Cistus - Cistus ladanifer L.

What is labdanum?

According to the introduction of the 2022 study by Frazão and colleagues, citing earlier literature, Cistus ladanifer L. exudes from its photosynthetic leaves and stems what is commonly named “labdanum gum”.

According to Frazão and colleagues, citing the literature, labdanum is a complex mixture of terpenoid and phenolic compounds, represented mainly by labdane-type diterpenes and methylated flavonoids.

Where does labdanum come from, and what is it called?

The introduction of Mediavilla and colleagues states that Cistus ladanifer secretes a large amount of exudate through trichomes on its leaves and photosynthetic stems; citing the literature, it characterises this exudate by two families of secondary metabolites, flavonoids and diterpenoids.

According to the same introduction, if the labdanum gum is distilled, labdanum oil is obtained; if the gum instead undergoes an alcoholic extraction followed by concentration, labdanum resinoid is produced. It also states that Cistus essential oil and hydrolate (also called hydrosol or floral water) are obtained by hydrodistillation or steam distillation of the leaves and stems.

How were the resin and the absolute of the Frazão study obtained?

In the study by Frazão and colleagues (2022), herbaceous/semi-woody terminal leafy stems (10–30 cm) were collected in August 2018 from a “Cistus ladanifer subsp. ladanifer” shrubland in Penha Garcia (Portugal), then kept fresh in a freezer at −20 °C until use. The subspecies was identified with “Flora Ibérica”, and two specimens were deposited in the herbarium of the Escola Superior Agrária de Castelo Branco under the code 004 ESACBA1 CIS CIS LAD 02. The authors chose the “Andalusian process” rather than the “Zamorean process”; according to them, the Zamorean process uses boiling water instead of alkalinisation to remove the resin from the plant material by melting it, and the resin precipitates on cooling. In the study, following the method described by Burguer, 25 g of plant material were extracted in 200 mL of aqueous Na2CO3 solution (25 g/L) for 1 h at 60 °C in a water bath; the solution was filtered through a stainless-steel sieve (106 µm aperture), then, after cooling, H2SO4 solution (5 M) was added until pH 2. The precipitated resin was separated from the supernatant by centrifugation at 3030× g for 15 min, then freeze-dried. The authors considered the Na2CO3 solution of the study (25 g/L; 0.24 M) a buffer solution, able to keep the pH at about 11 during the extraction, and in the study the acidification was taken to pH 2 instead of neutralising the solution.

Frazão and colleagues note that the terms “resinoid” and “absolute” are not consistent in the literature, and the study considers “labdanum absolute” the best term for the direct methanolic extract of crude labdanum resin.

In the study, the labdanum absolute was obtained by removing “waxes” from the labdanum resin: at most one gram of resin was dissolved in 20 mL of methanol in an ultrasound bath, left overnight at −20 °C, then centrifuged at 3030× g at −5 °C for 15 min. The procedure was repeated three times, the supernatants were joined, and three independent extractions were conducted. The labdanum absolute was then fractionated by molecular-sizing column chromatography as described by Vogt and Gülz: fractions showing purple bands were joined as the diterpene fraction (Dit) and fractions showing flavonoid bands as the flavonoid fraction (Flv), for each of the three independent absolutes.

What does the absolute contain?

