Ethnobotany, total polyphenol content, and cytotoxicity of African olive (Canarium schweinfurthii Engl.) Fruit Pulp

In Uganda, indigenous knowledge, total polyphenol content and cytotoxicity of Canarium schweinfurthii Engl. have not been documented, which may limit its utilization. Henceforth, this study aimed at conducting an ethnobotanical survey and determining total phenolic content, antioxidant capacity and cytotoxicity of C. schweinfurthii fruit pulp. The ethnobotanical survey was conducted in Kamuli, Luwero, and Mayuge districts, Uganda using validated questionnaires following purposive and snowball sampling. Following cold and hot water extraction of the fruit pulp extract, Total Polyphenol Content (TPC) was determined using the Folin-Ciocalteu method while the antioxidant capacity on human colon (Caco-2) cell lines was determined using the oxidative stress and 2′,7′-dichlorodihydrofluorescein diacetate staining model. Cytotoxicity at 1:2, 1:5, 1:10, 1:25, 1:50, 1:100, 1:200 and 1:1000 concentrations was determined using the human colon (Caco-2) cell lines and resazurin assay. The study revealed that various parts of C. schweinfurthii are used in the management of various health complications whereas the fruit is utilized as food. The TPC obtained for C.schweinfurthii fruit pulp was 2.48 ± 0.10 and 2.88 ± 0.02 mg GAE/g dry weight for cold and hot extracts, respectively. There was no significant antioxidant activity observed after treatment of human colon (Caco-2) cell lines with the different fruit pulp extract concentrations. Zero to very low cytotoxicity was observed in cell lines treated with 1:10, 1:25, 1:50, 1:100, 1:200 and 1:1000 fruit pulp extract. The findings of this study suggest that in addition to its utilization as a food, C.schweinfurthii fruit pulp is a potential therapeutic agent.