Antihypertensive effects of Dorstenia psilurus extract in fructose-fed hyperinsulinemic, hypertensive rats

The effect of evening primrose oil (Oenothera biennis) on the level of adiponectin and some biochemical parameters in rats with fructose induced metabolic syndrome

The effect of evening primrose oil on adiponectin level and some biochemical parameters in model of fructose-induced metabolic syndrome were investigated. The rats were divided into 4 groups: control, evening primrose oil, fructose, fructose + evening primrose oil. Body weight, daily feed and water consumptions and systolic blood pressures of animals were measured. At the end of trial, blood samples were taken, livers were excised and histopathological examination was performed. Glucose, uric acid, triglyceride, T.cholesterol, LDL, HDL, VLDL, ALT, AST, ALP, LDH, adiponectin, insulin, IL-6, TNF-α, TAC, and TOS levels were analysed. Some analysed parameters and systolic blood pressure of fructose + evening primrose oil group decreased significantly compared to fructose group and adiponectin, TAC, and HDL levels were significantly increased. As conclusion, evening primrose oil can be considered as antioxidant agent by reducing oxidative stress, increasing adiponectin levels and insulin sensitivity, anti-inflammatory properties, exhibiting anti-atherogenic effect by regulating dyslipidemia and systolic blood pressure.

Potential of Central, Eastern and Western Africa Medicinal Plants for Cancer Therapy: Spotlight on Resistant Cells and Molecular Targets

Cancer remains a major health hurdle worldwide and has moved from the third leading cause of death in the year 1990 to second place after cardiovascular disease since 2013. Chemotherapy is one of the most widely used treatment modes; however, its efficiency is limited due to the resistance of cancer cells to cytotoxic agents. The present overview deals with the potential of the flora of Central, Eastern and Western African (CEWA) regions as resource for anticancer drug discovery. It also reviews the molecular targets of phytochemicals of these plants such as ABC transporters, namely P-glycoprotein (P-gp), multi drug-resistance-related proteins (MRPs), breast cancer resistance protein (BCRP, ABCG2) as well as the epidermal growth factor receptor (EGFR/ErbB-1/HER1), human tumor suppressor protein p53, caspases, mitochondria, angiogenesis, and components of MAP kinase signaling pathways. Plants with the ability to preferentially kills resistant cancer cells were also reported. Data compiled in the present document were retrieved from scientific websites such as PubMed, Scopus, Sciencedirect, Web-of-Science, and Scholar Google. In summary, plant extracts from CEWA and isolated compounds thereof exert cytotoxic effects by several modes of action including caspases activation, alteration of mitochondrial membrane potential (MMP), induction of reactive oxygen species (ROS) in cancer cells and inhibition of angiogenesis. Ten strongest cytotoxic plants from CEWA recorded following in vitro screening assays are: Beilschmiedia acuta Kosterm, Echinops giganteus var. lelyi (C. D. Adams) A. Rich., Erythrina sigmoidea Hua (Fabaceae), Imperata cylindrical Beauv. var. koenigii Durand et Schinz, Nauclea pobeguinii (Pobég. ex Pellegr.) Merr. ex E.M.A., Piper capense L.f., Polyscias fulva (Hiern) Harms., Uapaca togoensis Pax., Vepris soyauxii Engl. and Xylopia aethiopica (Dunal) A. Rich. Prominent antiproliferative compounds include: isoquinoline alkaloid isotetrandrine (51), two benzophenones: guttiferone E (26) and isoxanthochymol (30), the isoflavonoid 6α-hydroxyphaseollidin (9), the naphthyl butenone guieranone A (25), two naphthoquinones: 2-acetylfuro-1,4-naphthoquinone (4) and plumbagin (37) and xanthone V1 (46). However, only few research activities in the African continent focus on cytotoxic drug discovery from botanicals. The present review is expected to stimulate further scientific efforts to better valorize the African flora.

Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families

Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

African flora has the potential to fight multidrug resistance of cancer

Background. Continuous efforts from scientists of diverse fields are necessary not only to better understand the mechanism by which multidrug-resistant (MDR) cancer cells occur, but also to boost the discovery of new cytotoxic compounds to fight MDR phenotypes. Objectives. The present review reports on the contribution of African flora in the discovery of potential cytotoxic phytochemicals against MDR cancer cells. Methodology. Scientific databases such as PubMed, ScienceDirect, Scopus, Google Scholar, and Web of Knowledge were used to retrieve publications related to African plants, isolated compounds, and drug resistant cancer cells. The data were analyzed to highlight cytotoxicity and the modes of actions of extracts and compounds of the most prominent African plants. Also, thresholds and cutoff points for the cytotoxicity and modes of action of phytochemicals have been provided. Results. Most published data related to the antiproliferative potential of African medicinal plants were from Cameroon, Egypt, Nigeria, or Madagascar. The cytotoxicity of phenolic compounds isolated in African plants was generally much better documented than that of terpenoids and alkaloids. Conclusion. African flora represents an enormous resource for novel cytotoxic compounds. To unravel the full potential, efforts should be strengthened throughout the continent, to meet the challenge of a successful fight against MDR cancers.

In vitro antioxidant properties, free radicals scavenging activities of extracts and polyphenol composition of a non-timber forest product used as spice: Monodora myristica

Background

Excessive production of free radicals causes direct damage to biological molecules such as DNA, proteins, lipids, carbohydrates leading to tumor development and progression. Natural antioxidant molecules from phytochemicals of plant origin may directly inhibit either their production or limit their propagation or destroy them to protect the system. In the present study, Monodora myristica a non-timber forest product consumed in Cameroon as spice was screened for its free radical scavenging properties, antioxidant and enzymes protective activities. Its phenolic compound profile was also realized by HPLC.

Results

This study demonstrated that M. myristica has scavenging properties against DPPH^•, OH^•, NO^•, and ABTS^• radicals which vary in a dose depending manner. It also showed an antioxidant potential that was comparable with that of Butylated Hydroxytoluene (BHT) and vitamin C used as standard. The aqueous ethanol extract of M. myristica barks (AEH); showed a significantly higher content in polyphenolic compounds (21.44 ± 0.24 mg caffeic acid/g dried extract) and flavonoid (5.69 ± 0.07 quercetin equivalent mg/g of dried weight) as compared to the other studied extracts. The HPLC analysis of the barks and leaves revealed the presence of several polyphenols. The acids (3,4-OH-benzoic, caffeic, gallic, O- and P- coumaric, syringic, vanillic), alcohols (tyrosol and OH-tyrosol), theobromine, quercetin, rutin, catechine and apigenin were the identified and quantified polyphenols. All the tested extracts demonstrated a high protective potential on the superoxide dismutase (SOD), catalase and peroxidase activities.

Conclusion

Finally, the different extracts from M. myristica and specifically the aqueous ethanol extract reveal several properties such as higher free radical scavenging properties, significant antioxidant capacities and protective potential effects on liver enzymes.

Free radicals quenching potential, protective properties against oxidative mediated ion toxicity and HPLC phenolic profile of a Cameroonian spice: Piper guineensis

Considerations on antioxidants derived from plants have continuously increased during this decade because of their beneficial effects on human health. In the present study we investigated the free radical scavenging properties of extracts from Piper guineense (P. guineense) and their inhibitory potentials against oxidative mediated ion toxicity. The free radical quenching properties of the extracts against [1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS•), hydroxyl radical (HO•), nitric oxide (NO•)] radical and their antioxidant potentials by FRAP and phosphomolybdenum were determined as well as their protective properties on liver enzymes. The phenolic profile was also investigated by HPLC. The results obtained, revealed that the extracts significantly inhibited the DPPH, NO, HO and ABTS radicals in a concentration depending manner. They also showed a significant ferrous ion chelating ability through FRAP and phosphomolybdenum antioxidant potential. Their polyphenol contents varied depending on the type of extracts and the solvent used. The hydroethanolic extracts (FFH) and the ethanolic extracts (FFE) of P. guineense leaves showed the higher level of phenolic compounds respectively of 21.62 ± 0.06 mg caffeic acid/g dried extract (CAE/g DE) and 19.01 ± 0.03 CAE/g DE. The HPLC phenolic compounds profile revealed a higher quantity of Eugenol, quercetin, rutin and catechin in the stem than in the leaves. The presence of these molecules could be responsible of the protective potentials of P. guineense extracts against lipid peroxidation and SOD, catalase and peroxidase. In conclusion, P. guineense extracts demonstrated significant antioxidant property and may be used as a prospective protector against metal related toxicity.

