Composition and Chemical Variability of Cleistopholis patens Trunk Bark Oil from Côte d'Ivoire.

The chemical composition of trunk bark oil from Cleistopholis patens (Benth.) Engl. & Diels, growing wild in Côte d'Ivoire, has been investigated by GC (FID) in combination with retention indices, GC/MS and 13 C-NMR. Moreover, one oil sample has been subjected to CC and all the fractions analyzed by GC (RI) and 13 C-NMR. In total, 61 components have been identified, including various sesquiterpene esters scarcely found in essential oils. 13 C-NMR was particularly efficient for the identification of a component not eluted on GC and for the quantification of heat-sensitive compounds. Then, 36 oil samples, isolated from trunk bark harvested in six Ivoirian forests have been analyzed. The content of the main components varied drastically from sample to sample: (E)-ß-caryophyllene (0.4 - 69.1%), ß-pinene (0 - 57%), α-phellandrene (0 - 33.2%), α-pinene (0.1 - 30.6%), ß-elemol (0.1 - 29.9%), germacrene D (0 - 25.4%), juvenile hormone III (0 - 22.9%), germacrene B (0 - 20.6%) and sabinene (tr-20.3%). Statistical analysis, hierarchical clustering and principal components analysis, carried out on the 36 compositions evidenced a fair chemical variability of the stem bark oil of this species. Indeed, three clusters have been distinguished: the composition of group I (ten samples) was dominated by ß-pinene and α-pinene, group II (nine samples) was represented by α-phellandrene and p-cymene and group III (16 samples) by ß-elemol. A sample displayed an atypical composition dominated by (E)-ß-caryophyllene.

Biocatalytic Synthesis of Terpene Esters and their Biological Activity in Human Glioma Cells.

BACKGROUND: Gliomas are highly malignant brain tumours with high resistance to chemotherapy. Therefore, investigations of new therapeutic molecules with high anti-glioma activity are of great importance. OBJECTIVES: In this work, biocatalytic esterification of terpene alcohols with proven anti-cancer activity was performed to enhance their potency to induce cell death in human glioblastoma multiforme T98G and anaplastic astrocytoma MOGGCCM cell lines in vitro. METHODS AND RESULTS: We used primary terpene alcohols and carboxylic acids with a length of two to nine carbon atoms. The structure of the alcohols had an influence on the esterification efficiency, which decreased in the following order: monocyclic > linear > bicyclic. Terpene alcohols and their esters only induced apoptotic cell death, which is highly desirable from a therapeutic point of view, but did not induce autophagy and necrosis. The esterification of perillyl alcohol with butyric acid caused a 4-fold increase in cell death induction in the T98G line. Citronellol valerate, caprylate, and pelargonate and myrtenol butyrate, caprylate and pelargonate also showed higher activity than their alcohol precursors. CONCLUSION: We have herein shown that esterification of natural alcohols by biocatalysis can be used for improving the activity of other compounds investigated for their anti-glioma activity.

Descriptors for terpene esters from chromatographic and partition measurements: Estimation of human odor detection thresholds.

We have used gas chromatographic retention data together with other data to obtain Abraham descriptors for 30 terpene esters. These include the air-water partition coefficient, as log Kw, for which no experimental values are available for any terpene ester. The other descriptors are the ester dipolarity, S, the hydrogen bond basicity, B, (the ester hydrogen bond acidity is zero for the esters studied), and L the logarithm of the air-hexadecane partition coefficient. Both S and B are larger than those for simple aliphatic esters, as expected from the terpene ester structures that include ring systems and ethylenic double bonds. These descriptors can then be used to obtain a large number of physicochemical and environmental properties of terpene esters. We have analyzed experimental results on human odor detection thresholds and have constructed another equation for the calculation of these thresholds, to go with a previous equation that we have reported. Then the descriptors for terpene esters can be used to estimate the important odor detection thresholds.

Synthesis and Pharmacological Properties of Novel Esters Based on Monoterpenoids and Glycine.

Esters based on mono- and bicyclic terpenoids with glycine have been synthesized via Steglich esterification and characterized by ¹H-NMR, IR, and mass spectral studies. Their analgesic and anti-inflammatory activities were investigated after transdermal delivery on models of formalin, capsaicin, and AITC-induced pain, respectively. Glycine esters of menthol and borneol exhibited higher antinociceptive action, whereas eugenol derivative significantly suppressed the development of the inflammatory process. The mechanism of competitive binding between terpenoid esters and TRPA1/TRPV1 agonists was proposed explaining significant analgesic effect of synthesized derivatives. For an explanation of high anti-inflammatory activity, competitive inhibition between terpenoid esters and AITC for binding sites of the TRPA1 ion channel has been suggested.

Synthesis and Pharmacological Properties of Novel Esters Based on Monocyclic Terpenes and GABA.

Novel esters of γ-aminobutyric acid (GABA) with monocyclic terpenes were synthesized via Steglich esterification and characterized by ¹H-NMR, IR and mass spectral studies. Their anticonvulsant, analgesic and anti-inflammatory activities were evaluated by a PTZ-induced convulsion model, AITC-induced hyperalgesia and AITC-induced paw edema, respectively. All studied esters, as well as their parent terpenes, were found to produce antinociceptive effects in the AITC-induced model and attenuate acute pain more than the reference drug benzocaine after their topical application. GABA esters of l-menthol and thymol were also shown to exceed the reference drug ibuprofen in their ability to decrease the inflammatory state induced by intraplantar injection of the TRPA1 activator AITC. The present findings indicate that GABA esters of carvacrol and guaiacol are not a classical prodrug and possess their own pharmacological activity. Prolonged antiseizure action of the ester based on the amino acid and guaiacol (200 mg/kg) was revealed at 24 h after oral administration. Furthermore, orally co-administered gidazepam (1 mg/kg) and GABA esters of l-menthol, thymol and carvacrol produce synergistic seizure prevention effects.