Acute Oral Toxicity Studies and Evaluation of Central Analgesic Activity of Various extracts of Leaves of Rhizophora apiculata

Abstract

The present study aimed to determine the acute toxicity and screening of central analgesic activity of various extracts of Rhizophora apiculata leaves. The animals (Mice) were divided into control (no drug) and extract-treated groups (n=5), which were treated with diethyl ether, ethyl alcohol, and aqueous extract of R. apiculata leaves in various doses for specific regulatory needs. The groups which were given the highest safe doses were observed for 14 days. Then, blood samples were collected from high dose treated live mice through the retro-orbital route and were analysed for haematological, biochemical, and histopathological study. Evaluation of central analgesic activity was carried out by using tail immersion and hot plate methods. No considerable alterations were observed in body weight and organ-to-body weight index with the administration of extracts. An increase in albumin, globulin, total protein content and high-density lipoproteins, white blood cells, mean corpuscular volume, and eosinophils were observed. And a decrease in low-density lipoproteins, very low-density lipoproteins, triglycerides, and red blood cells were observed. Lymphocyte and monocyte levels were also reduced. The results also showed that the ethyl alcohol and aqueous extracts have elevated the time taken to flick response in the tail immersion test, and reduced the number of jumps, paw lick responses in the hot plate method. It was concluded that the diethyl ether and ethanolic extracts were found to be safe, which falls under non-toxic chemicals (LD50>2000 smg/kg) whereas the aqueous extract was found safe up to 550 mg/kg beyond which, it was shown mortality. Ethyl alcohol and aqueous extracts were also proved to have analgesic activity.