Lawsone quantification in Lawsonia inermis L. by HPLC-MS: How does the temperature and pluviometry affect lawsone concentration?

•Four corps of Lawsonia Inermis from south eastern of Morocco showed different concentration of lawsone.•The temperature is the main factor influencing lawsone content.•Pluviometry and humidity affect and decrease the concentration of lawsone in Henna.•High Performance Liquid Chromatograhy coupled to Mass Spectrometry with an ElectroSpray Ionisation source is used to optimize the quantification of Lawsone in the plant.•The highest amount of Lawsone in Lawsonia inermis L is characterized in the regions of Morocco with the highest temperature.