Phytochemical analysis and antihyperglycemic activity of Castilleja arvensis.

Castilleja genus comprises approximately 211 species, some of them exhibiting potential in treating various diseases. Remarkably, despite its abundance, there is a significant lack of scientific studies that explore the chemical composition and/or therapeutic activity of this genus. In this work, the chemical composition of Castilleja arvensis was determined, and its antihyperglycemic activity was evaluated in vivo, in vitro, and ex vivo. Hydroalcoholic extract of C. arvensis (HECa) was obtained from the maceration of aerial parts. HECa was fractionated by liquid-liquid extractions to obtain the CH2Cl2 fraction (DF), EtOAc fraction (EF), n-BuOH fraction (BF) and aqueous residue (AR). The antihyperglycemic activity was determined in vivo through oral glucose and sucrose tolerance tests in normoglycemic CD-1 mice. Ex vivo assays were performed to determine intestinal glucose absorption, muscular glucose uptake and hepatic glucose production. α-glucosidase inhibitory activity was evaluated in vitro. Phytochemical screening was carried out through conventional chromatography techniques. Structure elucidation of the isolated compounds was performed by GC-MS and NMR experiments. HECa, its fractions and AR showed significant antihyperglycemic activity in vivo. According to the in vitro and ex vivo assays, this effect can be attributed to different mechanisms of action, including a delay in intestinal glucose absorption, an improvement in insulin sensitivity, and the regulation of hepatic glucose production. These effects may be due to different metabolites identified in fractions from the HECa, including genkwanin, acacetin, verbascoside and ipolamiide. Thus, current research shows that C. arvensis is an important source of bioactive compounds for the management of glycemia.

Evaluación del efecto hipoglucemiante de una fracción peptídica de las semillas de chía (Salvia hispanica L) en ratas macho Wistar inducidas con aloxano / Evaluation of the hypoglycemic effect of a peptide fraction of chia seeds (Salvia hispánica L) in male Wistar rats induced with alloxan

Introducción: se han realizado investigaciones sobre la diabetes con péptidos de diferentes fuentes alimentarias en animales experimentales para aplicarse después en los seres humanos. Objetivo: la finalidad de este trabajo fue evaluar en ratas el efecto hipoglucemiante de una fracción peptídica de chía obtenida por hidrólisis enzimática. Materiales y métodos: de la harina de chía se obtuvo una fracción rica en proteína que fue hidrolizada con pepsina-pancreatina, generándose una fracción peptídica (> 10 kDa) por ultrafiltración. Se utilizaron cinco grupos de ratas (uno de normoglucémicas y cuatro de diabetizadas con aloxano). Se realizó una curva de tolerancia a la sacarosa, proporcionándoles el disacárido antes de la medición. La sangre se tomó de la punta de la cola a los 0, 30, 60, 90 y 120 minutos. Resultados: el contenido proteico de la harina fue del 49,51 %. La fracción peptídica (> 10 kDa) presentó un 91 % de proteína; de esta se suministró una dosis de 50 mg/kg que demostró una tendencia a la disminución de la glucosa sanguínea en la primera hora, aunque no se encontró significancia entre el blanco y las dosis evaluadas. No hubo disminución de la absorción de glucosa frente al fármaco de referencia. A los 120 min del periodo postprandial no se encontraron diferencias entre las dosis, el blanco y la acarbosa, lo que denota un retorno al estado basal. Los valores en las ratas diabetizadas fueron opuestos a los de la acarbosa, por lo que no existió relación entre el mecanismo de acción del fármaco con el efecto analizado. Conclusión: las fracciones peptídicas de chía de > 10 kDa no presentaron efecto hipoglucemiante con la dosis única suministrada. (AU)

Introduction: diabetes research with peptides from foods has been conducted in animal experiments to be later applied to humans. Objective: the main purpose of this work was to evaluate in rats the hypoglycemic effect of a peptide fraction of chia seeds derived by enzymatic hydrolysis. Materials and methods: from chia flour a protein-rich fraction was obtained, which was hydrolyzed with pepsin-pancreatin system enzymes to yield a peptide fraction (> 10 kDa) by ultrafiltration. Five rat groups (one normoglycemic and four diabetized with alloxan) were used. A sucrose tolerance curve was performed, providing the disaccharide before measurement. Blood was taken from the tip of the tail at 0 (before sugar), 30, 60, 90, and 120 minutes. Results: the protein content of chia flour was 49.51 %. The peptide fraction (> 10 kDa) had 91 % of protein. A dose of 50 mg/kg showed in rats a tendency to decrease blood glucose within the first hour, but no significance was found between the target and the doses evaluated. There was no decrease in glucose absorption vs. the reference drug. At 120 min postprandial, no differences were found between doses, water, and acarbose, showing a return to the baseline status. The tolerance curve in diabetic rats was opposite to that of acarbose, so there was no relationship between the drug's mechanism of action and this analyzed effect. Conclusion: the peptide fraction of chia of > 10 kDa showed no hypoglycemic effect at the single dose that was administered. (AU)

[Evaluation of the hypoglycemic effect of a peptide fraction of chia seeds (Salvia hispánica L.) in male Wistar rats induced with alloxan]. / Evaluación del efecto hipoglucemiante de una fracción peptídica de las semillas de chía (Salvia hispanica L.) en ratas macho Wistar inducidas con aloxano.

