Browsing by Author "Lazarus, Geraldine Genevive"

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    In vitro anti-platelet aggregation activity of the extracts of bulbine natalensis
    (2011) Lazarus, Geraldine Genevive; Opoku, A.R.; Oyedeji, A.O.
    Bulbine natalensis Baker is a medicinal plant with succulent, aloe-like leaves from the Asphodelaceae family, commonly used by Zulu traditional healers to treat blood clotting-related diseases. The aim of this research was to test the anti-platelet aggregation effect of B.natalensis’ extracts on rat platelet aggregation separately induced by thrombin, ADP, collagen, epinephrine, papain, bromelain and trypsin. Fresh plant material was extracted sequentially using hexane, chloroform, ethyl acetate, methanol, and water. The chloroform extract had the highest yield of 0.20%. Phytochemical screening revealed the presence of anthraquinones, cardiac glycosides, saponins, tannins, flavonoids and alkaloids. The hexane extract revealed the highest contents of total phenols (5.028 mg/g); flavonoid (3.293 mg/g) and proanthocyanidin (2.565 mg/g). Hexane extract also displayed the highest ABTS scavenging activity (IC50 4.72 mg/ml) followed by the ethyl acetate extract (IC50 5.39 mg/ml). The water extract exhibited the highest reducing power; the activity was even greater than the standard antioxidant BHA. Studies reveal that B.natalensis is a good antioxidant. Brine shrimp lethality test indicated that all the extracts were highly toxic to the larvae. The ethyl acetate extract was the most toxic (LC50 2.21 mg/ml). Anti-platelet aggregation activities on rat platelets were observed. The chloroform extract inhibited ADP-induced clotting by 100% at doses 1 and 3 mg/ml with IC50 values of 5.32 mg/ml before tannin removal and >10 mg/ml after tannin removal. Two compounds (F6/1 and F6/5) were isolated and purified from the chloroform extract. It was apparent that the compounds were unstable and could not be