Guajavadimer A, a Dimeric Caryophyllene-Derived Meroterpenoid with a New Carbon Skeleton from the Leaves of <i>Psidium guajava</i>

Guajavadimer A (<b>1</b>), a dimeric sesquiterpene-based meroterpenoid which possessed an unprecedented two caryophyllenes, a benzylphlorogulcinol, and a flavonone-fused complicated stereochemical skeleton, was isolated from the leaves of <i>Psidium guajava</i> L. Its structure and absolute configuration were elucidated on the basis of spectroscopic data and X-ray crystallography. Guajavadimer A (<b>1</b>) showed moderate hepatoprotective activity against <i>N</i>-acetyl-<i>p</i>-aminophenol (APAP)-induced toxicity in HepG2 cells

Anti-inflammatory Sesquiterpene Derivatives from the Leaves of <i>Tripterygium wilfordii</i>

Twelve new dihydroagarofuran sesquiterpene polyol esters, triptersinines A–L (<b>1</b>–<b>12</b>), and eight known sesquiterpene pyridine alkaloids were isolated from the leaves of <i>Tripterygium wilfordii</i>. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, and NMR experiments (¹H–¹H COSY, NOESY, HSQC, and HMBC). Furthermore, in an in vitro bioassay, compounds <b>1</b>, <b>9</b>, <b>11</b>, <b>13</b>, <b>14</b>, and <b>18</b> showed moderate inhibitory effects on nitric oxide production in LPS-induced macrophages at 5 μM; all compounds were inactive when tested against five human cancer cell lines (IC₅₀ values >1 μM)

Neuroprotective Dihydroagarofuran Sesquiterpene Derivatives from the Leaves of <i>Tripterygium wilfordii</i>

Thirteen dihydroagarofuran derivatives, including 12 new sesquiterpenoid esters and one known sesquiterpenoid alkaloid, were obtained from the leaves of <i>Tripterygium wilfordii</i>. Spectroscopic techniques and the ECD method were used for the structure elucidation of the compounds. The structures of compounds <b>1</b> and <b>8</b> were confirmed by single-crystal X-ray crystallographic analyses. Compounds <b>8</b>, <b>9</b>, <b>11</b>, <b>12</b>, and <b>13</b> increased cell viability of the okadaic acid treated PC12 cells from 60.4 ± 23.0% to 72.4 ± 14.1, 71.5 ± 11.5, 75.7 ± 15.6, 81.2 ± 13.1, and 86.2 ± 25.5% at 10 μM, respectively

Neuroprotective Dihydroagarofuran Sesquiterpene Derivatives from the Leaves of <i>Tripterygium wilfordii</i>

Thirteen dihydroagarofuran derivatives, including 12 new sesquiterpenoid esters and one known sesquiterpenoid alkaloid, were obtained from the leaves of <i>Tripterygium wilfordii</i>. Spectroscopic techniques and the ECD method were used for the structure elucidation of the compounds. The structures of compounds <b>1</b> and <b>8</b> were confirmed by single-crystal X-ray crystallographic analyses. Compounds <b>8</b>, <b>9</b>, <b>11</b>, <b>12</b>, and <b>13</b> increased cell viability of the okadaic acid treated PC12 cells from 60.4 ± 23.0% to 72.4 ± 14.1, 71.5 ± 11.5, 75.7 ± 15.6, 81.2 ± 13.1, and 86.2 ± 25.5% at 10 μM, respectively

Neuroprotective Dihydroagarofuran Sesquiterpene Derivatives from the Leaves of <i>Tripterygium wilfordii</i>

Thirteen dihydroagarofuran derivatives, including 12 new sesquiterpenoid esters and one known sesquiterpenoid alkaloid, were obtained from the leaves of <i>Tripterygium wilfordii</i>. Spectroscopic techniques and the ECD method were used for the structure elucidation of the compounds. The structures of compounds <b>1</b> and <b>8</b> were confirmed by single-crystal X-ray crystallographic analyses. Compounds <b>8</b>, <b>9</b>, <b>11</b>, <b>12</b>, and <b>13</b> increased cell viability of the okadaic acid treated PC12 cells from 60.4 ± 23.0% to 72.4 ± 14.1, 71.5 ± 11.5, 75.7 ± 15.6, 81.2 ± 13.1, and 86.2 ± 25.5% at 10 μM, respectively

