Vernonia amygdalina Extract Loaded Microspheres for Controlling Phytophthora palmivora

Abstract

The adverse effects of modern fungicide consumption have caused many issues in the agroecosystem. Hence, under sustainable agriculture concepts, it is important to research alternatives to the currently used fungicide. The use of secondary metabolite-containing herbal extracts for treating plant diseases has become the latest trend in sustainable and green agriculture. However, the poor solubility and volatile nature of many compounds cause practical issues when using them in the field. Hence, bioactive compound delivery through nano- or micro-particles has become a successful technique to improve the solubility and delivery of secondary metabolites to targeted sites. In the current study, the ethyl acetate (EtOAc) extract from dried leaves of Vernonia amygdalina was tested against Phytophthora palmivora isolated from Durian (Durio zibethinus) root rot. Further, the potential of enhancing the effect of V. amygdalina EtOAc treatment through microspheres loaded with V. amygdalina EtOAc extract was also investigated. The microspheres encapsulated with Eudragit® E were synthesized under different electrospray conditions to obtain the microspheres with the highest efficacy. The poison media assays evaluated the fungal growth inhibition efficiency of the V. amygdalina EtOAc crude extract and the synthesized microspheres. The study reveals that the V. amygdalina EtOAc extract has the potential to suppress the growth of P. palmivora. Interestingly, the synthesized microspheres showed immense growth inhibition in P. palmivora, with a 61.10 µg/mL decrease in ED50 compared to the direct usage of V. amygdalina EtOAc extract.