Identification of Bioactive Components from Ruellia tuberosa L. on Improving Glucose Uptake in TNF-α-Induced Insulin-Resistant Mouse FL83B Hepatocytes

Abstract

Ruellia tuberosa L. (RTL) has been used as a folk medicine to cure diabetes in Asia. RTL was previously reported to alleviate hyperglycemia, insulin resistance (IR), abnormal hepatic detoxification, and liver steatosis. However, the potential bioactive compounds of RTL have still not been identified. The aim of this study was to investigate the bioactive compounds in RTL ethyl acetate (EA) fractions by using a glucose uptake assay in TNF-α-treated mouse FL83B hepatocytes to discover a mechanism by which to improve IR. The bioactive compounds were identified by the high-performance liquid chromatography (HPLC) assay. Using the Sephadex LH20 gel packing chromatography column, the EAF5 fraction was isolated from RTL and significantly increased glucose uptake in TNF-α-treated FL83B cells. Moreover, the MCI gel packing chromatography column separated EAF5 into five subfractions and had no significant cytotoxic effect in FL83B cells when treated at the concentration of 25 μg/ml. Among the subfractions, EAF5-5 markedly enhanced glucose uptake in TNF-α-treated FL83B cells. The possible bioactive compounds of the EAF5-5 fraction that were identified by the HPLC assay include syringic acid, p-coumaric acid, and cirsimaritin. The bioactive compound with the best effect of increasing glucose uptake was p-coumaric acid, but its effect alone was not as good as the combined effect of all three compounds of the EAF5-5 fraction. Thus, we speculate that the antidiabetic effect of RTL may be the result of multiple active ingredients.

Alleviative Effect of Ruellia tuberosa L. on Insulin Resistance and Abnormal Lipid Accumulation in TNF-α-Treated FL83B Mouse Hepatocytes

“…Although this compound is speculated, the components are quite complicated. Our recent study indicated the possible bioactive compounds of EA from RTL identified by high-performance liquid chromatography assay, including phenolic acids (syringic acid and p-coumaric acid) and flavanoid (cirsimaritin) on improving glucose uptake in hepatocytes [ 10 ].…”

“…The IR-induced paradigm was described as the previous method with slight modifications [ 10 ]. FL83B cells were seeded in 10 cm dishes and incubated at 37°C for 48 h to reach 80% confluence.…”

“…The cells were then transferred to another F12K medium containing 5 mM glucose, without (basal) or with 200 μ M insulin and 10 μ L different RTL fractions and incubated for 30 min at 37°C. An assay of glucose uptake was then performed as described previously [ 10 ].The fluorescence intensity of the cell suspension was evaluated by flow cytometry (FACScan, Becton Dickinson, Bellport, NY, USA) at an excitation wavelength of 488 nm and an emission wavelength of 542 nm. Fluorescence intensity reflected the cellular uptake of 2-NBDG.…”

“…Evidence-Based Complementary and Alternative Medicine 10 μL different RTL fractions and incubated for 30 min at 37°C. An assay of glucose uptake was then performed as described previously [10]. e fluorescence intensity of the cell suspension was evaluated by flow cytometry (FACScan, Becton Dickinson, Bellport, NY, USA) at an excitation wavelength of 488 nm and an emission wavelength of 542 nm.…”

Histopathological Profiles of Rats (Rattus norvegicus) Induced with Streptozotocin and Treated with Aqueous Root Extracts of Ruellia tuberosa L.

“…Ruellia tuberosa L. is broadly spread in Asian countries, i.e., Indonesia [ 6 ]. In traditional remedies, this flora is recognized as an antidiuretic, antidiabetic, analgesic, and antihypertensive [ 7 – 9 ].…”