Maniçoba, a quercetin-rich Amazonian dish

Nutrition, Healthcare Benefits and Phytochemical Properties of Cassava (Manihot esculenta) Leaves Sourced from Three Countries (Reunion, Guinea, and Costa Rica)

(1) Background: Manihot esculenta, cassava, is an essential food crop for human consumption in many parts of the world. Besides the wide use of its roots, cassava leaves have been used locally as green vegetables and for medicinal purposes. However, nutritional health data regarding cassava leaves is limited, therefore we investigated its composition and associated potential bioactivity interest for human health. (2) Methods: Cassava leaf bioactivity investigations focused on antioxidant properties (free radical scavenging) in association with immunomodulatory activities on inflammatory murine macrophages to measure the impact of cassava extract on the production of pro-inflammatory cytokines such as Interleukin-6, Tumor Necrosis Factor alpha, Monocyte Chemoattractant Protein-1, Prostaglandin-E2 and mediators such as nitric oxide. (3) Results: Antioxidant and immunomodulatory bioactivities were significant, with a concentration-dependent inhibition of cytokines production by inflammatory macrophages; (4) Conclusions: Taken together, our results tend to suggest that Manihot esculenta leaves might be underrated regarding the potential nutrition-health interest of this vegetal matrix for both human nutrition and prophylaxis of metabolic disease with underlying low grade inflammation status.

The influence of extraction methods on rutin yield of cassava leaves (Manihot esculenta Crantz)

Rutin, a well-known bioflavonoid, was found abundantly in cassava leaves. In the present study, extraction techniques including maceration, boiling, reflux, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) were optimised to increase the yield of rutin. Extraction parameters such as solvents, solid-liquid ratio, temperature, and time were optimised to give better extraction yields for each method. HPLC analysis showed a high content of rutin which is up to 2.4% per dry weight of cassava leaves. The extraction yields under optimised condition were found to be 16.00 ± 0.21, 20.38 ± 0.66, 22.33 ± 2.3, 24.49 ± 0.41, and 23.37 ± 1.00 g rutin per kg dry weight for maceration, boiling, reflux, UAE and MAE methods, respectively. Specifically, UAE reduced the extraction time to 90 min, using only 40–60% of aqueous ethanol. Meanwhile, MAE completed the extraction under 5 min and no significant differences in output was observed between the use of water and aqueous ethanol. Accordingly, with the extraction efficiency of up to 99 and 94%, respectively, both processes provided better results. The subsequent green purification using chilling method produced a typical cassava bioflavonoid containing 82% of rutin and 17% of nicotiflorin. This study informs a new abundant source of rutin and provides the optimum condition of extraction methods for high yield of rutin from cassava leaves.

Traditional Uses, Chemical Constituents, Biological Properties, Clinical Settings, and Toxicities of Abelmoschus manihot L.: A Comprehensive Review

Abelmoschus manihot, an annual herbal flowering plant, is widely distributed throughout eastern Europe and in temperate and subtropical regions of Asia. Its flowers have been traditionally used for the treatment of chronic kidney disease in China. Currently, more than 128 phytochemical ingredients have been obtained and identified from the flowers, seeds, stems, and leaves of A. manihot. The primary components are flavonoids, amino acids, nucleosides, polysaccharides, organic acids, steroids, and volatile oils. A. manihot and its bioactive constituents possess a plethora of biological properties, including antidiabetic nephropathy, antioxidant, antiadipogenic, anti-inflammatory, analgesic, anticonvulsant, antidepressant, antiviral, antitumor, cardioprotective, antiplatelet, neuroprotective, immunomodulatory, and hepatoprotective activities, and have effects on cerebral infarction, bone loss, etc. However, insufficient utilization and excessive waste have already led to a rapid reduction of resources, meaning that a study on the sustainable use of A. manihot is urgent and necessary. Moreover, the major biologically active constituents and the mechanisms of action of the flowers have yet to be elucidated. The present paper provides an early and comprehensive review of the traditional uses, chemical constituents, pharmacological activities, and pharmaceutical, quality control, toxicological, and clinical settings to emphasize the benefits of this plant and lays a solid foundation for further development of A. manihot.

