HPLC analysis of the bioactive components of clove extracts

Methods: Clove buds were ground into powder and used for the preparation of ethanol, methanol and aqueous extracts. These extracts were filtered with nylon membrane (0.45 µm) prior to High Performance Liquid Chromatography (HPLC) analysis. The chromatographic separations were performed on Zorbax Column (C18: 150 x 6 mm; 5 µm particle size; Flow rate: 1 ml/min) at 30^oC with Agilent 1200 series of HPLC equipment. Mobile phase comprises the mixture of methanol and water (80%; 90%). The system was continuously monitored by Diode Array Detector (DAD).

Results: The compounds in each sample were detected and analyzed by comparing their retention time in 210-360 nm range with the standard (eugenol). Result for both mobile phases (90% and 80%) shows slightly different profile for the separation of clove (MeOH, EtOH and H₂O). In 90% of methanol/water, MeOH extract demonstrated 9 peaks compared to 80% of methanol/water which is about 5 peaks of active components. While for EtOH extract 90% of methanol/water shows 8 peaks of active components compared to 5 peaks in 80% of methanol/water. Whereas 5 peaks in 90% compared to 4 peaks in 80% of methanol/water for H₂O extract of clove.

Conclusion: The chromatographic profile indicated the presence of bioactive components of clove extracts. It was found that 90% of methanol/water is the suitable mobile phase for the separation of the bioactive components of clove (MeOH, EtOH and H₂O) extracts.