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<br>Display Omitted<br> Two new phenolic acids (<b>1</b>⿿<b>2</b>) were isolated from the aerial parts of <b>Asterothamnus centrali-asiaticus</b>. Five knownphenolic acids (<b>3</b>⿿<b>7</b>) were also obtained from the title plant. <b>1</b>⿿<b>7</b> were evaluated for their anti-oxidant activity. <b>1</b>⿿<b>7</b> showed anti-oxidant activity with IC50 values ranging from 7.65 to 22.44 μg/mL.<br>Two new phenolic acids 2-hydroxy-5-[(6⿲-<b>O</b>-(<b>E</b>)-caffeoyl)-β-d-glucopyranosyl]-oxybenzoic acid (<b>1</b>) and 2-hydroxy-5-[(3⿲-<b>O</b>-(<b>E</b>)-caffeoyl)-β-d-glucopyranosyl]-oxybenzoic acid (<b>2</b>) were isolated from the aerial parts of <b>Asterothamnus centrali-asiaticus</b>, together with five known ones (<b>3</b>-<b>7</b>). Their structures were elucidated by extensive 1D and 2D NMR studies and HRESIMS investigations. The anti-oxidant activity of the isolates was evaluated through ABTS radical cation decolorization assay. The results showed that all of them exhibited anti-oxidant activity, and compound <b>7</b> was the most active compound with an IC50 value of 7.65 μg/mL.
The young leaves and shoots of Sibiraea laevigata, known as "Liucha", are used as tea by Tibetans to improve digestion after meals. Long-term consumption of "Liucha" will cause weight loss. In present work, we reported on the isolation and NMR and chemical analysis-based elucidation of seven new sorbitol O-caffeic acid ester derivatives named sorbitol esters A-G (1-7) and eighteen known phenolic compounds from S. laevigata. All of the isolates were evaluated for their antioxidant and α-glucosidase inhibitory activities. Among them sorbitol ester A (1), sorbitol ester D (4), sorbitol ester F (6), sorbitol ester G (7), isoferulic acid (15), methyl caffeate (18), trans-p-hydroxycinnamic acid (19), and kaempferol 3-O-β-d-(6″-E-p-coumaroyl)-glucopyranoside (25) showed more potent α-glucosidase inhibitory activity than the clinical drug acarbose.
The first phytochemical investigation on the roots of <b>Ligularia purdomii</b> led to the isolation and identification of 18 compounds, including two eremophilane sesquiterpenoids (<b>1</b> and <b>2</b>), three benzofuran derivatives (<b>3</b>-<b>5</b>), a triterpenoid (<b>6</b>), two steroids (<b>7</b> and <b>8</b>), nine phenolic components (<b>9</b>-<b>17</b>), and a monofatty glyceride (<b>18</b>). The structural elucidation of the isolated compounds was performed by spectroscopic data and comparison with the literature. Compounds (−)-syringaresinol (<b>11</b>), scopoletin (<b>13</b>), 3,5-dimethoxy-4-hydroxy-benzaldehyde (<b>14</b>), and glycerol monolinoleate (<b>18</b>) have not been recorded in <b>Ligularia</b> genus previously. The chemotaxonomic significance of these isolated compounds has been summarized.<br>• First phytochemical investigation on <b>L. purdomii.</b> • 18 compounds were identified from the acetone extract of <b>L. purdomii.</b> • Four compounds were reported from the genus <b>Ligularia</b> for the first time. • The results had important significance for chemotaxonomy of <b>L. purdomii.</b>
Nitraria tangutorum Bor., having edible berries, is valued for reputed health benefits in Qinghai-Tibet plateau. The phytochemical research on the fruit juice of N. tangutorum led to the isolation of twenty-six compounds including five new compounds, tangutorids A-D (1, 2, 3a, and 3b), and (3E,5E)-7-O-β-glucosyl-4-(2-methoxy-2-oxoethyl)hepta-3,5-dienoic acid (15). The structures of these compounds were elucidated through comprehensive spectroscopic analyses. Tangutorids A-F were the first examples of glucose-derived β-carbolines from natural products. The biogenetic pathways of 1-8 were proposed to involve Pictet-Spengler reactions and described starting from the co-isolated tryptophan (10) and corresponding aldehydes. All isolates were evaluated for their antioxidant and α-glucosidase inhibitory activities. Compounds 21, 22, and 24 showed antioxidant activity with SC50 values ranging from 12.2±1.9 to 30.4±2.7μg/mL, and compound 1 showed strong α-glucosidase inhibitory effect with IC50 value of 63.3±4.6μg/mL.