Suppressive effects of Vochysia divergens aqueous leaf extract and its 5-methoxyflavone on murine macrophages and lymphocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Vochysia divergens Pohl (Vochysiaceae), popularly known as "Cambará", is a tree that is resistant to the seasonal floods in the Pantanal, and usually found in monodominant stands called "Cambarazal". The inhabitants of the Pantanal exploit this tree for medicinal uses. Infusions and decoctions of its leaves are taken as teas, particularly for the treatment of asthma, flu and diarrhea, according to the local tradition transmitted empirically through the generations.

AIM OF THE STUDY

To evaluate the beneficial health effects related to the ethnomedicinal uses of V. divergens (Vd) by using biomonitored fractionation of an aqueous leaf extract.

MATERIALS AND METHODS

The aqueous leaf extract was obtained by decoction, and then the extract was fractionated by a combination of separation techniques including precipitation, organic partition and chromatography. Chromatographic analyses of the active samples were carried out using HPLC-DAD-MS. Flavonoid 1 was isolated from the n-BuOH fraction through classic chromatographic techniques. The inhibitory effects and cytotoxicity of the Vd extract, fractions and flavonoid 1 on NO and TNF-α production were assessed in LPS-stimulated RAW 264.7 macrophage cultures. Additionally, suppression on the proliferation of BALB/c lymphocytes was estimated by [³H] thymidine incorporation. The antioxidant activity of the samples was verified by SNP and DPPH assays and the suppression of the iNOS protein expression was evaluated through Western blotting.

RESULTS

The HPLC-DAD-MS analysis of the Vd extract led to the identification of 5-methoxyluteolin-7-O-β-glucopyranoside (2), rutin (4) and the tannin galloyl-HHDP-glucopyranoside (3), besides the main flavonoid 3',5-dimethoxyluteolin-7-O-β-glucopyranoside (1), which was biologically evaluated in comparison with luteolin aglycone. The Vd extract, n-BuOH fraction and flavonoid 1 inhibited NO and TNF-α production by LPS-stimulated macrophages. The reduction of NO levels was mediated mainly by suppression of the iNOS expression. In addition, both the Vd extract (IC₅₀ 13.6 µg/mL) and flavonoid 1 (IC₅₀ 19.8 µg/mL; 41.6 µM) strongly inhibited stimulated lymphocyte proliferation when compared to the immunosuppressive agent cyclosporin A (IC₅₀ 43.8 µg/mL; 36.4 µM). The Vd extract also showed a scavenging activity toward DPPH and NO free radicals. This is the first report describing the immunomodulatory potential of V. divergens and its major flavonoid (1).

CONCLUSION

Our findings showed that the aqueous leaf extract of V. divergens and its flavonoid reduced the production of excessive pro-inflammatory markers, collaborating with the Pantanal folk medicinal tradition that recommends the tea of cambará leaves for both asthma and flu. In addition, this study contributes to the knowledge of the pharmacological properties of 5-methoxy flavones, a poorly investigated subclass of flavonoids.

Polyphenols from Root, Tubercles and Grains Cropped in Brazil: Chemical and Nutritional Characterization and Their Effects on Human Health and Diseases

Throughout evolution, plants have developed the ability to produce secondary phenolic metabolites, which are important for their interactions with the environment, reproductive strategies and defense mechanisms. These (poly)phenolic compounds are a heterogeneous group of natural antioxidants found in vegetables, cereals and leguminous that exert beneficial and protective actions on human health, playing roles such as enzymatic reaction inhibitors and cofactors, toxic chemicals scavengers and biochemical reaction substrates, increasing the absorption of essential nutrients and selectively inhibiting deleterious intestinal bacteria. Polyphenols present in some commodity grains, such as soy and cocoa beans, as well as in other vegetables considered security foods for developing countries, including cassava, taro and beetroot, all of them cropped in Brazil, have been identified and quantified in order to point out their bioavailability and the adequate dietary intake to promote health. The effects of the flavonoid and non-flavonoid compounds present in these vegetables, their metabolism and their effects on preventing chronic and degenerative disorders like cancers, diabetes, osteoporosis, cardiovascular and neurological diseases are herein discussed based on recent epidemiological studies.