Antibacterial and antibiotic-potentiation activities of the methanol extract of some cameroonian spices against Gram-negative multi-drug resistant phenotypes

Background

The present work was designed to evaluate the antibacterial properties of the methanol extracts of eleven selected Cameroonian spices on multi-drug resistant bacteria (MDR), and their ability to potentiate the effect of some common antibiotics used in therapy.

Results

The extract of Cinnamomum zeylanicum against Escherichia coli ATCC 8739 and AG100 strains showed the best activities, with the lowest minimal inhibitory concentration (MIC) of 64 μg/ml. The extract of Dorstenia psilurus was the most active when tested in the presence of an efflux pump inhibitor, phenylalanine Arginine-β- Naphtylamide (PAβN), a synergistic effect being observed in 56.25 % of the tested bacteria when it was combined with Erythromycin (ERY).

Conclusion

The present work evidently provides information on the role of some Cameroonian spices in the fight against multi-resistant bacteria.

Dorstenpictanone: a new bicyclic polyprenylated compound from Dorstenia picta

One new bicyclic polyprenylated compound, dorstenpictanone (1), was isolated from Dorstenia picta. The structure of the new compound was elucidated by detailed spectroscopic analysis such as (1)H NMR, (13)C NMR, COSY, HMQC, HMBC, and HREIMS. The relative configuration of dorstenpictanone (1) was distinguished by comparative analysis of the NMR spectral data with known analogues together with the ROESY experiment.

Cytotoxicity of some Cameroonian spices and selected medicinal plant extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Several medicinal plants and spices are used traditionally to treat cancers in Cameroon.

AIM

Methanol extracts from thirty-four spices and plants, with related ethnobotanical use were investigated for their in vitro cytotoxicity on the human pancreatic cancer cell line MiaPaCa-2, leukemia CCRF-CEM cells and their multidrug resistant (MDR) subline CEM/ADR5000, and the normal human umbilical vein endothelial cells (HUVECs). In addition the anti-angiogenic properties of the most active extracts were investigated.

MATERIAL AND METHODS

The MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay was used for cytotoxic studies and the CAM-assay (chicken-chorioallantoic-membrane-assay) for anti-angiogenesis test.

RESULTS

The results of the cytotoxicity tests indicated that, when tested at 20 μg/ml, extracts from Xylopia aethiopica, Echinops giganteus, Imperata cylindrica, Dorstenia psilirus and Piper capense were able to inhibit more that 50% the proliferation of the three tested cancer cells (MiaPaCa-2, CEM/ADR5000 CCRF-CEM). The lowest IC(50) values of 6.86 μg/ml on MiaPaCa-2 and 3.91 μg/ml on CCRF-CEM cells were obtained with X. aethiopica, while the corresponding value of 6.56 μg/ml was obtained with P. capense on CEM/ADR5000 cells. Against leukemia cells, no cross-resistance was observed with I. cylindrica, P. capense and Zinziber officinalis. Extracts from D. psilirus and E. giganteus were able to inhibit angiogenesis by more than 50% in quail embryo.

CONCLUSION

The overall results of the present study provide supportive data on the use of some Cameroonian plants for cancer treatment.

Contribution of animal models to the understanding of the metabolic syndrome: a systematic overview

The metabolic syndrome (MetS) is one of the most important challenges to public health and biomedical research. Animal models of MetS, such as leptin-deficient obese mice, obese spontaneously hypertensive rats, JCR: LA-cp rats and the Ossabaw and Göttingen minipigs, have contributed to our understanding of the pathophysiological basis and the development of novel therapies. For a complex disease syndrome, no animal model can be expected to serve all needs of research. Although each animal model has limitations and strengths, used together in a complementary fashion, they are essential for research on the MetS and for rapid progress in understanding the aetiology and pathogenesis towards a cure. The purpose of this review is to assess how current animal models contributed to our knowledge of the human MetS, and to systematically evaluate the strengths and weaknesses of the currently available 78 animal models from 11 species.

