Patricio Rojas-Silva

Dietary polyphenols promote growth of the gut bacterium Akkermansia muciniphila and attenuate high fat diet-induced metabolic syndrome.

Dietary polyphenols protect against metabolic syndrome, despite limited absorption and digestion, raising questions about their mechanism of action. We hypothesized that one mechanism may involve the gut microbiota. To test this hypothesis, C57BL/6J mice were fed a high-fat diet (HFD) containing 1% Concord grape polyphenols (GP). Relative to vehicle controls, GP attenuated several effects of HFD feeding, including weight gain, adiposity, serum inflammatory markers (tumor necrosis factor [TNF]α, interleukin [IL]-6, and lipopolysaccharide), and glucose intolerance. GP lowered intestinal expression of inflammatory markers (TNFα, IL-6, inducible nitric oxide synthase) and a gene for glucose absorption (Glut2). GP increased intestinal expression of genes involved in barrier function (occludin) and limiting triglyceride storage (fasting-induced adipocyte factor). GP also increased intestinal gene expression of proglucagon, a precursor of proteins that promote insulin production and gut barrier integrity. 16S rRNA gene sequencing and quantitative PCR of cecal and fecal samples demonstrated that GP dramatically increased the growth of Akkermansia muciniphila and decreased the proportion of Firmicutes to Bacteroidetes, consistent with prior reports that similar changes in microbial community structure can protect from diet-induced obesity and metabolic disease. These data suggest that GP act in the intestine to modify gut microbial community structure, resulting in lower intestinal and systemic inflammation and improved metabolic outcomes. The gut microbiota may thus provide the missing link in the mechanism of action of poorly absorbed dietary polyphenols.

Complementary Approaches To Gauge the Bioavailability and Distribution of Ingested Berry Polyphenolics

Two different strategies for investigating the likely fate, after ingestion, of natural, bioactive berry constituents (anthocyanins and other non-nutritive flavonoids) are compared. A model of the human gastrointestinal tract (TIM-1) that mimicked the biological environment from the point of swallowing and ingestion through the duodenum, jejunum, and ileum (but not the colon) was used to monitor the stability and bioaccessibility of anthocyanins from both maqui berry and wild blueberry. TIM-1 revealed that most anthocyanins were bioaccessible between the second and third hours after intake. Alternatively, biolabeled anthocyanins and other flavonoids generated in vitro from berry and grape cell cultures were administered to in vivo (rodent) models, allowing measurement and tracking of the absorption and transport of berry constituents and clearance through the urinary tract and colon. The advantages and limitations of the alternative strategies are considered.

Innovations in Health Value and Functional Food Development of Quinoa (Chenopodium quinoa Willd.).

Quinoa (Chenopodium quinoa Willd., Amaranthaceae) is a grain-like, stress-tolerant food crop that has provided subsistence, nutrition, and medicine for Andean indigenous cultures for thousands of years. Quinoa contains a high content of health-beneficial phytochemicals, including amino acids, fiber, polyunsaturated fatty acids, vitamins, minerals, saponins, phytosterols, phytoecdysteroids, phenolics, betalains, and glycine betaine. Over the past 2 decades, numerous food and nutraceutical products and processes have been developed from quinoa. Furthermore, 4 clinical studies have demonstrated that quinoa supplementation exerts significant, positive effects on metabolic, cardiovascular, and gastrointestinal health in humans. However, vast challenges and opportunities remain within the scientific, agricultural, and development sectors to optimize quinoas role in the promotion of global human health and nutrition.

Isothiocyanate-rich Moringa oleifera extract reduces weight gain, insulin resistance, and hepatic gluconeogenesis in mice.