Polyphenol content and modulatory activities of some tropical dietary plant extracts on the oxidant activities of neutrophils and myeloperoxidase

Young leaves of Manihot esculenta Crantz (Euphorbiaceae), Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae) and Pteridium aquilinum (Dennstaedtiaceae) are currently consumed as green vegetables by peoples in sub-Saharan Africa, Latin America, Asia and their migrants living in Western Europe. Sub-Saharan peoples use Manihot, Abelmoschus and Hibiscus also in the folk medicine to alleviate fever and pain, in the treatment of conjunctivitis, rheumatism, hemorrhoid, abscesses, ... The present study investigates the effects of aqueous extracts of those plants on the production of reactive oxygen species (ROS) and the release of myeloperoxidase (MPO) by equine neutrophils activated with phorbol 12-myristate 13-acetate (PMA). The ROS production was measured by lucigenin-enhanced chemiluminescence (CL), and the release of total MPO by an ELISA method. The study also investigates the effect of the extracts on the activity of MPO by studying its nitration activity on tyrosine and by using a new technique called SIEFED (Specific Immunological Extraction Followed by Enzymatic Detection) that allows studying the direct interaction of compounds with the enzyme. In all experiments, the aqueous extracts of the plants developed concentration-dependent inhibitory effects. A moderate heat treatment did not significantly modify the inhibitory capacity of the extracts in comparison to not heated ones. Total polyphenol and flavonoid contents were determined with an HPLC-UV/DAD analysis and a spectroscopic method using Folin-Ciocalteu reagent. Some polyphenols with well-known antioxidant activities (caffeic acid, chlorogenic acid, hyperoside, rosmarinic acid and rutin) were found in the extracts and may partly explain the inhibitory activities observed. The role of those dietary and medicinal plants in the treatment of ROS-dependent inflammatory diseases could have new considerations for health.

Antioxidant and antiradical activities of Manihot esculenta Crantz (Euphorbiaceae) leaves and other selected tropical green vegetables investigated on lipoperoxidation and phorbol-12-myristate-13-acetate (PMA) activated monocytes

Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae), Manihot esculenta Crantz (Euphorbiaceae) and Pteridium aquilinum (Dennstaedtiaceae) leaves are currently consumed as vegetables by migrants from sub-Saharan Africa living in Western Europe and by the people in the origin countries, where these plants are also used in the folk medicine. Manihot leaves are also eaten in Latin America and some Asian countries. This work investigated the capacity of aqueous extracts prepared from those vegetables to inhibit the peroxidation of a linoleic acid emulsion. Short chain, volatile C-compounds as markers of advanced lipid peroxidation were measured by gas chromatography by following the ethylene production. The generation of lipid hydroperoxides, was monitored by spectroscopy using N-N'-dimethyl-p-phenylene-diamine (DMPD). The formation of intermediate peroxyl, and other free radicals, at the initiation of the lipid peroxidation was investigated by electron spin resonance, using α-(4-pyridyl-1-oxide)-N-tert-butylnitrone as spin trap agent. The ability of the extracts to decrease the cellular production of reactive oxygen species (ROS) in "inflammation like" conditions was studied by fluorescence technique using 2',7'-dichlorofluorescine-diacetate as fluorogenic probe, in a cell model of human monocytes (HL-60 cells) activated with phorbol ester. Overall the extracts displayed efficient concentration-dependent inhibitory effects. Their total polyphenol and flavonoid content was determined by classic colorimetric methods. An HPLC-UV/DAD analysis has clearly identified the presence of some polyphenolic compounds, which explains at least partially the inhibitions observed in our models. The role of these plants in the folk medicine by sub-Saharan peoples as well as in the prevention of oxidative stress and ROS related diseases requires further consideration.