Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Description based on contents viewed Oct. 2, 2008; title from PDF t.p. Includes bibliographical references (p. 34-42).

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A hipertensÃo, uma das doenÃas mais comuns em todo o mundo, Ã uma doenÃa crÃnica onde a pressÃo sanguÃnea elevada pode afetar a saÃde. A enzima conversora de angiotensina I (ECA) pode aumentar a pressÃo arterial atravÃs da conversÃo da angiotensina I no potente vasoconstritor angiotensina II. Sendo assim, a inibiÃÃo da atividade da ECA Ã considerada uma abordagem terapÃutica Ãtil para combater a hipertensÃo. Alpinia zerumbet, uma planta aromÃtica abundante no nordeste do Brasil, Ã comumente utilizada na medicina popular devido suas propiedades diurÃticas e hipotensivas. AlÃm disso, vÃrios estudos relatam atividade antihipertensiva para esta espÃcie. Dessa forma, Alpinia zerumbet pode ser uma importante fonte de inibidores de ECA. Sabendo disso, resolveu-se investigar os extratos dos rizomas desta espÃcie na busca de compostos inibidores de ECA. A prospecÃÃo quÃmica do extrato hexÃnico do rizoma permitiu o isolamento de cinco substÃncias: Um estilbeno denominado (E)-3,5-dimetoxiestilbeno, inÃdito na espÃcie em estudo; um diterpeno de esqueleto labdano denominado (E)-15,16-bis-norlabda-8,11-dieno-13-ona; uma chalcona denominada 2â,4â-dihidroxi-6â-metoxi-3â-(3ââ-metil-6ââ-metil-etil-2ââ-ciclohexenil)chalcona; um esterÃide denominado β-sitosterol, comumente encontrado em plantas; e um hidrocarboneto aromÃtico da classe kavapirona denominado 5,6-dehidrokawain. Na determinaÃÃo estrutural dos compostos isolados, foram empregadas tÃcnicas espectromÃtricas de anÃlise unidimensionais [ressonÃncia magnÃtica nuclear (RMN) de 1H e 13C, e tÃcnicas bidimensionais (1H-1H-COSY, HSQC, HMBC, NOESY). TambÃm foram realizados os testes de inibiÃÃo da enzima conversora de angiotensina, antioxidante, de inibiÃÃo da enzima acetilcolinestarase e larvicida dos extratos hexÃnicos e etanÃlicos dos rizomas de Alpinia zerumbet. Os dois extratos apresentaram potencial de inibiÃÃo da enzima conversora de angiotensina e antioxidante. Somente o extrato hexÃnico apresentou atividade larvicida, com CL50 823,1 ppm. Nenhum dos extratos em estudo apresentou potencial de inibiÃÃo da enzima acetilcolinesterase. / Hypertension is one of the most common diseases in the world, is a chronic disease in which high blood pressure can affect health. The angiotensin I converting enzyme (ACE) can increase blood pressure through the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II. Thus, inhibition of ACE activity is considered a useful therapeutic approach to combat hypertension. Alpinia zerumbet, a herb abundant in northeastern Brazil, is commonly used in folk medicine due to its diuretic and hypotensive properties. Moreover, several studies reported for this species antihypertensive activity. Thus, Alpinia zerumbet can be an important source of ACE inhibitors. Knowing this, we decided to investigate the extracts of the rhizomes of this species in the search for compounds ACE inhibitors. Prospecting chemical hexane extract of the rhizome allowed the isolation of five substances: A stilbene, named (E) -3,5-dimethoxystilbene, unprecedented in the species in this study, a labdane diterpene skeleton called (E) -15.16-bisnorlabda- 8,11-diene-13-one; one chalcone called 2â,4â-dihydroxy-6â-methoxy-3â-(3ââ-methyl-6ââ- methyl - ethyl -2ââ-cyclohexenyl) chalcone; a steroid called β-sitosterol, commonly found in plants, and an aromatic hydrocarbon class kavapirone, called 5,6- dehidrokawain. In the structural determination of individual compounds, spectrometric techniques were employed dimensional analysis [nuclear magnetic resonance (NMR) 1H and 13C and two dimensional techniques (1H-1H COSY, HSQC, HMBC, NOESY). Inhibition angiotensin converting enzyme, antioxidant potential, inhibition of acetilcolinestarase and larvicidal tests of ethanol and hexane extracts of the rhizomes of Alpinia zerumbet were tested. The two extracts showed potential for inhibition of angiotensin converting enzyme and antioxidant potential. Only the hexane extract showed larvicidal activity with LC50 823.1 ppm. None of the extracts studied showed potential inhibition of the enzyme acetylcholinesterase.

Philosophiae Doctor - PhD (Chemistry) / There is growing concern on endocrine disrupting compounds (EDCs). The presence of drugs in water supplies was first realized in Germany in the early 1990s when environmental scientists discovered clofibric acid. Clofibric acid has the ability to lower cholesterol in ground water below a water treatment plant. Endocrine disrupting compounds can be defined as those chemicals with the ability to alter daily functioning of the endocrine system in living organisms. There are numerous molecules that are regarded or referred to as EDCs such as but not limited to organochlorinated pesticides, industrial chemicals, plastics and plasticizers, fuels, estrogens and many other chemicals that are found in the environment or are in widespread use. 17?- estradiol is the principal estrogen found in mammals during reproductive years. Estriol is produced in large quantities during pregnancy. 17?-estradiol is the strongest, estriol the weakest. Estriol is water soluble, estrone and estradiol are not. Although estrogen is produced in women they are also at risk of over exposure to estrogen. Pesticides are extensively used today in agricultural settings to prevent and control pests. Various pesticides, including banned organochlorines (OCs) and modern non-persistent pesticides, have shown the ability to disrupt thyroid activity, disturbing the homeostasis of the thyroid system. Because these EDCs have adverse effects on health of both human and wildlife, it is imperative to develop viable costeffective analytical methods for the detection of these EDCs in complicated samples and at very low concentrations. Very high selectivity towards particular compounds is a very important property for the suitability of a detection method. This is because these compounds mostly coexist in complex matrices which makes the detection of a specific compound very challenging. It is paramount to develop highly sensitive and selective methods for the detection of these estrogens and phosphoric acid-based pesticides at trace levels. / 2021-08-31