SELECTED UNDERUTILIZED EDIBLE GREEN LEAVES: INHIBITION EFFECT ON THE FORMATION OF COLORECTAL CANCER RELATED COMPOUNDS AND ANTIMICROBIAL ACTIVITY

Neglected and underutilized species (NUS) has been appointed as central key to overcome the challenges relate to food security. They can be offer as alternative sources of health promoting compounds, but most of them have been insufficiently studied with regard to their bioactive characteristics. The present study was conducted to quantify total phenolic content, vitamin C and evaluate the effect on endogenous n-nitrosation and antibacterial capacity of leaves from seven neglected plants, named: culantro (Eryngium. foetidum), false roselle (Hibiscus. acetosella), roselle (Hibiscus sabdariffa), tree basil (Ocimum gratissimum), Barbados gooseberry (Pereskia aculeata), purslane (Portulaca oleracea) and tannia (Xanthosoma sagittifolium). Total phenolic content (TPC) was estimated by Folin-Ciocalteu method. Quantification of vitamin C was done by UPLC (Ultra high liquid chromatography), measuring the ascorbic acid and dehydroascorbic acid (DHAA) concentration. The effect on endogenous n-nitrosation was measured as apparent total nitroso compounds (ATNC), after an in vitro digestion model, and analyzed by chemiluminescence. The microorganisms tested for antimicrobial activity were: Bacillus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Streptococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. Total phenolic content varied from 12.55 mg GAE/g d.w. (E. foetidum) to 93.88 mg GAE/g d.w. (O. gratissimum). Total vitamin C varied from 5.36 mg/100g (P. aculeata) to 84.77 mg/100g d.w (X. sagittifolium). Maximum inhibition effect on apparent total nitroso compounds (ATNC) was presented by O. gratissimum and E. foetidum, nearly 78% and 63%, respectively. Conversely, H. acetosella, H. sabdariffa and X. sagittifolium promoted significant increase (p < 0.05) on ATNC. None of the NUS extracts inhibited growth of the Gram-positive bacteria. However, the yeast (C. albicans) and the Gram-negative bacteria, expect for P. aeruginosa, were sensitive to antimicrobial effects from H. acetosella, H. sabdariffa, and P. oleracea extracts. These results highlight the importance and the potential of the studied NUS as new sources of health-promoting compounds.