Effect of In-vitro Gastrointestinal Digestion and Dialysis Process on Phenolic Compounds and Antioxidant Capacity of Selected Underutilized Fruits in Sri Lanka

H A C O Hettiarachchi,S Jayatilake,K D P P Gunathilake

doi:10.4038/tar.v32i2.8468

Abstract

The stability of phytochemicals and their inherent bioactivity may change after being subjected to gastro-intestinal digestion. This study investigated the bioactive potential of Elaeocarpus serratus, Pouteria campechiana, Annona squamosa and Annona muricata in terms of polyphenolic content and the antioxidant capacity. The in-vitro digestion process was carried out to quantify bioaccessible and bioavailable phytochemicals through each digestion phase analyzed by Folin-Ciocalteu method, DPPH radical scavenging assay and the total antioxidant capacity (TAC) of fruit extracts. The total phenolic contents (TPC) of the methanolic extracts of A. squamosa, E. serratus, A. muricata and P. campechiana were 718, 525, 370 and 306 μg gallic acid equivalents per g fresh weight (μg GAE per g FW), respectively. The highest absorption of phenolic compounds during the digestion was observed for P. campechiana as indicated by the TPC of the dialysis phase of extract (44.90 μg GAE per g FW) when compared with the initial TPC of fresh methanolic extract, which was the lowest of the fruits tested. The DPPH radical scavenging activity of fresh methanolic extracts of E. serratus (95.3%), A. squamosa (95.2%) and A. muricata (94.0%) showed a significantly higher percentage than P. campechiana (37.2%). The TPC, DPPH radical scavenging and TAC in the extracts of all digestion phases were lower, compared to their fresh methanolic extracts and may be attributed to the partial release or degradation of phenolic compounds during the digestion.

Highlights

The significance of underutilized crop species in contributing to world food and nutrition security has received substantial coverage by scientists in recent years
It may be due to low amount of phenolic compounds present in P. campechiana methanolic extract, the radical scavenging ability reported in much lower value (Table 1)
Gastric phase aliquots of E. serratus, P. campechiana, A. squamosa and A. muricata reported a decrease in total antioxidant capacity (TAC) (30.80, 26.80, 13.77, 49.05 μg AAE per g fruit weight (FW), respectively) when compared with their fresh methanolic extracts

Summary

Introduction

The significance of underutilized crop species in contributing to world food and nutrition security has received substantial coverage by scientists in recent years. These crops belonging to categories such as cereals, legumes, vegetables, oilseeds, roots and tubers, aromatic and medicinal plants, fruits and nuts, have earned collective names such as ‘neglected and underutilized’ crops (Padulosi et al, 2011). According to Ravi et al (2010), these crops have traditionally been under cultivation and intrinsically linked with livelihood and cultural identity of local tribal communities They are very much recognized for their rich nutritious profile with high bioavailable minerals, vitamins, dietary fibre, and other phytochemicals. Elaeocarpus serratus (Ceylon Olive), Pouteria campechiana (Lawulu), Annona squamosa (WeliAatha-Custard Apple) and Annona muricata (Katu AnodaSoursop) are underutilized fruit crops, rich in phytochemicals because of which both are considered having good antioxidant properties to fight many oxidative stress-related chronic diseases

Methods

Results

Conclusion