Encapsulation of Psidium guineense Sw (Ambul Pera) extract in alginate nanoparticles to enhance antioxidant activity

Abstract

Food components that offer health benefits are often referred to as bioactive compounds. Many bioactive compounds exhibit their antioxidant, antidiabetic, anti-inflammatory, anticancer, and antimicrobial effects, contributing positively to human health. However, most bioactive compounds are sparingly soluble and may also be sensitive to light, oxygen, temperature and shear, which lead to adverse changes in colour, odour, and flavour. Due to the poor solubility of highly active bioactive compounds, they exhibit lower bioactivity in vivo than expected. Advancements in nanotechnology have enabled the enhancement of pharmacokinetic properties of both synthetic and natural compounds through the formulation of nanoparticles. Similarly, the formation of nanoparticles from phytochemicals has gained attention as a novel strategy to enhance their bioactivities. The present study focused on the nanoencapsulation of Psidium guineense Sw (Ambul Pera) fruit extracts in a sodium alginate matrix using the ionic gelation method. The primary objectives were to identify the most bioactive fraction of ambul pera and to evaluate the impact of nanoencapsulation on its antioxidant activity. Fruits were collected from the North Central Province of Sri Lanka and were ground into fine particles. Then ethanolic extraction was done by maceration, and solvent partition with hexane and ethyl acetate was carried out. Crude and the resulting fractions were then screened for antioxidant activity. Among the various solvent fractions tested, the aqueous fraction was selected for nanoparticle formulation based on its superior antioxidant potential. Nanoparticle synthesis was done by using the ionic gelation method. Then, characterisation and antioxidant activity were conducted for the synthesised nanoparticle. The results of the characterisation confirmed the successful encapsulation of ambul pera fruit in the sodium alginate matrix. The aqueous fraction of ambul pera fruit encapsulated alginate nanoparticles exhibited the highest antioxidant activity in ABTS, DPPH, and NO radical scavenging activity assays, accounting for the half maximal inhibitory concentration (IC 50) values of 0.032, 0.029, and 0.299 mg/ml, respectively. The results of this study revealed the potential of nanoencapsulated aqueous fraction of Psidium guineense Sw fruit for the development of dietary supplements with enhanced antioxidant activity.