Phytochemical study of <i>Caulerpa racemosa</i> (Forsk.) J. Agarth, an invading alga in the habitat of La Maddalena Archipelago

<div><p><i>Caulerpa racemosa</i> is a marine Chlorophyta widely distributed in tropical areas, introduced into the Mediterranean Sea since 1990. It has been invading the Mediterranean Sea causing ecological problems. This invasive event can be considered as one of the most serious in the history of species introduced into the Mediterranean Sea, even if <i>C. racemosa</i> has not triggered as much attention as the famous ‘killer alga’ <i>Caulerpa taxifolia</i>. The aim of this work is to analyse phytochemically <i>C. racemosa</i> in the northern Sardinia area for secondary metabolites. Marine algae shows the molecular pattern of bis-indole alkaloids, sesquiterpenes, diterpenes and sterols. The intention is to expand phytochemical analysis in order to understand just how significant the anti-tumour, anti-inflammatory and antinociceptive actions can be.</p></div

A new glucosidic phthalide from <i>Helichrysum microphyllum</i> subsp. <i>tyrrhenicum</i> from La Maddalena Island (Sardinia, Italy)

<p>In this study, we reported the analysis of the medium polarity fraction obtained from an accession of <i>Helichrysum microphyllum</i> subsp. <i>tyrrhenicum</i> from La Maddalena Island. Besides several compounds already evidenced in this species and related genera, i.e. micropyrone (<b>1</b>), arzanol (<b>2</b>), helipyrone (<b>3</b>), acetyl-bitalin derivatives (<b>4</b>, <b>5</b>), gnaphaliol (<b>6</b>), caffeic acid (<b>7</b>), ursolic acid (<b>8</b>), 7-<i>O</i>-β-(d-glucopyranosyl)-5-methoxy-1(<i>3H</i>)-isobenzofuranone (<b>9</b>), gnaphaliol-9-<i>O</i>-β-d-glucopyranoside (<b>11</b>) and gnaphaliol-3-<i>O</i>-β-d-glucopyranoside (<b>12</b>), the presence of a new glycosidic phthalide, 6-<i>O</i>-β-(d-glucopyranosyl)-4-methoxy-1(<i>3H</i>)-benzofuranone (<b>10</b>), was evidenced for the first time, which resulted in a structural isomer of compound (<b>9</b>). The occurrence of this new benzofuranone derivative is an additional evidence of the deep intraspecific variability expressed by this species, which was also stated for the non-volatile components, and may be a distinctive trait of the population growing on La Maddalena Island.</p

Time-of-addition assays with <i>S</i>. <i>desoleana</i> EO.

<p>A) Vero cells were treated with EO prior to virus infection (pre-treatment), during the infection period (during infection), or after infection (post-treatment). Data are presented as % of control. Values are means ± SEM of three independent experiments performed in duplicate. B) The histograms show the percentage of plaque area and plaque number of treated wells compared to that of untreated wells as a function of the concentration in the post-treatment assay. C) The images show representative plaques in Vero cells. The pictures and histograms shown are representative of many analyzed plaques, ranging from 15 to 25 per condition. * P< 0.0001.</p

Virus inactivation assay 10⁵ pfu of HSV-2 were incubated with 190 μg/ml of <i>S</i>. <i>desoleana</i> EO for 0 or 2 h at 37°C.

<p>The mixtures were then titrated on Vero cells at high dilutions at which the concentration of EO was not active. The titers, expressed as pfu/ml, are means and SEM for 3 independent experiments performed in duplicate.</p

Antiviral activity against HSV-2.

<p>Antiviral activity against HSV-2.</p

Antiviral activity against HSV-2 acyclovir resistant.

<p>Antiviral activity against HSV-2 acyclovir resistant.</p

Chemical composition (expressed as g/100g) of <i>S</i>. <i>desoleana</i> essential oil and its fractions.

<p>Chemical composition (expressed as g/100g) of <i>S</i>. <i>desoleana</i> essential oil and its fractions.</p

Time-of-addition assays with SD1 fraction.

<p>A) Vero cells were treated with SD1 fraction prior to virus infection (pre-treatment), during the infection period (during infection), or after infection (post-treatment). Data are presented as % of control. Values are means ± SEM of three independent experiments performed in duplicate. B) The histograms show the percentage of plaque area and plaque number of treated wells compared to that of untreated wells as a function of the concentration in the post-treatment assay. C) The images show representative plaques in Vero cells. The pictures and histograms shown are representative of many analyzed plaques, ranging from 15 to 25 per condition. * P< 0.0001.</p

¹H NMR spectra of MeOH/H₂O extract of <i>H</i>. <i>scruglii</i>.

<p>Numbers indicate the diagnostic signals of the isolated secondary metabolites 1–6.</p

Chemical structures of known metabolites isolated from <i>H</i>. <i>scruglii</i>.

<p>Chemical structures of known metabolites isolated from <i>H</i>. <i>scruglii</i>.</p