Natural food wrappers: nutritional components, antioxidant and antimicrobial activities

Abstract

This study investigated the nutritional contents, phytochemical components, as well as antioxidant and antimicrobial activities of the leaves of Thaumatococcus danielii Benth., Tectona grandis L., Macrostachyum megaphrynium (Benth) K. Schum, Musa paradisiaca L., Sterculia tragacantha Lindl and Theobroma cacao L. Traditionally, leaves of these plant species are used for wrapping food and they are components of recipes used in the treatment of various diseases such as: tuberculosis, bronchitis, inflammation, rheumatism and arthritis. Standard laboratory protocols were used for all experiments. The antioxidant activity of samples was determined using DDPH method. The extracts (100-200 mg/ml) of samples were screened against isolates (105-106cfu/ml) using agar well diffusion method. The test organisms were clinical isolates of Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, obtained via due process from University College Hospital (UCH), Ibadan. The samples had varied proximate components; M. paradisiaca had the highest crude fibre (12.13%) and crude protein (22.13%) contents. The mineral contents of the samples varied significantly (pd≤0.05). T. cacao recorded the highest magnesium (75.00mg/100g) and potassium (56.67mg/100g) contents. T. grandis was richest
in calcium (266.67mg/100g) and phosphorus (251.67mg/100g) whereas S. tragacantha had the highest content of sodium (1,346.67mg/100g). Ascorbic acid (8.33mg/100g) was the highest vitamin content in all samples. Some of the phytochemicals were present in high quantity in the samples. M. paradisiaca had the highest alkaloids content (1,833.33mg/100g). T. cacao recorded the highest concentration of flavonoids (1,538.33mg/100g). S. tragacantha was richest in saponins (1,421.67mg/100g) and M. macrostachyum had the highest tannins (1,571.67mg/100g) content. T. cacao gave an antioxidant activity of 29.13% against DDPH radicals. Furthermore, it displayed significant antimicrobial activity (9.3-38.3mm) against all test organisms. This study validated the antimicrobial and antioxidant activities of the samples. The nutritional and phytochemical components of the samples could be responsible for the observed bio-activities. Aside from using these leaves as food wrappers they could have therapeutic benefits, especially in the management of infectious and metabolic diseases.

Keywords: Food, Nutrients, Phytochemical components, Natural antioxidant, Anti-infective