Acción ixodicida de productos naturales de plantas nativas mexicanas

This work determined the acaricidal effect of 18 Mexican plants against Rhipicephalus microplus. The results of the larvicidal assay revealed that 5 methanolic extracts produced high activity (86-100 % mortality), 3 extracts exhibited relatively high activity (71-85 % mortality), 2 extracts displayed moderate activity (56-70 % mortality), 2 extracts presented low activity (31-55 % mortality) and 6 extracts showed non-significant acaricidal activity (0-30 % mortality). Extracts inducing >56 % mortality were subsequently assayed against engorged ticks of R. microplus by adult immersion test at a concentration of 5.0% w/v. In general terms, the results on larvae and adult ticks indicated that the methanolic extracts of Annona globiflora, Annona scleroderma, Litchi chinensis and Azadirachta indica showed the greatest activities. The crude extract of A. indica was subjected to chromatographic purification, which has led to the isolation of 3-O-butyl-(-)-epigallocatechin (1), 3-O-butyl-(-)-epicatechin (2), (-)-epigallocatechin (3), (+)-gallocatechin (4), (-)-epicatechin (5), β-sitosterol (6), stigmasterol (7), stigmasterol glucoside (8), triolein (9), azadirachtin A (10), and the octadecanoic acid-tetrahydrofuran-3,4-vinyl ester (11). The isolated compounds' chemical structures were identified by the interpretation of NMR and HRESI-MS spectroscopic data. The isolated compounds were assayed against engorged ticks of R. microplus at a concentration of 6 mM. Based on the results obtained, it was concluded that 3-O-butyl-(-)-epigallocatechin (1), 3-O-butyl-(-)-epicatechin (2), azadirachtin A (10), and octadecanoic acid-tetrahydrofuran-3,4-vinyl ester (11) show the highest effectiveness.

Bioactive compounds from Prosthechea karwinskii decrease obesity, insulin resistance, pro-inflammatory status, and cardiovascular risk in Wistar rats with metabolic syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

The orchid Prosthechea karwinskii is a species endemic to Mexico, which is used in traditional medicine to lower glucose levels in patients with diabetes, and to treat inflammation-related problems. Recent studies have shown that this orchids can reduce glucose, cholesterol, and triglyceride levels in Wistar rats, which were previously induced to have metabolic syndrome (MS).

AIM OF THE STUDY

To evaluate the effect of P. karwinskii leaves extract on the components of metabolic syndrome: obesity, insulin resistance, pro-inflammatory status, and cardiovascular risk in a Wistar rat model, and to identify the bioactive compounds in the extract.

MATERIALS AND METHODS

UPLC-ESI-qTOF-MS/MS was used to identify the compounds present in the extract. MS was induced in Wistar rats through administration of a 40% sucrose diet for 20 weeks. The rats were divided into five groups that received different treatments for 4 weeks: one group without any treatment, one group receiving metformin (200 mg/kg p.o.), and three groups receiving different doses of P. karwinskii leaves extract (100, 200, and 300 mg/kg p.o.). The animals' body weights were recorded weekly, and at the end of the experiment, they were sacrificed after fasting for 18 h to determine the levels of glucose, insulin, insulin resistance index, total cholesterol, triglycerides, and adiponectin in the serum, as well as levels of TNF-α and HS-CRP in the serum and liver homogenates. The abdominal and pericardial fat weights were also recorded.

RESULTS

The main bioactive compounds of the extract were quinic acid, neochlorogenic acid, chlorogenic acid, rutin, kaempferol-3-o-β-rutinoside, and embelin, known to exhibit MS-related bioactivity. Oral administration of P. karwinskii leaves extract at a dose of 300 mg/kg decreased weight gain, abdominal and pericardial fat deposits, and insulin resistance. At the end of the treatment, levels of triglycerides, TNF-α, HS-CRP, and adiponectin returned to levels similar to normal.