In the study, the labdanum absolute and its fractions were characterised qualitatively by UPLC-DAD-ESI-MS, and compounds were identified from their pseudo-molecular ions and by comparison with the literature. According to the abstract, labdane-type diterpenoids and methylated flavonoids were the main compounds in the labdanum absolute and in the diterpenoid and flavonoid fractions, “respectively”, a word the sentence does not explain further. The chromatogram of the flavonoid fraction revealed seven peaks that “could” be ascribed to flavonoids described in the literature; apigenin-4′-methyl ether (peak 3) and apigenin-7-methyl ether (peak 4) were distinguished from their order of elution in other reversed-phase chromatographic methods. The diterpene fraction revealed 14 peaks, of which only five “could” be assigned to compounds described in the literature, all labdane-type diterpenoids; the major peaks 13 and 15 were assigned to an oxo-labdenoic acid (“most likely” 6-oxo-cativic acid) and to labdanolic acid. The chromatogram of the absolute showed predominantly the same flavonoids as the flavonoid fraction, together with major non-identified peaks of compounds with longer retention times (peaks 20 and 23), which were lost when the purified diterpenoid and flavonoid fractions were obtained. The authors state that labdanolic acid does not absorb UV radiation and therefore cannot be detected by classical HPLC methods using DAD or UV detectors. In the absolute, some diterpenes were detected as lower-intensity peaks, and the major peak of the diterpene fraction (labdanolic acid, peak 15) was not detected in the absolute chromatogram. In Table 2 of the study, kaempferol-3-methylether (isokaempferide, peak 2) and a kaempferol-dimethylether (“3,7, jaranol, or 3,4′”, peak 5) each carry two “++” marks (“major peak” in the legend) among the “Absolute”, “Dit” and “Flv” columns. In the same table, oxo-labdenoic acid (peak 13) carries one “+” mark and one “++” mark, and 8α-methoxy-labdan-15-oic acid (peak 17) one “+” mark; peaks 20 and 23, whose “Compound” column shows a dash, carry a “++” mark, and peak 23 an additional “+” mark.

Which ECHA CHEM entries bear the name “Cistus ladaniferus”?

In the ECHA CHEM database, read on 03/10/2026, the entry “Cistus ladaniferus, ext.” carries EC number 289-711-7 and CAS number 89997-74-0, with the description “Extractives and their physically modified derivatives such as tinctures, concretes, absolutes, essential oils, oleoresins, terpenes, terpene-free fractions, distillates, residues […] obtained from Cistus ladaniferus, Cistaceae”.

A second entry with the same name, “Cistus ladaniferus, ext.”, carries EC number 639-656-3 and CAS number 8016-26-0. The entry “Gum of Cistus ladaniferus (Cistaceae) obtained from stems and leaves by extraction with alkaline solution” carries EC number 946-963-9, with no CAS number ("-"). The entry “Resinoid of Cistus ladaniferus (Cistaceae) obtained from labdanum gum by ethanol extraction” carries EC number 946-922-5, with no CAS number ("-"). The entry “Resinoid of Cistus ladaniferus (Cistaceae) obtained from labdanum gum by organic solvents extraction” carries EC number 946-442-6, with no CAS number ("-"). The entry “Concrete of Cistus ladaniferus (Cistaceae) obtained from labdanum gum by organic solvant extraction” (spelling of the database) carries EC number 946-927-2, with no CAS number ("-"). The entry “Concrete of Cistus ladaniferus (Cistaceae) obtained from stems and leaves by organic solvents extraction” carries EC number 947-090-6, with no CAS number ("-"). The entry “Absolute of Cistus ladaniferus (Cistaceae) obtained from labdanum concrete by ethanol extraction” carries EC number 947-313-7, with no CAS number ("-"). The entry “Absolute of Cistus ladaniferus (Cistaceae) obtained from labdanum resinoid by ethanol extraction” carries EC number 946-441-0, with no CAS number ("-"). The entry “Absolute of Cistus ladaniferus (Cistaceae) obtained from cistus concrete by ethanol extraction” carries EC number 947-724-1, with no CAS number ("-"). The entry “Absolute of Cistus ladaniferus (Cistaceae) obtained from cistus concrete by heat treatment and ethanol extraction” carries EC number 946-923-0, with no CAS number ("-").

What does the exudate of the leaves and stems contain, and how does it vary with organ, season and plant age?

