Nutritional, antioxidant, angiotensin-converting-enzyme and carbohydrate-hydrolyzing-enzyme inhibitory activities of underutilized leafy vegetable: African wild lettuce (Lactuca taraxacifolia Willd)

Oluwole Steve Ijarotimi,Ibiyinka Helen Adesanya,Timilehin David Oluwajuyitan

doi:10.1186/s40816-021-00282-4

Oluwole Steve Ijarotimi, Ibiyinka Helen Adesanya + Show 1 more

Open Access

https://doi.org/10.1186/s40816-021-00282-4

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Journal: Clinical Phytoscience	Publication Date: May 14, 2021
Citations: 9	License type: open-access

Affiliation: Federal University of Technology

Abstract

BackgroundAfrican wild lettuce (Lactuca taraxacifolia Willd.) is an underutilised indigenous leafy vegetable containing essential nutrients and medicinal properties. Hence, this study aimed to determine the chemical composition, antioxidant activities, α-amylase, α-glucosidase and angiotensin converting enzyme inhibitory potentials of wild lettuce leaves powder samples.MethodsFreshly harvested Wild Lettuce leaves were processed into whole leafy powder (WLF), extracted powder (WLE), residue (WLR) and leaf protein isolate (WPI). Chemical composition, antioxidant activities, α-amylase, α-glucosidase and angiotensin-converting enzyme inhibitory potentials of the powder samples were determined.ResultsCrude protein of Wild Lettuce leaves ranged from 23.27 to 46.57 and crude fiber from 4.17–37.37 g/100 g. Phosphorous was the most abundant element, while zinc had the lowest concentration. The samples essential amino acids, protein efficiency ratio, essential amino acid index and biological values were 39.83–50.65 mg/100 g protein. 2.79–3.51, 77.03–92.36% and 72.26–88.97%, respectively. Saponin, tannin, oxalate, phytate, terpennoids, flavonoid and phenol in the leafy vegetable samples were within tolerable levels. The African wild lettuce leaf protein isolate (WPI) had higher DPPH antioxidant activity (91.88%), percentage inhibitory properties on α-amylase (26.11%), α-glucosidase (64.24%) and angiotensin-1-converting enzyme (97.53%) than WLF (18.28, 25.44, 55.41 and 67.56), WLE (70.85, 24.97, 62.53 and 93.27) and WLR (53.07, 24.68, 50.03 and 85.28) respectively.ConclusionAfrican wild lettuce leaf samples, particularly protein isolate, contain essential nutrients, antioxidant activities and ability to inhibit angiotensin-1-converting, α-amylase and α-glucosidase enzymes Therefore, the leafy vegetable samples, particularly WPI, may be suitable as antioxidant, antidiabetic and antihypertensive agent.

Highlights

Medicinal plants utilization are becoming more popular in developed and developing counties due to the increasing inefficacy of many synthetics drugs used for the treatment chronic diseases like hypertension, diabetes [1, 2]
Source of wild lettuce powder Fresh wild lettuce leaves were sourced from Ilara Mokin, Ondo State of geographical coordinates of 7.3497° N 5.1067° E, and the leaves were authenticated in the Department of Crop Soil and Pest Management, Federal University of Technology, Akure, Nigeria
The mixture was filtered using muslin cloth and Whatman No.1 filter paper; and the filtrate was concentrated using rotary evaporator (Model 349/2, Corning Limited) at 40 °C for 36 h, and thereafter, it was freeze-dried to obtain wild lettuce leaf extract (WLE) and the residue obtained from the above filtrate was oven dried to obtain wild lettuce residue (WLR)

Summary

Introduction

Medicinal plants utilization are becoming more popular in developed and developing counties due to the increasing inefficacy of many synthetics drugs used for the treatment chronic diseases like hypertension, diabetes [1, 2]. Study has shown that many plants are rich source of natural antioxidants like vitamins A, C, E, and phenolic compounds such as flavonoids, tannins, and lignins, found in plants, all act as antioxidants [3]. In Nigeria wild leafy vegetables are underutilized which is attributed to poor knowledge of their health benefits. African wild lettuce leaf (Lactuca taraxacifolia Willd) is one of the underutilized wild vegetables in Nigeria. It is consumed as food and for its medicinal benefits [5]. African wild lettuce (Lactuca taraxacifolia Willd.) is an underutilised indigenous leafy vegetable containing essential nutrients and medicinal properties. This study aimed to determine the chemical composition, antioxidant activities, α-amylase, α-glucosidase and angiotensin converting enzyme inhibitory potentials of wild lettuce leaves powder samples

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