Two new tirucallane triterpenoids from Aphanamixis grandifolia

Two new tirucallane triterpenoids,2a-ethoxy-2,3-secotirucalla-2,29-epoxy-7-ene-23-oxo-3-oic acid(1)and(23E)-2a-hydroxytirucalla-7,23,25-triene-3-one(2),along with the known 2,3-secotirucalla-2,3;2,29-diepoxy-7-ene-3,23-dione(3),were isolated from the leaves and twigs of Aphanamixis grandifolia.Their structures were elucidated by extensive NMR and MS data,and compound 3 was further confirmed by X-ray crystal diffraction analysis.Antimicrobial activities and insecticidal activities of these three compounds were also evaluated.Compound 1 showed good antimicrobial activity against Staphylococcus aureus with the MIC value of 1.56μg/mL,while compounds 1 and 2 showed insecticidal activity at 100 ppm,with the corrected mortality 79.1%and 60.6%,respectively.

Limonoids and triterpenoids from the twigs and leaves of Dysoxylum hainanense

Four new limonoids,dysohainanins A-D(1-4),and two new triterpenoids,dysohainanins E and F(5 and 6),together with seven known ones were isolated from the twigs and leaves of Dysoxylum hainanense Merr.The structures of the new compounds were determined by a variety of spectroscopic methods.The cytotoxic activities of these compounds were evaluated,and the known compound ent-19-nor-4,16,18-trihydroxy-8(14)-pomaren-15-one(13)showed in vitro cytotoxicity against HL-60,A-549,MCF-7,and SW480 cells,with IC50 values of 24.3,28.1,30.7,and 22.5mM,respectively.Compounds 2 and 3 were tested their insecticidal activities using brine shrimp and both of them were inactive.

Mulberry Diels-Alder-type adducts:isolation,structure,bioactivity,and synthesis

Mulberry Diels-Alder-type adducts(MDAAs)are unique phenolic natural products biosynthetically derived from the intermolecular[4+2]-cycloaddition of dienophiles(mainly chalcones)and dehydroprenylphenol dienes,which are exclusively distributed in moraceous plants.A total of 166 MDAAs with diverse skeletons have been isolated and identified since 1980.Structurally,the classic MDAAs characterized by the chalcone-skeleton dienophiles can be divided into eight groups(Types A−H),while others with non-chalcone dienophiles or some variations of classic MDAAs are non-classic MDAAs(Type I).These compounds have attracted significant attention of natural products and synthetic chemists due to their complex architectures,remarkable biological activities,and synthetic challenges.The present review provides a comprehensive summary of the structural properties,bioactivities,and syntheses of MDAAs.Cited references were collected between 1980 and 2021 from the SciFinder,Web of Science,and China National Knowledge Internet(CNKI).

Discovery of a highly potent and orally available importin-β1 inhibitor that overcomes enzalutamide-resistance in advanced prostate cancer

Nuclear transporter importin-β1 is emerging as an attractive target by virtue of its prevalence in many cancers.However,the lack of druggable inhibitors restricts its therapeutic proof of concept.In the present work,we optimized a natural importin-β1 inhibitor DD1 to afford an improved analog DD1-Br with better tolerability(>25 folds)and oral bioavailability.DD1-Br inhibited the survival of castration-resistant prostate cancer(CRPC)cells with sub-nanomolar potency and completely prevented tumor growth in resistant CRPC models both in monotherapy(0.5 mg/kg)and in enzalutamidecombination therapy.Mechanistic study revealed that by targeting importin-β1,DD1-Br markedly inhibited the nuclear accumulation of multiple CRPC drivers,particularly AR-V7,a main contributor to enzalutamide resistance,leading to the integral suppression of downstream oncogenic signaling.This study provides a promising lead for CRPC and demonstrates the potential of overcoming drug resistance in advanced CRPC via targeting importin-β1.

Acid condensation and heat transfer characteristics on H-type fin surface with bleeding dimples and longitudinal vortex generators

Acid condensation rate is an important factor denoting the acid corrosion, and the reduction of the acid condensation can significantly relieve the acid corrosive effect on the wall surface and improve the security of the equipments. In this study, the characteristics of both heat transfer and acid condensation of the finned tube in heat exchanger were numerically studied. In the numerical model, we simulated the acid condensation by considering the vapor–liquid equilibrium effect and multi-component diffusion effect. Based on the H-type finned oval tube, we proposed three novel types of fins to both enhance the heat transfer and reduce the acid condensation. The parametric effects of gas temperature, acid vapor concentration, water vapor concentration, and Reynolds number were investigated on different fin structures. The results show that the tube bank with the new structured fins can improve the performance on both heat transfer and acid anticondensation.

Euphorstranoids A and B,two highly rearranged ingenane diterpenoids from Euphorbia stracheyi:structural elucidation,chemical transformation,and lipid-lowering activity

Euphorstranoids A(1)and B(2),two highly rearranged ingenane diterpenoids with an unusual 5/6/7/3 carbon ring system,were isolated from Euphorbia stracheyi.Their structures were determined by a combination of spectral,chemical,and X-ray diffraction methods.The plausible biosynthetic pathway of 1 and 2 was proposed and chemically mimicked.Compounds 1 and 2 significantly inhibited the triglyceride(TG)level in 3T3-L1 adipocytes via retarding cell adipogenesis at the early stage.