Novel ADM Ceylon Standardized Extract With Antioxidant and Antimicrobial Effects Evaluated in Caenorhabditis elegans Model

Abstract

Objectives The main objective is to develop a novel powdered extract from Ceylon tea, standardized to gallic acid, flavanols and xanthines, and to evaluate “in vivo” its functional properties. Methods Ceylon tea leaves and corresponding powdered extracts were obtained at laboratory and industrial scales. To analyze individual antioxidants, High Performance Liquid Chromatography (J. Chromatogr. A, 2000,881, 439–447) and Gas Chromatography (ACS Food Sci. Technol., 2021, 1, 4,596–604). Oxidative stress resistance (J. Agric. Food Chem., 2011, 59,2077–2085). C. elegans nematodes were egg-synchronized in NGM plates (control medium) and NGM plates containing Ceylon extract (0.1 to 2 mg/mL). Nematode viability was assessed after oxidative stress (2 mM H2O2). Vitamin C (10 μg/mL) was used as positive control. Experiments were carried out in duplicate. Infection assays (Antioxidants 2021, 10,536). Nematodes were age-synchronized by recovering the eggs from adults in agar plates, already seeded with E. coli OP50 (NGM), and NGM plates containing three different doses of Ceylon (0.1 to 1 mg/mL). The pathogen strain Staphylococcus aureus (ATCC25923) was used for infections. Nematodes were incubated at 25 °C and scored for survival during 5–10 days. Results Chromatographic analyses Industrial scale Ceylon extracts was standardized to gallic acid (1.8 ± 0.0%), monomeric, oligomeric flavanols and methyl xanthines, respectively 2.1 ± 0.1%, 0.2 ± 0.0%, & 4.2 ± 0.1%. The volatile composition showed characteristic profile of Camellia sinensis, with higher relative proportion of trans-2-hexenal (1.9 ± 0.1%), linalool (3.1 ± 0.3%) and benzaldehyde (3.5 ± 0.2%), together with limonene (12.0 ± 1.3%) and eugenol (13.0 ± 0.0%). Antioxidant activity and pathogen protection ADM® Ceylon extract showed significant protection both upon acute oxidative stress and S. aureus infection in the model of C. elegans. Thus, nematodes feeding 1 mg/mL of Ceylon extract, significantly increased their survival compared with control fed population (48% versus 28%). The extract (1 mg/mL) increased 20% survival vs control infected population. Conclusions ADM® Ceylon powdered extract is a novel standardized functional extract with potential antioxidant and protective effects against pathogens. Funding Sources Thanks to ADM® for funding this research work.