CONCLUSION

P. karwinskii extract (300 mg/kg) had an anti-obesity effect, decreased insulin resistance, pro-inflammatory status, and cardiovascular risk in rats with induced MS by increasing adiponectin levels and decreasing TNF-α and HS-CRP levels. The compounds identified in the extract could be responsible for these effects, acting alone or in synergy, as several compounds in the extract are known to have MS-related bioactivity. The foliar extract of P. karwinskii has potential as an effective alternative to a cocktail of drugs used to treat problems associated with MS.

High-sucrose diet potentiates hyperaldosteronism and renal injury induced by stress in young adult rats

Analyze the effect of stress and high-sucrose diet on serum aldosterone levels and the morphometric characteristics of the kidney in young adult rats. Wistar male rats aged 21 days old weaned were randomly assigned into four groups: control (C), stressed (St), high-sucrose diet (S30), and chronic restraint stress plus a 30% sucrose diet (St + S30). Rats were fed with a standard chow and tap water ad libitum (C group) or 30% sucrose diluted in water (S30 group) during eight weeks. The St and St + S30 groups were subject to restraint stress (1-hour daily in a plastic cylinder, 5 days per week), four weeks before euthanasia. At 81 days old, all animals were killed and blood samples and kidneys were collected. Stressed rats had an increase in the serum aldosterone and renal triacylglycerol, a decrease in the area of the renal corpuscle, glomeruli, proximal tubules, and aquaporin 2 expressions with loss of glomeruli. For its part, the high-sucrose diet decreased the area of the renal corpuscle, glomeruli, and aquaporin 2 expressions in the cortex. The combination of stress and high- sucrose diet maintained similar effects on the kidney as the stress alone, although it induced an increase in the creatinine levels and renal glycogen. Our results showed that chronic stress induces hyperaldosteronism and kidney injury. The intake of a high-sucrose diet may potentiate the renal injury promoted by stress.

Cd36 gene expression in adipose and hepatic tissue mediates the lipids accumulation in liver of obese rats with sucrose-induced hepatic steatosis

Obesity is considered a global epidemic and is mainly associated with the development of diabetes, cardiovascular diseases and Non-Alcoholic Fatty Liver (NAFLD). The pathogenesis between obesity and hepatic steatosis is partially known, but could involve differentiated or tissue-specific participation of the expression of Cd36 mRNA that codes for a receptor which is a transporter of free fatty acids (FFA) in different tissues, favoring the lipids storage. This relative expression was evaluated in adipose and liver tissue in rats with steatosis after consumption of sucrose for 30 and 40 weeks. Ten Wistar rats were divided into two experimental groups (St-30 and St-40), which received a standard diet plus 30 % sucrose in their water intake. These rats showed a significant increase in abdominal fat, serum biochemical determinations, HOMA-IR; as well as, changes in adipocytes size and mild portal hepatitis and grade 2 hepatic steatosis. The relative expression of Cd36 mRNA increased in liver tissue after 30 (4.5-fold) and 40 (8.5-fold) weeks of sucrose ingestión but no in adipose tissue; with respect to control group (P < 0.05). This expression was associated with a significant increase in the levles of sCD36 in serum, which is indicator of the presence of the FFA transporter in the hepatocyte membrane causing lipids accumulation. The above shows the link between the adipose and hepatic tissue for the accumulation of steatotic fat in the liver through time, mediated by the relative expression of cd36 mRNA that encodes for the FFA transporter.

Tissue Changes in the Development of Fatty Liver by Chronic Ingestion of Sucrose Associated with Obesity and Dyslipidemia in Rats

