Isolation, chemical characterization, and anti-inflammatory activity of coumarins, flavonoids, and terpenes from Tagetes lucida.

Tagetes lucida is widely used in traditional Mexican medicine for several disorders, including those associated with inflammation. In this work, fifteen compounds were identified (1-15) from T. lucida. Some of these compounds (1-8, 10, 12-14) were detected for the first time in the plant, and quercetagetin 7-O-ß-(6''-Protocatecoyl) glucopyranoside (13) has been identified for any plant species. The inflammation inhibition effects of these compounds were as follows: Amix (1-2) > 10 > 12a > 13 > 14a > Bmix (3-9) > 12; 12 and 13 showed a dose-response behavior. The mixture of 14 and 15 was not active. This work contributes to the knowledge of the anti-inflammatory capacity of T. lucida and the chemical identity of their bioactive compounds.

CHEMICAL CHARACTERIZATION OF A HYPOGLYCEMIC EXTRACT FROM CUCURBITA FICIFOLIA BOUCHE THAT INDUCES LIVER GLYCOGEN ACCUMULATION IN DIABETIC MICE.

BACKGROUND: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice. MATERIALS AND METHODS: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain. RESULTS: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract. CONCLUSION: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies.

Does a single time function adequately describe blood glucose concentration dynamics during an OGTT?

The Oral Glucose Tolerance Test is a commonly used test for diagnosis of Impaired Glucose Tolerance and Type 2 Diabetes Mellitus. In practice, there are two standard sample time intervals: deltat=60 min and deltat=30 min and two standard test time durations: 120 and 180 min. However, for an accurate description of blood glucose concentration dynamics, this number of samples is not enough. In the present work, test duration is considered beyond 180 min and a shorter time interval of deltat=10 min is proposed. Two main hypotheses are discussed: (a). Blood glucose concentration dynamics can be viewed as the impulse response of a "black box" system where the output is conformed by the algebraic sum of a set of exponentially damped sinusoidal functions and (b). There exists at least one endogenous excitation that acts as a counterregulatory mechanism against hypoglycemic tendencies.