Solvent-Free Microwave Extraction of Essential Oils from Litsea cubeba (Lour.) Pers. at Different Harvesting Times and Their Skin-Whitening Cosmetic Potential

Abstract

Litsea cubeba fruit, which has the highest content of essential oils in the plant, is an important woody oil plant resource. In this study, the influence of the solvent-free microwave extraction (SFME) and hydrodistillation (HD) techniques on the extraction of L. cubeba fruit essential oils was investigated in terms of yield, kinetics, and chemical composition, where the former conditions were optimized by the response surface design. The maximal essential oil yield was obtained under the optimal SFME process conditions (442 W and 24 min), where the irradiation time was the most important variable (p < 0.0001). Regardless of the extraction method used, the influence of harvesting time on L. cubeba fruit essential oils were quantitatively and qualitatively analyzed afterwards, where the SFME essential oil from July showed its superiority over the others regarding its higher extraction yield and better bioactivities. Compared with the HD method, the SFME approach could significantly enhance the yield of essential oils extracted from June to August by nearly 47% with the advantages of saving energy and low environmental impact. Interestingly, the SFME method could selectively extract monoterpene hydrocarbons such as D-limonene with relation to different compositions and bioactivities. Moreover, SFME essential oil showed a better inhibitory effect on tyrosinase and melanogenesis, indicating its skin-whitening potential as a new promising natural cosmetic ingredient.

Litsea cubeba essential oil: Extraction, chemical composition, antioxidant and antimicrobial properties, and applications in the food industry

“…Traditionally, water and petrochemical solvents such as n ‐hexane, ethanol, and isopropanol are commonly used in LCEO extraction. In recent years, with the development of the idea of green chemistry and sustainable industry, green solvents and green technology have been applied for both essential oil and kernel oil extractions of L. cubeba (Guo et al., 2021; Qiu et al., 2022; Zhuang et al., 2018). One type of green and sustainable solvent, namely, deep eutectic solvent (DES), has been combined with microwave‐assisted hydrodistillation to extract fruit LCEO, and the extraction conditions were optimized.…”

“…In this method, instead of adding an external solvent, the in situ water in plant cells was heated and used as a solvent. Compared with conventional hydrodistillation methods, the SFME approach significantly enhanced the yield of LCEO and improved its inhibitory ability on tyrosinase and melanogenesis (Qiu et al., 2022).…”

Phenotypic Diversity of Litsea cubeba in Jiangxi China and the Identification of Germplasms with Desirable Characteristics

“…Previous research on L. cubeba has focused on the extraction of EO [17][18][19], the components of EO [20][21][22][23], and on phenotypic variations with a focus on regional differences in EO yield, EO content, and EO composition [24][25][26]. Prior studies have analyzed the diversity of leaf and fruit traits in L. cubeba and detected extremely rich diversity among and within provenances [27]; explored the changes in the morphology and composition during fruit development [28]; analyzed the changes in EO content and EO components in L. cubeba in Fujian province [29]; and explored the relationship between the fresh fruit yield (FFY) and EO characteristics of wild L. cubeba [30].…”