According to Valares Masa and colleagues (2016, “Quantitative Variation…”), 20 individuals with a trunk base diameter of 20 mm (“approximately 12 years of age”) were selected to quantify the secondary metabolites of the leaves and stems, from a stand of the species (“jaral”) at Alburquerque, in the north-west of the province of Badajoz (south-west Spain, “39°08′05.1″ N–7°00′40.54″ O”). In this study, three types of samples were taken from each individual at the end of each season: young leaves (sprouts at the apical part), mature leaves (about 6 months old) and photosynthetic stems (the apex grown during the study year, 1.15–2.25 mm in diameter); samples were collected each season over two consecutive years. In the study, about 1 g wet weight of young leaves, mature leaves and stems was taken in three replicates per plant and sample type, and the exudate was extracted with chloroform at a ratio of 1:10 (w/v). The chloroform was evaporated under a fume hood at no more than 30 °C, the pellet was taken up in 3 mL of methanol, and the solution was kept frozen at −20 °C for 12 h to precipitate the waxes, which were then removed by centrifugation. The secondary metabolites were assayed by HPLC (Waters 996 photodiode array detector) on a Spherisorb C-18 reverse-phase analytical column (5 µ, 4.6 × 250 mm), with water/methanol/tetrahydrofuran 56/16/28 as the mobile phase at 0.75 mL/min; the chromatograms were recorded at 350 nm for flavonoids and 250 nm for diterpenes. The compounds were identified from their retention times and spectral characteristics, and the results were expressed relative to the dry weight of the leaf or stem. The legend of Figure 1 of the study names the flavonoids and diterpenes of the exudate of Cistus ladanifer: Ap (apigenin), Ap-4′ (apigenin 4′-methyl ether), Ap-7 (apigenin 7-methyl ether), K-3 (kaempferol 3-methyl ether), K-3.7 (kaempferol 3,7-di-O-methyl ether), D1 (6-acetoxy-7-oxo-8-labden-15-oic acid), D2 (7-oxo-8-labden-15-oic acid) and D3 (oxocativic acid). In Table 1 of the study (exudate of 20 individuals, mean of two years, mg/g dry weight), total flavonoids in young leaves, mature leaves and stems were 26.65, 13.99 and 9.90 in summer; 15.59, 10.71 and 12.58 in autumn; 6.78, 4.45 and 7.51 in winter; 9.29, 5.45 and 9.18 in spring. In the same table, total diterpenes in young leaves, mature leaves and stems were 1.56, 0.81 and 0.56 in summer; 3.32, 0.52 and 0.72 in autumn; 2.60, 0.48 and 1.46 in winter; 1.73, 0.62 and 1.26 in spring. Analysing the two families separately, the authors observe that most of the compounds are flavonoids, which form the majority in all seasons and organs. According to the authors, the major flavonoid is K-3.7, whose synthesis is clearly seasonal in both young and mature leaves, with greater amounts in summer; in stems, the highest secretion takes place in summer-autumn and the lowest in winter-spring. In this study, the amount of K-3.7 in the plant varies over the year from 2.91 mg/g dry weight in mature leaves in winter to 20.72 mg/g dry weight in young leaves in summer. Among the diterpenes, the most abundant in this study is D1 (6-acetoxy-7-oxo-8-labden-15-oic acid), whose synthesis differs significantly between young leaves, mature leaves and stems throughout the year; its amount varies over the year from 0.42 mg/g dry weight in mature leaves in winter to 3.03 mg/g dry weight in young leaves in autumn. The authors report that the amount of secondary metabolites in young leaves is greater than in mature leaves and stems in all four seasons, with a “very high variability” over the year, from 28.21 mg/g dry weight in young leaves in summer to 4.93 mg/g dry weight in mature leaves in winter. To quantify age-dependent variability, the study selected 110 plants of the population on the basis of their height and stem diameter, and determined their age by counting the annual growth rings. Three individuals per age range were retained and their young leaves, mature leaves and stems analysed, the data being grouped into 5-year age classes. According to the authors, individuals under one year old have only young leaves, and showed lower amounts of flavonoids and diterpenes than the young leaves of older plants; in the most senescent individuals, the amount of these compounds falls back, without a significant difference in total flavonoids and diterpenes from these leaves at earlier ages. Mature leaves are present in individuals over two years old, and the synthesis of flavonoids and diterpenes in them shows a significant decrease in senescent individuals (over 31 years). In stems, the synthesis of these compounds is less variable with age, and the study found no significant difference in total flavonoids and diterpenes at any age.

How do the diterpenes of the exudate vary across the seasons?

