Usuki Toyonobu

With a number of biologically active members, 2‐aroylchromones are valuable synthetic targets. A direct route towards 2‐aroylchromones from 2‐(methylsulfonyl)chromones and aldehydes via NHC‐catalyzed C‐C bond formation was developed. Yields of the synthesized 2‐aroylchromones were up to 85%. Chromones with angioprotective or antibacterial properties were easily synthesized using the method developed. Additionally, the synthetic utility of the afforded chromones was demonstrated by using them to synthesize the anticancer compound wrightiadione and analogues of it.

ABSTRACT This study examined the synthesis of silver nanoparticles (SNPs) with aqueous extracts of Cyclosorus dentatus and Nephrolepis biserrata fronds and the evaluation of their biological activities. Mixing of AgNO₃ solution and the aqueous extracts resulted in color change, indicating the formation of SNPs. UV‐Vis spectroscopy analysis gave a surface plasmon resonance (SPR) peak at approximately 420 nm, confirming the presence of the synthesized SNPs. Infrared analysis showed C‐O, N‐O, and C‐C vibrations or stretching and aliphatic vibrations of hydrocarbon chains of the synthesized SNPs. x‐Ray diffraction (XRD) analysis indicated the SNPs were face‐centered, cubic, and crystalline in nature, with crystallite sizes. The scanning electron microscopy (SEM) shows the aggregation of the spherical shape nanoparticles. The SNPs significantly reduced phosphomolybdenum and captured H₂O₂ with respective IC₅₀ values of 61.55 and 29.03 µg/mL for C. dentatus SNP (SNP‐Cd), and 92.61 and 9.07 µg/mL for N. biserrata SNP (SNP‐Nb), respectively. In terms of albumin‐denaturing activity, the SNPs gave an IC₅₀ value of 21.20 µg/mL for SNP‐Cd and 7.18 µg/mL for SNP‐Nb. Thus, this work confirmed that SNP‐Cd and SNP‐Nb are potential therapeutic agents for treating oxidative stress, inflammatory problems, and related diseases.

The leaves of Odontonema strictum, a tropical plant used for its antihypertensive properties, are rich in nutrients and biologically active phytochemicals, such as β-sitosterol, stigmasterol, umuravumbolide, deacetylumuravumbolide, dideacetylboronolide, deacetylboronolide, verbascoside, and isoverbascoside. In addition, its roots are rich in β-sitosterol, stigmasterol, and the iridoid glycoside β-O-methyl-unedoside. Ingestion of the roots was reported to have a sedative effect in a dog was previously reported on a dog eating the roots of this plant. In the present study, we report for the first time the cell proliferation- and neurite outgrowth-promoting effects in PC12 neuronal cells of the isolated organic compounds and crude extracts from O. strictum. Pituitary adenylate cyclase-activating peptide (PACAP) and quercetin were used as positive controls. At the concentration of 0.2 μg/mL, β-sitosterol was more potent than quercetin and displayed the same activity (>45 μm/cell) as PACAP (100 nM). At a low concentration (0.04 μg/mL), verbascoside and isoverbascoside showed the strongest neurite outgrowth-promoting effect (neurite length of 30 to 35 μm/cell). Our results indicate that phytomedicines made from O. strictum may be useful in preventing neurodegenerative diseases.

Jamaicamide B was isolated from the cyanobacterium Moorea producens in Jamaica and shows neurotoxicity. Herein we report the first total synthesis and structural confirmation of the marine natural product (9R)-jamaicamide B.