A new antifungal and antiprotozoal bibenzyl derivative from <i>Gavilea lutea</i>

<p>A new bibenzyl derivative (<b>4</b>), together with two glycosylated flavonoids (<b>1</b> and <b>2</b>), batatasin III (<b>3</b>) and the phenanthrene isohircinol (<b>5</b>) were isolated from the aerial parts of <i>Gavilea lutea</i>. Their structures were elucidated on the basis of spectroscopic studies including 1D and 2D NMR, UV, IR and HRESIMS. All isolated compounds were evaluated for their antifungal activity towards <i>Candida albicans</i>. The new compound <b>4</b> showed inhibitory activity with a MIQ of 50 μg. In addition, compound <b>4</b> exhibited a selective activity (IC₅₀ = 2.3 μg/mL) against <i>Leishmania donovani</i>.</p

Antitrypanosomal Quinoline Alkaloids from the Roots of <i>Waltheria indica</i>

Chemical investigation of the dichloromethane root extract of <i>Waltheria indica</i> led to the isolation and characterization of 10 quinoline alkaloids, namely, 8-deoxoantidesmone (<b>1</b>), waltheriones E–L (<b>2</b>–<b>9</b>), and antidesmone (<b>10</b>). Among these, compounds <b>2</b>–<b>9</b> have not yet been described in the literature. Their chemical structures were established by means of spectroscopic data interpretation including ¹H and ¹³C NMR, HSQC, HMBC, COSY, and NOESY experiments and UV, IR, and HRESIMS. The absolute configurations of the compounds were established by comparison of experimental and TDDFT-calculated ECD spectra. In addition, the isolated constituents were evaluated for their in vitro antitrypanosomal activity. Compounds <b>4</b>, <b>5</b>, and <b>8</b> showed potent and selective growth inhibition toward <i>Trypanosoma cruzi</i> with IC₅₀ values between 0.02 and 0.04 μM. Cytotoxicity for mouse skeletal L-6 cells was also determined for these compounds

Antifungal Quinoline Alkaloids from <i>Waltheria indica</i>

Chemical investigation of a dichloromethane extract of the aerial parts of <i>Waltheria indica</i> led to the isolation and characterization of five polyhydroxymethoxyflavonoids, namely, oxyanin A (<b>1</b>), vitexicarpin (<b>3</b>), chrysosplenol E (<b>4</b>), flindulatin (<b>5</b>), 5-hydroxy-3,7,4′-trimethoxyflavone (<b>6</b>), and six quinolone alkaloids, waltheriones M–Q (<b>2</b>, <b>7</b>, <b>8</b>, <b>10</b>, <b>11</b>) and 5­(<i>R</i>)-vanessine (<b>9</b>). Among these, compounds <b>2</b>, <b>7</b>, <b>8</b>, <b>10</b>, and <b>11</b> have not yet been described in the literature. Their chemical structures were established by means of spectroscopic data interpretation including ¹H and ¹³C, HSQC, HMBC, COSY, and NOESY NMR experiments and UV, IR, and HRESIMS. The absolute configurations of the compounds were established by ECD. The isolated constituents and 10 additional quinoline alkaloids previously isolated from the roots of the plant were evaluated for their in vitro antifungal activity against the human fungal pathogen <i>Candida albicans</i>, and 10 compounds (<b>7</b>, <b>9</b>, <b>11</b>–<b>16</b>, <b>18</b>, <b>21</b>) showed growth inhibitory activity on both planktonic cells and biofilms (MIC ≤ 32 μg/mL). Their spectrum of activity against other pathogenic <i>Candida</i> species and their cytotoxicity against human HeLa cells were also determined. In addition, the cytological effect of the antifungal isolated compounds on the ultrastructure of <i>C. albicans</i> was evaluated by transmission electron microscopy

Targeted Isolation of Monoterpene Indole Alkaloids from <i>Palicourea sessilis</i>

Phytochemical investigation of the alkaloid extract of <i>Palicourea sessilis</i> by LC-HRMS/MS using molecular networking and an in silico MS/MS fragmentation approach suggested the presence of several new monoterpene indole alkaloids. These compounds were isolated by semipreparative HPLC, and their structures confirmed by means of HRMS, NMR, and ECD measurements as 4-<i>N</i>-methyllyaloside (<b>3</b>), 4-<i>N</i>-methyl-3,4-dehydrostrictosidine (<b>4</b>), 4β-hydroxyisodolichantoside (<b>6</b>), and 4α-hydroxyisodolichantoside (<b>7</b>), as well as the known alkaloids alline (<b>1</b>), <i>N</i>-methyltryptamine (<b>2</b>), isodolichantoside (<b>5</b>), and 5-oxodolichantoside (<b>8</b>). In addition, the acetylcholinesterase inhibitory activity of the compounds was evaluated up to 50 μM

Targeted Isolation of Monoterpene Indole Alkaloids from <i>Palicourea sessilis</i>

Phytochemical investigation of the alkaloid extract of <i>Palicourea sessilis</i> by LC-HRMS/MS using molecular networking and an in silico MS/MS fragmentation approach suggested the presence of several new monoterpene indole alkaloids. These compounds were isolated by semipreparative HPLC, and their structures confirmed by means of HRMS, NMR, and ECD measurements as 4-<i>N</i>-methyllyaloside (<b>3</b>), 4-<i>N</i>-methyl-3,4-dehydrostrictosidine (<b>4</b>), 4β-hydroxyisodolichantoside (<b>6</b>), and 4α-hydroxyisodolichantoside (<b>7</b>), as well as the known alkaloids alline (<b>1</b>), <i>N</i>-methyltryptamine (<b>2</b>), isodolichantoside (<b>5</b>), and 5-oxodolichantoside (<b>8</b>). In addition, the acetylcholinesterase inhibitory activity of the compounds was evaluated up to 50 μM