Comtrifosides A and B, two new triterpenoid saponins from the leaves of .

The phytochemical composition of the leaves was studied for the first time. Two new triterpenoid saponins, named comtrifoside A () and comtrifoside B (), together with two other saponins () were purified by variously chromatographic techniques. For the first time, compound was informed from the genus, as well as all of the isolated compounds () were reported from .

Indicuen, a new hopane from Hale growing in Vietnam.

One new hopane-type triterpene, indicuen (), along with eight known compounds () were isolated from the -hexane extract of the lichen Hale. The chemical structures of isolated compounds were identified by interpretation of their spectroscopic data (1D, 2D NMR and HRESIMS) combined with DFT-NMR chemical shift calculations and subsequent assignment of DP4+ probabilities and by comparison with the literature. Indicuen represents for a rare hopane bearing a 1-carboxyethyl substituent at C-21 in lichens.

Lasibidoupins A and B, two new compounds from the stems of V.S. Dang & Naiki.

From the stems, two new compounds, including one new 9,10-anthraquinone, lasibidoupin A (), and one new 6,7-benzocoumarin, lasibidoupin B (), together with one known compound, 11--methyldamnacanthol () were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound was reported for the first time from this species.

Cycloartane-type triterpenoids from the whole plants of .

One new cycloartane-type triterpenoid, named macrobidoupoic acid A (as an C-24 epimeric mixture, , ), together with three known ones (-), were clarified by different chromatography from the whole plants. Triterpenoids ( & ) were detected for the first time from the genus. Chemical structures of them were illuminated using HR-ESI-MS, and NMR (1 D & 2 D) assessments.

A new diphenyl ether from Hale growing in Vietnam.

Chemical investigation of the lichen Hale led to the isolation of one new diphenyl ether, parmetherine D (), along with eight known compounds (). The structures were determined by analysis of MS and NMR data and by comparison with the literature. Compounds , , and were evaluated for -glucosidase inhibition.

Paresordin A, a new diphenyl cyclic peroxide from the lichen .

From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (), protocetraric acid (), 8'--methylprotocetraric acid (), and furfuric acid () were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds () possessed stronger -glucosidase inhibitory activity (IC = 43.

Usneaceratins A and B, two new secondary metabolites from the lichen .

Two new compounds, comprising one dibenzofuran, named usneaceratin A (), and one phenolic acid, named usneaceratin B (), together with one known dibenzofuran, isousnic acid (), and two known phenolics, orsellinic acid () and methyl orsellinate () were clarified from the lichen using variously chromatographic methods. Their structures were testified by comprehensive HR-ESI-MS, and NMR spectroscopic analysis, and comparison with published data. Their -glucosidase inhibitory activity of all compounds was measured.

Two new phenolic compounds from the lichen growing in Vietnam.

Two new phenolic compounds, cristiferides A-B () together with six known compounds, 2,4-dihydroxyphthalide (), lecanoric acid (), orsellinic acid (), 5-chloroorsellinic acid (), methyl haematommate (), and methyl β-orsellinate () were isolated from the lichen (Taylor) Hale (Parmeliaceae). The structures of isolated compounds were identified from its spectroscopic data and by comparison with the literatures. Compounds - and were evaluated for alpha-glucosidase inhibition.

Reticulatin, a novel C-spiroterpenoid from the lichen growing in Vietnam.

A novel C-spiroterpenoid, reticulatin (), was isolated from the lichen (Taylor) M. Choisy (Parmeliaceae). Five previously-reported compounds were also isolated: zeorin (), leucotylin (), lupeol (), betulinic acid (), and dihydroreynosin ().

α-Glucosidase Inhibition by Usnic Acid Derivatives.

This study investigated a set of new potential antidiabetes agents. Derivatives of usnic acid were designed and synthesized. These analogs and nineteen benzylidene analogs from a previous study were evaluated for enzyme inhibition of α-glucosidase.

Two new phenolic compounds from the Vietnamese lichen .

Chemical investigation of the lichen (Nyl.) Hale led to the isolation of two new phenolic compounds, 2-ethylhexyl orsellinate () and tinctorinone (). The structures were determined by analysis of their MS and NMR data as well as by comparison with literature data.

Development of a low-cost colorimeter and its application for determination of environmental pollutants.

Herein, a novel colorimeter based on the Beer-Lambert law was designed for detection of environmental pollutants in water with a high precision, simple, and miniaturized device using a tetracycline-Eu complex, cadmium reduction, diazotization, 1,10-phenanthroline, and periodate oxidation. The newly developed colorimeter could detect many environmental pollutants including tetracycline, nitrate, nitrite, Fe, and Mn, which were used to evaluate its performance. Simultaneously, a modified algorithm was applied to extend the linear response range.

Parmosidone K, a new -depsidone from the lichen .

Further phytochemical investigation on led to one new -depsidone, parmosidone K together with one known compound, barbatic acid. Their structures were determined by 1D and 2D NMR analysis, high resolution mass spectroscopy, and comparison their NMR data with those reported in literatures. Parmosidone K was evaluated for α-glucosidase inhibition and revealed the powerful activity with IC value of 3.

Three new phenolic compounds from the lichen Ach. (Ramalinaceae).

Three new phenolic compounds, peruvinides A-C were isolated from the lichen Ach. (Ramalinaceae). Their structures were unambiguously determined by extensive spectroscopic analyses and comparison with literature data.

Three new diphenyl ethers from the lichen (Nyl.) Hale (Parmeliaceae).

Three new diphenyl ethers, named praesorethers E, F and G (, and ), were isolated from the lichen . Their chemical structures were elucidated on the basis of extensively spectroscopic analysis including HR-ESI-MS and NMR as well as comparison with previously published data. These compounds were evaluated for the cytotoxicity against three human cancer cell lines (HeLa, NCI-H460 and MCF-7) using SRB assay.

Ricicomin A, a new alkaloid from the leaves of Linn.

From the leaves of Linn., one new alkaloid, named ricicomin A () together with three known ones, ricinine (), -demethylricinine () and 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid () were justified by repeated chromatographic methods. Their structures were determined by comprehensive IR, HR-ESI-MS and NMR analyses.

A new depsidone from the lichen Arch.

Chemical investigation of the lichen Arch led to the isolation of five depsidones, including one new compound ceratinalone along with four known compounds bailesidone stictic acid , 8'--methylstictic acid and 8'--ethylstictic acid . The structures were determined by analysis of their MS and NMR data as well as by comparison with literature values. Compounds and were evaluated the cytotoxic activity against HeLa (human epithelial carcinoma), NCI-H460 (human lung cancer), HepG2 (liver hepatocellular carcinoma), and MCF-7 (human breast cancer) cell lines, showing the moderate activity.

New erythritol derivatives from the fertile form of Roccella montagnei.

Chemical investigation of the methanol extract of the fertile form of Roccella montagnei collected in Vietnam afforded twelve secondary metabolites, including five new montagnetol derivatives, orsellinylmontagnetols A-D and a furanyl derivative together with seven known compounds. Their chemical structures were elucidated by analysis of 1D and 2D NMR and high resolution mass spectroscopic data. The relative stereochemistry of two chiral centers (C-2 and C-3) of orsellinylmontagnetols A and B was elucidated by comparison of their coupling constants and the specific rotation with those reported in the literature while the absolute stereochemistry was determined by the application of a modified Mosher method for the hydroxy group at C-3.