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Nat Prod Res ; 35(14): 2353-2359, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31617781


Geigeria poisoning, referred to as 'vermeersiekte' is an important plant poisoning in southern Africa. Three sesquiterpene lactones, isogeigerin acetate (1) ivalin (2) and geigerin (3) were isolated and purified from Geigeria aspera Harv. (Asteraceae). Structures were deduced using 1 and 2D NMR spectroscopy and mass spectrometry, while the absolute configurations of compounds 1 and 3 were determined for the first time by X-ray crystal diffraction analyses. Cytotoxicity of isogeigerin acetate, ivalin and geigerin were compared by exposing a murine skeletal myoblast (C2C12) cell line to varying concentrations of the three sesquiterpene lactones isolated. Cell viability was assessed using the methyl-thiazolyl-tetrazolium (MTT) assay. The EC50s were 3.746, 0.0029 and 3.792 mM for isogeigerin acetate (1), ivalin (2) and geigerin (3), respectively. The results indicate that ivalin is much more toxic, approximately 1000 times, in vitro compared to isogeigerin acetate and geigerin.

Geigeria/química , Lactonas/isolamento & purificação , Lactonas/farmacologia , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Animais , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Morte Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Lactonas/química , Camundongos , Espectroscopia de Prótons por Ressonância Magnética , Sesquiterpenos/química
Nat Prod Res ; 34(17): 2456-2464, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30732466


A new sesquiterpene lactone geigerianoloide (1) and four known flavonoids axillarin (2), quercetin (3), 3-methoxy-5,7,3',4'-tetrahydroxy-flavone (4) and hispidulin (5) were isolated from Geigeria alata (DC) Oliv. & Hiern. (Asteraceae). Structures were deduced using 1H- and 13C- NMR spectroscopy, mass spectrometry, while the structure of compound 1 was also deduced using X-ray crystallography technique.Geigeria alata is traditionally used for diabetes, therefore compounds were tested for anti-glycation activity, in which compounds 2 and 3 showed potent activities (IC50 values of 246.97 ± 0.83 and 262.37 ± 0.22 µM, respectively) compared to IC50 value 294.50 ± 1.5 µM of rutin. Moreover, compound 4 exhibited a comparable activity to rutin (IC50 = 293.28 ± 1.34 µM). Compound 5 showed a weak activity.Compounds 2, 3, and 4 exhibited potent DPPH radical scavenging activity (IC50 = 0.1 ± 0.00, 0.13 ± 0.00 and 0.15 ± 0.01 µM, respectively). Compounds 2, 3, and 4 demonstrated significant superoxide anion scavenging activity with IC50 values of 0.14 ± 0.001, 0.17 ± 0.00, and 0.11 ± 0.006 µM, respectively.

Antioxidantes/isolamento & purificação , Geigeria/química , Hipoglicemiantes/isolamento & purificação , Extratos Vegetais/química , Antioxidantes/química , Antioxidantes/farmacologia , Diabetes Mellitus/tratamento farmacológico , Flavonas/isolamento & purificação , Flavonoides/isolamento & purificação , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Hipoglicemiantes/farmacologia , Espectrometria de Massas , Estrutura Molecular , Extratos Vegetais/farmacologia , Sesquiterpenos/isolamento & purificação
Food Chem Toxicol ; 132: 110678, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323233