According to the abstract of Alías and colleagues (2012), the exudate of Cistus ladanifer L. consists mainly of two families of secondary metabolites, flavonoids and diterpenes. In this study, four populations of Cistus ladanifer with similar structural characteristics were selected at different points in the province of Badajoz (Extremadura, Spain). Four leaf samples (one per season) were collected over the year, for two years, from leaves born that same year and from randomly chosen individuals. In the study, about 0.5 g of leaves (2–3 leaves) was dipped several times into 2 mL of chloroform (5 replicates per determination); the chloroform was evaporated, and the exudates were taken up in 2 mL of methanol and kept at −20 °C for 12 hours to precipitate the waxes, which were then removed by centrifugation. The diterpenes of the leaves were assayed by HPLC (Waters 996 photodiode array detector), with 25 µL injected onto a Spherisorb 5 µ C-18 reverse-phase analytical column (4.6 × 250 mm) and a water/acetonitrile gradient as the mobile phase; the amount of each diterpene was calculated with its linear calibration equation. On the HPLC chromatogram of the diterpene extracts (recorded at 260 nm), the study labels D1, 6-acetoxy-7-oxo-8-labden-15-oic acid, D2, 7-oxo-8-labden-15-oic acid, and D3, oxocativic acid; the purified compounds were identified by comparing their NMR spectral characteristics with those described in the literature. In Table 1 of the study (mg/g dry weight, means of the four populations over two years), D1 was measured at 3.50 in spring, 3.28 in summer, 3.33 in autumn and 8.03 in winter, and D2 at 2.76, 2.03, 2.38 and 4.10; for both, the winter value carries a different letter (“b”) from the other three seasons (“a”). In the same table, D3 was measured at 6.51 in spring (“b”), 3.25 in summer (“a”) and 3.56 in autumn (“a”).

In Table 1, the total diterpenes of the leaves were 12.78 in spring, 8.57 in summer and 9.28 in autumn (same letter “a”), and 20.93 in winter (“b”). The authors state that the seasonal results are the means of the four populations over two years, that the amount of diterpenes in the leaves varied significantly between seasons (ANOVA; p < 0.05), and that the amount of the diterpenes of the exudate is “clearly greater” in winter, with clear and significant differences from the other seasons. For the laboratory trials, the study used plants bought from a commercial greenhouse, 20–30 cm tall and 2 years old, kept for 2 months under natural conditions before treatment. Four trials under controlled conditions (14-hour photoperiod, 9 individuals per trial) combined high (30 °C day, 15 °C night) or low (13 °C day, 4 °C night) temperatures with the absence or presence of water stress (watering every day, or moderate watering every 10 days); each trial lasted two months. According to the authors, Figure 2 shows a clear increase in the amount of the three diterpenes, especially at low temperature, with statistically significant differences for the plants not subjected to water stress; “under these conditions”, D1 increased by 115 %, D2 by 99 % and D3 by 64 %. A two-way ANOVA (Table 2 of the study) was run on the percentage variations in diterpene amount between the start and the end of each trial: the variations of D1 and D2 are explained by both temperature and water stress, those of D3 by temperature alone.

How much do individuals of the same population differ?

