Browsing by Author "Otmar Hoeglinger"

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Bioactive compounds and antioxidant capacity of African olive (canarium schweinfurthii engl.) fruit pulp and seed
(Sciencedirect, 2026-04-09) Tabula, Arthur; Tobias Pointner; Lili Daroczi; Pignitter Marc; Nakyinsige Khadijah; Bamuwamye Michael; Otmar Hoeglinger
This study characterized polyphenols and tocopherols, as well as determined the antioxidant capacity of the Canarium schweinfurthii Engl. fruit pulp and seed. Samples were obtained from Kamuli, Luwero and Mayuge districts of Uganda. Total polyphenol content was determined using the Folin-Ciocalteu assay. Polyphenols were fractionated using Liquid Chromatography-tandem Mass Spectrometry technique. Tocopherols (α-, γ- and δ-) were quantified using High Performance Liquid Chromatography-Ultraviolet. The antioxidant capacity of the fruit pulp was assessed using Trolox Equivalent Antioxidant Capacity (TEAC) and Ferric Ion Reducing Antioxidant Power (FRAP). Total polyphenol content of the fruit pulp and seed extracts ranged from 73.93 to 92.43 and 132.66 to 146.74 mg GAE/g, respectively. The fruit pulp and seed extracts contained phenolic acids (1.3-Dicaffeoylquinic acid, 4-hydroxybenzoic acid, chlorogenic acid, ferulic acid, gallic acid, quinic acid, cinnamic acid and p-coumaric acid), flavonoids (amentoflavone, eriodictyol, gallocatechol, herbacetin and quercetin-3-O-glucoside) and lignans (pinoresinol). The tocopherol content of the fruit pulp and seed extracts was correspondingly 3.83 to 4.98 mg/kg and 38.54 to 62.47 mg/kg. The major tocopherol isomers quantified were the alpha, gamma and delta. The antioxidant capacity of the fruit pulp extracts by TEAC assay was from 2.74 to 5.43 and by FRAP assay from 4.36 to 6.16 µmol TE/g dry weight. The fruit’s antioxidant capacity may be attributable to phenolic acids, flavonoids and lignans, and tocopherols. In addition to its use as a food, the gamut of bioactives and antioxidant capacity support Canarium schweinfurthii’s potential therapeutic applications.
Ethnobotany, total polyphenol content, and cytotoxicity of African olive (Canarium schweinfurthii Engl.) Fruit Pulp
(Discover Food, 2024-12-24) Arthur, Tabula; Khadijah Nakyinsige; Michael Bamuwamye; Praise Komujuni; Otmar Hoeglinger
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′-dichlorodihydrofuorescein 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 signifcant antioxidant activity observed after treatment of human colon (Caco-2) cell lines with the diferent 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 fndings of this study suggest that in addition to its utilization as a food, C.schweinfurthii fruit pulp is a potential therapeutic agent.