Analgesic Activity, Acute Oral Toxicity and Phytochemical Screening of Crude Extracts of Mystroxylon Aethiopicum (Thunb.) Loes. (Celastraceae.)

Abstract

Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. Analgesics i.e. Opioids and Non-steroidal anti-inflammatory drugs (NSAIDs) used to manage pain are less effective, inaccessible, and unaffordable and elicit deleterious side effects, hence warrants search for alternative and complementary strategies to avert pain without adverse effects and cheap. Due to folklore history of utilization in traditional medicine, easy accessibility, affordability and presumed low toxicity profiles, Medicinal plants like Mystroxylon aethiopicum have better chances of offering potent analgesic. Nonetheless, there’s scanty scientific data on analgesic efficacy, potency and toxicity. This study evaluated antinociceptive activity, acute oral toxicity and qualitative phytochemical composition of crude extracts of Mystroxylon aethiopicum. The plant was identified and authenticated by a taxonomist at the East Africa Herbarium. Methanolic and aqueous extracts from the plant were prepared according to standard maceration method. Experimental female Swiss albino mice aged 4-5weeks were obtained from the animal breeding unit, PHPT Department and handled as per set guidelines (OECD 2008) i.e.23± 2oC room temperature; 55-65 % Relative humidity; twelve (12)-hour daytime/night time cycle, well fed with standard mice pellets and clean drinking tap water ad libitum. Determination of analgesic activity of Mystroxylon aethiopicum extracts was done by acetic acid-induced writhing technique. The data obtained was tabulated in Microsoft Excel 365, exported to Graph Pad Prism statistical software version 8.4.3 for analysis; was subjected to descriptive statistics and expressed as 𝑥̅±𝑆𝐸𝑀. One-Way ANOVA with Tukey’s post hoc test were used to determine significant differentials among experimental groups and for pairwise comparison and separation of means respectively. The results revealed that both crude extracts of Mystroxylon aethiopicum possess analgesic activity. The mice treated with aqueous extract exhibited significantly low writhing frequency compared to those that received the methanolic extract (p<0.05). Acute oral toxicity was performed and analyzed as per the OECD 425 (2008) guideline monitoring for toxicity signs and fatality. There were no signs of toxicity and fatality in mice even at the cut-off dose (2000 mg/Kg bwt.) thereby conferring LD50 values >2000 mg/Kg bwt hence safe. Qualitative phytochemical screening was done following standard phytochemical screening methods described by Harborne, Evans and Trease and Savithrama. The data was tabulated and revealed presence of alkaloids, saponins, tannins, glycosides, phenols, flavonoid, terpenoids, saccharides and proteins. In conclusion, the Mystroxylon aethiopicum has analgesic activity, no toxicity signs and possesses active phytochemicals. Recommends for herbalist to continue using Mystroxylon aethiopicum in analgesic, further study Sub-acute/chronic toxicological studies on the studied plant extracts be conducted to fully profile and assure their safety.