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<p>Aflatoxin B1 (AFB1) from <i>Aspergillus flavus</i> is a potent hepatotoxin that threatens food safety worldwide. We evaluated whether under-utilized tea-fruit tissues (pericarp, seed coat, cotyledon) yield extracts with antifungal and anti-aflatoxigenic activity. Dried tissues were extracted by maceration in 70% methanol or 70% ethanol. Phytochemical screening and quantitative assays (total phenolics, flavonoids, catechins, saponins, terpenoids; HPLC for catechins/caffeine) characterized the extracts. Antifungal activity was assessed by disk diffusion and CLSI M38 broth microdilution (MIC/MFC); ergosterol content, mycelial dry weight, and AFB1 in culture filtrates (ELISA) quantified mode and extent of action against an aflatoxigenic <i>A. flavus</i> isolate (GJ01; NCBI PX489002). Pericarp extracts were richest in phenolics, flavonoids, catechins and xanthines; seed coat was enriched in saponins; cotyledons lacked key secondary metabolites and were excluded from antifungal testing. Antifungal assays demonstrated dose-dependent activity; methanolic seed coat extract was most potent (MIC 2&#xa0;mg/ml, MFC 4&#xa0;mg/ml), producing 18.3&#xa0;mm inhibition zones which, at 1280&#xa0;µg loading, were statistically non-significant (<i>p</i> &gt; 0.05) compared to 100&#xa0;µg amphotericin B, and 89% AFB1 reduction (61&#xa0;ppb vs. 554&#xa0;ppb control) at MIC, alongside significant ergosterol depletion (0.26% at MIC). Pericarp extracts were less active (MIC 4–8&#xa0;mg/ml, 30–55% AFB1 inhibition). Fungal biomass decreased at ≥ MIC. Although the biomass–AFB1 correlation was positive, it was not statistically significant (<i>p</i> = 0.073). This implies that growth inhibition was not the only mechanism of AFB1 inhibition by tea fruit extracts. These results suggest that saponins are likely key contributors to the observed antifungal and anti-aflatoxigenic effects, making the methanolic seed-coat extract a promising, sustainable candidate for further fractionation and mechanistic studies.</p>

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Tea (Camellia sinensis) fruits as a sustainable source of antifungal agents that suppress Aspergillus flavus and Aflatoxin B1

  • 期刊论文

  • 发表日期：

    2026年6月19日

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  • K. Gobikanila,
  • P. R. Jeyaramraja

摘要

Aflatoxin B1 (AFB1) from Aspergillus flavus is a potent hepatotoxin that threatens food safety worldwide. We evaluated whether under-utilized tea-fruit tissues (pericarp, seed coat, cotyledon) yield extracts with antifungal and anti-aflatoxigenic activity. Dried tissues were extracted by maceration in 70% methanol or 70% ethanol. Phytochemical screening and quantitative assays (total phenolics, flavonoids, catechins, saponins, terpenoids; HPLC for catechins/caffeine) characterized the extracts. Antifungal activity was assessed by disk diffusion and CLSI M38 broth microdilution (MIC/MFC); ergosterol content, mycelial dry weight, and AFB1 in culture filtrates (ELISA) quantified mode and extent of action against an aflatoxigenic A. flavus isolate (GJ01; NCBI PX489002). Pericarp extracts were richest in phenolics, flavonoids, catechins and xanthines; seed coat was enriched in saponins; cotyledons lacked key secondary metabolites and were excluded from antifungal testing. Antifungal assays demonstrated dose-dependent activity; methanolic seed coat extract was most potent (MIC 2 mg/ml, MFC 4 mg/ml), producing 18.3 mm inhibition zones which, at 1280 µg loading, were statistically non-significant (p > 0.05) compared to 100 µg amphotericin B, and 89% AFB1 reduction (61 ppb vs. 554 ppb control) at MIC, alongside significant ergosterol depletion (0.26% at MIC). Pericarp extracts were less active (MIC 4–8 mg/ml, 30–55% AFB1 inhibition). Fungal biomass decreased at ≥ MIC. Although the biomass–AFB1 correlation was positive, it was not statistically significant (p = 0.073). This implies that growth inhibition was not the only mechanism of AFB1 inhibition by tea fruit extracts. These results suggest that saponins are likely key contributors to the observed antifungal and anti-aflatoxigenic effects, making the methanolic seed-coat extract a promising, sustainable candidate for further fractionation and mechanistic studies.