Phytochemical characteristics of callus suspension culture of Helicteres angustifolia L. and its in vitro antioxidant, antidiabetic and immunomodulatory activities

Abstract Helicteres angustifolia L. ( H.angustifolia ) is an important medicinal plant. This study investigated the phytochemical characteristics of callus suspension cultures of H.angustifolia and its bioactive functions, such as antioxidant, antidiabetic and immunomodulatory activities. Results demonstrated that the cultures were rich in phenolic compounds, flavonoids, terpenoids, saponins and triterpenoids. Compared to the equivalent wild roots, the cultures yielded larger amounts of total phenolics (17.75 mg GAE g − 1 ), flavonoids (56.15 mg RE g − 1 ), saponins (29.21 mg OAE g − 1 ) and polysaccharides (13.69 mg g − 1 ), about 1.62-, 1.90-, 1.14- and 3.41-fold higher than those from the equivalent wild roots, respectively. Furthermore, as the valuable target product from in vitro culture, phenolic compounds were subjected to HPLC analysis, reflecting that some representative phenolic compounds fluctuated significantly under the cultivation conditions. Additionally, bioactive assays showed that the extract of callus suspension cultures (CE) possessed strong antioxidant activities, and rat maltase (IC 50  = 13.29 mg mL − 1 ) and sucrase (IC 50  = 13.76 mg mL − 1 ) inhibitory activities. As for the immunomodulatory activity, CE could stimulate the proliferation of macrophages (121.93 ± 1.76%) and the production of nitric oxide (200% of the control) and phagocytic activity (178% of the control) at 6.25 μg mL − 1 . Moreover, CE could mitigate DOX-induced macrophages damage to some extent. In conclusion, the callus suspension culture of H.angustifolia is a potential source for bioactive phytochemical compounds and functional foods.