Nutraceuticals from natural sources have shown potential new leads in functional food products. Despite a broad range of health-promoting effects, these compounds are easily oxidized and unstable, making their utilization as nutraceutical ingredients limited. In this study, the encapsulated stingless bees' propolis in liposome was prepared using soy phosphatidylcholine and cholesterol by thin-film hydration technique. Three different formulations of phosphatidylcholine composition and cholesterol prepared by weight ratio was conducted to extract high propolis encapsulation. Physicochemical changes in the result of the encapsulation process are briefly discussed using scanning electron microscopy and Fourier Transform Infrared Spectroscopy. A dynamic light-scattering instrument was used to measure the hydrodynamic diameter, polydispersity index, and zeta potential. The increment of the liposomal size was observed when the concentration of extract loaded increased. In comparing three formulations, F2 (8:1 w/w) presented the best formulation as it yielded small nanoparticles of 275.9 nm with high encapsulation efficiency (66.9%). F1 (6:1 w/w) formed large particles of liposomes with 422.8 nm, while F3 (10:1 w/w) showed low encapsulation efficiency with (by) 38.7%. The liposome encapsulation will provide an effective nanocarrier system to protect and deliver the flavonoids extracted from stingless bees' propolis.
Dye-sensitized solar cell (DSSC) is a photovoltaic device that can be produced from natural source pigments or natural dyes. The selection of natural dyes for DSSC application is currently under research. The utilization of natural dye materials that are easy to obtain, cost-effective, and non-toxic can reduce waste during DSSC fabrication. Natural dyes can be extracted from plants through extraction and chromatography methods. The suitability and viability of utilizing natural dyes as photosensitizers in DSSCs can be predicted using appropriate software simulation by varying related parameters to produce high power conversion efficiency. In this context, the purpose of the review is to highlight the evolution of performance improvement in the development of DSSCs with consideration of natural dye extraction and software simulation. This review also focuses on the results of extracting natural dyes from herbal ingredients, which are still very limited in information, and several parts of herbal plants that can be used as natural dye sources in the future of solid-state DSSCs have been identified. Based on the results of this review, the highest efficiency was obtained for the DSSC that used chlorophyll pigments as natural dyes using Peltophorum pterocarpum leaves with 6.07%, followed by anthocyanin pigments as natural dyes using raspberries (black) fruits with 1.5%, flavonoid pigments as natural dyes using Curcuma longa herbs with 0.64%, and flavonoid pigments as natural dyes using Indigofera tinctoria flowers with 0.46%.