Dynamics of annatto pigment synthesis and accumulation in seeds of Bixa orellana L. revealed by integrated chemical, anatomical, and RNA-Seq analyses.

Bixin is a commercially valuable apocarotenoid pigment found in the seed aril of Bixa orellana. The dynamics and regulation of its biosynthesis and accumulation during seed development remain largely unknown. Here, we combined chemical, anatomical, and transcriptomic data to provide stage-specific resolution of the cellular and molecular events occurring during B. orellana seed development. Seeds at five developmental stages (S1-S5) were used for analysis of bixin content and seed anatomy, and three of them (S1, S3, and S4) were selected for Illumina HiSeq sequencing. Bixin accumulated in large quantities in seeds compared with other tissues analyzed, particularly during the S2 stage, peaking at the S4 stage, and then decreasing slightly in the S5 stage. Anatomical analysis revealed that bixin accumulated in the large central vacuole of specialized cells, which were scattered throughout the developing mesotesta at the S2 stage, but enlarged progressively at later stages, until they occupied most of the parenchyma in the aril. A total of 13 million reads were generated and assembled into 73,381 protein-encoding contigs, from which 312 were identified as containing 1-deoxy-D-xylulose-5-phosphate/2-C-methyl-D-erythritol-4-phosphate (DOXP/MEP), carotenoid, and bixin pathways genes. Differential transcriptome expression analysis of these genes revealed that 50 of them were sequentially and differentially expressed through the seed developmental stages analyzed, including seven carotenoid cleavage dioxygenases, eight aldehyde dehydrogenases, and 22 methyltransferases. Taken together, these results show that bixin synthesis and accumulation in seeds of B. orellana are a developmentally regulated process involving the coordinated expression of DOXP/MEP, carotenoid, and bixin biosynthesis genes.

In silico, in vitro and in vivo studies indicate resveratrol analogue as a potential alternative for neuroinflammatory disorders.

Inflammaging is known as an imbalance between pro-inflammatory and anti-inflammatory immune mechanisms, being related to the onset of neurological disorders, such as major depression and Alzheimer's disease. Considering the known disadvantages regarding the FDA approved drug to manage such illnesses, resveratrol emerges as a natural drug candidate, despite its low bioavailability. In this study, resveratrol analogues were evaluated for their capacity of inhibiting acetylcholinesterase in silico, in vitro, and in vivo. Molecular docking simulations pointed out RSVA1 and RSVA6 as potent inhibitors, even more than resveratrol. Ellman's assay demonstrated RSVA6 as capable of inhibiting 92.4% of the enzyme activity. Further, male Swiss mice were pretreated with RSVA6 (100 mg kg-1) 60 min before receiving scopolamine (1 mg kg-1). The Novel Recognition Object (NOR), Object Location (OLT), and Buried Pellet tests (BPL) demonstrated an RSVA6 neuroprotective effect. In the second round of tests, mice received a single intraperitoneal injection of lipopolysaccharide (0.5 mg kg-1) 24 h before treatment with RSVA6 (1, 10, and 100 mg kg-1). The Open Field (OFT), Tail Suspension (TST), and Splash tests (ST) were evaluated. LPS had no significant effect on the crossing and rearing number, indicating an association between the immobility time and anhedonia observed in the TST and ST, respectively, with depressive-like behavior. RSVA6 significantly reduced the depressive-like behavior triggered by LPS in the TST and ST. Altogether, our data suggest RSVA6 as a potential drug candidate for the treatment of neuroinflammatory conditions.