Flavonoids are not volatile derivatives, so they cannot be distilled

The absence of flavonoids in the aromatic water obtained during extraction is common, as flavonoids are generally non-volatile and may not transfer into the aqueous phase during processes like steam distillation. Their extraction often requires different methods, such as solvent extraction. Additionally, the specific plant material used may not contain significant amounts of flavonoids.

The flavonoid content in your extraction process is influenced by several factors, including the nature of the solvent used, the extraction method, and the plant material itself. In your case, the extraction technique employed is hydrodistillation, which is primarily designed to extract volatile compounds, such as essential oils. These volatile compounds are efficiently extracted due to their ability to evaporate with steam.

However, flavonoids are generally non-volatile and polar compounds. Because of this, they tend to remain in the plant matrix during hydrodistillation or are extracted into the organic phase when a co-solvent is employed. This results in low concentrations of flavonoids in the distillate.

If your goal is to extract flavonoids, an alternative extraction method tailored to these compounds would be more effective. For further guidance on the best extraction techniques for flavonoids, consider the following study:

Article Selectivity of Current Extraction Techniques for Flavonoids ...

10.3389/fchem.2020.507887

If your focus is on hydrodistillation but you also want to explore the extraction of flavonoids, the referenced paper can provide valuable insights into the limitations and strengths of hydrodistillation,Article A hydrodistillation-based essential oils extraction: A quest...

essential oils are volatile components and are obtained by steam distillation. flavonoids are not and do not undergo this process.