Chemical polymorphism of the essential oils from populations of Thymus caespititius grown on the island S. Jorge (Azores).

The compositions of the essential oils obtained from ten populations of Thymus caespititius grown on S. Jorge (Azores) were studied by GC and GC-MS. All the oils analysed were dominated by their monoterpene fraction (69-9%). The sesquiterpene fraction was rather small (4-17%) and consisted mainly of oxygen-containing compounds (3-13%). Enantiomeric ratio of sabinene and alpha-terpineol was investigated in the oils from some populations. (+)-Sabinene was detected with high enatiomeric purity (96 99%). Although ( +)-alpha terpineol was the predominant enantiomer, its purity varied considerably (66-97%). Cluster analysis of all identified components grouped the oils into four main clusters that corresponded with their major components: alpha-terpineol (43-68%), carvacrol (32-52%), thymol (44-58%) and sabinene (41%). The essential oil from Th. caespititius showed a clear chemical polymorphism, that was particularly evident among four populations growing along a 200 m distance at Pico Verde.

Essential oils from Azorean Laurus azorica.

The essential oils isolated from leaves of ten and from unripe berries of eight populations of Laurus azorica (Seub.) Franco, collected on five islands of the Azorean archipelago, were analysed by GC and GC-MS. All oil samples were dominated by their monoterpene fraction (60-94%), alpha-pinene (15-37%) and 1,8-cineole (12-31%) being the main components of the leaf oils, while trans-beta-ocimene (27-45%) and alpha-pinene (12-22%) were the main components of the oils from the berries. The sesquiterpene fractions of the oils ranged from 3 to 17% and the main components were beta-caryophyllene (traces-8%) and beta-elemene (traces-3%) both in the leaf and berry oils. Some phenylpropanoid components were also present, in total amounting to 17%, trans-cinnamyl acetate (215% of the leaf oils) being the main component of this fraction. Cluster analysis of the enantiomeric composition of alpha- and beta-pinene in the oils from the leaves clearly showed two groups, one constituted by the two populations growing on the island S. Jorge, and the other constituted by the remaining populations.

Assay of 2,3-dihydroxybenzoic acid and related compounds in plant materials by high-performance liquid chromatography.

Salicylic acid and its putative biosynthetic precursors were assayed isocratically by RP-HPLC with UV detection at 280 nm. Optimum resolution was provided by an HPLC mobile phase consisting of MeOH-1% aqueous HOAc (40:60, v/v), at pH 4. Furthermore, for the analysis of 2,3-dihydroxybenzoic acid (2,3-DHBA) in Catharanthus roseus cell cultures after elicitation, a mobile phase consisting of acetonitrile-1% aqueous HCOOH containing 0.25% trichloroacetic acid (1:5, v/v), at pH 2, was used. The recovery for the free form of 2,3-DHBA was about 80% after a one-step extraction of the cells. The detection limit of 2,3-DHBA was 3 microg by using saligenin as an internal standard.

Antimicrobial activities of some Ocimum species grown in Rwanda.

The essential oils of four Ocimum species grown in Rwanda, i.e. O. canum, O. gratissimum, O. trichodon and O. urticifolium (synonym O. suave) including some chemotypes, were screened for antimicrobial activities. Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Trichophyton mentagrophytes var. interdigitale were used as test organisms. Different techniques were applied in the screening, such as the biogram and agar overlay techniques and a dilution technique yielding maximum inhibitory dilution (MID) values. Also some growth curves were determined. Although the results obtained by the diffusion techniques were rather different for some of the oil samples, all samples were found to be antimicrobially active.

Cardiovascular activity of the crude alkaloidal fraction from Tabernaemontana pandacaqui in the rat.

The effects of a crude alkaloidal (CA) fraction from the stem of Tabernaemontana pandacaqui Poir. on the blood pressure and heart rate were investigated in conscious as well as anesthetized rats. The CA fraction exerted a hypotensive activity in both experimental models. In pentobarbital anesthetized rats, an intravenous administration of the CA fraction caused two consecutive hypotensive and bradycardiac responses. In order to investigate the mechanism of the responses, the effect of the CA fraction on the blood pressure and the heart rate was tested in various experimental animals such as pithed rats, reserpinized rats under pentobarbital anesthesia and atropine- or chlorpheniramine-treated rats under pentobarbital anesthesia. The results obtained suggest that the hypotensive and bradycardiac responses of the first phase might involve cholinergic and central mechanisms, whereas those of the second phase involve mechanisms which are mediated by central, biogenic amines, acetylcholine and histamine.

