Evaluation of flavonoids from Bauhinia megalandra leaves as inhibitors of glucose-6-phosphatase system.
From the methanol extract of Bauhinia megalandra fresh leaves, eight flavonoids were isolated and evaluated by rat liver microsomal glucose-6-phosphatase (G-6-Pase) bioassay, which might be a useful methodology for screening antihyperglycaemic substances. All the flavonoids assayed showed an inhibitory effect on the intact microsomal G-6-Pase: quercetin and kaempferol exhibited the lowest effect; astilbin, quercetin 3-O-alpha-rhamnoside, kaempferol 3-O-alpha-rhamnoside and quercetin 3-O-alpha-arabinoside an intermediate effect. The highest inhibitory activity was shown by quercetin 3-O-alpha-(2''-galloyl)rhamnoside and kaempferol 3-O-alpha-(2''galloyl)rhamnoside. None of the flavonoids mentioned above showed an inhibitory effect on the disrupted microsomal G-6-Pase. Quercetin 3-O-alpha-(2''-galloyl)rhamnoside and kaempferol 3-O-alpha-(2''-galloyl)rhamnoside exhibited the lowest IC50 of all the flavonoids assayed. Also, the phlorizin IC50 is reported.
Estrada
Omar
O
Centro de Química Orgánica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Apartado postal 47102, Caracas, Venezuela. pittieri@yahoo.com
Hasegawa
Masahisa
M
Gonzalez-Mujíca
Freddy
F
Motta
Norma
N
Perdomo
Elsa
E
Solorzano
Alejandra
A
Méndez
Jeannette
J
Méndez
Bernardo
B
Zea
E Gabriela
EG
D000818:Animals; D036481:Bauhinia; D003920:Diabetes Mellitus / Q000517:prevention & control; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D005419:Flavonoids / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D005952:Glucose-6-Phosphatase / Q000037:antagonists & inhibitors*; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D020128:Inhibitory Concentration 50; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D051381:Rats
D004791:Enzyme Inhibitors; D005419:Flavonoids; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D005952:Glucose-6-Phosphatase