Chemical Composition of Essential Oil from Seven Ocimum basilicum L. Accessions, Brine Shrimp Lethality Bioassay and Inhibitory Activities Against GAPDH and APRT

Journal of Essential Oil Research: JEOR, Jan/Feb 2007 by Alves, Péricles B, Filho, Pedro S Freire, Moraes, Valéria R S, Blank, Arie F, Et al

Abstract

The leaf essential oils of seven Ocimum basilicum L. accessions were analyzed by a combination of GC and GC/ MS. They were tested for cytotoxicity using brine shrimp lethality test and for their ability to inhibit the enzymatic activity of the glycossomal glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Trypanosoma cruzi and adenine phosphoribosyltransferase (APRT) from Leishmania tarentolae. The oils showed significant activity (LC^sub 50^

Key Word Index

Ocimum basilicum, Lamiaceae, Brine shrimp lethality test, Trypanosoma cruzi, Leishmania tarentolae, essential oil composition, linalool, methyl chavicol, methyl eugenol, geraniol, α-muurolol.

Plant Name

Ocimum basilicum L. (Lamiaceae).

Source

The leaves of Ocimum basilicum L. were collected from the Germoplasin Bank of Ocimum from the Universidade Federal de Sergipe, São Cristovão, Sergipe, Brazil (1).

Plant Part

The essential oils were obtained by hydrodistillation of 75 g of dry leaves and flowers harvested at full bloom, for 2 h using a Clevenger-type apparatus, from the leaves of genotypes Ames7772 (yield: 0.467%), PI358466 (0.407%), PI368700 (1.03%), NSL6421 (0.692%), PI207498 (0.327%), PI253157 (0.330%), PI296390 (0.769%).

Previous Work

The sweet basil (Ocimum basilicum L.) has several culinary, ornamental, medicinal and aromatic uses. Ocimum basilicum has been used in the treatment of acne, fevers, throat congestions, stomachache, headaches, coughs, diarrhea, constipation, warts, worms, insect bites, and kidney malfunctions. It has also exhibited diuretic, appetite stimulant, insecticidal, antibacterial and antifungal properties (2-12).

To the best of our knowledge, there is no report on the oil composition and biological activities of these O. basilicum L. genotypes.

Present Work

GC-FID: Analyses were carried out using a Shimadzu 17A gas chromatograph instrument equipped with J&W Scientific DB-5 fused silica capillary column (30 m x 0.25 mm, 0.25 µm film thickness); the column temperature program was 80°C for 1.5 min, with 4°C increases per min to 180°C, then 10°C/min to 300°C, ending with a 10 min isothermal at 300°C. Injector and detector temperatures were 250°C in and 280°C, respectively. Hydrogen was used as carrier gas at a flow rate 1.5 mL/min in the split mode, with an injection volume, 0.5 μL solution in ethyl acetate. The percent composition of each component was determined from the area of the component divided by the total area of all components isolated under these conditions.

GC/MS; Mass spectra were obtained using a Shimadzu QP5050A gas chromatograph-mass spectrometer. The carrier gas was He and the column and program was the same as that for the GC-FID experiments. The MS were taken at 70 eV with a scanning speed of 0.85 scan/s from m/z 40 to 550. The retention indices were obtained by co-injecting the oil sample with a C^sub 9^-C^sub 19^ linear hydrocarbon mixture. The volatile components were analyzed by GC-FID and GC/MS, and identification was made on the basis of comparison of retention indices (13) as well as by computerized matching of the acquired mass spectra with those stored in NIST21 and NIST107 mass spectral library of the GC/MS data system and other published mass spectra (14). Chemical compositions of oils are reported in Table I.

Cytotoxicity using Brine shrimp lethality test, inhibitory activity against glycossomal glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Trypanosoma cruzi and adenine phosphoribosyltransferase (APRT) from Leishmania tarentolae was determined according to procedures described below.

Brine shrimp lethality test: The brine shrimp lethality bioassay is an efficient, rapid and inexpensive test that has a good correlation with cytotoxic activity in some human solid tumors and with pesticidal activity (15-17).

Brine shrimp eggs were hatched in a shallow rectangular container (6 cm × 9.5 cm) filled with artificial sea water which was prepared with a commercial salt mixture and double-distilled water (38 g/L). A plastic divider was clamped in the container to make two unequal compartments. The eggs were sprinkled into the larger compartment which was darkened, while the smaller compartment was illuminated. After 48 h, the phototropic nauplii were collected by pipette from the lighted side, having been separated by the divider from their shells.

Samples were prepared by dissolving 20 mg of oils in 2 mL of hexane (Solution A-1000 μg/mL). Solution B (100 μg/mL) was prepared by diluting 0.2 mL of A to 1.8 mL with hexane and the solution C (10 μg/mL) was prepared by diluting 0.2 mL of B to 1.8 mL with hexane. Three replicates containing 0.5 mL of the oil solution were prepared for each dose level.

After solvent evaporation, a drop of dimethyl sulfoxide (DMSO) and 10 shrimp were transferred to each sample vial using a pipette, and artificial sea water was added to make 5 mL. The nauplii can be counted macroscopically in the stem of the pipette against a lighted background. The vials were maintained under illumination. Survivors were counted after 24 h, and the LC^sub 50^ at each dose and control were determined by using a Probit program.