SCOPE Moringa oleifera (moringa) is tropical plant traditionally used as an antidiabetic food. It produces structurally unique and chemically stable moringa isothiocyanates (MICs) that were evaluated for their therapeutic use in vivo. METHODS AND RESULTS C57BL/6L mice fed very high fat diet (VHFD) supplemented with 5% moringa concentrate (MC, delivering 66 mg/kg/d of MICs) accumulated fat mass, had improved glucose tolerance and insulin signaling, and did not develop fatty liver disease compared to VHFD-fed mice. MC-fed group also had reduced plasma insulin, leptin, resistin, cholesterol, IL-1β, TNFα, and lower hepatic glucose-6-phosphatase (G6P) expression. In hepatoma cells, MC and MICs at low micromolar concentrations inhibited gluconeogenesis and G6P expression. MICs and MC effects on lipolysis in vitro and on thermogenic and lipolytic genes in adipose tissue in vivo argued these are not likely primary targets for the anti-obesity and anti-diabetic effects observed. CONCLUSION Data suggest that MICs are the main anti-obesity and anti-diabetic bioactives of MC, and that they exert their effects by inhibiting rate-limiting steps in liver gluconeogenesis resulting in direct or indirect increase in insulin signaling and sensitivity. These conclusions suggest that MC may be an effective dietary food for the prevention and treatment of obesity and type 2 diabetes.

Antiparasitic compounds from Cornus florida L. with activities against Plasmodium falciparum and Leishmania tarentolae

AIM OF THE STUDY The objective of this study was to identify the antiplasmodial constituents from the bark of Cornus florida L., a plant traditionally used in North America for the treatment of malaria. METHODS AND MATERIALS Dried and powdered bark was extracted with 95% ethanol. The resultant extract was subjected to in vitro antiplasmodial-guided fractionation against Plasmodium falciparum (D10 strain). Antiplasmodial IC(50) values were calculated for pure compounds. Compounds were also assayed against Leishmania tarentolae, and rat skeletal myoblast L6 cells to assess antileishmanial activity and cytotoxicity, respectively. RESULTS Antiplasmodial-guided fractionation afforded 8 compounds: betulinic acid (1), ursolic acid (2), β-sitosterol (3), ergosta-4,6,8,22-tetraene-3-one (4), 3β-O-acetyl betulinic acid (5), 3-epideoxyflindissol (6), 3β-O-cis-coumaroyl betulinic acid (7), 3β-O-trans-coumaroyl betulinic acid (8), of which, (6) is for the first time here isolated from a natural product and (4), (7) and (8) are reported for the first time from this genus. In vitro IC(50) values against P. falciparum for (4) (61.0 μM) (6) (128.0 μM), (7) (10.4 μM), (8) (15.3 μM) are reported for the first time. Antileishmanial IC(50) values are reported here for the first time for (4) (11.5 μM), (6) (1.8 μM), (7) (8.3 μM) and (8) (2.2 μM). Cytotoxicity against L6 cells is reported for all compounds. CONCLUSIONS The compounds isolated in this study, while displaying moderate in vitro antiplasmodial activity, do not fully support the historical importance of C. florida as an antimalarial remedy in North America. The traditional remedy may exert its well documented effects by mechanisms unrelated to direct antiplasmodial action. While not traditionally used to treat Leishmania, this work shows that several constituents of C. florida possess promising in vitro antileishmanial activity.

Leishmanicidal activity of a daucane sesquiterpene isolated from Eryngium foetidum

