Adolfo Andrade-Cetto

Hypoglycemic effect of Cecropia obtusifolia on streptozotocin diabetic rats

The hypoglycemic effects of water and butanolic extracts prepared from leaves of Cecropia obtusifolia (Cecropiaceae) were examined in streptozotocin induced diabetic rats. A single oral administration of a water extract at doses of 90 and 150 mg/kg and of a butanol extract at doses of 9 and 15 mg/kg significantly (P<0.05) lowered the plasma glucose levels in diabetic rats after 3 h administration. Glibenclamide was used as reference and showed similar hypoglycemic effect to the tested extracts at a dose of 3 mg/kg. The flavone, isoorientin and 3-caffeoylquinic acid (chlorogenic acid), were isolated as the important constituents of the plant and were identified as the main constituents in both extracts, too.

Ethnobotanical study of the medicinal plants from Tlanchinol, Hidalgo, México

UNLABELLED The people in Mexico still depend upon the use of medicinal plants to treat simple health problems, including those who live in regions like Tlanchinol Hidalgo, where it is still possible to find people who speak the pre-Hispanic Nahua language. This area is surrounded by rain forest, which is more or less well conserved, so ethnopharmacological field studies are quite relevant. The cultural knowledge about the use of medicinal plants converge with the richness in the surrounding flora making this region ideal for the selection of traditionally used medicinal plants. AIM OF THE STUDY To present the results of an ethnopharmacological field survey conducted in the municipality of Tlanchinol Hidalgo, Mexico analyzed with two different quantitative tools, with the aim of selecting the most important species used in traditional medicine. MATERIALS AND METHODS Direct interviews with the people were performed in several short visits to the municipality of Tlanchinol Hidalgo. The plants were collected, and the species were determined. The interviews were analyzed with two quantitative tools. First, the factor informant consensus highlighted the agreement in the use of plants and the fidelity level defined as: the ratio between the number of informants who independently suggested the use of a species for the same major purpose and the total number of informants who mentioned the plant for any use. Furthermore, we analyzed the use-mentions for the plants. RESULTS The results of the factor informant consensus showed that the gastrointestinal category had the greatest agreement, followed by the respiratory and dermatological categories. The most important species according to their fidelity are: Coleus blumei, Plantago australis and Lippia dulcis for the gastrointestinal category; Borago officinalis, Foeniculum vulgare, and Eucalyptus globulus for the respiratory category; and Ageratum houstonianum and Solanum nigrescens for the dermatological category. CONCLUSION As a result of the present study, we recommend the plants listed in Table 2 for further ethnopharmacological studies, especially Lippia dulcis var Mexicana.

From the field into the lab: useful approaches to selecting species based on local knowledge

Ethnopharmacological field studies are indispensable for identifying plants that can be selected for their pharmacological effects and chemical composition. Although the subjective interpretation of results by the researcher is crucial, quantitative data analysis is a useful tool to identify the most promising pharmacological plants. It has been stated that such semi-quantitative information increases the likelihood of finding promising ethnopharmacological leads, but so far no critical review has assessed what standards best meet the requirements of biomedical research. Systematic database searches using SCOPUS, Science Direct, Web of Knowledge, Science Citation Index, and Medline with the keywords “ethnobotany,” “ethnopharmacology,” “index,” and “consensus” in research from the last 5 years form the basis of the current analysis, which identifies particularly useful tools like factor of informant consensus, fidelity level, use-value, and relative importance. A key feature for further field studies is that they should provide clear information on a range of topics like; detailed data of the importance of these resources within a culture, data of the uses of the species, how and where the plants are collected, drying and storage processes, preparation method, used doses, and administration. In addition, they must include a collection of records about how the people feel after the plant use, disappearance of specific symptoms and possible side effects.

Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients

The hypoglycemic effect of a water extract from aerial parts (0.33 g/kg) of Equisetum myriochaetum Schlecht and Cham (Equisetaceae) was analyzed in 11 recently diagnosed type 2 diabetic patients. A single dose of this extract was orally administered. Glucose and insulin were determined at 0, 30, 60, 90,120 and 180 min after administration. The same patients served as the control group and received only colored water as placebo. The administration of the extract significantly reduced the blood glucose levels of the type 2 diabetic patients within 90, 120 and 180 min. There were no significant changes in the insulin levels. The results demonstrate that the water extract of the aerial parts of E. myriochaetum shows a hypoglycemic effect in type 2 diabetic patients starting 90 min after its administration.

Ethnopharmacological field study of the plants used to treat type 2 diabetes among the Cakchiquels in Guatemala

ETHNOPHARMACOLOGICAL RELEVANCE Type 2 diabetes is characterized by tissue resistance to the action of insulin, combined with a relative deficiency in insulin secretion. In Guatemala, type 2 diabetes results in significant mortality rates. The low incomes of the indigenous population results in the use of alternative therapies such as medicinal plants to treat the illness. We could not find any previous study related to the use of medicinal plants to treat diabetes in Guatemala. The aim of this work is to determine the most effective plant species used in traditional medicine to treat type 2 diabetes. MATERIALS AND METHODS We performed an ethnopharmacological field study among the Cakchiquels of Chimaltenango to select the most prominent plants used to treat the disease. Type 2 diabetic patients from their community health centers were interviewed using structured questionnaires. Two mathematical tools were used to identify potential plant species: the Disease Consensus Index and the Use Value. International databases, including SCOPUS, PubMed, and Google Scholar, were used to identify whether the plants with the highest scores were known to elicit hypoglycemic effects. RESULTS After analyzing the data, we can propose the following plants as the most prominent among the Cakchiquels of Chimaltenango to treat type 2 diabetes: Hamelia patens Jacq., Neurolaena lobata (L.) R.Br.ex Cass., Solanum americanum Mill., Croton guatemalensis Lotsy, and Quercus peduncularis Née. CONCLUSIONS The Cakchiquel patients interviewed did not understand type 2 diabetes; however, they associated the onset of their disease with a negative emotion, such as shock, sadness or anger. Despite changes in lifestyle, influences of advertising, the availability of innovative treatments and the use of oral hypoglycemic treatments provided by health facilities serving indigenous communities, the Cakchiquel continue to use medicinal plants as adjunctive treatment. While they are unaware whether the plants can cause additional harm, they consider their consumption beneficial because they feel better. There were 11 plants identified with UVs greater than 0.5 and high DCIs; from these 64% of the plants have been identified as having hypoglycemic effects; this finding supports the traditional selection by the Cakchiquels of medicinal plants to treat T2D.

Pyrrolizidine alkaloids from Ageratum houstonianum Mill.

Four pyrrolizidine alkaloids (PA) were isolated from Ageratum houstonianum and their structures elucidated by spectroscopical methods. Besides the already known lycopsamine three new PA were found. Their structures are the 2S-2-hydroxy-2,3-dimethyl-butanoyl-O(9) as well as the O(7) esters of retronecine and the O(9) derivative of heliotridine.

Effect of Opuntia streptacantha Lem. on alpha-glucosidase activity.

ETHNOPHARMACOLOGICAL RELEVANCE In Mexico, Opuntia streptacantha is used as part of a traditional medicine in the treatment of diabetes mellitus. Several studies have reported an anti-hyperglycemic effect from the plant, but none have focused on finding a mechanism of action to explain these results. This paper focuses on one of the most recurrent hypotheses for the effect of O. streptacantha: the mechanism of action is the hydrolysis of disaccharides, either by enzymatically inhibiting the alpha glucosidase inhibitors (AGIs) or mechanically acting as a barrier. MATERIALS AND METHODS To test our hypothesis, three different experiments were performed. A maltose tolerance test was carried out using the total extract (TE) and the juice of the plant. Six different extracts were tested in a free-enzyme assay, four of which were aqueous extracts varying according to the procedure of removing the insoluble particles in an attempt to reduce the loss of the water-soluble compounds. The main component of the total extract, a derivative of (4-hydroxy)-phenyl acetic acid, was also tested. For both the maltose tolerance test and the free-enzyme assay, acarbose was used as a control drug. Finally, an everted small intestine assay was also performed. RESULTS AND CONCLUSIONS The maltose tolerance test confirmed that an anti-hyperglycemic effect occurs at doses of 100 mg/kg TE and 4 mL/kg juice. No inhibition on AGIs was observed in the free-enzyme assay, and neither a mechanic nor enzymatic effect on disaccharide hydrolysis was observed in the everted intestine assay. CONCLUSIONS The anti-hyperglycemic effect of O. streptacantha was confirmed, and the results presented here contribute to the understanding that this effect is not due to the action on alpha-glucosidases or related to the intestinal hydrolysis of disaccharides.