A diet high in sucrose, which is a common food constituent, induces obesity and non- alcoholic fatty liver (NFLD) caused by high caloric intake; however, it is important to investigate those sequential changes in the hepatic parenchyma related to sugar consumption which are associated to obesity and dyslipidemia. We analyzed the effects of long-term sucrose intake on fatty liver development, by the administration of 30% sucrose in drinking water in healthy Wistar rats during 30 weeks. Serum variables, body fat index, caloric intake and microscopic examination of liver tissue were monitored. In the first week, grade 1 steatosis was observed with ballooned hepatocytes, with a caloric intake of 125 ± 1.90 kcal / day / 100 g of body weight; together with a gain of 71% in abdominal fat with respect to the control group and dyslipidemia. During the 10 to 20 weeks period, steatosis grade 2 with noticeable inflammation (steatohepatitis), polymorphic cells and ballooned hepatocytes were evident. After 10 weeks, the caloric intake was 72.9 ± 5.99 kcal / day / 100 g of body weight with 199% of gain in abdominal fat in SUC groups with respect control group (p < 0.01) and moderate dyslipidemia; while after 20 weeks, the caloric intake was 61.6 ± 4.65 kcal / day / 100 g of body weight with 208% of gain in abdominal fat and also moderate dyslipidemia. After 30 weeks steatosis grade 3 with marked inflammation (steatohepatitis), periportal fibrosis, globose and fat-filled hepatocytes were observed, with a caloric intake of 52.3 ± 3.05 kcal / day / 100 g of body weight and 232% of gain in abdominal fat that was related to severe dyslipidemia. In conclusion, the sequential changes in the development of NAFLD were associated with the ingestion of sucrose and obesity since the first week of administration.

Enhanced Bioavailability of Curcumin Nanoemulsions Stabilized with Phosphatidylcholine Modified with Medium Chain Fatty Acids

BACKGROUND

Curcumin is a natural, oil-soluble polyphenolic compound with potent anticancer, anti-inflammatory, and antioxidant activities. In its free form, it is very poorly absorbed in the gut due to its very low solubility. The use of nanoemulsions as carrier is a feasible way for improving curcumin bioavailability. To this end, the choice of emulsifying agent for stabilizing the nanoemulsions is of the upmost importance for achieving a desired functionality.

METHODS

Phosphatidylcholine (PC) and phosphatidycholine enriched (PCE) with medium chain fatty acids (42.5 mol %) in combination with glycerol as co-surfactant, were used for preparing oil-in water nanoemulsions coded as NEPC and NEPCE, respectively.

RESULTS

NEPCE displayed significantly smaller mean droplet size (30 nm), equal entrapment efficiency (100%), better droplet stability and suffered lower encapsulation efficiency loss (3%) during storage time (120 days, 4ºC) than NEPC. Bioavailability, measured in terms of area under the curve of curcumin concentration versus time, and maximum curcumin plasma concentration, was in general terms significantly higher for NEPCE than for NEPC, and for curcumin coarse aqueous suspension (CCS). Also, NEPCE produced significantly higher curcumin concentrations in liver and lung than NEPC and CCS.

CONCLUSION

These data support the role of phosphatidylcholine enriched with medium chain fatty acids to increase the bioavailability of nanoemulsions for therapeutic applications.

Preparation, characterization and bioavailability by oral administration of O/W curcumin nanoemulsions stabilized with lysophosphatidylcholine

Curcumin is the main and most abundant bioactive component in Curcuma longa L. with documented properties in the prevention and treatment of chronic degenerative and infectious diseases. However, curcumin has low solubility in aqueous media, hence low bioavailability when administered orally. The use of nanoemulsions as carriers can provide a partial solution to bioavailability restrictions. In our study, O/W nanoemulsions of curcumin were prepared using lysophosphatidylcholine, a phospholipid with proven emulsification capacity; nevertheless, such qualities have not been previously reported in the preparation of nanoemulsions. Lysophosphatidylcholine was obtained by enzymatic removal of one fatty acid residue from phosphatidylcholine. The objective of our work was to formulate stable curcumin nanoemulsions and evaluate their bioavailability in BALB/c mice plasma after oral administration. Formulated nanoemulsions had a droplet size mean of 154.32 ± 3.10 nm, a polydispersity index of 0.34 ± 0.07 and zeta potential of -10.43 ± 1.10 mV; stability was monitored for 12 weeks. Lastly, in vivo pharmacokinetic parameters, using BALB/c mice, were obtained; namely, C_max of 610 ± 65.0 μg mL^-1 and T_max of 2 h. Pharmacokinetic data revealed a higher bioavailability of emulsified as opposed to free curcumin. Research regarding other potential emulsifiers that may provide better health benefits and carry nano-encapsulated bioactive compounds more effectively, is necessary. This study provides important data on the preparation and design of nanoencapsulated Curcumin using lysophosphatidylcholine as an emulsifier.

