Phytochemicals from Flemingia vestita (Fabaceae) and Stephania glabra (Menispermeaceae) alter cGMP concentration in the cestode Raillietina echinobothrida.
Cyclic GMP (cGMP) mediates various physiological functions of nitric oxide (NO) synthesized by nitric oxide synthase (NOS). A crude peel extract and purified fraction of Flemingia vestita, as well as a crude rhizome extract of Stephania glabra and fractions were tested with respect to the activity of NOS, NO efflux and cGMP concentration in the cestode Raillietina echinobothrida in order to find out the possible mode of anthelmintic action of these plant-derived components. For comparison purposes, the parasites were also treated with pure genistein, sodium nitroprusside (SNP-a known NO donor), and the reference drug, praziquantel (PZQ). At the time of onset of paralysis in the parasites, a significant increase (32%-87%) in the NOS activity and a two to three fold increase of NO efflux into the incubation medium were observed in the treated parasites in comparison to their respective controls. The cGMP concentration in the treated parasites' tissue was also increased by 44%-103%. However, in the presence of NG-nitro-L-arginine methyl ester, a potent inhibitor of NOS, there was no increase in the cGMP concentration in the parasite tissue. This study indicates that the phytochemicals, in particular genistein and tetrahydropalmatine, from F. vestita and S. glabra, respectively, disturb the downstream signalling pathway of NO, as indicated by the change in cGMP concentration in the parasite tissue.
Department of Zoology, North Eastern Hill University, Shillong-793022, India.
Bidyadhar
B
Das
Veena
V
Tandon
Larisha M
LM
Lyndem
Alexander I
AI
Gray
Valerie A
VA
Ferro
D000818:Animals; D000923:Anticestodal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D002589:Cestoda / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007887:Fabaceae / Q000737:chemistry; D005638:Fruit; D019833:Genistein / Q000302:isolation & purification / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D011223:Praziquantel / Q000494:pharmacology; D027343:Rhizome; D015398:Signal Transduction / Q000187:drug effects; D031607:Stephania / Q000737:chemistry; D013997:Time Factors; D015854:Up-Regulation
D000923:Anticestodal Agents; D001600:Berberine Alkaloids; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D010936:Plant Extracts; D009599:Nitroprusside; D009569:Nitric Oxide; C014215:tetrahydropalmatine; D011223:Praziquantel; D019833:Genistein; D019001:Nitric Oxide Synthase; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester