Identification and α-glucosidase inhibitory activity evaluation of two new coumarins derived from Mansonia gagei J. R. Drumm.

Five coumarins were isolated from the heartwood of Mansonia gagei, which included two newly discovered compounds, namely 11-hydroxypopulene E (1) and mansorin D (2), along with three previously identified compounds. The structures were determined through the utilisation of comprehensive spectroscopic data, ECD calculations, and a thorough comparison with existing literature data. The α-glucosidase inhibitory activities of all isolated compounds were assessed in yeast. Out of the compounds tested, compound 2 exhibited the most significant activity, displaying a percentage inhibition of 34.33% at a concentration of 200 µM.

Tinctoric acid A-B, two new hopan-type triterpenoids from the Vietnamese lichen, Parmotrema tinctorum (Despr. ex Nyl.) hale with α-glucosidase inhibitory activity.

Two new hopan-type triterpenoids, namely tinctoric acid A-B (1-2), were isolated from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale. Their structures were elucidated by extensive spectroscopic analyses (1D and 2D NMR). The absolute configuration at C-22 of 1 was established through DP4 probability. Compounds 1-2 were evaluated for their inhibitory activity against α-glucosidase and found to be more potent than those of positive control (acarbose, IC50 168 µM) with values IC50 74.7 and 98.2 µM, respectively. Both of these compounds interacted well with enzyme α-glucosidase MAL32 through H-bonds and hydrophobic interaction.

Tinctorin, a new spiroterpenoid from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale growing in Vietnam.

A new spiroterpenoid, namely tinctorin (1), along with one known compound, norreticulatin (2), were isolated from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale. Their structures were elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. The absolute configuration of 2 was established for the first time. Compound 1 was evaluated for its inhibitory activity against α-glucosidase and found to be inactive.

α-Glucosidase inhibition of sesquiterpenoids from the heartwood of Mansonia gagei.

Nine undescribed sesquiterpenoids, along with ten known compounds, were isolated from the ethyl acetate extract of Mansonia gagei heartwood. Their structures were determined by spectroscopic data analysis (FTIR, 1D, 2D NMR, and HRESIMS), and their absolute configurations were established by ECD calculation. The isolated compounds were evaluated for their inhibitory effect against α-glucosidase from yeast. The results showed that mansonone U, mansonialactam, heliclactone and mansonone S exhibited exceptionally potent activities when compared to the positive control, acarbose, with IC50 values of 12.38 ± 0.71, 0.20 ± 0.05, 13.12 ± 2.85, and 12.05 ± 1.91 µM, respectively. Among them, mansonialactam possessed the most potent inhibitory activity against yeast α-glucosidase, and it showed an uncompetitive inhibition mode.

Gagones A-F: Six prenylated chalcones from the heartwood of Mansonia gagei.

Six undescribed prenylated chalcones gagones A-F were isolated from the acetone fraction of Mansonia gagei heartwood. Their structures were unambiguously established based on spectroscopic analysis (HRESIMS, 1D and 2D NMR), as well as comparison to literature data. Their absolute configurations were elucidated using DP4 and electronic circular dichroism calculations. Isolated compounds were evaluated for their inhibitory activity against α-glucosidase and DPPH assay. All of the tested compounds exhibited better activity than that of acarbose (IC50 93.6 ± 0.5 µM). Among them, gagone D exhibited the highest α-glucosidase inhibitory with the IC50 value of 3.6 ± 0.4 µM. For antioxidant activity, gagones A-C, and E showed more active than that of ascorbic acid (IC50 30.2 ± 0.5 µM) with the IC50 values of 13.2 ± 0.7, 20.1 ± 0.4, 19.3 ± 0.5 and 12.8 ± 0.2 µM, respectively.

A new neolignan and a new phenolic acid from the heartwood of Mansonia gagei J.R. Drumm.

One new neolignan (1) and one new phenolic compound (2), together with four known compounds (3-6) were isolated from the heartwood of Mansonia gagei. Their structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR and HRESIMS. The absolute configuration of 2 was established based on the DP4+ protocol and by comparison of experimental and calculated ECD spectra. All isolated compounds were evaluated by DPPH assay for antioxidant activity, while compounds 3-6 were assayed using the MTT-based colorimetric assay for cytotoxicity against lung cancer cell line A549. In terms of antioxidant activity, 1 and 3 exhibited stronger activity (IC50 14.91 ± 1.10 and 17.46 ± 0.16 µM, respectively) than the positive control, ascorbic acid (IC50 30.20 ± 0.47 µM). Among the compounds tested for cytotoxicity, compound 3 showed the highest activity, with an IC50 value of 26.04 ± 2.95 µM.

Impacts of effluent from different livestock farm types (pig, cow, and poultry) on surrounding water quality: a comprehensive assessment using individual parameter evaluation method and water quality indices.

Water pollution within and nearby different livestock farm types was assessed comprehensively for the first time in Vietnam. The samples of wastewater, ground water, and surface water were collected from 130 pig farms, 80 poultry farms, and 40 cow farms. Water quality was first assessed by individual parameter evaluation method in which measured values of water quality parameters were compared with the permissible limits in the national technical regulations on livestock's effluent (QCVN 62), surface water quality, and ground water quality. Subsequently, the overall quality of surface and ground water samples was evaluated by mean of water quality index (WQI). The results showed the large variations in effluent's quality, implying the considerable differences in wastewater treatment efficiency within and among farm types. Effluent from livestock farms was highly polluted by organic matters (expressed as BOD5 and COD) and especially by microorganisms (expressed as total coliform-CF). Almost all wastewater samples contained higher number of CF than QCVN 62 (3900 MPN/100ml), with mean concentration of CF in effluent from cow farms, pig farms, and poultry farms were 1.2e+07 ± 5.0e+07 MPN/100ml, 8.8e+04 ± 7.1e+04 MPN/100ml, 1.5e+06 ± 4.2e+06 MPN/100ml, respectively. Improperly treated livestock's waste was likely to have impacts on quality of ground water and receiving surface water bodies. High CF contamination in effluent leads to 70% of the ground water samples in cow farms and poultry farms classified as unsuitable for drinking water supply by WQI values. Although effluent from poultry farms had smaller quantity and better quality, their receiving surface water bodies exhibited the worst quality, with average WQI of 37.5 ± 16.2 compared to 49.9 ± 12 of pig farms and 50.3 ± 20.8 of cow farms. This result suggests that livestock's effluent was not only pollution source of surface water bodies nearby livestock farms.