The effects of Aloe vera [gel] on clotting time, prothrombin time and plasma fibrinogen concentration in albino Wistar rats

Abstract

Background: Published reports on the effects of Aloe vera gel on blood coagulation in experimental animals are relatively scanty.
Aim: To determine the effect of Aloe vera gel on clotting time, prothrombin time and plasma fibrinogen concentration in albino Wistar rats.
Methods: A total of 28 adult albino Wistar rats divided into 4 groups (Groups 1, 2, 3 and 4) consisting of 7 rats in each group were used for the study. Groups 1, 2 and 3 served as the experimental groups, while Group 4 rats served as control. Rats in Groups 1, 2 and 3 were given respectively 200mg/kg/day, 100mg/kg/day and 50mg/kg/day of the Aloe vera gel on alternative days for 14 days. Rats in Group 4 [control] were given 1ml of distilled water in a similar manner. All the doses were given intra-peritoneal. The gel was obtained from the transparent mucilage of the leaves of the Aloe vera plant. Blood samples were obtained from the rats by direct cardiac puncture under chloroform anaesthesia. Prothrombin time was determined using 0.0325M calcium chloride and commercial thromboplastin; clotting time was determined using the Lee-White method as described by Ochei and Kolhatkar (2000). Plasma fibrinogen concentration was determined by the clot weight method as described by Ingram (1961).
Results: Results obtained indicate that treatment with the Aloe vera gel significantly prolonged (p<0.05) in a dose dependent manner the prothrombin time in Groups 1 and 2 rats: with values of 15.00±1.00seconds and 13.00±0.82seconds respectively, compared to the control group value of 7.301.520seconds. Similarly, treatment with the Aloe vera gel significantly prolonged (p<0.05) in a dose dependent manner the clotting time in all experimental rat groups. The value of the clotting time in control group was found to be 213±20.80seconds. Treatment with Aloe vera extract prolonged the clotting time in Groups 3, 2 and 1 to values of 222±21.60seconds, 327±34.03seconds and 356±15.20seconds respectively. In addition, treatment with Aloe vera was found to significantly decrease (p<0.05) the plasma fibrinogen concentration in a similar dose dependent manner. The values for Groups 1 and 2 were found to be 80.0±10.0g/dl and 97.5±9.57g/dl respectively, both values were found to be significantly higher (p<0.05) than the value obtained for the control rats which was 21.3±5.78g/dl.
Conclusion: The present study suggests that Aloe vera gel could inhibit blood clotting via actions on both the intrinsic and extrinsic pathways. Further studies are however recommended in this regard.


Keywords: Aloe vera, Clotting time, Plasma fibrinogen concentration, Prothrombin time

Port Harcourt Medical Journal Vol. 2 (1) 2007: pp. 56-60