Nanoemulsions Containing Cosmos caudatus Kunth Extract: Formulation and Characterization for Antioxidant Potential
Izaz Aqeiluz Zahara,a,1 Siti Mariyah Ulfa,a,2 Noraini Ahmad,b,3*Anna Safitria,c,4*

aDepartment of Chemistry, Faculty of Mathematics and Natural Sciences, Brawijaya University, Jl. Veteran, Malang 65145, East Java, Indonesia
bDepartment of Chemistry, Faculty of Science, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
cResearch Centre of SMONAGENES (Smart Molecules of Natural Genetic Resources), Brawijaya University, Jl. Veteran, Malang 65145, East Java, Indonesia
Coreresponding email: a.safitri[at]ub.ac.id

Abstract

Plant derived antioxidants have attracted considerable scientific interest due to their therapeutic potential. However, their application in clinical and pharmaceutical settings is frequently hindered by low water solubility, physicochemical instability, and limited bioavailability, all of which compromise their biological efficacy. Leaves of Cosmos caudatus K. are rich in flavonoids known for strong radical scavenging activity. Despite these benefits, such polyphenolic constituents are prone to degradation and display poor dispersion in aqueous environments, restricting their stability and delivery efficiency. This study aimed to formulate and optimize a nanoemulsion encapsulating C. caudatus extract using the low energy Phase Inversion Composition (PIC) method. Optimization was performed through Response Surface Methodology employing a three factor Central Composite Design to assess the effects of medium chain triglyceride (MCT) oil, Tween 80, and Span 80 on droplet size, polydispersity index (PDI), and loading capacity. The optimized formulation (1 MCT oil, 0.85 Tween 80, 0.25 Span 80) generated nanosized droplets (106.6 nm) with narrow size distribution (PDI 0.205) and a loading capacity of 56.52 percent. Transmission electron microscopy confirmed spherical morphology and homogeneous dispersion. The system exhibited measurable antioxidant activity, with IC50 values of 94.93 (DPPH), 75.45 (FRAP), and 82.03 (H2O2 scavenging). Although nanoemulsification did not significantly enhance intrinsic antioxidant potency compared with the crude extract, it substantially improved dispersion characteristics and physicochemical stability. These findings demonstrate that PIC assisted nanoemulsification combined with statistical optimization represents a rational lipidbased delivery strategy for flavonoid rich antioxidants with potential pharmaceutical and nutraceutical applications.

Keywords: Nanoemulsion, Cosmos caudatus Kunth, Antioxidant, Tween 80, Span 80

Topic: Biochemistry