Storage conditions affect the essential oil composition of cultivated Balm Mint Herb (Lamiaceae) in Iran

• Balm Mint is an aromatic and medicinal plant.
• Lemon balm is beneficial for a wide variety of human disorders.
• Lemon balm has therapeutic properties.
• EO producers and consumers could employ this phenomenon benefits.

Lemon balm (Melissa officinalis L.) is one of the most important herbs known for curing Alzheimer's disease. In this study, the effect of time and temperature on the quality of essential oils was investigated. The essential oil of air-dried samples was obtained by hydro-distillation and was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Changes in essential oil compositions were detected during storage for four months in a refrigerator (4 °C), a freezer (−20 °C), and at room temperature. The results indicated that, at room temperature, the proportions of compounds with lower boiling temperatures such as citronellal (25.8–12.6%), neral (18.9–4.0%) and geranial (27.0–4.6%) were decreased. Furthermore, the oil compositions showed the least alterations and M. officinalis kept its primary quality when stored at low temperatures, particularly at −20 °C.