Impact of Drying Methods on Qualitative and Quantitative of Monarda citriodora Cerv. ex Lag. Essential Oil Yield

A genus of Monarda belongs to the family (Lamiaceae), the largest group of angiosperms. The crop has been grown extensively across the world for its flavoring and therapeutic properties as well as for its high-quality essential oil. The present research was designed to study the impact of different drying methods i.e (shed drying, sun-drying, microwave, oven-drying at (40 degrees, 50 degrees, and 60 degrees C), freeze-drying (0 degrees, -10 degrees, and -20 degrees C), and vacuum drying (30 degrees, 45 degrees and 60 degrees C) on the qualitative and quantitative analysis of Monarda citriodora essential oil. Dried and fresh plant samples were hydro-distilled using the clevenger apparatus, and essential oil analyzed by Gas Chromatography (GC) and Gas Chromatography mass spectrophotoscopy (GC/MS). The results showed that different drying methods had significant effects on essential oil yield as shed-drying (2.6 ml) >freeze-drying (2.2 ml at 0 degrees C) >oven drying (2.1 ml) >fresh drying (2.0 ml) >sun drying (2.0 ml) >microwave (0.15 ml). The major compounds obtained by GC/MS were thymol (92.46%) >g-terpinene (10.48%) >o-cymene (9.31%) >carvacrol (8.88%) >cyclohexene (3.51%). The highest essential oil yield was observed under shed dried (2.6 ml) and the major essential oil compound, thymol (92.46%), was observed under microwave-2 (4.0 min, 4.0 min, 4.0 min, and 3.0 min) combination. The results show an inversely proportional correlation between essential oil compounds. Thus, it has been summarized that the M. citriodora plant dry under the shed-drying method was the most appropriate and suitable method for obtaining a high-quality essential oil yield and microwave-2 (MV-2) combination for oil composition.