Abstract Context: Eryngium foetidum L. (Apiaceae) is a traditional herb that has been used for numerous medicinal applications, including as a treatment for parasitic infections, especially in the Neotropics from where it originates. Objective: This study evaluates the in vitro leishmanicidal and cytotoxicity activities of isolated compounds based on a bioassay-guided fractionation approach. Materials and methods: Defatted aerial parts of E. foetidum were subjected to extraction with methanol followed by partitioning with n-hexane, ethyl acetate and 50% methanol. Then, the first two fractions were subsequently fractionated by column chromatography and HPLC. Compound identity was confirmed by mass spectrometry and NMR spectroscopy. Leishmania tarentolae (promastigotes) and L. donovani (amastigotes) were used as testing parasites. L6 rat myoblasts were used for cytotoxicity. All extracts and fractions were tested at 20 μg/mL. Results: The initial methanol extract showed 20% growth inhibition of L. tarentolae. Then, the n-hexane and ethyl acetate fractions were also active showing approximately 40% growth inhibition. From these two fractions, the following compounds were isolated: lasidiol p-methoxybenzoate (1), a daucane sesquiterpene; and 4-hydroxy-1,1,5-trimethyl-2-formyl-cyclohexadien-(2,5)-[α-acetoxymethyl-cis-crotonate] (2), a terpene aldehyde ester derivative. Compound 1 inhibited the growth of both L. tarentolae and L. donovani with IC50 values of 14.33 and 7.84 μM, respectively; and showed no cytotoxicity (IC50 > 50 μM). Compound 2 was inactive in the L. tarentolae assay (IC50 > 50 μM). Discussion and conclusion: This study presented the bioassay-guided fractionation with the leishmanicidal and cytotoxicity activities of two compounds isolated for the first time from an Eryngium species.

Antiplasmodial activity of cucurbitacin glycosides from Datisca glomerata (C. Presl) Baill

The traditionally used antimalarial plant, Datisca glomerata (C. Presl) Baill, was subjected to antiplasmodial assay guided fractionation. This led to the isolation of seven cucurbitacin glycosides, datiscosides I-O, along with two known compounds, datiscoside and datiscoside B, from the aerial parts of D. glomerata. Their structures and relative stereochemistry were determined on the basis of mass spectrometry, 1D and 2D NMR spectroscopic data. Antiplasmodial IC(50) values were determined for all isolated compounds against a chloroquine sensitive strain of Plasmodium falciparum (D10), which were also evaluated in vitro for their antileishmanial activity against Leishmania tarentolae. Cytotoxicity was evaluated against rat skeletal muscle cells (L6) and Chinese ovarian hamster cells (CHO). The antiplasmodial activity of the compounds was moderate and ranged from 7.7 to 33.3 μM. None of the compounds showed appreciable antileishmanial activity. The compounds displayed cytotoxicity against L6 but not CHO mammalian cells.

Discovering the Pharmacological Potential of Ecuadorian Market Plantsusing a Screens-to-nature Participatory Approach

Objective: Edible plants of medicinal value can serve as a resource for sustainable development in Ecuador, a country rich in agrobiodiversity and traditional ecological knowledge. This study surveyed the nematicidal, antimicrobial, and antioxidant potential of plants sold in local Ecuadorian markets through participatory scientific discovery workshops with local Ecuadorian students and researchers, while simultaneously enhancing the knowledge and technological capacity of workshop participants. Methods: Edible plants were purchased from city markets at 3 distinct research sites in Ecuador - Cuenca, Quito, and Santa Elena. Botanical identification and traditional uses of each plant were assessed via herbarium specimen preparation and reference to ethnobotanical texts. Portable screens-to-nature (STN) extraction and assay technologies were employed to rapidly and qualitatively detect roundworm lethality, antibacterial, antifungal, and free radical scavenging activities of the plants during 3-day STN workshops at each research site. Participant learning was assessed through a retrospective pretest-posttest administered at the end of each STN workshop. Results: A total of 50 plants were collected, representing 30 vascular plant families and a wide variety of traditional uses. Thirty-two participants among 3 STN workshops identified 1 plant with nematicidal activity, 14 plants with antibacterial activity, 20 plants with antifungal activity, and 41 plants with antioxidant activity. Nearly half of the plants (24 species) demonstrated both antimicrobial and antioxidant activities, correlating to their reported uses to treat both infectious and chronic/metabolic disorders in traditional Ecuadorian medicine. During the STN workshops, participant knowledge of pharmacological screening increased by 77%, whereas knowledge of biodiversity and conservation increased by 69%. Conclusion: This study demonstrated that STN technologies, employed through a participatory research approach, are highly efficient in the detection of biochemical activities of traditionally used plants. Furthermore, edible Ecuadorian plants possess nematicidal, antimicrobial and antioxidant properties with potential for further development as functional foods, botanical supplements, or cosmetics.