Vermicompost Supply Modifies Chemical Composition and Improves Nutritive and Medicinal Properties of Date Palm Fruits From Saudi Arabia.

Soad Al Jaouni,Hamada Abdelgawad,Hussein S H Mohamad,Mohammed A M Wadaan,Wael N Hozzein,Han Asard,Sherif H Hassan,Samy Selim

doi:10.3389/fpls.2019.00424

Abstract

To meet the increased demand for phytochemicals, plant cultivation in soil amended with biofertilizers has been developed. Here, we aimed to use vermicompost as an environmentally safe biofertilizer to enhance the nutritive and medicinal value of five common cultivars of Saudi date palm; namely Phoenix dactylifera L. var. Ajwa, Hulwa, Ruthana, Sefri, and Luban. To determine changes in the fruit nutritive composition, primary metabolites, antioxidants, phenolic compounds and mineral profiles were analyzed in the fruits from non-fertilized and vermicompost-fertilized date palms. We also tested how changes in the fruit chemical compositions due to vermicompost fertilization affected their medicinal potentials. Applying vermicomposts generally increased primary metabolites, vitamins, and mineral content as well as the medicinal potential of the date palm fruits. This positive effect is possibly explained by the role of vermicomposts in improving soil health and fertility. Furthermore, clustering analyses and principal component analysis (PCA) indicated cultivar-specific responses. PCA analysis also revealed that the bioactivities of the date palm fruit extracts and their antioxidants tended to display correlated output values. One of the highly accumulated phenolic compounds, β-D-glucogallin, was extracted and purified from P. dactylifera L. var. Ajwa fruits and showed significant antioxidant, anticancer, antibacterial, antimutagenic, and antiprotozoal activities. Overall, applying vermicompost is an innovative approach to increase the nutritive quality and medicinal potential of date palm fruits.

Highlights

Fruits constitute a major part of the daily human diet, and in the Middle East date fruits are important because of their nutritive value
In March of each year, 10 kg of vermicomposts were applied to the soil surface and followed by irrigation
One strategy to improve the intake of these phytochemicals is through increasing the date fruit yield and quality (Khalid et al, 2017)

Summary

Introduction

Fruits constitute a major part of the daily human diet, and in the Middle East date fruits are important because of their nutritive value. Date palms (Phoenix dactylifera L., Palmae) are the source of these fruits and are widely cultivated in the Middle East (Al-Farsi and Lee, 2008). There are about 5000 varieties of date palm fruits grown in different regions of the world. Extracts of date palm fruits were reported to have antibacterial, antioxidant and antifungal properties (Selim et al, 2012; Hamad et al, 2015). They have the potential to supply antioxidants in different pharmaceutical and medicinal applications. Considering the nutritive values of date palm fruits, the importance of studying their biochemical composition, nutritive, and medicinal potential is increasingly recognized

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