HPLC Quantification and Stability Analysis of Chlorogenic Acid in Vernonia amygdalina Preparations Under Different Storage Conditions in Ibadan

The standardisation and stability of bioactive marker compounds in herbal preparations are critical requirements for ensuring consistent therapeutic outcomes. Chlorogenic acid, a prominent polyphenolic constituent of Vernonia amygdalina widely consumed in South West Nigeria, serves as an important quality marker for preparations derived from this species. This study quantifies chlorogenic acid content and evaluates its stability under varying storage conditions in V. amygdalina tea infusion and encapsulated powder preparations manufactured in Ibadan, Oyo State. HPLC-DAD analysis with a validated quantitative method was employed for chlorogenic acid quantification, with method validation covering specificity, linearity, accuracy, precision, detection limit, and quantification limit. Preparations were stored under four conditions: room temperature in the dark, room temperature in light, refrigeration (4 degrees C), and elevated temperature (40 degrees C, 75% RH) over six months. Chlorogenic acid content was measured at baseline, one, three, and six months. Initial chlorogenic acid content was 12.8 mg/g in the dry powder and 0.84 mg/100 mL in infusion. The greatest stability was observed in refrigerated dark storage conditions (8.3% content loss at 6 months). Elevated temperature and light exposure produced 41% and 38% degradation respectively. Antioxidant activity declined in parallel with chlorogenic acid content. These findings define optimal storage parameters for V. amygdalina preparations and provide HPLC stability data applicable to product monograph development. Keywords: Vernonia amygdalina, chlorogenic acid, HPLC, stability, storage conditions