Aroma profiles of the curry leaf, Murraya koenigii (L.) Spreng. chemotypes: Variability in north India during the year

Murraya koenigii (L.) Spreng. (Rutaceae) is characterized by a large chemical intraspecific variability among the land races. This fact makes it difficult to detect real changes occurring in their essential oil composition during annual cycle. Based on this, variations of essential oil yield and composition in two chemotypes (‘A’ and ‘B’) of M. koenigii were assessed in spring, summer, rainy, autumn and winter seasons under foot hill conditions of northern India. The essential oil yield ranged from 0.15% to 0.18% in chemotype ‘A’, while it varied from 0.12% to 0.14% in chemotype ‘B’. Essential oils of both chemotypes from different seasons were analysed by gas chromatography (GC–FID) and gas chromatography–mass spectrometry (GC–MS). A total of fifty-eight constituents representing 93.7–98.8% of chemotype ‘A’ and fifty-six constituents forming 96.1–98.7% of the total composition of chemotype ‘B’ were identified. Chemotype ‘A’ was characterized by higher percentages of α-pinene (34.6–41.9%), sabinene (26.1–36.1%), (E)-caryophyllene (2.4–5.4%) and terpinen-4-ol (1.5–5.3%), whereas chemotype ‘B’ was dominated by higher amount of α-pinene (52.7–65.3%), β-pinene (10.7–12.9%), (E)-caryophyllene (3.1–10.3%) and limonene (5.1–7.8%). Comparative results showed considerable variations in the essential oil composition of both chemotypes due to season of collection. Present study concluded that the M. koenigii leaves of desired quality may be obtained by selecting suitable chemotype and season.

► Seasonal changes in the aroma composition of Murraya koenigii was investigated.
► Existence of two distinct chemotypes was noticed.
► Noteworthy changes were noticed in yield and composition due to collection time.
► Accumulation pattern of the constituents was different in both chemotypes.
► Collection time may useful for obtaining good yield of targeted molecule(s).