Anti-hyperglycemic potential and chemical constituents of Aristolochia triangularis Cham. leaves - A medicinal species native to Brazilian forests.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia triangularis Cham. has been used in Brazilian traditional medicine for various therapeutic purposes, including as a leaf-based infusion for diabetes management. AIM OF THE STUDY: This study was designed to chemically characterize an infusion of in natura A. triangularis leaves and evaluate the in vivo anti-hyperglycemic properties of this infusion. MATERIALS AND METHODS: Chemical composition was examined using liquid-liquid extraction procedure, chromatographic methods, NMR, and LC-MS/MS. The in vivo anti-hyperglycemic activity of the freeze-dried infusion of A. triangularis leaves (Inf-L-At) was assessed using oral glucose tolerance test (OGTT). Initially, normoglycemic male rats were pre-treated with orally administered Inf-L-At at doses of 62.5, 125, and 250 mg/kg for two consecutive days. On the day of the OGTT, fasting animals received a glucose load (4 g/kg) 30 min after treatment with Inf-L-At, and the blood glucose levels were verified at 15, 30, 60, and 180 min. Intestinal maltase, lactase, and sucrase activities and muscle and liver glycogen contents were also assessed after the OGTT. RESULTS: Inf-L-At extract led to glycemic reduction with no dose-response at 15, 30, and 60 min comparable to that of the antidiabetic drug glibenclamide and was accompanied by an increase in hepatic and muscle glycogen contents. Additionally, there was a significant statistically decrease in the in vitro activity of disaccharidases. Maltase and sucrase activities were inhibited at all doses, whereas lactase activity was inhibited only at 62.5 and 250 mg/kg. In total, 75 compounds were found in the infusion, including seven new ones, (7S*,8S*,7ꞌS*,8ꞌR*)-4,4ꞌ-dihydroxy-3,3ꞌ-dimethoxy-7,9ꞌ-epoxylignan-7ꞌ-ol; 4ꞌ-hydroxy-3ꞌ-methoxy-3,4-methylenedioxy-7,9ꞌ-epoxylignan-9,7ꞌ-diol; triangularisines A, B, and C; N-ethyl-N-methyl-affineine; and N-methyl pachyconfine, and one previously not described as a natural product, epi-secoisolariciresinol monomethyl ether. CONCLUSION: The results demonstrated the anti-hyperglycemic activity of the infusion from A. triangularis leaves and showed that it is a rich source of lignoids, alkaloids, and glycosylated flavonoids, which are known to exhibit antidiabetic effects and other biological properties that can be beneficial for patients with chronic hyperglycemia, thus certifying the popular use of this herbal drink.

Effects of Bidens gardneri Baker leaves aqueous extract in glucose homeostasis of rats.

Bidens gardneri Baker, popularly known as "picão-vermelho", has been used, traditionally, as a medicinal plant for the treatment of Diabetes mellitus. This study aimed to evaluate antidiabetic effect of leaves from B. gardneri aqueous extract (BGAE). We also evaluated in vitro anti-glycation potential. Chemical composition was analyzed based on a colorimetrics and HPLC methods. The oral glucose tolerance test (OGTT), was performed in rats with different doses (30, 100 and 300 mg/kg). Alloxan-induced diabetic and hypercaloric diet-fed rats were treated with 300 mg/kg of BGAE, orally, for 10 days and then 10 weeks, respectively. The activity of intestinal disaccharidases (maltase, sucrase and lactase) and quantification of muscle and liver glycogen content were also evaluated. On chemical analysis, the extract showed high phenolics content and the chromatogram showed 4-O-caffeoylquinic acid as the major component. The extract presented inhibition in the formation of advanced glycation end products (AGEs) and disaccharidases activity. In OGTT the dose of 300 mg/kg significantly decreased the blood glucose. In diabetic animals, BGAE significantly decreased blood glucose levels, preventing weight loss. In addition, in hypercaloric diet-fed rats, the extract prevented hyperglycemia. Our results suggest that, aqueous extract of B. gardneri has a potential for therapeutic intervention of diabetes.

Chemical constituents of Cochlospermum regium (Schrank) Pilg. root and its antioxidant, antidiabetic, antiglycation, and anticholinesterase effects in Wistar rats.

The main physiological consequence of diabetes mellitus is chronic hyperglycemia. This condition is related to the formation of free radicals including advanced glycation end products (AGES) and to an increase in inflammatory processes. Cochlospermum regium (Schrank) Pilg., part of the Bixaceae family, is a cerrado plant known for its anti-inflammatory effects. The objectives of this study were to analyze the constituent compounds of C. regium roots and to evaluate the antioxidant, antiglycation, antidiabetic, and anticholinergic effects of its hydromethanolic extract through in vitro and in vivo experimental models. The presence of phenols, flavonoids, condensed tannins, and flavonols was analyzed by liquid chromatography - photodiode array (LC/PDA) analysis. Whereas antioxidant activity was investigated via DPPH, ABTS, ß-carotene/linoleic acid, and malondialdehyde colorimetric assays. Inhibition of AGEs was examined via a bovine serum albumin system whose glycosylating agent was glucose. Antidiabetic potential was examined in normoglycemic Wistar rats that received glucose overload, in alloxan-induced diabetic rats, and in rats that received a hyperglycemic diet. Disaccharidase inhibition was assessed using in vitro and in vivo methods, as was acetylcholinesterase (AChE) inhibition in brain structures. The hydromethanolic extract (CRHE) possessed a high concentration of phenolic compounds and showed antioxidant effects. The LC-DAD results revealed that CRHE contained a high concentration of phenolic acids and the majority was gallic acid. Treatment with CRHE caused significant inhibition of AGE formation. The oral glucose tolerance test (OGTT) in normoglycemic animals showed a reduction in blood glucose levels after treatment with 100 mg/kg CHRE, accompanied by an increase in hepatic glycogen content. There was also a significant reduction in the fasting glucose levels of alloxan-induced diabetic animals after 7 days of treatment with daily doses of 100 mg/kg. After 14 weeks of hyperglycemic diet, the last four or which were combined with 100 mg/kg CRHE treatment, there was a decrease in blood triglyceride levels. There was also a statistically significant decrease in the enzymatic activity of maltase, lactase and sucrase. The results demonstrate that oral administration of 30 and 100 mg/kg CRHE inhibited AChE activity in different brain structures. Thus, the extract of C. regium showed promising antioxidant, antiglycation, and antidiabetic effects that may be related to its high phenolic content.