A new diarylheptanoid, (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-6-Oacetylglucoside (<i>1</i>), together with two known diarylheptanoids, (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-glucopyranoside (<i>2</i>) and hirsutanonol (<i>3</i>), were isolated from Saxifraga tangutica. The structures of <i>1-3</i> were elucidated using 1D and 2D NMR spectral data, including high-resolution mass spectra (HR-ESI-MS). It was found that the new compound was acetyl-substituted (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-glucopyranoside.
A new isocoumarin, along with 10 known compounds, was isolated from the aerial parts of Aconitum gymnandrum. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Among the known compounds, compound 11 was obtained as a natural product for the first time, which was previously reported as a synthetic product. In addition, compounds 1-5, 7 and 9 were tested for their cytotoxicity against four human cancer cell lines. The results showed that compounds 3, 4 and 7 displayed cytotoxicity against lung cancer A549 and gastric cancer MGC80, respectively, whereas 5 and 9 showed selective cytotoxicity against hepatocellular carcinoma HepG2.
<br>Display Omitted<br>• Two new monoterpenes named sibiscolactons A and B (<b>1</b> and <b>2</b>) were isolated from <b>Sibiraea laevigata</b>. • New compounds’ absolute configurations were established by electronic circular dichroism (ECD) calculations. • Eight known phenylpropanoids (<b>3</b>-<b>10</b>) were also obtained from the title plant. • <b>1</b>-<b>10</b> were evaluated for their cytotoxic activity. • Compound <b>3</b> displayed moderate cytotoxicity with IC50 values ranging from 10.8 to 49.2 μg mL−1.<br>Chemical investigation of the ethanol extract of the stalks and infructescence of <b>Sibiraea leavigata</b> led to the isolation of two new monoterpenes named (4<b>R</b>)-2-(2-hydroxy-4-methyl-3-pentenyl)furan-2(5<b>H</b>)-one (<b>1</b>) and (2<b>R</b>,4<b>R</b>)-2-(2-hydroxyethyl)-4-(2-methyl-1-propenyl)furan-5<b>H</b>-2-one (<b>2</b>) along with eight known phenylpropanoids (<b>3-10</b>). Their structures were established on the basis of the interpretation of spectroscopic data and electronic circular dichroism (ECD) calculations. In addition, all of these isolates were evaluated for their cytotoxic activity. The results showed that compound <b>3</b> displayed moderate cytotoxicity with IC50 values ranging from 10.8 to 49.2 μg mL−1 against five cell lines. While <b>1</b> showed selective promotion effects on proliferation of gastric cancer MGC803 and RSC96 cell lines.
