Common Mistakes and Troubleshooting

A frequent methodological error is testing a crude extract at excessively high concentrations in a cell-based assay, producing non-specific cytotoxicity...

A frequent methodological error is testing a crude extract at excessively high concentrations in a cell-based assay, producing non-specific cytotoxicity that is then misreported as a genuine pharmacological effect; concentration ranges should always be selected to remain within, or only modestly exceed, physiologically achievable levels. Inconsistent IC50 values across repeated antioxidant or cytotoxicity experiments most often trace back to extract instability during storage, variation in DMSO vehicle concentration, or, in cell-based assays, drift in cell passage number, and are best addressed by preparing fresh extract stock for each experimental run and maintaining strict cell culture passage limits. Where an in-vivo efficacy signal fails to replicate a promising in-vitro result, poor oral bioavailability of the active constituent is among the most common explanations, and should prompt ADMET-oriented investigation before the extract's biological activity itself is called into question.