ABSTRACT
Essential oils(EOs) from Chinese medicinals, which can be used as adjuvants and exert certain therapeutic effect, are directly used in Chinese medicine formulas. Conventional research strategy for EOs from Chinese medicinals is to compare the efficacy of the prescriptions before and after the addition of EOs, and the penetration-enhancing mechanisms of EOs remain unclear. In modern research on EOs from Chinese medicinals, the method for studying chemical penetration enhancers is often used, which fails to reflect the overall efficacy of EOs. This study clarified the property regularity of EOs from Chinese medicinals as transdermal penetration enhancers, and thereby proposed a research model which integrated the medicinal and adjuvant properties of EOs from Chinese medicinals via "component-delivery-effect" characterization route. The core concept is that constituents of EOs from Chinese medicinals and their delivery process play a key role in their external application. This research model is expected to serve as a reference for further research on EOs from Chinese medicinals for transdermal application.
Subject(s)
Adjuvants, Pharmaceutic , Administration, Cutaneous , China , Drugs, Chinese Herbal/pharmacology , Oils, Volatile/pharmacologyABSTRACT
Objective:To investigate the skin irritation of essential oils(EOs) extracted from interior-warming medicines. Method:Three EOs from interior-warming medicines(Cinnamomi Cortex, Caryophylli Flos and Alpiniae Officinarum Rhizoma) were selected as research objects.The in vitro skin cytotoxicity and in vivo skin irritation of these EOs were determined and compared.Moreover, the skin irritation was also predicted by the novel skin test panels. Result:Toxicity of these three EOs to human skin fibroblasts(HSF) was significantly different, half-inhibitory concentration(IC50) values of EOs from Cinnamomi Cortex, Alpiniae Officinarum Rhizoma and Caryophylli Flos were (11.16±0.28), (53.33±1.71), (226.70±17.61) mg·L-1, respectively.However, in vivo skin irritation evaluation showed that the local toxicity of these three EOs was in the order of EO of Cinnamomi Cortex > EO of Caryophylli Flos > EO of Alpiniae Officinarum Rhizoma. The evaluation results of skin test panels for these three EOs were in accordance with the results of in vivo skin irritation evaluation. Conclusion:Toxicity of these three EOs against skin cells in vitro is inconsistent with their in vivo skin irritation. Skin test panels are expected to be able to accurately predict in vivo skin irritation of EOs instead of cytotoxicity evaluation.
ABSTRACT
To compare the penetration-enhancing effect of cinnamon oil and its main components (cinnamaldehyde) on ibuprofen and their self-percutaneous absorption behavior in vitro. Firstly, cinnamon oil was extracted by steam distillation, then the compositions were analyzed by gas chromatography mass spectrometry (GC-MS) and the cinnamaldehyde content in cinnamon oil was determined by high performance liquid chromatography (HPLC). With azone as positive control, ibuprofen as model drug, cinnamon oil and cinnamaldehyde as penetration enhancers (PE) were prepared and administered to the SD rat's abdominal skin. The penetration-enhancing effects of cinnamon oil and cinnamaldehyde and their own transdermal absorption properties were compared. The results showed that yield of cinnamon oil was (3.55±0.36)% (=3), and the cinnamaldehyde content in cinnamon oil was (73.48±0.21)% (=3). As compared with blank group, the enhancing rate (ER) of cinnamon oil, cinnamaldehyde, and azone was 3.56, 1.13, 2.47 respectively. The cumulative penetration rate of cinnamaldehyde in cinnamon oil and cinnamaldehyde monomer in 24 h was (63.30±0.98)%, (51.03±3.34)% (=4) respectively. The penetration-enhancing effect of cinnamon oil was significantly better than that of cinnamaldehyde, indicating the existence of muti-component synergy. The penetration rate of cinnamaldehyde in cinnamon oil was higher than that of cinnamaldehyde monomer, suggesting that a "pull effect" may be present.