Identification of Physical Characteristics and Curcuminoid Biomarkers in Turmeric Products Sold in Vientiane Capital

Abstract

Turmeric (Curcuma longa L.) is a medicinal plant widely utilized in the pharmaceutical, food, and cosmetic industries due to its diverse therapeutic benefits. In Lao PDR, turmeric products are both locally manufactured and imported, highlighting the necessity for stringent quality control. This study aimed to identify the physical characteristics and quantify the major chemical biomarkers (curcuminoids) of ten turmeric products sold in Vientiane Capital, including four powders, three capsules, two boluses, and one tablet. The methodology involved microscopic examination, determination of moisture content and total ash, and quantitative analysis of curcuminoids using HPLC-UV. The results of the microscopic examination confirmed the botanical identity of turmeric by identifying parenchymatous cells, fibers, scattered oil droplets, vessels, and cork cells. HPLC-UV analysis revealed that curcuminoid contents ranged from 7.70% to 84.55%, with the bolus form containing the lowest concentration, while powder and capsule forms showed significantly higher levels. Moisture content ranged from 3.7% to 11.97%, and total ash values ranged from 1.15% to 15.28% (with eight samples below the 10% limit). Method validation demonstrated excellent analytical performance with a precision (%RSD) of 1.81, LOD of 0.015 µg/ml, LOQ of 0.046 µg/ml, and a recovery rate of 105.23%, all within acceptable scientific standards. The findings indicate that different dosage forms contain varying levels of active compounds, likely influenced by manufacturing processes. This underscores the importance of standardized production to ensure the safety, consistency, and efficacy of turmeric products.