Helichrysum italicum (immortelle): Italian, Adriatic oils

What is Helichrysum italicum, and what do the two studies document?

In the World Checklist of Vascular Plants (WCVP, Kew), extract read on 21/09/2026, Helichrysum italicum (Roth) G.Don is a name of rank “Species” with the status “Accepted”, in the family Asteraceae (identifier 3091303). Mancini et al. (2011) analysed one oil of H. italicum subsp. italicum, hydrodistilled for 3 h from fresh aerial parts gathered at Marina di Camerota, southern Italy, in May 2010. Ninčević Runjić et al. (2025) analysed the oils of eighteen natural populations of H. italicum from the eastern Adriatic coast of Croatia, grown in two field trials (Split and Vojnić Sinjski) and hydrodistilled from dried inflorescences (with stem and leaves).

Which plant material did Mancini et al. (2011) study?

According to Mancini et al. (2011), the aerial parts of “Helichrysum italicum (Roth) Donssp. italicum” were gathered at Marina di Camerota (National Park of Cilento and Diano Valley, southern Italy), at full flowering, in May 2010. The plant was identified by V. De Feo, and a voucher specimen labelled DF47/2010 was deposited in the herbarium of the Medical Botany Chair at Salerno University.

How was the Mancini oil obtained and analysed?

Hydrodistillation

According to Mancini et al. (2011), one hundred grams of fresh aerial parts were ground in a Waring blender, then hydrodistilled for 3 h according to the standard procedure of the European Pharmacopoeia. The authors report that hydrodistillation yielded 0.02 % of a pale yellow oil, a value they give “on a dry mass basis”. The oil was solubilised in n-hexane, filtered over anhydrous sodium sulphate and stored under N2 at +4 °C in the dark until tested and analysed.

Gas chromatography and identification

Analytical gas chromatography was carried out on a Perkin-Elmer Sigma-115 chromatograph with a flame ionisation detector (FID), an HP-5 MS capillary column (30 m × 0.25 mm i.d., 0.25 μm film), a programme from 40 °C (5 min) to 270 °C at 2 °C/min then 270 °C (20 min), and splitless injection (1 μL of a 1:1,000 n-pentane solution). Injector and detector temperatures were 250 °C and 290 °C; the analysis was also run on an HP Innowax column (50 m × 0.20 mm i.d., 0.25 μm film), with helium as carrier gas (1.0 mL/min) in both cases. GC/MS was performed on an Agilent 6,850 Ser. II apparatus with a DB-5 capillary column (30 m × 0.25 mm i.d., 0.33 μm film), coupled to an Agilent MSD 5973 detector, at 70 eV, scanning from 40 to 500 amu (5 scans/s), under gas chromatographic conditions “as reported in the previous paragraph” according to the authors, with a transfer line at 295 °C. Most constituents were identified by comparing their Kovats retention indices with those of the literature or of authentic compounds, the indices being determined against a homologous series of n-alkanes (C10–C35) under the same conditions. Identification was completed by comparing mass spectra with the NIST 02 and Wiley 275 libraries, with spectra from the literature and with a home-made library. Relative concentrations were obtained by peak area normalisation, without calculating response factors. In the note to Table 1, Ri a is the Kovats index on the HP-5 MS column, Ri b the Kovats index on HP Innowax, and the identification codes are 1 = Kovats index, 2 = mass spectrum, 3 = co-injection with the authentic compound.

Which compounds does Table 1 of Mancini et al. (2011) list?

Class subtotals

In Table 1 of Mancini et al. (2011), “Essential oil composition (%)”, the subtotal “Sesquiterpenoid hydrocarbons” is 0.7 %, “Oxygenated sesquiterpenoids” 73.6 %, “Hydrocarbons” 11.4 %, “Fatty acids” 0.9 % and “Others” 1.4 %.

