Report of Acute oral toxicity (safety) evaluation of Prosopis juliflora - Mesocarp in Swiss albino mice and Sprague Dawley rats Volume-I

Abstract

Introduction: Prosopis juliflora is one of the most economical and ecological tree species of arid /semiarid regions which provides for many needs of poor rural population. The utilization of its mesocarp in cereal flour and substituting chicory in coffee for human consumption has been reported from other countries. In India, Central Arid Zone Research Institute (CAZRI), Jodhpur, has taken up the task to replace the mesocarp by 20 - 25% in wheat for human consumption under the NAIP program. In view of this, the pre - clinical safety evaluation of such food products is a mandatory requirement as per FSSAI. Therefore, pre - clinical safety evaluation has been undertaken at Centre for Advanced Research FDTRC, National Institute of Nutrition, ICMR in mice & rats following guidelines of FSSAI / OECD7. The study includes acute toxicity (safety) study (14 days) in mice, rats and sub - chronic toxicity (safety) study (90 days) in rats. The present report is on acute (14 days) oral toxicity (safety) evaluation in mice and rats. Methodology: The acute toxicity (safety) evaluation (14 days) has been conducted in healthy Swiss albino mice and Sprague Dawley rats after ethical approval (P8/1 - 2011/BDK). All experimental animals viz., mice and rats have been obtained from National Center for Laboratory Animal Science (NCLAS), NIN, Hyderabad. The powdered test material supplied by the sponsor was subjected to compositional analysis and administered orally in a water suspension as per SOP (No.17/PHARM/NIN/CO1/ATI/2007/OL) [Annexure - II (A & B)]. Acute toxicity (safety) evaluation (14 days) in Swiss albino Mice: This investigation has been conducted in 32 Swiss albino mice (16M+16F), aged 4 - 6 weeks, and weighing 18 - 20gm. The animals were caged individually in polycarbonate cages for ten days for acclimatization. This was followed by randomization of animals in two groups i.e., Group - I and Group - II, to be exposed to the test compound at avconcentration of 1.6 and 3.2 times higher than the test limit7 of 2 gm/kg respectively. The test material was fed in a concentration of 3.2 gm/kg to Group - I and 6.4 gm/kg to Group - II orally in suspension form for 2 - 4 times in 24 hours. In view of gastric emptying time, the volume of suspension for administration was kept at a maximum of 0.4 ml (SOPNo.17/PHARM/ NIN/CO1/ATI/2007/OL). Acute toxicity (safety) evaluation (14 days) in Sprague Dawley rats: This investigation was conducted on 20 Sprague Dawley rats (10M+10F), aged 6 - 8 weeks and weighing 180 - 200gm. The animals were caged individually for twelve days for acclimatization. This was followed by randomization of animals in two groups i.e., Group - I and Group - II to be exposed to the test compound at a concentration of 1.1 and 2.2 times higher than the test limit7 of 2 gm/kg respectively. The test material was fed in a concentration of 2.2 gm/kg to Group - I and 4.5 gm/kg to Group - II orally in suspension form for 2 - 4 times in 24 hours. In view of gastric emptying time, the volume of suspension for administration was kept at a maximum of 3ml (SOP - No.17/PHARM/NIN/CO1/ATI/ 2007/OL). Study parameters: All the animals in both investigations were initially monitored for lethality, in every hour for 10 hours, followed by daily observations till the 14th day. The body weight and feed intake were recorded bi - weekly. The live phase, cage side observations, physical and neurological activities were monitored daily for two weeks and recorded bi - weekly. This is followed by euthanization of animals to conduct gross necropsy and collection of all vital organs. The data was compiled and analyzed for significant differences between individual groups. Results: Mice study: No pre - terminal deaths were recorded in mice which received test material more than 1.6 and 3.2 times higher than the maximum test limit material of 2gm/kg. There were no abnormalities in live phase, physical activity and neurological activity throughout the study period. There was no significant difference in body weight of animals which received 3.2gm/kg and 6.4 gm/kg of test material. No gross necropsy changes were observed. Rat study: No pre - terminal deaths were recorded in rats which received test material more than 1.1 and 2.2 times higher exposure than the maximum test limit material of 2gm/kg. There were no abnormalities in live phase, physical activity and neurological activity throughout the study period. There was no significant difference in body weight of animals which received 2.2 gm/kg and 4.5 gm/kg of test material. No gross necropsy changes were observed. Conclusion: Mice: There was no mortality in mice exposed to Prosopis juliflora (mesocarp) test material more than 1.6 and 3.2 times higher than the maximum test limit material of 2gm/kg. Rats: There was no mortality in rats exposed to Prosopis juliflora (mesocarp) test material more than 1.1 and 2.2 times higher than the maximum test limit material of 2gm/kg. Study Impression: All animals when exposed to maximum of 3.2 times (6.4gm/kg) and 2.2 times (4.5gm/kg) of Prosopis juliflora (mesocarp) higher than that of maximum test limit 2gm/kg with single exposure in 24 hrs in mice and rats respectively, does not cause any mortality and all animals were active till end of the study.