Biochemical composition and aroma of Melaleuca citrolens Barlow (Myrtaceae) leaves from different regions of Australian Northern Territory

Abstract

Melaleuca citrolens Barlow (gulbarn) leaves (Myrtaceae family) infusion is the traditional herbal drink of Australian indigenous community from the Northern Territory (NT). The present study was conducted to determine the biochemical content and aroma of M. citrolens leaves from five different regions (R1-R5) of NT. The total phenolic and flavonoid content of M. citrolens leaves were varied from 78.02 to 126.07 mg GAE/ g dry powder and 4.55 to 9.16 mg QE/ g dry powder, respectively (P<0.05). Ultra-high-performance liquid chromatography shown that gallic acid and gallyoylquinic acid were the major phenolic compounds present in all the samples. Minerals, heavy metals and organic acid content of the M. citrolens samples were influenced by the different region (P<0.05). Antioxidant activity of M. citrolens collected from region-2 was highest while the lowest value was observed from region-1 (P<0.05). Aroma evaluation of samples revealed that M. citrolens from region 2 and 5 showed higher strength whereas region 3 and 4 samples showed lower strength (P<0.05). In conclusion, the biochemical content and aroma of M. citrolens leaves were varied with the different regional habitat. M. citrolens leaves collected from region 2 and 5 suggested for the high quality of aroma as well as high phenolic content and antioxidant activities.