According to Valares Masa and colleagues (2016, “Intra-Population Variation…”), the sampling site was a rockrose formation (a stand of Cistus ladanifer L.) in the municipality of Alburquerque (south-west Spain; 39°09′38.30″ N, 6°58′43.02″ W), at 289 m above sea level, under a Mediterranean climate, in shrubland dominated by Cistus ladanifer. Voucher specimens from this study were deposited at the herbarium of the University of Extremadura under UNEX 36259. The sampling area measured 200 m × 50 m (10,000 m²), with homogeneous climatic and soil characteristics and nutrient-poor soils; 100 individuals with a trunk base diameter of 20 mm (“approximately 12 years of age”) were selected there, 10 m apart from each other. At the beginning of autumn (4 October 2010), three sprouts of young leaves (4–6 leaves per sprout) were collected from each individual, all on the same day, and the exudate of each sample (n = 300) was extracted on the day of collection. In the study, about 1 g of young leaves was weighed and the exudate extracted with chloroform at a ratio of 1:10 (wt:v); the chloroform was evaporated under a fume hood at no more than 30 °C, the pellet taken up in 4 mL of methanol, and the solution kept frozen at −20 °C for 12 h to precipitate the waxes, which were removed by centrifugation. The HPLC chromatograms were recorded at 350 nm for flavonoids and 250 nm for diterpenes, and the results were expressed relative to the dry weight of the leaves. The authors state that the flavonoids and diterpenes identified in Cistus ladanifer are not commercially available and were therefore extracted from the exudate, then separated on Sephadex LH-20 with methanol, a procedure that separates the flavonoids from the diterpenoids and the other phenolics. The purified flavonoids were apigenin, kaempferol 3-methyl ether, apigenin 4′-methyl ether, apigenin 7-methyl ether and kaempferol 3,7-di-O-methyl ether, and the purified diterpenes 6β-acetoxy-7-oxo-8-labden-15-oic acid, 7-oxo-8-labden-15-oic acid and oxocativic acid. According to the authors, the results showed intra-population variation: all individuals had the same composition of secondary metabolites, but in different amounts, and the variation in secretion among the individuals analysed was quantitative. In this study, kaempferol 3,7-di-O-methyl ether was the most abundant chemical species of the flavonoid group. By UPGMA clustering, the authors found four distinct groups (A to D) among the 100 plants studied, group A comprising 66 % of the individuals. Diterpene contents ranged from 2.10 mg/g dry weight (group D) to 1.21 mg/g dry weight (group A), these variations being significant; the individuals of group A synthesise the lowest concentrations of all flavonoids (23.00 mg/g dry weight) and of diterpenes (1.21 mg/g dry weight). Group B, formed by 8 % of the individuals, had a profile corresponding to the highest concentrations of flavonoids and moderate concentrations of diterpenes (1.60 mg/g dry weight).

A third group, C, also formed by 8 % of the individuals, showed low amounts of all flavonoids except kaempferol 3,7-di-O-methyl ether, present at a high level, and moderate amounts of diterpenes, oxocativic acid reaching there its greatest amount of all the groups (0.2 mg/g dry weight). Group D, formed by 18 % of the individuals, showed moderate concentrations of flavonoids and the highest concentrations of diterpenes, its amount of 6β-acetoxy-7-oxo-8-labden-15-oic acid being greater than in the other groups (1.93 mg/g dry weight). According to the authors, most individuals of the population (66 %) showed low amounts of all the compounds studied and were evenly distributed over the area; the individuals with higher levels of most compounds (group B) and those with moderate amounts (C and D) were distributed among those with lower amounts (group A), and the B and C individuals were randomly distributed.

What do the studies report on cistus essential oil?

How was the plant material of the Mediavilla study harvested and stored?

The study by Mediavilla and colleagues (2021) was performed on 12.97 ha of abandoned cropland covered by rockrose (Cistus ladanifer) at Hiendelaencina, Guadalajara (Spain), at 1030 m above sea level, in October 2018; the shrubs had a mean height of 0.5 m, an estimated age of 5 to 10 years and an average ground crown cover of 40 %. In the study, a harvester-baler cut the standing shrubs about 15 cm above the ground and compressed the biomass into large round bales. The bales were stored indoors for three periods, 1–7 days (just harvested), 15–30 days and 100–120 days, then shredded to 30 mm just before the distillation tests. The bales from mechanised harvesting, with an average weight of 359 kg of wet matter per bale and an average moisture content of 30.7 %, were stored indoors under good ventilation to prevent mould growth during storage.

How was the oil distilled and analysed in this study?

Ten water steam distillation tests were performed, each corresponding to a different storage time (1, 2, 4, 7, 15, 20, 30, 100, 110 and 120 days); for each test, four consecutive 5 kg samples of Cistus ladanifer milled to 30 mm were distilled, the oil was accumulated and the yield was calculated for the whole distillation. The oils of each storage period were then blended and analysed. In these batch tests, the study used a 30-litre stainless-steel still and saturated steam (0.5 bar) from an electric boiler, with a steam flow of 15 kg/h and an extraction time of 30 min per sample, counted from the fall of the first drop of distillate; the temperature inside the still was kept at 98 °C. The oil yield was calculated as a percentage (weight/weight) on a biomass dry basis. The oil components were analysed by GC (FID)-MS as relative area percentages, on DB-WAX UI fused silica columns (60 m × 0.25 mm, film thickness 0.5 µm) with retention time locking.

Does storage change the yield of oil?

