BACKGROUND Newhall navel orange (Citrus sinensis Osbeck cv. Newhall) is the major navel orange cultivar planted in China. Almost all Newhall navel orange peels produced in that country are currently discarded, which is not only harmful to the environment but also a waste of resources. It is therefore necessary to carry out research to explore the utilization potential of this resource. RESULTS A 95% ethanol extract (EE) of Newhall orange peel was prepared and fractionated into three subextracts: petroleum ether extract (PEE), ethyl acetate extract (EtOAcE), and water extract (WE) by simple liquid / liquid extractions. These four extracts were then subjected to antioxidant, antibacterial, and tyrosinase inhibition assays. Interestingly, EtOAcE was significantly superior to all other three extracts, exhibiting the best biological effects. The total polyphenol content (TPC), total flavonoid content (TFC), and primary individual flavonoids of these four extracts were analyzed and compared. This was followed by principal component analysis (PCA) and the Pearson's correlation test. The result indicates that the primary bioactive compounds responsible for the biological effects of the EtOAcE are sinensetin, 4′,5,6,7‐tetramethoxyflavone, nobiletin, 3,3′,4′,5,6,7‐hexamethoxyflavone, and narirutin. In view of its easy preparation and potent biological effects, EtOAcE might demonstrate excellent application potential in various industrial areas. CONCLUSIONS This study successfully identified EtOAcE as a potent naturally occurring antioxidant, antibacterial, and tyrosinase inhibitory agent, which might add value to the utilization of Newhall navel orange peel in the food, cosmetic, and pharmaceutical industries. © 2020 Society of Chemical Industry

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To elucidate potential ecological and evolutionary processes associated with the assembly of plant communities, there is now widespread use of estimates of phylogenetic diversity that are based on a variety of DNA barcode regions and phylogenetic construction methods. However, relatively few studies consider how estimates of phylogenetic diversity may be influenced by single DNA barcodes incorporated into a sequence matrix (conservative regions vs. hypervariable regions) and the use of a backbone family‐level phylogeny. Here, we use general linear mixed‐effects models to examine the influence of different combinations of core DNA barcodes ( rbcL , matK , ITS, and ITS2) and phylogeny construction methods on a series of estimates of community phylogenetic diversity for two subtropical forest plots in Guangdong, southern China. We ask: (a) What are the relative influences of single DNA barcodes on estimates phylogenetic diversity metrics? and (b) What is the effect of using a backbone family‐level phylogeny to estimate topology‐based phylogenetic diversity metrics? The combination of more than one barcode (i.e., rbcL + matK + ITS) and the use of a backbone family‐level phylogeny provided the most parsimonious explanation of variation in estimates of phylogenetic diversity. The use of a backbone family‐level phylogeny showed a stronger effect on phylogenetic diversity metrics that are based on tree topology compared to those that are based on branch lengths. In addition, the variation in the estimates of phylogenetic diversity that was explained by the top‐rank models ranged from 0.1% to 31% and was dependent on the type of phylogenetic community structure metric. Our study underscores the importance of incorporating a multilocus DNA barcode and the use of a backbone family‐level phylogeny to infer phylogenetic diversity, where the type of DNA barcode employed and the phylogenetic construction method used can serve as a significant source of variation in estimates of phylogenetic community structure.