Journal of Nuts (Mar 2024)
Comparative HPLC, GC-MS Analysis and In vitro Antifungal Activity of Walnut Kernels against Alternaria mali in Apple
Abstract
Natural plant products are suitable, eco-friendly, and toxicologically safe for using in integrated disease management approaches. Present work was carried out to decipher the potential of walnut kernels against Alternaria mali, the causal agent of leaf and fruit blotch on apples. Bioactive compound profiling of extracts was also done through HPLC and GC-MS to reveal the potential role of the compounds for disease management. In the present study, a comparative analysis of the anti-fungal activity and concentration of active substances using HPLC and GC-MS in different walnut extracts has been carried out on the inhibition of A. mali. The extracts of walnut kernels belonging to different eco-geographical regions viz. CS (Char-e-Sharief), KG (Kulgam), TM (Tangmarg), and KW (Kupwara) of Kashmir valley were prepared. The extracts prepared were added to potato dextrose agar (PDA) @ 1000, 2000, and 3000 ppm for evaluation against A. mali. The results revealed the efficacy of the different walnut extracts, with a maximum inhibition of mycelia growth in the range of 60%, 62.2%, and 71.1% at 3000ppm. Among them, the TM (Tangmarg) extract showed the highest inhibition (71.1%). The bioactive compounds were identified by using GC-MS chromatographic technique. The Quercetin content was quantified in the kernels of walnut, collected from four locations in Kashmir valley using HPLC. Among the selected genotypes, the highest Quercetin content was observed in samples collected from TM (Tangmarg) (0.765mg g-1) followed by KW (Kupwara) (0.705 mg g-1). The major phenolic components identified by GC/MS were methyl-7,8-Octadecadienoate, hexadecanoic acid, linoleic acid, epicatechin, and tocopherol. The results of the present study can be utilized further in the development of formulation from walnut kernels for evaluation under field conditions.
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