| Summary: | This study aimed to optimise potential extraction conditions using response surface methodology (RSM) for yielding maximum levels of total phenolic content (TPC) and 2,2-diphenyl-1-picryhydrazyl radical (DPPH•) scavenging capacity of henna (Lawsonia inermis) stems. The ranges for selected independent variables, namely acetone concentration (20-90%, v/v), extraction time (10-90 min) and extraction temperature (25-45°C) were identified by screening tests. Optimum conditions obtained for extraction of TPC were 47.0% acetone, extraction time of 47.6 min and extraction temperature of 37.3°C. The result also showed that 75.8% acetone, extraction time of 26.2 min and extraction temperature of 41°C yielded the highest DPPH• scavenging capacity. The optimized extraction conditions have resulted in TPC and DPPH• scavenging capacity of 5232.4 mg GAE/100 g DW and 6085.7 g TE/100 g DW, respectively which similar to the predicted values. Therefore RSM has successfully optimized the extraction conditions for TPC and radical scavenging capacity of henna stems.
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