Preparation of phenylbutanoid-rich Zingiber cassumunar extracts and simultaneous HPLC analysis of phenylbutanoids

Zingiber cassumunar are used increasingly as ingredients in marketed phytomedicines. Therefore, methods for the preparation of active constituent-rich extract, which yield products with batch-to-batch consistency, are required. Four anti-inflammatory phenylbutanoids, (E)-4-(3,4-dimethoxy-phenyl)but-3-en-l-ol, (E)-4-(3,4-dimethoxyphenyl)but-3-en-l-yl acetate, (E)-1-(3,4-dimethoxy-phenyl)butadiene and (E)-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene, isolated from Z. cassumunar, were used as standard markers for quantitative determination and preparation of phenylbutanoid-rich Z. cassumunar extracts (PZEs). A reversed-phase HPLC method was established for the simultaneous determination of the phenylbutanoids in Z. cassumunar extracts. The parameters of linearity, repeatability, reproducibility, accuracy, specificity, and sensitivity of the method were evaluated. Systematic extraction studies to maximize phenylbutanoid content revealed that hexane was the most appropriate solvent for extraction. A one-step purification of the hexane crude extract of Z. cassumunar, using silica gel vacuum chromatography, provided the PZEs. The content of phenylbutanoids in the PZEs was up to 48.3% w/w dry weight.