Phytochemical investigation on <b>Asterothamnus centrali-asiaticus</b> afforded four new sesquiterpenes, asterothamnones A-D (<b>1</b>-<b>4</b>), and three new benzofuran derivatives (<b>5</b>-<b>7</b>) together with ten known compounds (<b>8</b>-<b>17</b>). Their structures were elucidated using 1D and 2D NMR and X-ray diffraction analyses. Compounds <b>1</b>-<b>4</b> were verified to be unusual eudesmane sesquiterpenes possessing 4,6-dien-3-one or 1,4,6-triene-3-one conjugated system. The absolute configurations of compounds <b>1</b>-<b>8</b> were established by means of calculated electronic circular dichroism (ECD). Furthermore, all isolates were evaluated for their cytotoxic and anti-oxidant activities. Results showed that <b>10</b>, <b>12</b> and, <b>14</b> exhibited cytotoxic activity against HepG2 cancer cells and <b>14</b> displayed cytotoxicity against MGC-803 cancer cells. Compounds <b>10</b> and <b>17</b> showed anti-oxidant effect.<br><br>Display Omitted
A new flavonoid, along with 16 known ones, was separated from the aerial parts of Asterothamnus centrali-asiaticus. Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR techniques and HRESIMS. To confirm the structure of the new compound, computational prediction of its 13C chemical shifts was performed. All of the 17 flavonoids were reported from A. centrali-asiaticus for the first time. In addition, all flavonoids were evaluated for their antioxidant and α-glucosidase inhibitory activities. The results showed that 10 of them exhibited antioxidant activity. Meanwhile, four flavonoids displayed α-glucosidase inhibitory effect with IC50 values ranging from 38.9 to 299.7 μM.
<br>Display Omitted<br>• Three new monoterpene glycosides (<b>1</b>-<b>3</b>) were isolated from <b>Sibiraea laevigata</b> (L.) Maxim. • Fourteen known compounds (<b>4</b>-<b>17</b>) were also obtained from the title plant. • All of the isolated compounds were evaluated for their anti-oxidant and α-glucosidase inhibitory activities. • Compounds <b>7</b> and <b>17</b> exhibited α-glucosidase inhibitory effect with IC50 values of 220.0 and 113.0 μM, respectively.<br>Three new compounds, 3,7-dimethy-7-methoxy-3-octene-5-one-1-<b>O</b>-<b>β</b>-d-glucopyranoside (1), 3,7-dimethy-7-methoxy-3(<b>Z</b>)-octene-5-one-1-<b>O</b>-<b>β</b>-d-glucopyranoside (2) and 3,7-dimethy-3-hydroxy-6-octene-5-one-1-<b>O</b>-<b>β</b>-d-glucopyranoside (3), together with fourteen known compounds (4-17) were isolated from the leaves and shoots of <b>S. laevigata</b>. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including one- and two-dimensional NMR, as well as mass spectral data. All isolates were evaluated for their α-glucosidase inhibitory and antioxidant activities. The results demonstrated that 3,7-dimethyl-3(Z),6-ocatdien-5-one-1-<b>O</b>-<b>β</b>-d-glucoside (7) and sitosteryl <b>β</b>-d-glucoside (17) exhibited α-glucosidase inhibitory effects with IC50 values of 220.0 and 113.0 μM, respectively.
Traditional Tibetan medicine is important for discovery of drug precursors. However, knowledge of the chemical composition of traditional Tibetan medicines is very limited due to the lack of appropriate chromatographic purification methods. In the present work, Salvia prattii was taken as an example, and an off-line hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography preparative method was developed for the purification of phenylpropanoids with high purity from a crude sample of Salvia prattii. Based on the separation results of four different chromatographic stationary phases, the first-dimensional preparation was performed on an XAmide preparative column with the crude sample concentration of 62.0 mg/mL, and five main fractions were obtained from the 12.4 g crude sample with a recovery of 54.8%. An XCharge C18 preparative column was applied in the second-dimensional preparation to further isolate the phenylpropanoids from the redissolved first-dimensional fractions with concentration of approximately 50.0 mg/mL. The purities of the phenylpropanoids isolated from the crude sample of Salvia prattii were higher than 98%, indicating that the method was efficient for the purification of phenylpropanoids with high purity from Salvia prattii. Additionally, this method showed great potential in the preparation of phenylpropanoids and can serve as a good example for the purification of phenylpropanoids from other plant materials.