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The new natural products reported in 2019 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2019 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification. [ABSTRACT FROM AUTHOR]

Phytochemical investigation on the stems of Schisandra glaucescens resulted into the isolation of three new lanostane triterpenoids, 12-hydroxyschiglausin B (1), 12-hydroxykadsuphilactone B (2), and 20R-hydroxyschinalactone C (3). Structural elucidation of all the compounds was accomplished by spectral methods. The isolated compounds were tested in vitro for cytotoxic activities. As a result, triterpenoids 1 and 2 showed cytotoxic activities for all six tested tumor cell lines with IC50 values less than 15 μM. [ABSTRACT FROM AUTHOR]

Our current natural product program researches the second metabolites of a fungus Penicilliumcrustosum YN-HT-15 isolated from the red soil (Yunnan Province, China), to discover potential antitumor chemical entities. Two new compounds were isolated from the ethyl acetate extract of the fermentation broth of the fungus, and their structures were characterized as 1-(2′,4′-dihydroxy-5′-methyl-3′-methylsulfanylmethyl-phenyl)-ethanone (1) and R-3-(3′-acetyl-2′,6′-dihydroxy-5′-methylphenyl)-2-methyl-propionic acid methyl ester (2) on the basis of spectroscopic data. [ABSTRACT FROM AUTHOR]

A new polyoxygenated cyclohexene bonianol A (1) and another new polyoxygenated seco-cyclohexene bonianol B (2) were isolated from the leaves of Uvaria boniana, and their structures were established on the basis of spectroscopic methods including IR, HR-ESI-MS, 1D, and 2D NMR. [ABSTRACT FROM AUTHOR]

Two new C28 sterols with a cyclopentane ring at C-22 and 26, alkesterol A (1) and alkesterol B (2), along with β-sitosterol (3), were isolated from the berries of Physalis pubeacens L. (cape gooseberry). The structures of the new compounds were established by HR-EI-MS, 1D and 2D (1H-1H COSY, HSQC, HMBC) NMR experiments. The known compound was identified by comparison of spectral data with published references. The two new compounds showed some cytotoxic activities by MTT assay. [ABSTRACT FROM AUTHOR]

Eight new iridoids (1–8) and an ionone glucoside (9), together with 31 known compounds (10–40), were isolated from the whole plants of Rehmannia henryi. The structures of these compounds were elucidated on the basis of their spectroscopic data and chemical evidence. [ABSTRACT FROM AUTHOR]

Two new triterpenoid saponins, oleiferoside N and oleiferoside O, were isolated from the EtOH extract from the roots ofCamellia oleiferaC. Abel. Their structures were elucidated as 16α-acetoxy-21β,22α-O-diangeloyloxy-23,28-dihydroxyolean-12-ene 3β-O-β-d-xylopyranosyl-(1 → 3)-α-l-arabinopyranosyl-(1 → 3)-β-d-glucuronopyranoside (1), 16α-acetoxy-21β-O-angeloyloxy-23,28-dihydroxy-22α-O-(2-methylbutanoyloxy)olean-12-ene 3β-O-β-d-xylopyranosyl-(1 → 3)-α-l-arabinopyranosyl-(1 → 3)-β-d-glucuronopyranoside (2), on the basis of spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR) and acid hydrolysis. Both were characterized to be oleanane-type saponins with sugar moieties linked to C-3 of the aglycone. Cytotoxic activities of two saponins were evaluated against four human tumor cell lines (A549, B16, BEL-7402, and MCF-7) by using the MTTin vitroassay. Compounds1and2showed moderate cytotoxic activities toward the tested cell lines. [ABSTRACT FROM PUBLISHER]

Camellia oleifera C. Abel has been widely cultivated in China, and a group of bioactive constituents such as triterpeniod saponin have been isolated from C. oleifera C. Abel. In the current study, a new triterpeniod saponin was isolated from the EtOH extract of the roots of C. oleifera C. Abel, named as oleiferoside W, and the cytotoxic properties of oleiferoside W were evaluated in non-small cell lung cancer A549 cells. At the same time the inducing apoptosis, the depolarization of mitochondrial membrane potential (Δψ), the up-regulation of related pro-apoptotic proteins, such as cleaved-PARP, cleaved-caspase-3, and the down-regulation of anti-apoptotic marker Bcl-2/Bax were measured on oleiferoside W. Furthermore, the function, inducing the generation of reactive oxygen species (ROS) and apoptosis, of oleiferoside W could be reversed by N-acetylcysteine (NAC). In conclusion, our findings showed that oleiferoside W induced apoptosis involving mitochondrial pathway and increasing intracellular ROS production in the A549 cells, suggesting that oleiferoside W may have the possibility to be a useful anticancer agent for therapy in lung cancer. [ABSTRACT FROM AUTHOR]

The combination of gemcitabine (Gem), busulfan (Bu), and melphalan (Mel) is a promising regimen for autologous stem-cell transplantation (SCT) for lymphomas. To further improve the efficacy of [Gem + Bu + Mel], we added poly(ADP-ribose) polymerase (PARP) inhibitor olaparib (Ola). We hypothesized that Ola would inhibit the repair of damaged DNA caused by [Gem + Bu + Mel]. Exposure of J45.01 and Toledo cell lines to IC10–20 of individual drug inhibited proliferation by 6–16%; [Gem + Bu + Mel] by 20–27%; and [Gem + Bu + Mel + Ola] by 61–67%. The synergistic cytotoxicity of the four-drug combination may be attributed to activation of the DNA-damage response, inhibition of PARP activity and DNA repair, decreased mitochondrial membrane potential, increased production of reactive oxygen species, and activation of the SAPK/JNK stress signaling pathway, all of which may enhance apoptosis. Similar observations were obtained using mononuclear cells isolated from patients with T-cell lymphocytic leukemia. Our results provide a rationale for undertaking clinical trials of this drug combination for lymphoma patients undergoing SCT. [ABSTRACT FROM AUTHOR]