Biologically active substances of potato and birch bark: content and mechanisms of the pharmacological action. [Doctoral thesis in partial fulfillment of the requirements of the doctor degree in pharmacy (Dr.pharm.), subdiscipline of pharmacology] | Kartupeļu un bērzu tāss bioloģiski aktīvo vielu izpēte: saturs un farmakoloģiskās darbības mehānismi. Promocijas darbs
2010
Saleniece, K., University of Latvia, Riga (Latvia). Faculty of Medicine
English. This doctoral thesis is devoted to studies of the CNS effects of the plant triterpenes betulin, betulinic acid and lupeol, as well as those of potatoes. Our studies revealed that betulin selectively binds to the first subtype of the melanocortin receptor. Betulin also antagonizes α–MSH induced augmentation of cAMP production in cells. In addition, betulin binds to A type receptors of the brain neuromediator γ–amino butyric acid (GABAA). We found variable concentrations of benzodiazepines (diazepam) in potato tubers, with a novel demonstration that potato juice can initiate CNS effects due to elevated content of GABA or GABA-ergic compounds in the potato. We monitored levels of glycoalkaloids in potato varieties grown in Latvia and demonstrated that content of the glycoalkaloids α-solanin and α-chakonine is low. The level of poliphenols in potatoes, calculated as equivalents of gallic acid, was similar to that found in green and black tea: 0,95 mg/ml of potato juice.
Show more [+] Less [-]Latvian. Promocijas darbs ir veltīts augu triterpēnu: betulīna, betulīnskābes, lupeola un pārtikas produkta – kartupeļu CNS efektu izpētei, kā arī glikoalkaloīdu un polifenolu satura noteikšanai kartupeļos. Atklāts, ka betulīns selektīvi piesaistās pie melanokortīnu receptoru pirmā apakštipa un antagonizē α-MSH peptīda izraisīto cAMF stimulāciju. Betulīns piesaistās arī pie smadzeņu darbību bremzējošā mediatora γ–aminosviestskābes (GASS) A tipa receptora GASSA, bet betulīnskābe un lupeols nesaistās ne ar melanokortīnu, ne ar GASSA receptoriem. Kartupeļos novērots mainīgs benzodiazepīnu (diazepama) saturs un pirmo reizi pierādīts, ka kartupeļiem piemīt CNS efekti. Divas sezonas monitorēts glikoalkaloīdu α-solanīna un α-hakonīna līmenis Latvijā audzētos kartupeļos un pierādīts, ka to saturs kartupeļos nepārsniedz Pasaules Veselības organizācijas noteikto līmeni 200 mg/kg kartupeļu.
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