The objective of this manuscript was to investigate and optimise the potential of nanostructured lipid carriers (NLCs) as a carrier system for nobiletin (NOB), which was prepared by high-pressure homogenisation method. Additionally, this study was focused on the application of NOB-loaded NLC (NOB-NLC) in functional food. Response surface method with a three-level Box-Behnken design was validated through analysis of variance, and the robustness of the design was confirmed through the correspondence between the values measured in the experiments and the predicted ones. Properties of the prepared NOB-NLC, such asaverage, polydispersity, entrapment efficiency, zeta potential, morphology, and crystallinity, were investigated. NOB-NLC exhibited a spherical shape with a diameter of 112.27 ± 5.33 nm, zeta potential of −35.1 ± 2.94 mV, a polydispersity index of 0.251 ± 0.058, and an EE of 81.06% ± 6.02%. Results from X-ray diffraction and differential scanning calorimetry of NOB-NLC reviewed that the NOB crystal might be converted to an amorphous state. Fourier transform infrared spectroscopic analysis demonstrated that chemical interaction was absent between the compound and lipid mixture in NOB-NLC.

Obesity is one of the most common and major health concerns worldwide. Weight management through dietary supplements with natural plant extracts has become the focus of current research. Sweet orange essential oil (SOEO) is a natural plant extract, with many bioactivities. In order to evaluate the weight loss effect of SOEO microcapsules and investigate the underlying mechanism, we fed high-fat diet-induced obese SD rats with SOEO microcapsules for 15 days and found that SOEO microcapsules reduced body weight gain by 41.4%, decreased total cholesterol level, alleviated liver and adipose tissue pathological alteration. The results of fluorescence quantitative PCR revealed that decreasing the expression of peroxisome proliferators-activated receptor-γ, upregulating of uncoupling protein 2, hormone sensitive lipase and carnitine palmitoyltransferase I, inhibiting the expression of acetyl-CoA carboxylase appear to be the mechanism of SOEO microcapsules to lose weight. This study suggests that SOEO microcapsule is a potential dietary supplement for weight loss. Abbreviations: SOEO: sweet orange essential oil; TC: total cholesterol; TG: triglyceride; LDL-c: low-density lipoprotein cholesterol; HDL-c: high-density lipoprotein cholesterol; PPARα: peroxisome proliferators-activated receptor-α; PPARγ: peroxisome proliferators-activated receptor-γ; UCP2: uncoupling protein 2; HSL: hormone sensitive lipase; CPT1: carnitine palmitoyltransferase I; ACC: acetyl-CoA carboxylase; NPY: neuropeptide Y; LEP: leptin; INS: insulin; ALT: alanine aminotransferase; AST: aspartate aminotransferase.