LC-MS Fingerprinting Development for Standardized Precipitate from Agastache mexicana, Which Induces Antihypertensive Effect through NO Production and Calcium Channel Blockade.

The aim of this work was to evaluate the vasorelaxant and antihypertensive effects of a standardized precipitate of the hydroalcoholic extract from Agastache mexicana (PPAm), comprising ursolic acid, oleanolic acid, acacetin, luteolin and tilianin, among others. In the ex vivo experiments, preincubation with L-NAME (nonspecific inhibitor of nitric oxide synthases) reduced the relaxation induced by PPAm; nevertheless, preincubation with indomethacin (nonspecific inhibitor of cyclooxygenases) did not generate any change in the vasorelaxation, and an opposed effect was observed to the contraction generated by CaCl2 addition. Oral administration of 100 mg/kg of PPAm induced a significant acute decrease in diastolic (DBP) and systolic (SBP) blood pressure in spontaneously hypertensive rats, without changes in heart rate. Additionally, PPAm showed a sustained antihypertensive subacute effect on both DBP and SBP for 10 days compared to the control group. On the other hand, human umbilical vein cells treated with 10 µg/mL of PPAm showed a significant reduction (p < 0.05) in intracellular adhesion molecule-1, compared to the control, but not on vascular cell adhesion molecule-1. In conclusion, PPAm induces a significant antihypertensive effect in acute- and subacute-period treatments, due to its direct vasorelaxant action on rat aortic rings through NO production and Ca2+ channel blockade.

Anti-Helicobacter pylori Potential of Three Edible Plants Known as Quelites in Mexico.

"Quelites" are edible plants that are part of the traditional agro-ecosystems in Mexico. These plants, despite their already known nutritional properties, are now considered neglected and underutilized species. With the objective of promoting their reinsertion in the markets and mainly, in daily diets, efforts have been made to study them from multidisciplinary approaches to demonstrate their beneficial properties. To generate evidence of an added health-promoting value that would encourage quelites consumption, in the present work, the anti-Helicobacter pylori activity of three representative quelite species, Anoda cristata (Alache), Cnidoscolus aconitifolius (Chaya), and Crotalaria pumila (Chepil), was tested. H. pylori is considered the etiological agent of gastritis, ulcer, and gastric cancer, and represents a public health problem in Mexico and worldwide. Aqueous (AQ) and dichloromethane-methanol (DM) extracts were obtained from the three species of quelites to investigate their effect on H. pylori growth and on two of its colonization factors (adherence and urease activity). DM extracts from Chaya, Chepil, and Alache exert the best inhibitory effect on bacterial growth, with minimum inhibitory concentrations of 62.5, 125, and 250 µg/mL, respectively. AQ and DM extracts inhibit bacterial adhesion by 30% to 50%. None of them has an effect on urease activity. The two flavonoids present in A. cristata, acacetin and diosmetin, inhibit H. pylori growth by ∼90% with 3.9 µg/mL. These results provide new information about the anti-H. pylori potential of three edible quelites, and give an added value, since their routine consumption may impact on the prevention and/or control of H. pylori-associated diseases.

Vasorelaxant mode of action of dichloromethane-soluble extract from Agastache mexicana and its main bioactive compounds.

CONTEXT: Agastache mexicana (Kunth) Lint & Epling (Lamiaceae) is a plant used in Mexican traditional medicine for the treatment of hypertension, anxiety and so on. OBJECTIVE: To determine the vasorelaxant effect and functional mode of action of dichloromethane-soluble extract from A. mexicana (DEAm) and isolate the constituents responsible for the pharmacological activity. MATERIALS AND METHODS: Extracts were prepared from the aerial parts of A. mexicana (225.6 g) by successive maceration with hexane, dichloromethane and methanol (three times for 72 h at room temperature), respectively. DEAm (0.01-1000 µg/mL), fractions (at 174.27 µg/mL), acacetin and ursolic acid (UA) (0.5-500 µM) were evaluated to determine their vasorelaxant effect on ex vivo rat aorta ring model. In vivo UA antihypertensive action was determined on spontaneously hypertensive rats. RESULTS AND DISCUSSION: DEAm induced a significant vasorelaxant effect in concentration-dependent and endothelium-independent manners (EC50 = 174.276 ± 5.98 µg/mL) by a calcium channel blockade and potassium channel opening. Bio-guided fractionation allowed to isolate acacetin (112 mg), UA (2.830 g), acacetin/oleanolic acid (OA) (M1) (155 mg) and acacetin/OA/UA (M2) (1.382 g) mixtures, which also showed significant vasodilation. UA significantly diminished diastolic (80 mmHg) and systolic blood pressure (120 mmHg), but heart rate was not modified. CONCLUSION: DEAm produced significant vasorelaxant action by myogenic control cation. The presence of acacetin, OA and UA into the extract was substantial for the relaxant activity of DEAm. In vivo antihypertensive action of UA corroborates the use of A. mexicana as an antihypertensive agent on Mexican folk medicine.

Mexican propolis flavonoids affect photosynthesis and seedling growth.

As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 µM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli.

Hypoglycemic, antihyperglycemic, and antioxidant effects of the edible plant Anoda cristata.

ETHNOPHARMACOLOGICAL RELEVANCE: Some studies refer that the entire plant of Anoda cristata is consumed as food and medicine; in particular for treating diabetes, inflammation, fever, cough, and wounds. The aim of this study was to establish the preclinical efficacy of Anoda cristata as hypoglycemic and/or antihyperglycemic agent using well-known animal models. MATERIALS AND METHODS: The acute toxicity was analyzed by the Lorke method. Acute hypoglycemic as well as oral glucose and sucrose tolerance tests were used to determine the hypoglycemic and antihyperglycemic action of Anoda cristata. Several preparations of the plant, including a mucilage (M), an aqueous (T-AE), a free mucilage aqueous (FM-AE), and an organic (OE) extracts, were tested in healthy and NA-STZ-hyperglycemic mice. Glibenclamide (15mg/kg), acarbose (5mg/kg ) and metformin (200mg/kg) were used as positive controls. The major compounds acacetin (1) and diosmetin (2), isolated from an infusion of the plant applying chromatographic methods, were evaluated as hypoglycemic agents using the same assays. The FM-AE was tested also in rats with metabolic syndrome induced by a high-fructose fed. Finally some assays were performed to determine the antioxidant capacity of the FM-AE in vitro. RESULTS: The results demonstrated that the extracts and compounds from Anoda cristata were effective for reducing blood glucose levels in healthy and NA-STZ-hyperglycemic mice when compared with vehicle groups (p<0.05). The FM-AE exerted also positive effect over different biochemical parameters altered in rats with metabolic syndrome induced by a fructose diet. FM-AE has also antioxidant action effectively trapping ONOO(-) and ROO(•) radicals. The major flavonoids isolated from the plant, namely acacetin (1) and diosmetin (2), caused significant hypoglycemic effect and possessed antioxidant activity. CONCLUSION: Anoda cristata is effective to diminish glucose levels in vivo and to ameliorate different disorders related with the metabolic syndrome in rats. According to the results, the efficacy of Anoda cristata preparations could be due to the presence of active principles with different mode of actions at the molecular level, including α-glycosidases inhibitors, insulin secretagogues, glucose entrapment and radical trapping agents.