Neuropharmacological activities of the crude alkaloidal fraction from stems of Tabernaemontana pandacaqui Poir.

The crude alkaloidal (CA) fraction from the stem of Tabernaemontana pandacaqui Poir. was studied for its pharmacological activity on the central nervous system (CNS) of animals. The CA fraction was found to produce symptoms of CNS depression in conscious rats and mice, viz. reduction in spontaneous motility, potentiation of pentobarbital sleeping time, prolongation of latency of convulsions induced by pentylenetetrazole and antinociception. However, the fraction could not antagonize oxotremorine-induced tremor. The observations suggest that the CA fraction possesses a CNS depressant activity.

Cardiovascular effects of Tabernaemontana pandacaqui.

Intravenous injection of ethanolic extracts of the stem, leaf and flower of Tabernaemontana pandacaqui caused hypotension in pentobarbital anesthetized rats. At high doses (100-300 mg/kg), the flower extract showed a transient hypertensive effect preceeding hypotensive activity. The effects of the extracts on the heart rate of anesthetized rats correlated well with the negative chronotropic and inotropic activity observed with isolated atrium. The hypotensive activity was not inhibited by antihistaminic and antimuscarinic agents. The extracts had no effect on the pressor effects induced by norepinephrine or dual carotid occlusion. These results suggest that the hypotensive action of the extracts is not mediated through histaminic and muscarinic receptors stimulation, alpha-adrenoceptor blockade or interference of sympathetic transmission.

Hippocratic screening of ethanolic extracts from two Tabernaemontana species.

Ethanolic extracts of roots, stems, leaves and flowers of Tabernaemontana divaricata and T. pandacaqui were studied by an observational (hippocratic) screening method in rats. Extracts of all plant parts caused sedation, decreased respiration and decreased skeletal muscle tone. Except for the leaf extract of T. pandacaqui, the extracts caused vasodilatation of ear vasculature. Analgesic activity was found for all extracts of both Tabernaemontana species, except for the flower extract of T. divaricata. Lethal doses of the extracts caused the animals to die from respiratory paralysis. Intensity of pharmacological activities was greater with the root and stem extracts. The extracts of T. pandacaqui were more potent than those of T. divaricata.

Anti-inflammatory, antipyretic and antinociceptive activities of Tabernaemontana pandacaqui Poir.

Studies on carrageenin-induced rat paw edema, yeast-induced hyperthermia in rat and writhing response induced by acetic acid in mice showed that the alcoholic extract of stems of Tabernaemontana pandacaqui (T. pandacaqui) has significant anti-inflammatory, antipyretic and antinociceptive activities. These activities are due to alkaloidal components since they were also observed when the crude alkaloidal (CA) fraction separated from alcoholic extract was tested in the same models.

Natural products in therapy. Prospects, goals and means in modern research.

A review is presented which shows the vegetable kingdom as an almost inexhaustible reservoir of potential drugs. Some historical aspects about the use of plants and their constituents in medicine are dealth with. A number of problems connected with the search for new prototype drugs of biological origin is reported as well as modern methods used in this promising research. Some examples are given concerning recent results of investigations of plants used in traditional and modern medicine in China. Special attention is paid to the present role of natural products in therapy: as biologically active compounds as such, as starting materials for (semi)synthetic drugs and, last but not least, as source of inspiration or as models for the synthesis of new drugs with better therapeutic, chemical or physical properties than the original compounds.

Acetoxychavicol Acetate, an Antifungal Component of Alpinia galanga1.

The essential oils from fresh and dried rhizomes of ALPINIA GALANGA showed an antimicrobial activity against gram-positive bacteria, a yeast and some dermatophytes, using the agar overlay technique. The main components of the oils were also tested and terpinen-4-ol was found most active. An N-pentane/diethyl ether extract of dried rhizomes was active against TRICHOPHYTON MENTAGROPHYTES. 1'-Acetoxychavicol acetate, 1'-acetoxyeugenol acetate and 1'-hydroxychavicol acetate identified by MS and NMR were found in the antifungally active fractions obtained by LSC. Acetoxychavicol acetate was active against the seven fungi tested and its MIC value for dermatophytes ranged from 50 to 250 microg/ml. Dried sliced rhizomes contained 1.5% of this compound. The compound was not found in rhizomes of ALPINIA OFFICINARUM, ZINGIBER OFFICINALE and KAEMPFERIA GALANGA.

