Hormonelike substances from plants

Abstract

The plants are not capable to synthesise substances with the same chemical structure like hormones from humans or animals. But it is quite clear that substances which can influence the homeostasis of hormones in other living organisms can be found in plants. Some constituents of the plants are chemically very similar to hormones and they can demonstrate some activities of hormones. Besides, they can influence the concentration of hormones in the humans, mainly trough the changes in the metabolic pathways or they can change the effects of hormones without influence in concentration or natural activity of endocrine glands; gossypol prevents spermatogenesis without altering the other endocrine function of the testicles. Plants can be used as a row material for the extraction of substances which can be transformed to the hormones or their derivatives. This transformation can be obtained only in laboratory conditions and can not be performed in the human body. From this approach plant's steroids are the most important. Diosgenin from the tuber of Dioscorea species is the main and the most important molecule for the semi-synthesis of sex hormones as well as cortisone. The substances known as phytoestrogens have a great importance for the every day use as OTC or dietary supplements for the prevention and/or therapy of mild symptoms of menopause. Some plants are capable to accumulate substances with estrogen like activities known as phytoestrogens. Those substances do not have steroid structure. Mainly, they belong to polyphenols (coumestanes, isoflavones, flavonoids, stilbenes, lignans). Because of specific chemical characteristics, these compounds have affinity for binding to α and/or β oestrogen receptors. Up to day, the best knowledge we have for isoflavones and their application in the treatment of mild symptoms of menopause. The results of clinical studies of isoflavons have shown only the positive effect on the ratio between lipid fractions in serum and influence to the reduction of cardiovascular diseases. The isoflavones (genistein and daidzein) are the most used as soybean (Glycine max) and red clover (Trifolium pratense) preparations. Daily dose with confirmed therapeutic efficacy corresponds to 40-160 mg of isoflavones.

Biljke nisu sposobne da sintetišu supstance koje su hemijski identične humanim i animalnim hormonima. Ipak, sasvim je sigurno da biljke sadrže supstance koje mogu da utiču na hormonsku homeostazu u živim organizmima. Neki sastojci biljaka su hemijski veoma slični hormonima pa se smatralo da, do određene granice, mogu ispoljiti i hormonsku aktivnost; ovakve tvrdnje treba i dokazati. Zatim, pojedini sastojci biljaka mogu uticati na koncentraciju hormona, najčešće, preko uticaja na metaboličke puteve i enzime koji ih usmeravaju. Dalje, sastojci biljaka mogu uticati na hormonsku aktivnost, a da ne utiču na aktivnost žlezda sa unutrašnjim lučenjem i/ili da ne dovode do promene koncentracije hormona u krvi; npr. gosipol sprečava spermatogenezu, a da pri tom ne utiče na ostale endokrine funkcije testisa. Ipak, najvažnija je činjenica da biljke predstavljaju sirovinu za ekstrakciju supstanci koje će biti prevedene u hormone ili derivate hormona. Transformacija jedinjenja dobijenih iz biljaka može biti izvedena samo u laboratorijskim (industrijskim) uslovima i ne može se obaviti u ljudskom organizmu. Sa ovog stanovišta, najvažnija su prirodna steroidna jedinjenja. Diosgenin iz krtole Dioscorea vrsta je najvažnije prirodno jedinjenje za polusintezu steroidnih seksualnih hormona i kortizona. Treba spomenuti fitohormone; nemaju hemijsku strukturu sličnu hormonima, ali mogu ispoljavati neke hormonske efekte. U okviru ovakve grupe, najpoznatiji su fitoestrogeni (koumestana, izoflavona, flavonoida, stilbena i lignana). Svakodnevno se koriste u obliku lekova za samolečenje i dijetetskih suplemenatar za prevenciju nastanka i terapiju blažih oblika simptoma menopauze. Fitoestrogeni se mogu specifično vezati za α i/ili β estrogene receptore. Najbolje proučeni izoflavoni i njihova terapijska primena; potvrđen je pozitivan efekat na odnos u okviru frakcija lipida u serumu, što se može povezati sa manjom incidencom kardiovaskularnih problema. Najčešće se koriste genistein i daidzein iz soje (Glycine max) i crvene deteline (Trifolium pratense). Dnevna doza ovih izoflavona, za koju je potvrđena klinička efikasnost, iznosi 40-160 mg.