Chemical composition, enantiomeric analysis and anticholinesterase activity of Lepechinia betonicifolia essential oil from Ecuador.

CONTEXT: Due to the interesting potential of essential oils (EO) against cholinesterases and their close relation in Alzheimer's disease, the EO of Lepechinia betonicifolia (Lam) Epling (Lamiaceae), a native shrub from Ecuador, was assessed. Chemical profiling and enantiomeric distribution were also recorded for the first time. OBJECTIVE: To analyse the chemical profile including the enantiomeric composition and anticholinesterase effect exerted by EO of L. betonicifolia. MATERIALS AND METHODS: The EO of L. betonicifolia fresh aerial parts was obtained by hydrodistillation in a Clevenger-type apparatus. Physical properties were determined according to standard norms. The chemical composition was determined by GC-MS and GC-FID. Enantioselective GC-MS analysis was carried out by using a capillary chiral column. Anticholinesterase effect was assessed by Ellman's method with acetylthiocoline as substrate and Ellman's reagent (DTNB) to detect its hydrolysis at 405 nm for 60 min. Donepezil was used as a reference drug. EO was dissolved in methanol to reach 10 mg/mL concentration and two more 10× dilutions were included. RESULTS: Thirty-nine constituents were identified corresponding to 97.55% of the total oil composition. The main components were ß-pinene (30.45%), sabinene (27.98%), α-pinene (4.97%), ß-phellandrene (4.79%), E-caryophyllene (4.44%) and limonene (3.84%). L. betonicifolia EO exerted a strong inhibitory effect over the AChE enzyme with an IC50 value of 74.97 ± 1.17 µg/mL. DISCUSSION AND CONCLUSIONS: Current chemical characterisation and anticholinesterase effect of EO of L. betonicifolia encourage us to propose this EO as a candidate for the preparation of functional foods or as adjuvant therapy for Alzheimer's disease.

Effects of retinoic acid on the neural crest-controlled organs of fetal rats.

Prenatal exposure of rat embryos to retinoic acid induces severe malformations involving various organs. The mechanisms of this embryopathy are known only in part. This study describes the malformations of the neural crest-derived organs in this model and shows that many of them fit into the pattern of disturbed neural crest organogenic control. Pregnant rats were exposed to either all-trans retinoic acid (125 mg/kg; n=17) or vehicle ( n=10) on E10. Fetuses were recovered on E21 and external and internal malformations were sought. The craniofacial area, the trachea, parathyroids, thymus, thyroid, heart, great vessels, and adrenals were examined. In contrast with normal controls, 100% of retinoic acid animals had craniofacial, 94% anorectal, 90% limb, and 55% neural tube defects. The thymus was absent or ectopic in 76%, the parathyroids were absent or single in 88%, and the thyroid was abnormal in 41%. There were neural crest-type (outflow tract and/or pharyngeal aortic arch defects) cardiovascular malformations in 90% and the adrenals were absent in 52%. Interestingly, 9 of 11 (88%) animals with neural tube defects had absent adrenal glands. This association was significant ( p<0.01) by Fisher exact test. Among the complex mechanisms of retinoic acid teratogenesis, severe disturbances of the neural crest pathway play a leading role. The simultaneous development of neural tube defects and adrenal agenesis suggests common pathogenic pathways.