Chemical investigation of the lichen Parmotrema tsavoense led to the isolation of 5 new depsidones, parmosidones F – J (1 – 5). These compounds were structurally elucidated using spectroscopic methods including HRESIMS and 2D NMR data. Compounds 1, 3, and 4 were evaluated for their inhibition of α-glucosidase. All exhibited potent α-glucosidase inhibitory activity with IC50 values ranging from 10.7 to 17.6 µM, which was much lower than that of the positive control acarbose (IC50 449 µM).

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Phytochemical analysis of Euphorbia antiquorum stem extracts afforded two new ent-atisane compounds, ent-3α-acetoxy-16β,17,18-trihydroxyatisane (1) and ent-3α,14,16β,17-tetrahydroxyatisane (2) together with three known compounds, 20-deoxy-16-hydroxyingenol (3), ent-14[S],16α,17trihydroxyatisan-3-one (4), and agallochaol C (5). Their structures were elucidated by spectroscopic data analysis and comparison with published NMR data. Compounds 1-5 were evaluated for α-glucosidase inhibition and cytotoxicity. Compounds 1, 4, and 5 revealed significant inhibitory activity against α-glucosidase with the IC 50 values of 119.9, 135.5, and 134.3 µM, respectively. None showed activity in cytotoxicity assay.

A new ent-atisane diterpenoid, ent-3-acetoxy-1,16,17-trihydroxyatisane (1), along with four known compounds, 3,3′,4′-tri-O-methylellagic acid (2), (R)-(+)-lasiodiplodin (3), taraxerol (4), and syringic acid (5) were isolated from the aerial parts of Euphorbia antiquorum L. The structure of compound 1 was identified by interpretation of their spectroscopic data and comparison with those reported in the literature.

Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16β,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16β,17-acetonide (3), ent-3α-acetoxy-16β,17-dihydroxyatisane (4), ent-16β,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive.

Plant-derived coagulants have exhibited a good potential in wastewater treatment due to their “green” characteristics, high coagulating-flocculating activity, cost-effectiveness, and biodegradability. Nevertheless, research studies have focused mainly on bench-scale experiments; pilot-scale and full-scale simulations are still limited. Herein, we firstly report a pilot-scale study of real domestic textile wastewater treatment using Cassia fistula coagulant. The material characterizations using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and dynamic light scattering (DLS) revealed that the natural gum extracted from C. fistula seed possessed a rough and irregular surface containing a high molecular weight galactomannan. The bench-scale investigation was initially conducted to determine the optimal pollutant concentration, initial pH, and coagulant dosage in the coagulation-flocculation process. The pilot-scale study revealed that C. fistula coagulant is an effective material for real textile wastewater treatment, showing percentage removal of 93.83% at a volume of 30 L and a coagulant dosage of 1.17 mg·L−1. Coagulation-flocculation using C. fistula seed gum could be an efficient primary wastewater treatment prior to membrane or biological methods to meet Vietnamese environmental standards. The main mechanisms of textile wastewater treatment involve adsorption/bridging interactions via hydrogen bonding and electrostatic attraction between negatively charged carboxylate groups of the coagulant and positively charged pollutants.

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