Planta Med 2013; 79 - PH9
DOI: 10.1055/s-0033-1352086

RP-HPLC-DAD/MS/MS-based metabolic profiling of glycogen phosphorylase inhibitory active fractions of Nauclea latifolia stem bark

SO Abd Algaffar 1, HA Ali 2, SA Khalid 3
  • 1University of Science and Technology, Faculty of Pharmacy, Omdurman, P.O. Box 11507 Khartoum, Sudan
  • 2National Center for Research, Commission for Biotechnology and Genetic Engineering, Khartoum, Sudan
  • 3University of Science and Technology, Faculty of Pharmacy, Omdurman, P.O. Box 11507 Khartoum, Sudan University of Khartoum, Faculty of Pharmacy, Department of Pharmacognosy, P.O. Box 1996 Khartoum, Sudan

Nauclea latifolia Smith (Rubiaceae) are commonly prescribed in African traditional medicine as a remedy for a number of diseases including diabetes mellitus.1 Although a series of experimental animal studies have established its antidabetic activity little is known about the possible mechanism of its action.2, 3 This prompted us to investigate the in vitro inhibitory action of the methanolic extract of N. latifolia stem bark and fractions therefrom on human liver glycogen phosphorylase (HLGP).

N. latifolia stem bark methanolic extract and the chloroform and ethyl acetate fractions significantly inhibited HLGP at a concentration of 5 mg/ml with 85%, 69% and 98%, respectively. On the other hand, in vitro screening with 2,2-diphenyl-1-picrylhydrazyl (DPPH) at concentration of 12.5 µg/ml revealed a prominent radical scavenging activity (RSA) of the chloroform fraction (85%) and relatively lower RSA of the methanolic (68%) and ethyl acetate fraction (77%) which seems not to be closely correlated with anti-diabetic activity.

RP-HPLC-DAD coupled with tandem mass spectrometry performed on the ethyl acetate fraction which was associated with the most significant HLGP inhibitory activity resulted in the identification of chlorogenic acid, its glucoside, caffiec acid dimer, noengenin and noengenin dimmer, apigenin7-O-pentouronic acid, quercetin, luteolin 7-methoxy, isorhamnetin and isorhamnetin 3-methoxy

References:

[1] Gidado, A.; Ameh DA.; Atawodi, SE. and Ibrahim. S. Hypoglycaemic activity of Nauclea latifolia Sm. (Rubiaceae) in experimental animals. Afr. J. Trad. CAM, 2008, 5 (2), 201 – 208.

[2] Gidado, A. and Atawodi, S E. Effect of Nauclea latifolia leaves aqueous extract on blood glucose levels of normal and alloxan induced diabetic rat. African Journal of Biotechnology, 2005, 4(1), 91 – 93.

[3] Iwueke, AV. and Nwodo, FO. Antidiabetic effect of Sarcocephalus latifolus aqueous root extract in experimental rat model. Animal Research International. 2007, 4(2), 698 – 701.