A,D-<i>seco</i>-Limonoids from the Stems of <i>Clausena emarginata</i>

Twelve new A,D-<i>seco</i>-limonoids, clauemargines A–L (<b>1</b>–<b>12</b>), and three known analogues were isolated from the stems of <i>Clausena emarginata</i>. The absolute configurations of <b>1</b> and <b>5</b> were confirmed by X-ray crystallography and ECD spectroscopy, respectively. Compounds <b>1</b>, <b>2</b>, <b>8</b>–<b>10</b>, and <b>13</b> showed moderate inhibitory effects on LPS-induced NO production (IC₅₀ values < 10 μM)

Nototronesides A–C, Three Triterpene Saponins with a 6/6/9 Fused Tricyclic Tetranordammarane Carbon Skeleton from the Leaves of <i>Panax notoginseng</i>

Three triterpene saponins, nototronesides A–C (<b>1</b>–<b>3</b>), possessing an unprecedented 6/6/9 fused tricyclic tetranordammarane core, were isolated from the leaves of <i>Panax notoginseng</i>. Their structures were elucidated on the basis of spectroscopic data, and the structure of sapogenin (<b>1a</b>) was further confirmed by X-ray crystallography. The existence of <b>1</b>–<b>3</b> adds a new dimension to the diversity of the triterpene family. Moreover, compound <b>2</b> showed a moderate neuroprotective effect on serum deficiency-induced cellular damage in PC12 cells

Lupane Triterpenoids from the Stems of <i>Euonymus carnosus</i>

Fifteen new lupane-type triterpenoids (<b>1</b>–<b>15</b>) and 10 known triterpenoids (<b>16</b>–<b>25</b>) were isolated from the stems of <i>Euonymus carnosus</i>. The structures of the new compounds were elucidated on the basis of spectroscopic analyses, and the absolute configuration of compound <b>1</b> was confirmed by X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. In addition, the compounds were tested for their cytotoxic activity against five human cancer cell lines and their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line. Compound <b>11</b> exhibited moderate cytotoxicity against several human cancer cell lines, and compounds <b>1</b>, <b>2</b>, <b>4</b>, <b>5</b>, <b>20</b>, and <b>25</b> showed neuritis inhibitory activity against microglial inflammation factor, with IC₅₀ values of 7.39, 7.48, 7.80, 3.48, 2.54, and 6.09 μM, respectively

Carbazole Alkaloids from the Stems of <i>Clausena lansium</i>

Ten new carbazole alkaloids, claulansines A–J (<b>1</b>–<b>10</b>), and seven known analogues (<b>11</b>–<b>17</b>) were isolated from the stems of <i>Clausena lansium</i>. Their structures were established on the basis of extensive spectroscopic analyses, and their absolute configurations were determined by CD experiments and computational methods. Screening results indicated that compounds <b>1</b>, <b>6</b>, <b>8</b>–<b>10</b>, <b>13</b>, <b>14</b>, and <b>17</b> showed selective neuroprotective effects at the concentration of 10 μM

Cantharimide and Its Derivatives from the Blister Beetle <i>Mylabris phalerata</i> Palla

Eleven new monoterpenoids including three 1-methyl cantharimide-type derivatives (<b>1</b>–<b>3</b>), five 1,2-dimethyl cantharimide-type derivatives (<b>4</b>, <b>5</b>, <b>7</b>–<b>9</b>), and three 1-hydroxymethyl-2-methyl cantharimide-type derivatives (<b>10</b>–<b>12</b>), together with seven known cantharimides (<b>6</b>, <b>13</b>–<b>18</b>), were isolated from <i>Mylabis phalerata</i> Palla. The planar structures and absolute configurations of compounds <b>1</b>–<b>14</b> were fully elucidated on the basis of spectroscopic analysis, ECD spectra, single-crystal X-ray diffraction analysis, and chemical methods. Compounds <b>6</b>, <b>15</b>, <b>16</b>, and <b>18</b> were found to be potent inhibitors of HBV virus, with IC₅₀ values of 62, 42, 58, and 19 μM