Functional potential of phenolic-rich sorghum toasted flours in cancer prevention and gut microbiota modulation

• Ano de defesa: 2024
• Autor(a) principal: Paes, Laise Trindade
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Ciência e Tecnologia de Alimentos
• Palavras-chave em Português: Farinha de sorgo - Uso terapêutuco; Antioxidantes; Colón (Anatomia) - Câncer - Prevenção; Plasmodium falciparum; Fenóis; Microbioma gastrointestinal; Ciência e Tecnologia de Alimentos
• Link de acesso: https://locus.ufv.br/handle/123456789/32914; https://doi.org/10.47328/ufvbbt.2024.555

Sorghum, rich in dietary fibers and phenolic compounds, offers promising health benefits. The aim of this thesis was to investigate: 1) the bioactivity of sorghum phenolic-rich extracts against cancer cells and malaria-causing Plasmodium; 2) the potential protective effects of white and tannin toasted sorghum flours against early-stage dimethylhydrazine (DMH)-induced colon cancer in rats, and 3) the influence of these flours and their phenolic extracts on gut microbiota. In the in vitro study, using warm water and 70% ethanol/water as solvents to generate phenolic- rich extracts from sorghum toasted flours, 145 phenolic compounds were identified. White sorghum ethanolic extract (WSE) showed the lowest IC50 on EA.hy926 and A549 cancer cells, while tannin sorghum ethanolic extract (TSE) showed the lowest IC50 on HCT-8 cells. All extracts reduced the adhesion and invasion of HCT-8 cells, indicating antimetastatic potential. WSE also demonstrated toxicity to both chloroquine-resistant and sensitive strains of Plasmodium falciparum. In the in vivo study, 40 male rats were divided into 4 groups and subjected to various diets, including control (G1), tannin and white toasted sorghum flour diets with DMH colon induction (G2, G3, respectively), and DMH only (G4). Oxidative stress assessments indicated an enhanced activity of superoxide dismutase (SOD) and glutathione (GSH) in the liver of rats fed with tannin-rich sorghum flour, suggesting improved defense against oxidative stress induced by DMH. Moreover, aberrant crypt foci (ACF) assays demonstrated a lower incidence of ACF in rats supplemented with sorghum flours (G2: 51.75 ± 26.84, G3: 64.38 ±18 ACF ≤ 3 crypts), suggesting a preventive effect against carcinogenesis. Additionally, determination of short-chain fatty acids (SCFAs) revealed higher acetate levels observed in the group supplemented with white sorghum flour (G3: 36.12 ± 7.01 mM) compared to other groups, and higher propionate levels observed in the same group (G3: 10.51 ± 1.43 mM) compared to the negative control (G1). In vitro fecal fermentation of digested white (WSD) and tannin sorghum flours (TSD), as well as white (WSE) and tannin sorghum extract (TSE) with fructooligosaccharides (FOS) showed the highest acetate concentration in samples of white sorghum phenolic extracts (WSE) and tannin sorghum phenolic extracts (TSE) with FOS. Propionate levels were highest in WSE + FOS, followed by TSE + FOS, compared to FOS alone. WSD supplemented with its phenolic extract, WSE, showed increased acetate and propionate levels, unlike TSD + TSE, emphasizing the influence of phenolic compounds on modulation of SCFA. These findings highlight the promising role of toasted sorghum flours in fighting oxidative stress and cancer cells proliferation in vitro, in mitigating early-stage colon carcinogenesis, and modulating gut microbiota and SCFA, warranting further exploration of their preventive and therapeutic potentials. Keywords: Antioxidant activity; Colon carcinogenesis; Plasmodium falciparum; Phenolic composition; Gut microbiota modulation.