Antimicrobial screening of essential oils and extracts of some Humulus lupulus L. cultivars.

The essential oils as well as solvent extracts of 11 hop cultivars, 1 hop variety and a wild type of hop were screened for their antimicrobial activities using the agar overlay technique. The oils were isolated from the cones of the various hop plants by hydrodistillation, the extracts were obtained by soaking the hop cones in chloroform. The oils and the extracts showed activity against the Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and the fungus (Trichophyton mentagrophytes var. interdigitale), but almost no activity against the Gram-negative bacterium (Escherichia coli) and the yeast (Candida albicans) used in the screening. The peak area percentages of the main volatile components and the contents of the bitter acids of the extracts were determined for all cultivars using chromatographic methods.

Antimicrobial activities of essential oils. A 1976-1986 literature review on possible applications.

The testing of essential oils for antimicrobial activities is reviewed with respect to various possible applications. Consideration is given to the screening for antimicrobially active oils or constituents, for disinfecting or antiseptic properties and for food conserving properties. The role of essential oils in biological interactions and their potential as therapeutic agents are also discussed.

Composition of the Essential Oil of Ocimum gratissimum Grown in Rwanda1.

The essential oil of OCIMUM GRATISSIMUM, growing wild in Rwanda, was investigated by LSC, GLC, and GC-MS. The oil contained 35% thymol and 11% eugenol, which may indicate the occurrence of a new chemotype of the species. A large amount of hydrocarbons (42%) including 18% P-cymene was also found. The oil showed a relatively strong antimicrobial effect. The oil of O. GRATISSIMUM, cultivated in Rwanda from seeds collected in Cameroon, consisted of 47% thymol and only 0.3% eugenol. This sample contained 49% hydrocarbons, including 23% gamma-terpinene. Most of the constituents detected in the oil samples were not previously known to be present in the essential oil of O. GRATISSIMUM.

Monoterpenes in the essential oil of Origanum majorana.

The essential oil of Origanum majorana L. plants, wild growing in Turkey, was investigated by means of LSC and GLC. The oil contained about 65% carvacrol and 4% thymol.

Phthalides in the essential oil from roots of Levisticum officinale.

The composition of the phthalide mixture of the essential oil from roots of Levisticum officinale Koch was investigated. The phthalide mixture was analyzed by combining separation methods - GLC, LSC and TLC - and subsequently using spectroscopic methods - IR, MS and NMR. E- and Z-butylidenephthalide, E- and Z-ligustilide, senkyunolide and validene-4,5-dihydrophthalide were found to be present; isosenkyunolide and propylidenephthalide were tentatively identified. The influence of the isolation procedure on the composition of the phthalide mixture was tentatively studied by comparison of mixtures isolated by solvent extraction and hydrodistillation respectively.

Composition of the essential oil of Ocimum canum grown in Rwanda.

The essential oil from leaves and flowers of Ocimum canum Sims, growing wild in Rwanda, was investigated by LSC, GLC and GC-MS. All samples were characterized by a high content of linalool (60-90%). Neither camphor nor citral and methyl cinnamate, compounds reported to be characteristic for different types of O. canum, could be detected. All monoterpene hydrocarbons were present in minor amounts (less than 1.5%). The oil samples with the lowest linalool content consisted of relatively large amounts of sesquiterpene hydrocarbons such as bergamotene (about 10%) and beta-caryophyllene (about 5%). Oct-1-en-3-ol and 3-octanol were the only oxygen-containing components, besides linalool, that amounted to more than 1% in most of the oil samples.

In Vitro Production of Essential Oil from Proliferating Shoots of Rosmarinus officinalis1.

The 40-day-old IN VITRO proliferating shoots of ROSMARINUS OFFICINALIS L. var. GENUINA forma ERECTUS produced an appreciable quantity of essential oil, i.e., 1.8% fw, which was similar in its constituents to that obtained from 1-year-old plants, whether naturally grown or IN VITRO-raised potted plants. However, the quantity of various constituents identified so far was generally, but marginally, less in the former case than the latter two kinds of 1-year-old plants with the exception of bornyl acetate and 1,8-cineole, the concentrations of which were higher in the proliferated shoots than the plants. The essential oil content of 1-year-old naturally grown plants was 2.4% fw, while it was 2.38% fw in the IN VITRO-raised potted plants of the same age.