RESUMO
This study was aimed to investigate the action mechanism ofHypoxis Hemerocallidea (African Potato, AP) on the AMPK signal pathway of skeletal muscles in diabetic rats. Among 40 male SD rats, 10 rats were used as the normal group, and the other 30 rats were fed with high-fat food for one month, and then injected with STZ for the model establishment. After the successful model establishment, rats were divided into the model group, pioglitazone hydrochloride group and the AP group. Intragastric administration was given for 5 weeks in each group. Then, the skeletal muscle tissues were embedded and sliced for immunohistochemistry test. The protein expression of p-AMPKα, p-AS16 and GLUT4 in skeletal muscles was detected by western blot. The 100 mmol·L-1 glucose was used in the establishment of C2C12 skeletal muscle cells insulin resistance model. AP drug-containing serum was used in the establishment of the treatment group. The control group was the normal cells. Glucose consumption, cell proliferation, SOD content, and MDA content were detected. And the protein expressions of p-AMPKα, p-AS160, GLUT4 were detected with the western blot and RT-PCR. The results showed that compared with the normal group, AP can up-regulate p-AMPKa protein express (P < 0.01), increase skeletal AS160 phosphorylation level (P < 0.01), and up-regulate the GLUT4 level (P < 0.01). Compared with the normal group, the high glucose caused the decrease of C2C12 skeletal muscle cell activity and the decrease of glucose consumption (P < 0.05), decrease of SOD, increase of MDA (P < 0.01), and the decrease of p-AMPKα, p-AS160, GLUT4 protein expression (P < 0.01). After 48 h intervention, the SOD of C2C12 skeletal muscle cells in the AP drug-containing serum group was significantly increased (P < 0.01), the MDA content was decreased (P < 0.05), the AMPKa and AS160 phosphorylation levels were increased (P < 0.01), the GLUT protein expression was increased (P < 0.01). It was concluded that the induced AMPKa and AS160 phosphorylation promoted GLUT 4 expression may be one of the action mechanism of insulin resistance of skeletal muscles in diabetes.
RESUMO
The Hypoxis corm has a catalogue of medicinal uses and also serves as a source of food. Most scientific research on Hypoxis has centred on Hypoxis hemerocallidea although many other species are exploited medicinally. Hypoxis corms look similar and this has resulted in different species being prescribed and sold as the same species raising important public health issues of the efficacy and quality of the medicines sold. The aim of this study was to investigate and compare the phytochemical profiles and cytotoxicity of Hypoxis hemerocallidea, Hypoxis rigidula, Hypoxis galpinii and Hypoxis obtusa. Corm methanolic extracts of the four species were qualitatively screened for different phytochemicals following standard methods. Tests indicated presence of terpenoids, saponins, cardiac glycosides, tannins and reducing sugars and negative for alkaloids, flavonoids and anthraquinones in the four Hypoxis species. Cytotoxic effects of the plants were assessed through Brine shrimp lethality (BSL) bioassay. LC50 values ranged from 6.3 -409 mg/ml showing that the plants are non toxic.