Compound rows

In the same table, Menthol is listed at 1.1 %, (Z)-Caryophyllene at 0.1 % and α-Bisabolene at 0.6 %. iso-Italicene epoxide is listed at 16.8 %, cis-Cadinene ether at 0.5 % and (E)-Nerolidol at 0.5 %. Caryophyllenyl alcohol is listed at 1.4 %, Neryl isovalerate at 0.5 % and Caryophyllene oxide at 1.4 %. Guaiol is listed at 2.3 %, cis-Isolongifolanone at 1.4 % and Isolongifolan-7-α-ol at 0.9 %. 10-epi-γ-Eudesmol is listed at 0.9 %, (Z)-Bisabolol-11-ol at 1.4 % and 1,10-di-epi-Cubenol at 2.3 %. γ-Eudesmol is listed at 1.4 %, allo-Aromadedrene epoxide at 2.3 %, β-Eudesmol at 1.4 % and α-Eudesmol at 0.9 %. 4α-H-Eudesm-11-en-4-ol is listed at 1.4 %, α-Betulenol at 1.8 % and (E)-Bisabol-11-ol at 0.5 %. 14-Hydroxy-9-epi-(E)-caryophyllene is listed at 0.5 %, β-Bisabolol at 0.5 %, (Z)-Nerolidyl acetate at 2.3 % and epi-α-Bisabolol at 0.9 %. 8-Cedren-13-ol is listed at 4.2 %, (Z)-α-trans-Bergamotol at 4.7 %, Selin-7(11)-en-4-ol at 1.4 % and Amorpha-4,9-dien-14-al at 2.8 %. A row named “Sesquiterpene” is listed at 1.4 %, (2E,6Z)-Farnesal at 1.4 %, (E)-Nerolidyl acetate at 0.9 % and Guaiol acetate at 0.5 %. 6S,7R-Bisabolone is listed at 2.3 %, 2,6-Bisaboladien-12-ol at 2.3 % and β-Costol at 7.5 %. Tetradecene is listed at 0.7 %, Pentadecane at 0.9 %, Hexadecene at 9.8 %, Octanedioic acid, diethyl ester at 0.9 % and n-Tridecanol at 1.4 %.

Which populations did Ninčević Runjić et al. (2025) study, and how were they grown?

According to Ninčević Runjić et al. (2025), seed samples from eighteen natural populations of H. italicum were collected in three geographical regions (northern, central and southern Adriatic), covering the native distribution range of immortelle along the eastern Adriatic coast in Croatia. The seeds used in the field trials were sampled at random from individuals of each population (about 25 individuals, one flower head per individual). The seed samples of all populations are kept in the Collection of Medicinal and Aromatic Plants of the University of Zagreb, Faculty of Agriculture, under accession numbers MAP02672-MAP02689; identified voucher specimens are deposited in the ZAGR Virtual Herbarium (Zagreb, Croatia), IDs 38977, 38981, 38983, 44230–44237 and 59856–59862.

The two field trials

Immortelle seedlings were raised in a greenhouse at the Institute for Adriatic Crops and Karst Reclamation in Split, then planted in two field trials: at the Institute in Split (43°30’18.23.”N, 16°29’59.51”E, as the source writes it) and in Vojnić Sinjski (43°36’00.19.”N, 16°42’22.77”E). The authors write that the field trial at the Institute in Split represents a “typical coastal habitat”; its soil is a rendzic leptosol developed on flysch deposits, with high carbonate content, alkaline reaction, low organic matter content and clay-loamy texture. The experimental field in Vojnić Sinjski represents a “hinterland”, in the authors’ words; its soil is a calcic cambisol developed on limestone, with neutral reaction, moderate organic matter content and clay-loamy texture. The field trials were set up as randomised complete block designs (RCBD) with two replicates, in rows 0.8 m apart with 0.4 m between plants; each of the 18 populations was represented by 20 plants in two replicates, and no fertiliser, irrigation or plant protection was applied. The immortelle inflorescences (with stem and leaves) were harvested at full flowering and air-dried at room temperature; 72 samples were analysed in total (18 populations × 2 field trial locations × 2 replicates).

How were the Adriatic oils obtained and analysed?

Hydrodistillation

According to Ninčević Runjić et al. (2025), the essential oil was isolated from 100 g of dry plant material per sample by hydrodistillation in a Clevenger-type apparatus for two and a half hours. Because of the very small amount of essential oil, pentane (1 mL) was added to the burette of the apparatus as an oil-capturing solvent, and the oil samples were dried over anhydrous sodium sulfate.

Gas chromatography and identification

The quantitative and qualitative analysis of the essential oil was carried out by gas chromatography with flame ionisation detection (GC-FID) and by gas chromatography-mass spectrometry (GC-MS), in the laboratory of the Institute for Medicinal Plants Research “Dr. Josif Pančić” in Belgrade, Serbia. The quantitative analysis was performed on an HP-5890 Series II (“Hawlett-Packard”, as written in the source; Waldbronn, Germany) with a split-splitless injector, an HP-5 capillary column (25 m × 0.32 mm, film 0.52 μm) and a flame ionisation detector (FID); the carrier gas was hydrogen (1 ml/min), the injector was at 250 °C, and the column temperature was programmed linearly from 40 to 260 °C (4 °C/min). Quantification is based on the percentage of the area of each identified compound against the total peak area, and the percentage of compounds was calculated from the flame ionisation detector (FID) measurements. The GC/MS analysis was performed under “almost equal” analytical conditions, on an HP G 1800C Series II GCD system (Palo Alto, CA, USA) with an HP-5MS column (30 m × 0.25 mm × 0.25 μm); the carrier gas was helium, the transfer line (MSD) was at 260 °C, the EI mass spectrum (70 eV) was scanned over m/z 40-400, and 1 μL of sample dissolved in ethanol (20 μl/2 ml) was injected in split mode (1:30). Compounds were identified by comparing their mass spectra and retention indices with those of authentic samples and/or the NIST/Wiley databases, using several search engines (PBM/NIST/AMDIS) and available literature data.

