Nobiletin, a citrus flavonoid has been associated with various beneficial biological activities. 4′-Demethylnobiletin (4DN) is a major metabolite of nobiletin and its tissue level was found to be much higher than that of nobiletin after oral administration of nobiletin in mice. Anti-inflammatory effects of 4DN were studied in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. The results showed 4DN not only dose-dependently inhibited LPS-induced nitric oxide production, but also significantly reduced expression of pro-inflammatory mediators, namely PGE2, IL-1β and IL-6. 4DN potently suppressed the expression of iNOS and COX-2 at both protein and mRNA levels. 4DN also inhibited nuclear translocation of NF-κB and AP-1. Furthermore, we demonstrated that 4DN activated transcription factor Nrf2 and its dependent genes including HO-1 and NQO1 whose expression may contribute to anti-inflammatory effects. The results demonstrated anti-inflammatory effects of 4DN and provided a scientific basis for using nobiletin as a nutraceutical to inhibit inflammation–driven diseases.

MicroRNA (miRNA) acts as a critical regulator of gene expression at post-transcriptional and occasionally transcriptional levels in plants. Identification of reliable miRNA genes, monitoring the procedures of transcription, processing and maturation of the miRNAs, quantification of the accumulation levels of the miRNAs in specific biological samples, and validation of miRNA–target interactions become the basis for thoroughly understanding of the miRNA-mediated regulatory networks and the underlying mechanisms. Great progresses have been achieved for sequencing technology. Based on the high degree of sequencing depth and coverage, the high-throughput sequencing (HTS, also called next-generation sequencing) technology provides unprecedentedly efficient way for genome-wide or transcriptome-wide studies. In this review, we will introduce several HTS platform-based methods useful for plant miRNA research, including RNA-seq (RNA sequencing), RNA-PET-seq (paired end tag sequencing of RNAs), sRNA-seq (small RNA sequencing), dsRNA-seq (double-stranded RNA sequencing), ssRNA-seq (single-stranded RNA sequencing) and degradome-seq (degradome sequencing). In particular, we will provide some special cases to illustrate the novel use of HTS methods for investigation of the processing modes of the miRNA precursors, identification of the RNA editing sites on miRNA precursors, mature miRNAs and target transcripts, re-examination of the current miRNA registries, and discovery of novel miRNA species and novel miRNA–target interactions. Summarily, we opinioned that integrative use of the above mentioned HTS methods could make the studies on miRNAs more efficient.

Luteolin and sulforaphane are well-known food bioactives with anti-inflammatory properties. In this study, we demonstrated the synergistic interactions between luteolin and sulforaphane against lipopolysaccharide-induced inflammation in macrophages.