Introduction: Can the quality of herbal medicinal products be assured along the value chains? This question has been a global concern especially with recent attempts to integrate herbal medicines into the conventional health-care system. A key quality assurance strategy is the development of analytical methods to monitor and evaluate the pre-manufacturing, in-process and post-market quality of raw materials, semi-finished and finished herbal medicinal products, respectively. For this purpose, the stem bark of Chlorophora regia (Moraceae) used for several indications including treatment of rheumatism, lumbago, asthma, burns and wounds was selected. The aim was to develop a validated reverse-phase High Performance Liquid Chromatography (RP-HPLC) method, using a biomarker, for the quality control of the stem bark ingredients and its finished medicinal products.
Method: Powdered stem bark of C. regia was extracted with methanol/chloroform (4:1) in order to isolate and purify a biomarker using column chromatography on silica gel (70–230 mesh) and sephadex LH 20 (25–100 μm). The isolated biomarker was characterized and identified as Regiafuran A using detailed spectroscopic techniques including IR, NMR (1D and 2D) and comparing to established data in literature. A RP-HPLC method using µBondapakTM C-18 column (3.9 × 300 mm, 5 µm) with PDA detection (250 nm), gradient elution (0.1% v/v Trifluoroacetic acid (A) and Methanol (B)), was developed to analyse the biomarker.
Results and Discussion: The retention time of the biomarker was found to be 14.1 ± 0.02 min and was subsequently identified in the extract based on the retention time. The analytical performance parameters of the developed method was in accordance with the ICH guidelines. The method was linear within the range of 2-32 μg/mL, with a correlation coefficient (r) of 0.9998. The limits of detection (LOD) and quantification (LOQ) were 0.57 μg/mL and 1.73 μg/mL, respectively. Inter-day and intra-day precisions of less than 2% were obtained with an average percentage recovery of 103.04 ± 1.140.
Conclusion: The developed method is thus standard for the routine chemical analyses, stability studies and fingerprinting of the stem bark of C. regia and products containing the stem-bark extracts.