J. W. Alencar

Chemical variation during daytime of constituents of the essential oil of Ocimum gratissimum leaves

Abstract Variation of chemical composition of the essential oil of Ocimum gratissimum eugenol type was studied for 11 h during the daytime. Microwave oven technique was used for the serial extraction and the obtained oils were analysed by GC/MS. A considerable variation was observed in the eugenol yield, 98% at 12.00 am. to 11% at 05.00 p.m. These results show the influence of the solar light on eugenol production and can be useful to indicate the optimal time for collection of the plant.

Essential oil composition of two chemotypes of Lippia alba Grown in northeast Brazil

ABSTRACT Essential oils of six types of Lippia alba (Mill.) N.E. Brown, an aromatic shrub used in folk medicine in northeastern Brazil under the name “cidreira” were analyzed by GC/MS. The results showed neral (27.18–30.40%) and geranial (35.63–40.95%) as the main chemical constituent in three samples, while carvone (42.30–54.69%) was the main constituent in three other samples. These differences allowed for the classification of two chemotypes.

Volatile Constituents of Psidium pohlianum Berg, and Psidium guyanensis Pers.

ABSTRACT The chemical composition of two wild Psidium species (Psidium pohlianum Berg, and P. guyanensis Pers.) collected in the National Park of Araripe, Crato-CE, Northeast of Brazil, are described and compared. Besides 1,8-cineole as the major constituent (40.5–60.3%), α-pinene, β-eudesmol and γ-eudesmol were found to be common compounds in both species. β-Pinene, elemol and spathulenol were found only in P. guyanensis, whereas p-cymene and α-terpinyl acetate were identified only in P. pohlianum.

Medicinal Plants of Northeast Brazil Containing Thymol and Carvacrol - Lippia sidoides Cham. and L. gracillis H.B.K. (Verbenaceae)

Abstract Lippia sidoides Cham, and L. gracillis H.B.K. (Verbenaceae) are wild aromatic small trees or shrubs of Northeast Brazil vegetation. Chemical analysis of the oils obtained from the two plants by GC/MS revealed that L. sidoides contained thymol (73.1%), while L. gracillis contained carvacrol (47.7%) and p-cymene (19.2%) as main components.

Essential Oil of Mentha x villosa Huds. from Northeastern Brazil

Abstract An oil produced from Mentha x villosa Huds. by steam distillation of plant material collected in Fortaleza was analyzed by GC/MS and retention indices. The oil was found to be rich in piperitenone oxide (55.4%) and γ-muurolene (13.1%).

Volatile constituents of Eugenia uniflora leaf oil from northeastern Brazil

ABSTRACT The leaf oil of Eugenia uniflora L. [syn. Stenocalyx michelii (Berg.) Legrand] was investigated by GC/MS, retention data, and 13C-NMR spectroscopy. The main constituents were selina-1,3,7(11)-trien-8-one (48.52%) and oxidoselina-1,3,7(11)-trien-8-one (17.33%).

Constituents of Brazilian Chamomile Oil

ABSTRACT The constituents of the essential oil obtained from flowerheads of Chamomilla recutita (L.) Rausch. plants growing around Medianeira city, in Parana State, Brazil, were analyzed by GC/MS. The major constituents identified in the oil were similar to those found in oils from other parts of the world. The Brazilian oil contained the following major components: bisabolol oxide B (23%), bisabolol oxide A (17%), (Z)-β-farnesene (16%), α-bisabolol (13%), chamazulene (8%) and chamo-spiroether (5%).

Volatile Constituents from Leaves and Inflorescence Oil of Ocimum tenuiflorum L. f. (syn. O. sanctum L.) Grown in Northeastern Brazil

Abstract Ocimum tenuiflorum L.f. (syn O. sanctum L.) (Labiatae) is an ayurvedic medicinal plant from India that was introduced in Northeastern Brazil in 1970. Oils produced by steam distillation and microwave distillation from leaves and inflorescences were analyzed by GC/MS and retention indices. The leaf oil contained eugenol (79.0–82.7%) and β-caryophyllene (7.9–9.8%) as major constituents, whereas the inflorescence oil was rich in eugenol (17.6–60.0%), β-caryophyllene (24.5–40.7%) and caryophyllene oxide (5.9–18.5%).

Essential Oils from Brazilian Aristolochia

ABSTRACT The chemical composition of the essential oils from Brazilian species of the genus Aristolochia are being reported for the first time. The oils, which were obtained by steam distillation from seven Brazilian Aristolochia species: A. gigantea, A. macroura, A. cymhifera, A. rodriguesia, A. birostris, A. papillaris and A. triangularis, were analyzed by GC/MS and found to be rich in sesquiterpenes. The major components of the various oils were:—A. birostris: β-caryophyllene (13.9%), α-humulene (16.4%) and germacrene A (13.3%); A. cymhifera: n-undecane (17.7%) and dodecane (12.4%); A. gigantea: β-caryophyllene (8.8–19.3%), germacrene D (16.3–24.9%), γ-elemene (0–21.6%), trans-α-bergamotene (2.3–12.5%), (E)-nerolidol (0–23.4%), linalool (0–14.6%), nerol (0–11.5%) and geraniol (0–26.2%); A. macroura: δ-elemene (1.2–12.4%), α-copaene (2.5–13.3%), β-caryophyllene (10.6–15.3%), α-humulene (15.5–20.5%), γ-elemene (10.4–11.6%) and (E)-nerolidol (0–33.1%), farnesene (12.7%); A. papillaris: calarene (13.6%), α...

The essential oil of Croton adenocalyx A. DC

ABSTRACT The chemical composition of the essential oil from leaves of Croton adenocalyx determined by GC/MS is reported. The major compounds found in the oil were: α-pinene (30.9%), β-pinene (13.4%), β-caryophyllene (12.6%), and γ-elemene (10.6%). Sixteen additional compounds were also identified.