In Table 1 of the study, the mean essential oil yield (%, dry basis) was 0.075 (standard deviation 0.012; relative standard deviation 15.5) for the first period (1–7 days), 0.066 (0.014; 21.9) for 15–30 days and 0.052 (0.0068; 13.0) for 100–120 days. The authors observed a decreasing trend in the yield, but their statistical analysis showed that this decrease was not significant at the 95.0 % confidence level, the p-value of the F-test being 0.0911, greater than 0.05. Although not statistically significant, the decrease relative to the fresh plant distillation was 12.0 % for 15 to 30 days of storage and 30.7 % for 100 to 120 days.

What is the composition of the oil in this study?

In the oils analysed in the study, quantified as relative area percentages, monoterpene hydrocarbons and oxygenated sesquiterpenes were the principal phytochemical groups. Among the monoterpene hydrocarbons of the three storage periods (0–7, 15–30 and 100–120 days), α-pinene was the main compound (49.65 %, 47.42 % and 46.67 %), followed by camphene (2.60 %, 2.49 % and 2.56 %), limonene (2.08 %, 1.81 % and 1.52 %) and p-cymene (1.47 %, 1.26 % and 1.33 %). Among the oxygenated monoterpenes, bornyl acetate (2.71 %, 2.32 % and 2.48 %) stands out, followed by trans-pinocarveol (1.56 %, 1.59 % and 0.99 %). Among the sesquiterpene hydrocarbons, alloaromadendrene (1.50 %, 1.13 % and 1.68 %) was the main compound identified; among the oxygenated sesquiterpenes, viridiflorol (10.03 %, 11.98 % and 12.50 %) followed by ledol (2.85 %, 3.41 % and 3.51 %) were the most abundant. In Table 2 of the study (relative areas, %), the totals for 0–7, 15–30 and 100–120 days of storage were: monoterpene hydrocarbons 60.92, 58.23 and 56.50; oxygenated monoterpenes 10.34, 10.37 and 8.15; sesquiterpene hydrocarbons 6.54, 6.05 and 6.63; oxygenated sesquiterpenes 14.57, 17.81 and 18.64; total identified 94.39, 94.15 and 92.30. According to the authors, when the storage period increases, total monoterpene hydrocarbons and total oxygenated monoterpenes tend to decrease while total oxygenated sesquiterpenes tend to increase, especially between 0–7 and 100–120 days (14.57 % against 18.64 %). α-Pinene, verbenene, limonene and β-phellandrene are the monoterpene hydrocarbons with the higher decrease, and no qualitative differences were observed in the composition of the oil between the storage periods. Comparing their data with analyses found in the literature and market data from industrial scale, where the conditions to obtain the oil can be different, the authors report quantitatively relevant differences, mainly in sesquiterpene alcohols such as viridiflorol, whose content is higher in their experiments than in most of the analyses of commercial and non-commercial oils reported.

What does the El Karkouri study report?

According to the introduction of El Karkouri and colleagues (2021), Cistus ladanifer is represented in Morocco by two varieties that differ mainly by the colour of the petals: “C. ladanifer var. albiflorus Dun”, with completely white petals, and “C. ladanifer var. maculatus Dun”, with petals spotted with crimson. In this study, Cistus ladanifer was harvested in the El Harcha forest (province of Khemisset, circle of Oulmès, 150 km south-east of Rabat; rural commune of Teddas, Middle Atlas region, semi-arid climate), then dried in the shade at room temperature and stored. The plant was identified by Professor Mohammed Fennan, with a voucher specimen under collection number RTCBME10.

In the study, the essential oil was extracted by hydrodistillation in a Clevenger-type apparatus, recovered in small opaque bottles and stored at 4 °C; the extraction yield is expressed as the volume of oil (mL) relative to the mass of plant material (g), with a formula that includes the moisture content of the plant material. The study reports an extraction yield of around 0.21 ± 0.01 % (volume per mass). Comparing with yields from the literature, the authors find that the essential oil yield of Cistus ladanifer, although highly variable, remains relatively low regardless of the region and the time of harvest. According to El Karkouri and colleagues (2021), the GC-MS analysis revealed 35 compounds in the essential oil of C. ladanifer, divided into oxygenated sesquiterpenes (34.02 %), oxygenated monoterpenes (33.14 %), linear esters (10.38 %), monoterpenes (9.11 %) and sesquiterpenes (4.29 %). In Table 2 of the study (GC/MS, DB-5 column, “Percentage” column), the oil contained, among other compounds, p-cymene 6.11, trans-pinocarveol 11.02, borneol 4.80, bornyl acetate (“Bornylacetate”) 9.38, ledol 8.85 and sclareol 4.60.

