Influence of Boiling, Steaming and Frying of Selected Leafy Vegetables on the In Vitro Anti-inflammation Associated Biological Activities

Abstract

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.

In Vitro Anti-Inflammatory Properties of Selected Green Leafy Vegetables

“…This test was carried out as described by Okoli et al [12], with some modifications as described in Gunathilake et al [13]. Briefly, 0.05 mL of blood cell suspension and 0.05 mL of hydromethanolic extracts of leaves were mixed with 2.95 mL phosphate buffer (pH 7.4).…”

“…Protein denaturation assay was done according to the method described by Gambhire et al [14], with some modifications as described in Gunathilake et al [13]. The reaction mixture (5 mL) consisted of 0.2 mL of 1% bovine albumin, 4.78 mL of phosphate buffered saline (PBS, pH 6.4), and 0.02 mL of extract, and the mixture was mixed, and was incubated in a water bath (37 °C) for 15 min, and then the reaction mixture was heated at 70 °C for 5 min.…”

Effect of Different Cooking Methods on Polyphenols, Carotenoids and Antioxidant Activities of Selected Edible Leaves

“…Methanolic extracts of leaves were prepared according to the method described in Gunathilake et al [ 11 ]. One gram of cooked leafy vegetable samples were weighed and mixed with 8 mL of 70% methanol and vortexed at high speed for thirty minutes and then centrifuged (Hettich, EBA 20, Tuttlingen, Germany) for 10 min at 792× g .…”

Passiflora edulis: An Insight Into Current Researches on Phytochemistry and Pharmacology

“…Different processing methods affected the composition and activity of passion fruit. Steaming and boiling compared to frying protect the health-promoting properties of passion fruit (Gunathilake et al, 2018b). Today, passion fruit has been processed into a range of products on the basis of the attractive health effects and full of phytonutrients.…”