NMR-based stability evaluation of (E)-1-(3',4'-dimethoxyphenyl)butadiene (DMPBD) from Zingiber cassumunar Roxb....

The active compound (E)-1-(3',4'-dimethoxyphenyl)butadiene (DMPBD) isolated from the rhizomes of Zingiber cassumunar Roxb. has potent anti-inflammatory and anticancer activities. Although DMPBD is one of the promising drug candidates for phytomedicine, its limited stability impedes its widespread use. For the development of new drugs, the assessment of their chemical stability is essential, ensuring they maintain their properties within specified limits throughout the period from production until use.

In the present study, we aimed to evaluate the stability of DMPBD under various conditions, including different solvents, temperatures, and lighting conditions, to identify the factors affecting stability and optimize the storage and handling conditions.

DMPBD samples subjected to the different conditions tested were monitored by quantitative ¹H NMR (qHNMR), using an internal standard for the determination of the absolute quantity of DMPBD as a function of time and the changes thereof within 1 month.

Significant decomposition of DMPBD was observed in chloroform-d₁, whereas its content remained constant in methanol-d₄. The content of DMPBD was maintained upon storage at temperatures below 4°C, both as methanolic solution and in the crude extract. Exposure to light had a slight negative impact on its contents. Some degradation products could be identified as resulting from O₂-induced cleavage of the diene moiety.

For pharmacological/therapeutic applications, DMPBD should be stored in the form of the crude extract or as a purified material in methanolic solution. Ideally, the storage temperature should be below 4°C and O₂ should be excluded.