International Journal of Food Properties (Dec 2022)

Changes in the antioxidant properties of Ocimum africanum leaves aqueous extract from the southeastern region of Nigeria after in vitro gastrointestinal digestion

  • Godson Oseahumen Omoike,
  • Betty Omenebelle George,
  • Emilia Onyinye Ugwu,
  • Joel Okpoghono

DOI
https://doi.org/10.1080/10942912.2022.2120494
Journal volume & issue
Vol. 25, no. 1
pp. 2000 – 2008

Abstract

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The potential for antioxidant compounds to be released from the original food matrix is greatly determined by bioaccessibility. Digestive enzymes have a substantial impact on the antioxidant properties of dietary items after ingestion. The present study aimed to determine the antioxidant properties of Ocimum africanum leaves aqueous extract (OALAE) before and after in vitro digestion. In vitro gastro-pancreatic digestion of extracted samples (steamed, air dried and fried) was done using artificial gastric fluid, and 4 mL of artificial intestinal fluid. Antioxidant analyses were carried out on the OALAE samples (group 1: steamed, group 2: fried, group 3: air dried and group 4: garlic acid standard), before digestion (undigested), post-intestinal digestion with enzymes and post-intestinal digestion without enzymes. The trends of antioxidant properties of the OALAE (in-vitro) were as follows: air dried > steamed > fried. A significant (p < 0.05) decrease in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), reduced glutathione (GSH), vitamin E, vitamin C, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and non-heme iron content of OALAE in post-intestinal digestion with enzyme and post-intestinal digestion without enzyme was found compared to the undigested extract in group 1, 2, 3, and 4. Significant decrease was observed in antioxidant activity (illustrated using DPPH, ABTS, FRAP, and TAC) of post-intestinal digestion with enzyme compared to post-intestinal without enzymes in group 1, 2, 3 and 4. The results suggested that antioxidant properties of O. africanum leaves are unstable and may show limited activity after stimulated gastrointestinal digestion.

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