Influence of Boiling, Steaming and Frying of Selected Leafy Vegetables on the In Vitro Anti-inflammation Associated Biological Activities
Department of Food Science & Technology, Faculty of Livestock, Fisheries & Nutrition, Wayamba University of Sri Lanka, Makandura, Gonawila 10250, Sri Lanka
Department of Food Science and Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda 60170, Sri Lanka
Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada
Author to whom correspondence should be addressed.
Plants 2018, 7(1), 22; https://doi.org/10.3390/plants7010022
Received: 14 February 2018 / Revised: 11 March 2018 / Accepted: 13 March 2018 / Published: 16 March 2018
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
The aim of the present study was to evaluate the effect of cooking (boiling, steaming, and frying) on anti-inflammation associated properties in vitro of six popularly consumed green leafy vegetables in Sri Lanka, namely: Centella asiatica, Cassia auriculata, Gymnema lactiferum, Olax zeylanica, Sesbania grnadiflora, and Passiflora edulis. The anti-inflammation associated properties of methanolic extracts of cooked leaves were evaluated using four in vitro biological assays, namely, hemolysis inhibition, proteinase inhibition, protein denaturation inhibition, and lipoxygenase inhibition. Results revealed that the frying of all the tested leafy vegetables had reduced the inhibition abilities of protein denaturation, hemolysis, proteinase, and lipoxygenase activities when compared with other food preparation methods. Steaming significantly increased the protein denaturation and hemolysis inhibition in O. zeylanica and P. edulis. Steaming of leaves increased inhibition activity of protein denaturation in G. lactiferum (by 44.8%) and P. edulis (by 44%); hemolysis in C. asiatica, C. auriculata, and S. grandiflora; lipoxygenase inhibition ability in P. edulis (by 50%), C. asiatica (by 400%), and C. auriculata leaves (by 250%); proteinase inhibition in C. auriculata (100%) when compared with that of raw leaves. In general, steaming and boiling in contrast to frying protect the health-promoting properties of the leafy vegetables.