Which compounds did Ninčević Runjić et al. (2025) find in the 18 populations?

Number of compounds and their variability

According to Ninčević Runjić et al. (2025), the analysis of the essential oils of the 18 populations detected 90 compounds, of which 84 were identified; 50 of these compounds were present in all 18 populations, and eighteen compounds exceeded 5 % in at least one sample from the 18 populations. The authors write that the coefficients of variation of the 18 compounds show high chemical diversity of the H. italicum populations; across all samples, β-curcumene (C62) shows the highest variability (198.94 %) and β-selinene (C58) the lowest (33.86 %). In their analysis of variance of the 18 most represented compounds, population (sampling site) was a significant source of variation for nine compounds, the field trial location had no significant effect on any compound, and the population × location interaction was significant only for neryl propionate (C51).

Neryl acetate, ar-curcumene, β-selinene and α-pinene

Neryl acetate was the major compound in the authors’ words, with a lowest content of 5.38 % (P18 Cavtat) and an average of 16.22 %; the highest content of neryl acetate was observed in the northwestern populations.

ar-Curcumene, another major compound according to the authors, had a lowest content of 4.85 % (P03 Lošinj) and an average of 9.73 %; together with β-selinene, its content was higher in the southern immortelle populations.

β-Selinene, another major compound according to the authors, ranged from 6.05 % (P04 Rab) to 14.75 % (P12 Brač); together with ar-curcumene, its content was higher in the southern populations.

α-Pinene, another major compound according to the authors, ranged from 1.88 % (P07 Obrovac) to 10.55 % (P16 Živogošće) (average = 5.77 %), but did not differ significantly among populations.

Population averages in Table 1

Table 1 of Ninčević Runjić et al. (2025) gives as “average values (%) of the populations” 2.49 % for limonene (C13), 2.40 % for linalool (C21), 2.48 % for nerol (C35), 3.98 % for trans-caryophyllene (C48), 2.96 % for neryl propanoate (C51), 3.89 % for δ-selinene (C59), a value followed by the superscript “a” in the table, and 0.39 % for β-curcumene (C62). The article writes code C51 both “neryl propionate” and “neryl propanoate”; neither name is preferred here.

How do Ninčević Runjić et al. (2025) group the populations into chemotypes?

The authors calculated the Euclidean distance matrix between all pairs of populations on nine oil compounds and used it in a cluster analysis by Ward’s method (CLUSTER procedure of SAS); the optimal number of clusters was set by the pseudo F-statistic (PSF), and the populations were thus classified into clusters representing different chemotypes. Their cluster analysis classified the populations into three chemotypes. The first principal component separated the northwestern populations (P01 Krk, P02 Cres, P03 Lošinj and P04 Rab), later assigned to chemotype A, rich in nerol (C35), neryl acetate (C42) and neryl propionate (C51). The southeastern populations (P12 Brač, P13 Hvar, P15 Omiš, P16 Živogošće, P17 Slano and P18 Cavtat), assigned to chemotype C, are rich in ar-curcumene (C57), β-selinene (C58) and δ-selinene (C59). The central Adriatic populations (P07 Obrovac, P08 Benkovac, P09 Kistanje, P10 Unešić, P11 Seget and P14 Sinj; chemotype B), with two northwestern populations (P05 Zrće, Pag, and P06 Miškovići, Pag), showed average values of these compounds and lay around the centre of the biplot.

References

• Govaerts R. (ed.), World Checklist of Vascular Plants (WCVP), Royal Botanic Gardens, Kew — https://sftp.kew.org/pub/data-repositories/WCVP/wcvp.zip
• Mancini E., De Martino L., Marandino A., Scognamiglio M.R., De Feo V., « Chemical Composition and Possible in Vitro Phytotoxic Activity of Helichrsyum italicum (Roth) Don ssp. italicum », Molecules 2011;16(9):7725-7735, doi:10.3390/molecules16097725 — https://www.ebi.ac.uk/europepmc/webservices/rest/PMC6264769/fullTextXML
• Ninčević Runjić T., Pljevljakušić D., Runjić M., Grdiša M., Šatović Z., « Phenotypic plasticity vs. local genetic adaptation: essential oil diversity of natural immortelle (Helichrysum italicum (Roth.) G.Don) populations along eastern Adriatic coast », Frontiers in Plant Science 2025;16:1467421, doi:10.3389/fpls.2025.1467421 — https://www.ebi.ac.uk/europepmc/webservices/rest/PMC11836004/fullTextXML