The authors write that the chemical composition of Cistus ladanifer essential oil varies considerably depending on the source, the plant material and the extraction method.

What do the ECHA CHEM and ISO records list for the essential oil?

In the ECHA CHEM database, read on 03/10/2026, the entry “Essential oil of Cistus ladaniferus L (Cistaceae) obtained from stems and leaves by distillation” carries EC number 946-570-2, with no CAS number ("-"). In the ISO catalogue for ICS 71.100.60, the draft ISO/FDIS 21099, titled “Essential oil of rockrose labdanum (Cistus ladanifer L.)”, was listed as “[Under development]”, at stage 50.20, under ISO/TC 54. In the ISO catalogue record for ISO 21099:2026, read on 06/10/2026, the standard, titled “Essential oil of rockrose labdanum (Cistus ladanifer L.)”, is listed as published (“Status: Published”), with publication date “2026-05”, edition 1, at stage “International Standard published [60.60]”, under ISO/TC 54.

⚠️ Important Precautions

Precautions for this plant are being verified against sources; their absence here does not mean there are none.

References

• Frazão D.F., Martins-Gomes C., Steck J.L., Keller J., Delgado F. et al., « Labdanum Resin from Cistus ladanifer L.: A Natural and Sustainable Ingredient for Skin Care Cosmetics with Relevant Cosmeceutical Bioactivities », Plants 2022;11(11):1477, doi:10.3390/plants11111477 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=9183103&rettype=xml
• Mediavilla I., Blázquez M.A., Ruiz A., Esteban L.S., « Influence of the Storage of Cistus ladanifer L. Bales from Mechanised Harvesting on the Essential Oil Yield and Qualitative Composition », Molecules 2021;26(8):2379, doi:10.3390/molecules26082379 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=8073065&rettype=xml
• El Karkouri J., Bouhrim M., Al Kamaly O.M., Mechchate H., et al., « Chemical Composition, Antibacterial and Antifungal Activity of the Essential Oil from Cistus ladanifer L. », Plants 2021;10(10):2068, doi:10.3390/plants10102068 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=8539845&rettype=xml
• European Chemicals Agency (ECHA), ECHA CHEM, search for « Cistus ladaniferus », consulted 03/10/2026 — https://chem.echa.europa.eu/api-substance/v1/substance?pageIndex=1&pageSize=20&searchText=Cistus%20ladaniferus
• International Organization for Standardization (ISO), online catalogue, ICS 71.100.60 « Essential oils », archived copy of 19/03/2026 (Internet Archive) — https://web.archive.org/web/20260319152944id_/https://www.iso.org/ics/71.100.60/x/
• International Organization for Standardization (ISO), catalogue record « ISO 21099:2026 — Essential oil of rockrose labdanum (Cistus ladanifer L.) », edition 1, 2026-05, consulted 06/10/2026 — https://www.iso.org/standard/88099.html
• Valares Masa C., Sosa Díaz T., Alías Gallego J.C., Chaves Lobón N., « Quantitative Variation of Flavonoids and Diterpenes in Leaves and Stems of Cistus ladanifer L. at Different Ages », Molecules 2016;21(3):275, doi:10.3390/molecules21030275 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=6274041
• Alías J.C., Sosa T., Valares C., Escudero J.C., Chaves N., « Seasonal Variation of Cistus ladanifer L. Diterpenes », Plants 2012;1(1):6-15, doi:10.3390/plants1010006 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=4844260
• Valares Masa C., Alías Gallego J.C., Chaves Lobón N., Sosa Díaz T., « Intra-Population Variation of Secondary Metabolites in Cistus ladanifer L. », Molecules 2016;21(7):945, doi:10.3390/molecules21070945 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=6274576