Flavonoid production by calli and cell suspension cultures of Aquilaria malaccensis: A threatened tropical tree

Aquilaria tissues are rich in f lavonoid compound. In this study, we investigated the effects of different types and concentrations of plant hormones, carbon sources, medium pH, and medium strength on the growth and flavonoid content of callus cul tures. The medium favourable for cal lus growth and f lavonoid production was full -strength Murashige and Skoog (MS) medium supplemented with 2.0 mgL⁻¹ 2,4-dichlorophenoxy acetic acid (2,4-D), 0.5 mgL⁻¹ 6-benzylaminopurine (BAP), and 20 gL⁻¹ sucrose (pH 5.7). To increase flavonoid production, phenylalanine (Phe) was added to growth media at concentrations ranging from 20 to 100 mgL⁻¹. Addition of Phe at 60 mgL⁻¹ to the cell suspension culture resulted in the highest total flavonoid yield; the total flavonoid content in these cel ls was nearly 5-fold than in control cells, and 2-fold than in call i grown on solid medium containing 60 mgL⁻¹ Phe. HPLC analysis revealed that the 60 mgL⁻¹ Phe-supplemented cel l suspension cul ture contained rutin as the major flavonoid, followed by quercetin and kaempherol. Our results show that supplementation with Phe enhanced the flavonoid content and induced production of additional compounds in callus and cel l suspension cultures of A. malaccensis.