Pyrone glycosides from Acosmium panamense (Benth.) Yacovlev.

Abstract Besides caffeic acid three pyrones have been isolated from aquous bark extracts from Acosmium panamense and their structures were determined using spectroscopical methods. Besides the already described desmethylyangonine its O4′-mono as well as the di(1-6)glucoside are found the first time.

Effects of medicinal plant extracts on gluconeogenesis

Correspondence: Adolfo Andrade-Cetto Laboratorio de Etnofarmacologia, Departamento de Biologia Celular, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Coyoacan 04510, D.F. Mexico Email aac@ciencias.unam.mx Abstract: On a global level, type 2 diabetes mellitus (T2DM) is the most common endocrine disorder. T2DM is defined as an elevated blood glucose level associated with the absence of or inadequacy in pancreatic insulin secretion. The liver plays a key role in maintaining blood glucose levels during fasting by synthesizing glucose, mainly from lactate and amino acids through a process called gluconeogenesis. Because hepatic glucose production is increased at least twofold in patients with T2DM, targeting this pathway may lead to a blood glucose reduction in these patients. Botanical agents show promise for the development of new compounds to treat T2DM. Important mechanisms of action function via the inhibition of gluconeogenesis can occur in one of five ways: direct enzyme inhibition; through the downregulation of mRNA levels of fructose-1,6-bisphosphatase and glucose-6-phosphatase (G-6-P); through the activation of AMP-activated protein kinase, which leads to decreased levels of cAMP response elementbinding protein, a key transcription factor for gluconeogenic enzyme phosphorylation; through the expression of the glucokinase gene, which stimulates glucokinase activity and inhibits G-6-P; and through the inhibition of phosphoenolpyruvate carboxykinase, which decreases gluconeogenesis and enzymatically inhibits G-6-P and fructose-1,6-diphosphatase.

Effect of Larrea tridentata (creosote bush) on cholesterol gallstones and bile secretion in hamsters

Larrea tridentata (Sesse and Moc. ex DC.) Coville is used for the treatment of gallstones in traditional Mexican medicine. The possible prevention or elimination of gallstones by ethanolic and aqueous extracts of the leaves and twigs of L. tridentata was tested in hamsters fed a rich carbohydrate, fat‐free diet. In addition, the effects of the ethanolic extract and its main metabolite, nordihydroguaiaretic acid, on bile secretion in the perfused liver were tested. In the experiment on prevention of gallstones, the dry ethanolic extract at a level of 0.5% of diet completely inhibited gallstone formation, lowered biliary moles percent cholesterol and increased the proportion of chenodeoxycholic acid of hepatic bile. The dry aqueous extract at a level of 1% of diet did not affect gallstone frequency or biliary parameters. In the experiment on elimination of gallstones, the ethanolic extract significantly reduced gallstone frequency, gallbladder bile cholesterol concentration and moles percent cholesterol. Both the ethanolic extract and nordihydroguaiaretic acid had cholestatic effects in the perfused liver, with an EC50 of 34 and 28 mg dL−1, respectively, when perfused for 10 min. This effect was reversible with concentrations up to 40 mg dL−1. The results indicate that L. tridentata could be useful in the treatment of gallstone disease, however care must be taken due to its hepatotoxicity.