Geigeria alata Benth. & Hook.f. ex Oliv. & Hiern (Asteraceae) is used in Sudanese folk medicine for treatment of diabetes. The study aimed to estimate the acute oral toxicity of trans-3,5-dicaffeoylquinic acid (3,5-diCQA) from G. alata roots and to assess its antihypeglycemic, antioxidant and antihypertensive effects on chemically-induced diabetic spontaneously hypertensive rats (SHRs). The structure of 3,5-diCQA was established by NMR and HRMS spectra. Type 2 diabetes was induced by intraperitoneal injection of streptozotocin. 3,5-diCQA was slightly toxic with LD50 = 2154 mg/kg. At 5 mg/kg 3,5-diCQA reduced significantly (p < 0.05) the blood glucose levels by 42%, decreased the blood pressure by 22% and ameliorated the oxidative stress biomarkers reduced glutathione, malondialdehyde, and serum biochemical parameters. The beneficial effect on antioxidant enzymes was evidenced by the elevated glutathione peroxidase, glutathione reductase, and glutathione S-transferase activitiy in the livers of diabetic animals. 3,5-diCQA prevents the histopathological changes related to diabetes and hypertension. 3,5-diCQA was more potent α-glucosidase inhibitor (IC50 27.24 µg/mL) than acarbose (IC50 99.77 µg/mL). The antihyperglycemic action of the compound was attributed to the α-glucosidase inhibition. The beneficial effects of 3,5-diCQA on streptozotocin-induced diabetic hypertensive rats support the traditional use of G.alata for the management of diabetes.

Ácido Clorogênico/análogos & derivados , Diabetes Mellitus Experimental/tratamento farmacológico , Hipertensão Essencial/complicações , Geigeria/química , Animais , Biomarcadores/metabolismo , Glicemia/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Ácido Clorogênico/isolamento & purificação , Ácido Clorogênico/farmacologia , Ácido Clorogênico/uso terapêutico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Hipertensão Essencial/metabolismo , Inibidores de Glicosídeo Hidrolases/farmacologia , Fígado/metabolismo , Masculino , Estresse Oxidativo , Ratos , Ratos Endogâmicos SHR , Urinálise
Phytochem Anal ; 28(3): 176-184, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27910164


INTRODUCTION: Geigeria alata is a traditional plant used in Sudanese folk medicine for treatment of diabetes, cough, epilepsy and intestinal complaints. OBJECTIVE: To analyze phenolic acids in Geigeria alata roots and leaves and to evaluate their antioxidant and antimicrobial activities. METHODOLOGY: Phenolic acids in the aqueous-methanol extracts were identified by LC-MS. Major compounds were isolated using low-pressure liquid chromatography. The quantitative analysis of phenolic acids was performed by a validated HPLC-UV method with limits of detection ranging from 0.04 to 0.57 µg/mL. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazine-6-sulphonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) methods were used for antioxidant activity evaluation. In addition, the minimal inhibitory concentration and the minimal bactericidal concentration against a panel of pathogenic bacteria and fungi were determined by the broth microdilution test. RESULTS: For the first time protocatechuic, caffeic, p-coumaroylquinic, caffeoylsinapoylquinic, caffeoylferuloylquinic, three feruloylquinic, six caffeoylquinic acids, and a caffeic acid hexoside were detected in Geigeria alata roots by LC-MS. HPLC-UV analyses showed that 3,5-dicaffeoylquinic acid (25.96 ± 2.08 mg/g dry weight (DW)) was the most abundant phenolic acid in roots, while 4,5-dicaffeoylquinic acid (8.99 ± 0.56 mg/g DW) was the main compound present in leaves. 3,5-Dicaffeoylquinic acid demonstrated stronger radical scavenging activity and reducing power compared with the crude extracts and the positive control 5-caffeoylquinic acid. 3,4,5-Tricaffeoylquinic acid revealed the highest antibacterial potential against the penicillin sensitive and resistant Staphylococcus aureus strains, as well as methicillin-resistant S. aureus. CONCLUSION: The caffeoylquinic acids content of up to 6.22% in Geigeria alata roots establishes this species as a new source rich in these bioactive molecules. Copyright © 2016 John Wiley & Sons, Ltd.

Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão/métodos , Geigeria/química , Anti-Infecciosos/análise , Anti-Infecciosos/química , Antioxidantes/análise , Antioxidantes/química , Ácidos Cafeicos/análise , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Cromatografia Líquida , Flavonoides/análise , Espectrometria de Massas/métodos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Raízes de Plantas/química , Plantas Medicinais/química , Polifenóis/análise , Ácido Quínico/análogos & derivados , Ácido Quínico/análise
J Endocrinol ; 214(3): 329-35, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22736483


In Sudanese folk medicine, Geigeria alata roots have been used for the management of diabetes for a long time. However, its antidiabetic activity is unreported. In this study, G. alata methanolic extract was tested for its antidiabetic, antioxidant, and ß-cell modulatory effects in a streptozotocin-induced diabetic rat model. In this model of diabetic rats, the oral glucose tolerance test with G. alata extract at 125, 250, and 500  mg/kg doses revealed the efficacy of the 250  mg/kg dose in improving glucose tolerance comparable to the standard drug glibenclamide. Diabetic rats were treated with a 250  mg/kg dose of G. alata extract orally for 2  h (acute) or 14 days (chronic). In the case of acute treatment, the extract lowered blood glucose levels significantly at 120  min both in nondiabetic and diabetic rats. Chronic treatment of diabetic rats with 250  mg/kg of G. alata extract resulted in a significant decrease in blood glucose level closer to that of nondiabetic rats. Interestingly, increased serum insulin, improved ß-cell function, and antioxidant status were observed in G. alata-treated diabetic rats. G. alata also showed strong antioxidant and α-glucosidase inhibitory activities in in vitro assays. These data show direct evidence that G. alata has antidiabetic activity and suggest that the antidiabetic activity is due to enhanced insulin secretion, modulation of ß-cell function, and improvement of antioxidant status.

Antioxidantes/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Geigeria/química , Células Secretoras de Insulina/efeitos dos fármacos , Insulina/metabolismo , Extratos Vegetais/farmacologia , Animais , Antioxidantes/toxicidade , Artemia , Bioensaio/métodos , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Feminino , Teste de Tolerância a Glucose , Inibidores de Glicosídeo Hidrolases , Hipoglicemiantes/farmacologia , Hipoglicemiantes/toxicidade , Insulina/sangue , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Masculino , Extratos Vegetais/toxicidade , Raízes de Plantas/química , Ratos , Ratos Wistar , Testes de Toxicidade/métodos
J S Afr Vet Assoc ; 79(4): 178-84, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19496318


Changes in the oesophageal diameter and function together with changes in body weight, feed intake and the cardiac pulmonary flow index were investigated during experimentally induced poisoning with Geigeria ornativa and subsequent recovery. This was performed under varying conditions for individual sheep. Results showed an increase in the oesophageal diameter index (ODI) during vermeersiekte, accompanied with a decrease in oesophageal function (OF). Cessation of G. ornativa intake resulted in a considerable although incomplete recovery of the ODI. Recovery of the OF for the different sheep, however, varied between 0 and 100%. Detrimental changes in the oesophageal diameter and function were also measured in sheep receiving only subclinical doses of G. ornativa. Decreases in body weight and feed intake commenced 1 to 3 weeks before the onset of vermeersiekte, while indications of a decline in these 2 parameters were also noticed with ingestion of subclinical amounts of G. ornativa. An increase in the cardiac pulmonary flow index (CPFI) to a value indicating the onset of heart failure was found in 1 of the sheep showing clinical signs of vermeersiekte. The CPFI returned to normal after termination of G. ornativa intake.

Esôfago/anatomia & histologia , Esôfago/fisiologia , Geigeria/intoxicação , Intoxicação por Plantas/veterinária , Doenças dos Ovinos/fisiopatologia , Animais , Área Sob a Curva , Velocidade do Fluxo Sanguíneo/veterinária , Relação Dose-Resposta a Droga , Ingestão de Energia/fisiologia , Intoxicação por Plantas/fisiopatologia , Distribuição Aleatória , Recuperação de Função Fisiológica , Ovinos , Fatores de Tempo , Redução de Peso