BackgroundExercise promotes energy metabolism (e.g., metabolism of glucose and lipids) in skeletal muscles; however, reactive oxygen species are also generated during exercise. Various spices have been reported to have beneficial effects in sports medicine. Here, we investigated the effects of piperine, an active compound in black pepper, to determine its effects on metabolism during acute endurance exercise.MethodsICR mice (n = 18) were divided into three groups: nonexercise (CON), exercise (EX), and exercise with piperine (5 mg/kg) treatment (EP). Mice were subjected to enforced exercise on a treadmill at a speed of 22 m/min for 1 h. To evaluate the inflammatory responses following exercise, fluorescence-activated cell sorting analysis was performed to monitor changes in CD4+ cells within the peripheral blood mononuclear cells (PBMCs) of mice. The expression levels of metabolic pathway components and redox-related factors were evaluated in the soleus muscle by reverse transcription polymerase chain reaction and western blotting.ResultsThere were no changes in the differentiation of immune cells in PBMCs in both the EX and EP groups compared with that in the CON group. Mice in the EX group exhibited a significant increase in the expression of metabolic pathway components and redox signal-related components compared with mice in the CON group. Moreover, mice in the EP group showed greater metabolic (GLUT4, MCT1, FAT/CD36, CPT1, CS) changes than mice in the EX group, and changes in the expression of redox signal components were lower in the EP group than those in the EX group.ConclusionOur findings demonstrate that piperine promoted beneficial metabolism during exercise by regulating carbohydrate/fat metabolism and redox signals. Therefore, piperine may be a candidate supplement for improvement of exercise ability.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-017-0194-2) contains supplementary material, which is available to authorized users.

The demand for and range of use of secondary metabolites of plants have recently gradually increased, as they are more available than synthetic compounds in medical treatments. Plant tissue culture is a useful means of the producing secondary metabolites and productivity can be controlled by changing the background sources of light, pH, carbon source, amino acid, precursor, polarity, and plant growth regulator.

Recently, the demand for and range of use of the secondary metabolites of plants, which are more available than synthetic compounds, has been gradually increased, in medical treatment. Plant tissue culture is useful method for the production of secondary metabolites and it is possible to control productivity by changing the culture conditions, for example, of light, pH, carbon source, amino acid, precursor, polarity, plant growth regulator etc. 1-5)Cynanchum wilfordii HEMSLEY (Asclepiadaceae) is a perennial herb of which the benefits were previously described. [6][7][8] In Korea, its roots, which are known as backhasuo, have been used in folk medicine for the prevention and treatment of various geriatric diseases including vascular disorders, diabetes mellitus, ischemia-induced diseases, and aging progression. 6)The roots of this plant have been reported to contain some polyoxypregnane glycosides. [8][9][10][11][12] In addition, recently one steroidal alkaloid, gagaminine, was isolated for the first time from this plant.13) Gagaminine has also been isolated from other species in the Cynanchum genus 14,15) and evaluated for its potent inhibitory effects on the activity of aldehyde oxidase, an oxygen radical generating enzyme, and hepatic lipid peroxidation in an in vitro assay.13) The structure of this active compound ( Fig. 1) contains a pregnane skeleton with two ester bonds bound with cinnamic acid at C-12 and nicotinic acid at C-20. Thus the introduction of an ester group at the corresponding carbon positions in the skeleton could not easily be achieved using any chemical approach. However, cell cultures often produce secondary metabolites in significant quantities 16) which would be useful for animal tests and are regarded as genetically more stable. In our previous work, we reported the establishment and cultivation of stem cultures of C. wilfordii and presented the results designed to optimize growth and gagaminine content in these cultures. 17) In this report, we describe the comparative results of the effects of various culture conditions, such as 2,4-dichlorophenoxyacetic acid (2,4-D), known as one of the most effective plant growth regulators 17) ; different sucrose and various initial cell concentrations; light and dark conditions; and different temperatures on cell growth and gagaminine production in suspension culture of C. wilfordii. Gagaminine, a steroidal alkaloid isolated from the roots of Cynanchum wilfordii, exhibited potent inhibitory effects on aldehyde oxidase activity and lipid peroxidation. To determine whether it would be possible to mass produce this active component, which would be useful for animal tests, we tried to synthesize it using in vitro cell culture methods with various growth conditions. In a previous study it was found that calli were easily induced from the stem of this medicinal plant and cultivated effectively on MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) 2 mg/l. In this work we attempted to determine the effects of various culture conditions on cell gro...