Phytochemical characterization, antioxidant, enzyme inhibitory and anti-inflammatory activities of Hedychium coccineum Buch.-Ham. ex Sm. rhizome

Hedychium coccineum Buch.-Ham. ex Sm. is a highly valuable plant with ornamental, edible, and medicinal properties. However, there are few studies on its phytochemicals and biological activities. Therefore, this study focused on phytochemical analyses of H. coccineum rhizome water extract (WE) and 70 % ethanol extract (EE) and their antioxidant, enzyme inhibitory, and anti-inflammatory properties. Chemical composition analysis indicated H. coccineum rhizome WE and EE had high total phenolic (37.33–42.45 mg GAEs/g extract) and flavonoid (33.79–212.06 mg REs/g extract) contents and further UHPLC-Q-Orbitrap-MS analysis identified 75 compounds, including 14 phenolic compounds and 23 flavonoids. In the DPPH and ABTS radical scavenging tests, WE (29.88 ± 1.41 μg/mL and 26.60 ± 0.70 μg/mL, respectively) and EE (18.15 ± 0.51 μg/mL and 11.73 ± 0.30 μg/mL, respectively) displayed superior antioxidant effects than the positive control BHT (76.07 ± 8.40 μg/mL and 49.85 ± 4.46 μg/mL, respectively). Except for the weak inhibition on tyrosinase and cholinesterases, it is interesting that the α-glucosidase inhibitory capacities of WE (IC50: 22.87 ± 2.17 μg/mL) and EE (IC50: 5.41 ± 0.44 μg/mL) were superior to that of acarbose (IC50: 226.69 ± 16.14 μg/mL). Additionally, H. coccineum rhizome WE and EE at non-toxic doses significantly suppressed the LPS-induced secretion of pro-inflammatory mediators (NO) and cytokines (TNF-α and IL-6) in RAW264.7 cells. Hence, H. coccineum rhizome can be a potential source of active natural compounds for application in functional foods and pharmaceuticals.