YZL-51N functions as a selective inhibitor of SIRT7 by NAD+ competition to impede DNA damage repair.

The NAD+-dependent deacetylase SIRT7 is a pivotal regulator of DNA damage response (DDR) and a promising drug target for developing cancer therapeutics. However, limited progress has been made in SIRT7 modulator discovery. Here, we applied peptide-based deacetylase platforms for SIRT7 enzymatic evaluation and successfully identified a potent SIRT7 inhibitor YZL-51N. We initially isolated bioactive YZL-51N from cockroach (Periplaneta americana) extracts and then developed the de novo synthesis of this compound. Further investigation revealed that YZL-51N impaired SIRT7 enzymatic activities through occupation of the NAD+ binding pocket. YZL-51N attenuated DNA damage repair induced by ionizing radiation (IR) in colorectal cancer cells and exhibited a synergistic anticancer effect when used in combination with etoposide. Overall, our study not only identified YZL-51N as a selective SIRT7 inhibitor from insect resources, but also confirmed its potential use in combined chemo-radiotherapy by interfering in the DNA damage repair process.

Structurally Diverse Alkaloids with Anti-Renal-Fibrosis Activity from the Centipede Scolopendra subspinipes mutilans.

Twelve new alkaloids, scolopenolines A-L (1-7, 9-11, 13, 14), along with six known analogues, were isolated from Scolopendra subspinipes mutilans, identified by analysis of spectroscopic data and quantum chemical and computational methods. Scolopenoline A (1), a unique guanidyl-containing C14 quinoline alkaloid, features a 6/6/5 ring backbone. Scolopenoline B (2) is a novel sulfonyl-containing heterodimer comprising quinoline and tyramine moieties. Scolopenoline G (7) presents a rare C12 quinoline skeleton with a 6/6/5 ring system. Alkaloids 1, 8, 10, and 15-18 display anti-inflammatory activity, while 10 and 16-18 also exhibit anti-renal-fibrosis activity. Drug affinity responsive target stability and RNA-interference assays show that Lamp2 might be a potentially important target protein of 16 for anti-renal-fibrosis activity.

Isolation and target identification of anti-renal fibrosis compounds from Cordyceps militaris.

Four undescribed compounds including one aromatic glucoside derivative, cordyceglycoside A (1), one new isoleucine derivative inner salt, cordycepisosalt A (2), a rare four-membered lactam, cinerealactam B (3), and one sesquiterpene derivative, cordycepsetp A (4), together with six known compounds were isolated from Cordyceps militaris. The structures including absolute configurations of these new compounds, were unambiguously elucidated by spectroscopic data analysis and single crystal X-ray diffraction. Biological evaluation of compounds 1-4 showed that 3 displays anti-renal fibrotic activities in TGF-ß1 induced NRK-52e cells. Furthermore, DARTS coupled with LC-MS/MS analysis was used to identify candidate target proteins for 3. Subsequently, C1qbp knockdown using siRNA allowed us to validate the target protein of 3.

Eight new 2-(2-phenylethyl)chromone derivatives from agarwood of Aquilaria sinensis with anti-inflammatory activity.

Eight previously unknown 2-(2-phenylethyl)chromone derivatives, called aquichromones A - E (1-3, 5 and 6) and 8-epi-aquichromone C (4), including two pairs of enantiomers [(±)-1 and (±)-2] were isolated from the agarwood of Aquilaria sinensis. The structures and absolute stereochemistry of these natural products were elucidated by using spectroscopic and computational methods. The result of biological assay showed that two members of this group, 4 and 5, have significant dose-dependent anti-inflammatory activity.

Retro-dihydrochalcones from the resin of Daemonorops draco and their inhibitory activities against renal fibrosis.

Daedracoflavan A-E (1-5), five new flavonoids were isolated from the resin of Daemonorops draco. Their structures including absolute configurations were established by using spectroscopic and computational methods. All the compounds are new chalcones with the same retro-dihydrochalcone skeleton. Compound 1 features the presence of a cyclohexadienone unit originating from a benzene ring, and the ketone group of C-9 reduced to a hydroxyl group. The bioactivity of all isolated compounds was evaluated in kidney fibrosis and found that compound 2 could dose-dependently inhibit the expression of fibronectin, collagen I, and α-SMA in TGF-ß1-induced rat kidney proximal tubular cells (NRK-52E). Interestingly, the replacement of a proton by a hydroxyl group at C-4' seems to play a crucial role in anti-renal fibrosis activity.