Impact of micronized starfruit (Averrhoa carambola L.) fiber concentrate on lipid metabolism in mice

The objective of this study was to evaluate the effect of micronized insoluble fiber from starfruit bagasse as an ingredient of a functional food (FF) or as micronized insoluble fiber-rich fraction (IFRF) and its effects in vivo on lipids metabolism in a murine model. Experimental animals were divided in four isoproteic (15.8%) treatments differing on the fiber and cholesterol level used. The micronized IFRF particle size ranged from 37.5 to 149 μm. Treatments with added IFRF and those including the FF lowered serum triacylglycerols, total cholesterol (TC), high-density lipoproteins (HDL), and low-density lipoproteins (LDL) concentrations (IFRF: 14.2, 25.4, 55.06, and 12.18%, respectively; FF: 30.18, 39.47, 35.11, and 43.18%, respectively). IFRF produced the overall highest serum hypolipidemic effect and prevented the development of non-alcoholic fatty liver. Both the IFRF and the FF exhibited hypolipidemic effects that suggest a potential role of starfruit insoluble fiber as a component of FFs aimed against cardiovascular diseases.

Alteration of some inflammatory biomarkers by dietary oxysterols in rats

Oxysterols are structurally similar to cholesterol, but are characterized by one or more additional oxygen-containing functional groups. These compounds are implicated in inflammation given their ability to cause irreversible damage to vascular cells. The aim of this study was to study the alteration of some inflammatory biomarkers in Wistar rats in response to dietary oxysterols. Eighteen rats were randomly divided into three groups of six rats each. A standard diet supplemented with 1% (w/w) pure cholesterol (Chol group) or 1% (w/w) of an oxidized cholesterol mixture (COPs group) was fed for 8 weeks. Blood serum was separated; abdominal, pericardial, and epididymal adipose tissue was removed carefully. The COPs subjects exhibited significant increase in blood pressure and serum triacylgycerols as well as increased body fat index and pericardic, abdominal, and epididymal adipose tissue. These effects were accompanied by elevated circulating levels of plasma high-sensitivity C-reactive protein, tumor necrosis factor alpha, and resistin. We suggest that dietary oxysterols have an important pro-inflammatory effect.

Effect of conjugated linoleic acid on body fat, tumor necrosis factor alpha and resistin secretion in spontaneously hypertensive rats

Conjugated linoleic acid (CLA) is a naturally occurring group of dienoic derivaties of linoleic acid found mainly in beef and dairy products. CLA has been reported to reduce body fat, as well as to possess anticarcinogenic, antiatherogenic and procatabolic activities in animals. The objective of this study was to evaluate the effect of CLA supplementation to spontaneously hypertensive rats (SHR) on body fat, biochemical parameters of serum related tumor necrosis factor alpha (TNF-alpha) and resistin secretion. Thirty rats were divided in three groups, the first group of spontaneously hypertensive rats received a standard diet (V-SHR group, n=10), a second group of SHR was fed 1.5% of conjugated linoleic acid (CLA-SHR group, n=10) and the third was the control, non-hypertensive group (KW, n=10) also on a standard diet including 7.5% of sunflower oil during eight weeks. After CLA diet administration, spontaneously hypertensive rats showed a significant reduction in blood pressure, serum glucose, cholesterol and triacylglycerols, together with reduction of index of body fat, pericardic, abdominal and epididymal adipose tissue. These effects were accompanied by a decrease in the secretion of TNF-alpha and resistin.