Design, synthesis and biological evaluation of bakuchiol derivatives as multi-target agents for the treatment of Alzheimer's disease.

The concept of multi-target-directed ligands offers fresh perspectives for the creation of brand-new Alzheimer's disease medications. To explore their potential as multi-targeted anti-Alzheimer's drugs, eighteen new bakuchiol derivatives were designed, synthesized, and evaluated. The structures of the new compounds were elucidated by IR, NMR, and HRMS. Eighteen compounds were assayed for acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in vitro using Ellman's method. It was shown that most of the compounds inhibited AChE and BuChE to varying degrees, but the inhibitory effect on AChE was relatively strong, with fourteen compounds showing inhibition of >50% at the concentration of 200 µM. Among them, compound 3g (IC50 = 32.07 ± 2.00 µM) and compound 3n (IC50 = 34.78 ± 0.34 µM) showed potent AChE inhibitory activities. Molecular docking studies and molecular dynamics simulation showed that compound 3g interacts with key amino acids at the catalytically active site (CAS) and peripheral anionic site (PAS) of acetylcholinesterase and binds stably to acetylcholinesterase. On the other hand, compounds 3n and 3q significantly reduced the pro-inflammatory cytokines TNF-α and IL-6 released from LPS-induced RAW 264.7 macrophages. Compound 3n possessed both anti-acetylcholinesterase activity and anti-inflammatory properties. Therefore, an in-depth study of compound 3n is expected to be a multi-targeted anti-AD drug.

Phylotranscriptomic analyses reveal deep gene tree discordance in Camellia (Theaceae).

Gene tree discordance is a significant legacy of biological evolution. Multiple factors can result in incongruence among genes, such as introgression, incomplete lineage sorting (ILS), gene duplication or loss. Resolving the background of gene tree discordance is a critical way to uncover the process of species diversification. Camellia, the largest genus in Theaceae, has controversial taxonomy and systematics due in part to a complex evolutionary history. We used 60 transcriptomes of 55 species, which represented 15 sections of Camellia to investigate its phylogeny and the possible causes of gene tree discordance. We conducted gene tree discordance analysis based on 1,617 orthologous low-copy nuclear genes, primarily using coalescent species trees and polytomy tests to distinguish hard and soft conflict. A selective pressure analysis was also performed to assess the impact of selection on phylogenetic topology reconstruction. Our results detected different levels of gene tree discordance in the backbone of Camellia, and recovered rapid diversification as one of the possible causes of gene tree discordance. Furthermore, we confirmed that none of the currently proposed sections of Camellia was monophyletic. Comparisons among datasets partitioned under different selective pressure regimes showed that integrating all orthologous genes provided the best phylogenetic resolution of the species tree of Camellia. The findings of this study reveal rapid diversification as a major source of gene tree discordance in Camellia and will facilitate future investigation of reticulate relationships at the species level in this important plant genus.

The complete chloroplast genome sequence of Camellia rostrata S. X. Yang & S. F. Chai (Theaceae), a critically endangered yellow camellia from southwest China.

Camellia rostrata S. X. Yang & S. F. Chai is a recently described yellow camellia species from Guangxi, China. It is a critically endangered species according to the IUCN Red List Categories and Criteria. Here, we report the complete chloroplast (cp) genome based on next-generation sequencing technology. The complete cp genome of C. rostrata is 156,547 bp in length and consists of a large single-copy (LSC, 86,199 bp) region, a small single-copy (SSC, 18,204 bp) region, and a pair of inverted repeats (IRs, 26,072 bp). The genome contains 135 genes including 40 tRNA, eight rRNA, and 87 protein-coding genes. Phylogenetic analysis resolved C. rostrata in a clade containing C. huana and C. impressinervis, both of which are classified to Camellia sect. Archecamellia. Our findings support the placement of C. rostrata in C. sect. Archecamellia as proposed by a previous study. The cp genome of C. rostrata provides valuable bioinformatic resources for the protection and utilization of this yellow camellia species.

Two P5CS genes from common bean exhibiting different tolerance to salt stress in transgenic Arabidopsis.

Many plants accumulate proline in response to salt stress. Δ-pyrroline-5-carboxylate synthetase (P5CS) is the rate-limiting enzyme in proline biosynthesis in plants. Plasmid DNA (pCHF3-PvP5CS1 and pCHF3-PvP5CS2) containing the selectable neomycin phosphotransferase gene for kanamycin resistance and Phaseolus vulgaris P5CS (PvP5CS1 and PvP5CS2) cDNA was introduced into Arabidopsis plants using Agrobacterium-mediated gene transfer. Southern blot, northern blot and RT-PCR analyses demonstrated that the foreign genes were integrated into Arabidopsis chromosomal DNA and expressed. Single-gene transformants were analysed in this study. Transgenic plants expressed higher levels of PvP5CS1 and PvP5CS2 transcripts under salt stress conditions than under normal conditions. When treated with 0, 100 and 200 mM NaCl, the average proline content in leaves of transgenic plants was significantly higher (P < 0.01) than control plants. The average relative electrical conductivity (REC) of transgenic lines was significantly lower (P < 0.01) than control plants under salt stress condition. Biomass production of transgenic lines was significantly higher (P < 0.05) than control plants under 200 mM NaCl stress treatment. These results indicated that introducing PvP5CS1 and PvP5CS2 cDNA into transgenic Arabidopsis caused proline overproduction, increasing salt tolerance. Although the expression of PvP5CS1 in L4 lines and PvP5CS2 in S4 lines was the same under salt stress condition, the S4 lines accumulated 1.6 and 1.9 times more proline than the L4 lines under 100 and 200 mM NaCl treatments, respectively. The REC of S4 plants was 0.5 (100 mM NaCl) and 0.6 times (200 mM NaCl) that of L4 plants. The biomass production of S4 plants was 1.6 times (200 mM NaCl) more than in L4 plants. Total P5CS enzyme activity of S4 was significantly higher than that of L4. These results implied that the PvP5CS2 protein had stronger capacity to catalyze proline synthesis than PvP5CS1 under salt stress condition.