Dang Ngoc Quang

Four iridoid glycosides, 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester (1), 6-O-p-methoxy-trans-cinnamoyl-8-O-acetylshanzhiside methyl ester (2), 6-O-cis-p-coumaroylshanzhiside methyl ester (3), and ipolamiide (4) have been purified and structurally elucidated from Barleria lupulina Lindl. (Acanthaceae) collected in Luang Namtha province, Laos. Compound 1, at a concentration of 128 μg/mL, inhibited the growth of the A549 cancer cell line by 31% and nitric oxide production in RAW 264.7 cells by 30%. This is the first report on the chemical constituents of Lao’s Barleria lupulina.

Six phenylethanoid glycosides, acetylmartynoside A (1), martynoside (2), 3-O-methylpoliumoside (3), isoaceteoside (4), leucosceptoside A (5), 2-(3-hydroxy-4-methoxyphenyl)-ethyl-O-(α-l-rhamnosyl)-(1→3)-O-(α-l-rhamnos-yl)-(1→6)-4-O-E-feruloyl-β-d-glucopyranoside (6) were isolated for the first time from the whole plant of Barleria prionitis Linn. Their structures were elucidated by 1D and 2D NMR and mass spectra. In addition, the antioxidant activity of compounds 1-6 was investigated. All of the compounds showed Keap1 protein inhibitory effects with estimated binding affinities in the range of –9.639 to –9.084 kcal/mol by molecular docking and moderate DPPH free radical scavenging activity with their IC50 values in the range of 110–389 μM. Furthermore, the predicted toxicity results of all six compounds 1–6 indicated a level of 5 and a high LD50 value (LD50 = 5000 mg/kg), which showed low toxicity and high safety for oral consumption in humans.

Curcuma longa is only a rich source of curcumin (1) and its major analogues demethoxycurcumin (2) and bisdemethoxycurcumin (3) among the Curcuma species. The content ratio of these three curcumins in turmeric is depended on the varieties and growing environment. Recently, curcumin (1) has been reported as potential inhibitor of hepatic and enzymatic protein tyrosine phosphatase 1B (PTP1B) and its related disorders such as hypertriglyceridemia, hyperlipidemia and liver steatosis. Thus, we further purified curcumins (1–3) from C. longa and investigated their inhibitory effects against PTP1B and α-glucosidase enzymes. As the result, curcumins (1–3) exhibited potential PTP1B inhibition with IC50 values of 37.8 ± 1.4, 45.3 ± 0.7, and 72.6 ± 1.1 μM, respectively, and α-glucosidase inhibition with similar manner (IC50 values of 78.2 ± 0.2, 82.4 ± 0.6, and 90.6 ± 1.0 μM, respectively). These results reveal a key role of methoxylation in the variation of PTP1B and α-glucosidase inhibitory activity for these curcumins. In addition, density functional theory (DFT) was used accompanying with molecular docking (MD) to analyze the ligand stability and the interaction of curcumins (1–3) with PTP1B and glucoside hydrolase proteins. Assay-based results and the MD data obtained are highly correlation suggesting that the deterioration of the enzyme activity caused by the distortion of structural conformation of PTP1B and glucoside hydrolase may be related to the arrangement of amino acids in protein structure. This reported for the first time that inhibitory effects of curcumins (1–3) against PTP1B and glucoside hydrolase have been examined in vitro and in silico as well.

Two new lanostane triterpnenoids named endertiins A and B (1 and 2) together with two known compounds as ganodecalone A (3) and ergosterol (4) have been successfully isolated from the cultivated fruit bodies of the mushroom Humphreya endertii Stey (Ganodermataceae). Their structures were elucidated by a combination of HR-MS and 2 D NMR spectroscopic analyses. In addition, endertiins A and B (1 and 2) were evaluated their cytotoxicity against two cancer cell lines, MCF7 (human breast carcinoma) and LU (human lung carcinoma). The result showed that endertiin A (1) could inhibit the growth of MCF-7 cells with its IC₅₀ value of 71.16 ± 6.25 µg/ml. Graphical Abstract

Five fungal secondary metabolites named 1,2,4,5-tetrachloro-3,6-dimethoxybenzene (1); ergosterol (2); ergosterol peroxide (3); (E)- 4-(3,4-dihydroxyphenyl)but-3-en-2-one (4) and [Bi-1,4-cyclohexandien-1-yl]-3,3’,6,6’-tetrone, 4, 4’-dihydroxyl-2,2’,5,5’-tetramethyl (5) were purified from ethyl acetate extract of the fruit bodies of Phellinus gilvus collected at Pu Mat national park, Nghe An province. Their structures were charaterized by 1D, 2D NMR and GC-MS spectroscopies. Especially, the structure of compound 1 was confirmed by X-ray crystallographic analysis. The antimicrobial and cytotoxicity activities of compounds 1 were also evaluated. This is the first report on the chemical constituents of Vietnamese Phellinus gilvus.

A new chalcone named as balanochalcone (1) together with eight known compounds, methyl caffeate (2), β-hydroxydihydrochalcone (3), methyl gallate (4), dimethyl-6,9,10-trihydroxybenzo[kl]xanthene-1,2-dicarboxylate (5), p-coumaric acid (6), quercetin (7), scopoletin (8) and pinoresinol (9) have been isolated from the ethyl acetate extract of Vietnamese Balanophora laxiflora Hemsl. Their structures were characterised by IR, UV, HR-ESI-MS, 1D and 2D NMR and CD spectroscopies. Compounds 2 and 5 showed moderate cytotoxicity against four cancer cell lines, KB (a human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma) and HepG2 (hepatocellular carcinoma). In addition, compounds 1 and 5 showed moderate antioxidant activity.