The protective role of amla (Emblica officinalis Gaertn.) against fructose-induced metabolic syndrome in a rat model

We investigated the effects of amla (Emblica officinalis Gaertn.) on fructose-induced metabolic syndrome using a rat model. Male Wistar rats were fed a high-fructose (65 %) diet or standard chow for 1 week, and treated with an ethyl acetate (EtOAc) extract of amla, a polyphenol-rich fraction, at 10 or 20 mg/kg body weight per d, or vehicle, for 2 weeks. Serum glucose, TAG, total cholesterol and blood pressure levels of the high-fructose diet-fed rats were increased compared with those of the normal rats (P < 0·001). However, the EtOAc extract of amla ameliorated the high fructose-induced metabolic syndrome, including hypertriacylglycerolaemia and hypercholesterolaemia. Also, the elevated levels of hepatic TAG and total cholesterol in rats given the high-fructose diet were significantly reduced by 33·8 and 24·6 %, respectively (P < 0·001), on the administration of the EtOAc extract of amla at the dose of 20 mg/kg with the regulation of sterol regulatory element-binding protein (SREBP)-1 expression. The protein levels of PPARα and SREBP-2 were not affected by the feeding of the high-fructose diet or EtOAc extract of amla. In addition, oral administration of the amla extract at the dose of 20 mg/kg significantly inhibited the increased serum and hepatic mitochondrial thiobarbituric acid-reactive substance levels (21·1 and 43·1 %, respectively; P < 0·001). Furthermore, the amla extract inhibited the increase of cyclo-oxygenase-2 with the regulation of NF-κB and bcl-2 proteins in the liver, while the elevated expression level of bax was significantly decreased by 8·5 and 10·2 % at the doses of 10 and 20 mg/kg body weight per d, respectively. These findings suggest that fructose-induced metabolic syndrome is attenuated by the polyphenol-rich fraction of amla.

Triprenylated flavonoids from Dorstenia psilurus and their alpha-glucosidase inhibition properties

Six new unusual C-4'-prenylated flavonols, dorsilurins F-K (1-6), together with six known compounds were isolated from the roots of Dorstenia psilurus, and their structures were elucidated on the basis of spectroscopic evidence. The isolated compounds exhibited moderate to low alpha-glucosidase inhibitory activity. Dorsilurin F (1), with three unmodified prenyl groups, was the most active, while dorsilurin K (6), with only one unmodified prenyl group, was the least active compound. Furthermore, NMR data of dorsilurin C (7), isolated some years ago from the same plant, have been revised.

A New Synthetic Route of 2-Aroyl- and 2-Benzyl-Benzofurans and their Application in the Total Synthesis of a Metabolite Isolated from Dorstenia gigas

The Lewis acid-catalyzed cyclization of the (Z)-3-(dimethylamino)-2-aryloxy-1-arylprop-2-en-1-ones 4a–h leads to a regioselective and short synthesis of 2-aroylbenzofurans 2a–h. The Wolff–Kishner reduction of the latter yielded a series of substituted 2-benzylbenzofurans 3a–h. This methodology was applied in the first total synthesis of the metabolite 2-(4-hydroxybenzyl)-6-methoxybenzofuran 1, which was isolated from the tropical plant Dorstenia gigas, and obtained through a six-step route and in a 24% overall yield.

Leaf methanol extract of Bidens pilosa prevents and attenuates the hypertension induced by high-fructose diet in Wistar rats

Chronic fructose treatment in rats has repeatedly been shown to elevate blood pressure in association with insulin resistance and hyperinsulinemia. The purpose of the current study was to investigate the effect of the leaf methanol extract of Bidens pilosa on systolic blood pressure (SBP) and plasma glucose, insulin, cholesterol, triglycerides and creatinine levels in rats with fructose-induced hypertension. Wistar rats that drank a 10% fructose solution for 3-6 weeks showed significant increase not only in plasma insulin and cholesterol levels but also in SBP. B. pilosa extract was able to prevent the establishment of hypertension and lower elevated blood pressure levels. The extract also reduced the highly elevated plasma insulin levels provoked by the high fructose diet. These results suggest that the leaf methanol extract of B. pilosa exerts its antihypertensive effect in part by improving insulin sensitivity.