Essential oil obtained from the leaves of Cymbopogon flexuosus, gramineae by distillation

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitising properties of Cymbopogon flexuosus (Lemongrass oil) were evaluated in a weight of evidence approach of 4 studies available from published literature.

In the available Guinea Pig Maximization Test (GPMT, according to Magnusson and Kligman), 10 Dunkin/Hartley guinea pigs were induced with intradermal injections of 0.25% Lemongrass oil and by topical application of 50% Lemongrass oil. At 6-8 days after the topical application induction the animals were challenged with topical application of 10% Lemongrass oil. A sensitization reaction was triggered in 4/10 animals (40%), indicating a positive response according to the CLP criteria (>30% positive response indicates sensitization). Based on the response of 40% with a 0.25% intradermal induction dose, this study leads to a classifcation as skin sensitiser category 1B.

Also an Open Epicutaneous Test was available in which 6-20 guinea pigs were induced by daily topical application of the test substance for 3 weeks. The treatment sites were left uncovered. On days 21 and 35, the animals were challenged by topical application of 5% Lemongrass oil on the contralateral flank. Lemongrass oil did not cause a sensitization reaction in the treated animals under the conditions of this study.

Additionally, two Modified Draize tests (one with Lemongrass oil Guatemala, that was used for read-across) were available in which 10 Dunkin-Hartley guinea pigs were tested for skin sensitisation. In one test the animals were first induced by intradermal injections followed by a challenge after 14 days, consisting of intradermal and topical exposure. In the other test, the intradermal injections were followed by 2 or more intradermal and topical challenges after 12-15 days. In both tests, 4 previously untreated controls were treated in exactly the same way as the test animals. 24 hours after the challenge, the treatment sites were examined for erythema, edema and necrosis. The general outcome of the studies was that the tested substance did not trigger a sensitization reaction the animals tested.

In summary, the available data on Cymbopogon flexuosus indicates a positive result for skin sensitisation (category 1B) in one study and a negative result in the other three available studies. Based on these results and the fact that the main constituent Citral (Neral+Geranial) is classified for skin sensitisation 1B (H317), Cymbopogon flexuosus itself is also considered to be skin sensitising category 1B.

Migrated from Short description of key information:
Skin sensitisation:
- Maximisation test (OECD406): sensitising
- Open Epicutaneous Test (OET): not sensitising
- Modified Draize test (2x): not sensitising

Justification for selection of skin sensitisation endpoint:
No selection is made as a Weight of Evidence approach was followed which is described below.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on Weight of Evidence of the available data and the classification of the main constituent, Cymbopogon flexuosus is considered to cause skin sensitisation. Given the result of the GPMT test, the test substance should be classified for skin sensitisation (Skin Sens. 1B) in accordance with the criteria as outlined in Annex I of 1272/2008/EC.