/Visible spectrophotometry at 427 nm and its content was not less than 5%. Conclusion: The affordable and reliable monograph of Curcuma longa was established to ensure its quality and regulate its usage.