INTRODUCTION: Introduction: diabetes research with peptides from foods has been conducted in animal experiments to be later applied to humans. Objective: the main purpose of this work was to evaluate in rats the hypoglycemic effect of a peptide fraction of chia seeds derived by enzymatic hydrolysis. Materials and methods: from chia flour a protein-rich fraction was obtained, which was hydrolyzed with pepsin-pancreatin system enzymes to yield a peptide fraction (> 10 kDa) by ultrafiltration. Five rat groups (one normoglycemic and four diabetized with alloxan) were used. A sucrose tolerance curve was performed, providing the disaccharide before measurement. Blood was taken from the tip of the tail at 0 (before sugar), 30, 60, 90, and 120 minutes. Results: the protein content of chia flour was 49.51 %. The peptide fraction (> 10 kDa) had 91 % of protein. A dose of 50 mg/kg showed in rats a tendency to decrease blood glucose within the first hour, but no significance was found between the target and the doses evaluated. There was no decrease in glucose absorption vs. the reference drug. At 120 min postprandial, no differences were found between doses, water, and acarbose, showing a return to the baseline status. The tolerance curve in diabetic rats was opposite to that of acarbose, so there was no relationship between the drug's mechanism of action and this analyzed effect. Conclusion: the peptide fraction of chia of > 10 kDa showed no hypoglycemic effect at the single dose that was administered.

INTRODUCCIÓN: Introducción: se han realizado investigaciones sobre la diabetes con péptidos de diferentes fuentes alimentarias en animales experimentales para aplicarse después en los seres humanos. Objetivo: la finalidad de este trabajo fue evaluar en ratas el efecto hipoglucemiante de una fracción peptídica de chía obtenida por hidrólisis enzimática. Materiales y métodos: de la harina de chía se obtuvo una fracción rica en proteína que fue hidrolizada con pepsina-pancreatina, generándose una fracción peptídica (> 10 kDa) por ultrafiltración. Se utilizaron cinco grupos de ratas (uno de normoglucémicas y cuatro de diabetizadas con aloxano). Se realizó una curva de tolerancia a la sacarosa, proporcionándoles el disacárido antes de la medición. La sangre se tomó de la punta de la cola a los 0, 30, 60, 90 y 120 minutos. Resultados: el contenido proteico de la harina fue del 49,51 %. La fracción peptídica (> 10 kDa) presentó un 91 % de proteína; de esta se suministró una dosis de 50 mg/kg que demostró una tendencia a la disminución de la glucosa sanguínea en la primera hora, aunque no se encontró significancia entre el blanco y las dosis evaluadas. No hubo disminución de la absorción de glucosa frente al fármaco de referencia. A los 120 min del periodo postprandial no se encontraron diferencias entre las dosis, el blanco y la acarbosa, lo que denota un retorno al estado basal. Los valores en las ratas diabetizadas fueron opuestos a los de la acarbosa, por lo que no existió relación entre el mecanismo de acción del fármaco con el efecto analizado. Conclusión: las fracciones peptídicas de chía de > 10 kDa no presentaron efecto hipoglucemiante con la dosis única suministrada.

Antihyperglycemic and hypoglycemic activity of Mayan plant foods in rodent models.

BACKGROUND: Postprandial hyperglycemia and decreased insulin secretion are relevant to risk factors in the development of type 2 diabetes and its complications. Plant foods with antidiabetic properties could be an affordable alternative in the prevention and treatment of this disease. In the present study, the antihyperglycemic and hypoglycemic activity of Bixa orellana, Psidium guajava L., Cucurbita moschata, Raphanus sativus L. and Brassica oleracea var. capitata - Mayan plant foods - were evaluated at doses of 5 and 10 mg kg-1 . Antihyperglycemic activity was measured in healthy Wistar rats and those with obesity induced by high-sucrose diet (group HSD) (20%). The hypoglycemic activity was measure in healthy CD1 mice. RESULTS: Fasting glucose, Lee index and the body weight of HSD rats increased significantly (P ≤ 0.05) after 12 weeks of induction compared to healthy rats. In healthy rats, P. guajava and Bixa orellana (10 mg kg-1 ) demonstrated higher and statistically different (P ≤ 0.05) antihyperglycemic activity compared to control acarbose (0.5 mg kg-1 ). In the HSD rat group, all Mayan plant foods (10 mg kg-1 ) demonstrated antihyperglycemic activity statistically equal (P ≤ 0.05) to control acarbose. However, Brassica oleracea and R. sativus registered the highest antihyperglycemic activity. Bixa orellana and P. guajava (5 mg kg-1 ) showed similar hypoglycemic activity (P ≤ 0.05) to glibenclamide (0.5 mg kg-1 ) but was not significant (P ≤ 0.05) compared to insulin (5 UI kg-1 ). CONCLUSION: The present study provides valuable evidence on the possible health benefits of Mayan plant foods. These foods could contribute to the development of therapeutic diet strategies for the prevention and treatment of diabetes. © 2021 Society of Chemical Industry.

α-Glucosidase inhibitory activity and in vivo antihyperglycemic effect of secondary metabolites from the leaf infusion of Ocimum campechianum mill.

ETHNOPHARMACOLOGICAL RELEVANCE: Wild basil (Ocimum campechianum Mill.), an aromatic herb of the Lamiaceae family known as "albahaca de monte" (Spanish) or "x'kakaltun" (Mayan) in Yucatan, is used in Mayan traditional medicine to treat diabetes, as well as to alleviate fever symtoms, stomach pain, conjunctivitis, and various skin affections. AIM OF THE STUDY: To isolate and identify the bioactive metabolites responsible for the α-glucosidase inhibitory activity previously detected in the leaf infusion O. campechianum. MATERIALS AND METHODS: The bioassay-guided fractionation and purification of the lyophilized infusion was carried out using a liquid-liquid partition procedure, followed by successive chromatographic purifications of the semipurified fractions. The isolated metabolites were identified by comparing their spectroscopic data with those reported in the literature. The liophylized infusion, together with the semipurified fractions, and the pure metabolites were tested for their antioxidant and α-glucosidase inhibitory activities, as well as their antihyperglycemic effect. RESULTS: Chromatographic purification of the semipurified fractions led to the isolation of the polymethoxylated flavones 5-demethyl nobiletin (1) and 5-demethyl sinensetin (2), together with luteolin (3), methyl rosmarinate (4) and rosmarinic acid (5). Metabolites 4 and 5 appear to be responsible for the α-glucosidase inhibitory activity and the antihyperglycemic effect detected in the lyophilized infusion. A Lineweaver-Burk double reciprocal plot confirmed that the higher α-glucosidase inhibitory activity of 4 is of non-competitive nature. Both 4 and 5 caused a decrease in blood glucose higher than that caused by acarbose, a result that appears to be related to their strong α-glucosidase inhibitory activity. Even though flavonoids 1-3 did not show a good inhibition of α-glucosidase, these products decreased blood glucose in the in vivo model, suggesting a different antihyperglycemic mechanism. CONCLUSIONS: The results confirm both the traditional use of O. campechianum and the importance of the leaf infusion as a potential source of antihyperglycemic agents. The isolation of 5-demethyl nobiletin (1) and 5-demethyl sinensetin (2) from O. campechianum and other Ocimum spp. suggests that polymethoxyflavones can be considered chemotaxonomical markers for the genus.

Protein hydrolysates and ultrafiltered < 1 KDa fractions from Phaseolus lunatus, Phaseolus vulgaris and Mucuna pruriens exhibit antihyperglycemic activity, intestinal glucose absorption and α-glucosidase inhibition with no acute toxicity in rodents.

BACKGROUND: Protein hydrolysates from food plants, such as legumes, have emerged as a new alternative to treat hyperglycemia, an important risk factor contributing to the development of type 2 diabetes mellitus (T2DM) and its complications. The aim of this work was to assess the antihyperglycemic activity and inhibition of α-glucosidase, and intestinal glucose absorption, and acute toxicity of total hydrolysates and < 1 kDa fractions from Phaseolus lunatus L., Phaseolus vulgaris L., and Mucuna pruriens (L.) DC., obtained by hydrolysis with Alcalase®-Flavourzyme® or pepsine-pancreatin enzymatic systems. RESULTS: In vivo results showed that three of six total hydrolysates and four of six < 1 kDa fractions suppressed starch-induced postprandial hyperglycemia (ED50 range between 1.4 and 93 mg kg-1 ). In vitro, total hydrolysates and fractions, particularly from M. pruriens, inhibited carbohydrate intestinal absorption (from 19.2 to 40%), and α-glucosidase activity (IC50 from 0.86 to 75 mg mL-1 ). Finally, none of the hydrolysates and fractions tested did not show any signs of toxicity (LD50 > 5000 mg kg-1 ). CONCLUSION: These results suggest that hydrolysates and < 1 kDa fractions from P. lunatus, P. vulgaris and M. pruriens are suitable candidates to treat or prevent T2DM. © 2018 Society of Chemical Industry.