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Química

Evaluation of bioactive extracts of Parapiptadenia rigida and Piptadenia gonoacantha using supercritical CO2

Avaliação de extratos bioativos de Parapiptadenia rigida e Piptadenia gonoacantha usando CO2 supercrítico

Autores:
1MOURA, Bruna S.;
2,3CATUNDA JÚNIOR, Francisco E. A.*;
2CARVALHO, Mário G.;
1MENDES, Marisa F.;
Instituições
1UFRRJ, Departamento de Engenharia Química, Seropédica, RJ, Brasil.
2UFRRJ, Departamento de Química, Seropédica, RJ, Brasil.
3Faculdades INTA, Núcleo de Bioprospecção e Experimentação Molecular Aplicada-Nubem, Sobral, CE, Brasil.
*Correspondência:
cearajr@gmail.com

Resumo

A avaliação e composição do perfil de extratos das folhas de Parapiptadenia rigida e Piptadenia gonoacanthausando CO2 supercrítico em diferentes condições de temperatura (40, 60, 80ºC) e pressão (100, 150, 200 bar) foram estudadas. Os experimentos foram realizados numa unidade contendo, principalmente, um extrator de aço inoxidável e uma válvula micrométrica de amostragem. A melhor pressão para extração foi de 200 bar. Para a espécie Parapiptadenia rigida, a melhor temperatura de extração foi 60ºC (0,73%), sendo 80ºC para Piptadenia gonoacantha (1,13%). Benzenosulfonamida esteve presente em todos os extratos e confere aos extratos uma característica interessante devido à atividade antifúngica contra patógenos de plantas.

Palavras-chave:
Parapiptadenia rígida.
Piptadenia gonoacantha.
Fluido supercrítico.
Extratos.
Benzenosulfonamida.
Solubilidade.

Abstract

The evaluation and composition of the leaves extracts profile of Parapiptadenia rigida and Piptadenia gonoacantha using supercritical CO2 in different conditions of temperature (40, 60, 80ºC) and pressure (100, 150, 200 bar) were studied. Experiments were performed in a unit mainly containing a stainless steel extractor and a micrometer valve for sampling. The better pressure for the extraction was 200 bar. The best temperature for extraction was 60ºC for Parapiptadenia rigida (0.73%), and 80ºC for Piptadenia gonoacantha (1.13%). Benzene sulfonamide was presented in all extracts and makes an interesting characteristic of the extracts due to the antifungal activity against plant pathogens.

Key-words:
Parapiptadenia rigida.
Piptadenia gonoacantha.
Supercritical fluid.
Extracts.
Benzenesulfonamide.
Solubility.

Introduction

The Piptadenia genus belongs to Mimosoideae (Leguminosae) family and contains about 133 tropical species commonly found in Brazil and South America. The Piptadenia species are known, in Brazil, as "angico" and in Argentina and Paraguay, as "cebil". The plants of this genus have been used in the tannery industry due to its bark that is rich in tannins. Also, they helped the forests recovery because they can growth in poor and degraded soil (CORREA, 1984; LORENZI, 2002). There are 15 names of scientific species for Parapiptadenia genus and among these 6 names of species are accepted (MORIN, 2016). The Parapiptadenia rigida (Benth) Brenan, and the former synonym Piptadenia rigida, species is a tree that reaches between 20 and 30 m in height. It is popularly known as angico red and is often found in the Atlantic Forest. The wood is heavy, very hard, and inelastic and has great durability under natural conditions. It can be used in carpentry, joinery, and for firewood and coal. The plant has ornamental features that recommend it for the landscaping in general (LORENZI, 2002).

The Piptadenia gonoacantha (Mart.) J.F. Macbr. specimens have characteristics of small spines. It can reach up to 20 m high and it can be found in Atlantic Forest, in Southeast and South regions of Brazil, including the state of Mato Grosso do Sul. Although it is an under appreciated species due to its blade-shaped spines, it is important in reflorestation. The wood is moderately heavy, hard to cut and measured resistance to pest attack. It is used in furniture, interior finishes, making toys, packaging, brains and door panels, wood and coal (LUNZ, 2004; BEDETTI, MODOLO; and DOS SANTOS ISAIAS, 2014).

Although the species P. rigida e P. gonoacantha have been used in industry, there are not works in literature regarding the components present in this species able to withstand the attack of Scolytidae (species of caterpillar).

One of extraction processes of essential oils that have prominent among other industrial processes is the supercritical fluid extraction. Williams (1981) defined it as a single process where solvents are employed in operational conditions above their critical points to extract soluble components of a mixture.

One of the advantages of supercritical fluid extraction is the possibility of easy recovery of solvent after the extraction process, just by adjusting the temperature and pressure, and the solvent could be continually recycled (STAHL, QUIRIN; and GERARD, 1987).

This process, in which the products extracted have a high purity due to the absence of organic solvent, is generally fast and does not cause environmental damage when using carbon dioxide as supercritical solvent. A solvent widely used in supercritical fluid extraction is carbon dioxide. It has low critical temperature (Tc=31.04 °C) and pressure (Pc=73.8 bar), allowing the extraction of thermolabile products without changing the properties of the extracts. Also, it is inert, offers no risk of secondary reactions, harmless, non-explosive, non-polluting, and non-toxic. The process of separation of solvent and extracted product is simple, because CO2 is a gas at ambient temperature and pressure and has low cost (HERRERO, CIFUENTES; and IBAÑEZ, 2006).

The extraction is much easier because the properties of the fluids in the supercritical state, such as compressibility similar to a gas, density similar of a liquid, ability to dissolve solutes like a liquid, viscosity like of gas and values of diffusivity intermediate between gas and liquid varying with density. The properties of a fluid in a critical condition are very sensitive to small changes in pressure, temperature and, consequently, in density (PEREIRA; and MEIRELES, 2010).

The objective of this research was to evaluate the efficiency of the extraction of leaves of  Parapiptadenia rigida and Piptadenia gonoacantha using CO2 in a supercritical state in different operational conditions of temperature and pressure and the composition profile related to bioactive components.

Materials and methods

Materials

The leaves samples of Parapiptadenia rigida and Piptadenia gonoacantha were collected in the Forest Institute (FI) of the Federal Rural University of Rio de Janeiro by Professor Acácio Geraldo de Carvalho and Professor José Aguiar Sobrinho. A voucher specimen (RBR 6939) and (RBR 21438), respectively, has been deposited at RBR Herbarium, Biology Institute (Universidade Federal Rural do Rio de Janeiro). After collection, the leaves were dried at ambient temperature and stored in a well-ventilated location.

Carbon dioxide with a minimum purity of 99.9% (White Martins, Rio de Janeiro) was used as solvent in the supercritical extraction.

Experimental methodology

Hydrodistillation
The hydrodistillation extraction of the leaves was done with 348 g of P. rigida and 191 g of P. gonoacantha using 1000 mL of distilled water in a period of three hours in the boiling point of water.

At the end of extraction, the mixture of extracted oil and water was submitted to an extraction with dichloromethane (3 x 50 mL) in a separation funnel. The organic fraction was treated with anhydrous sodium sulphate in excess. The extract fraction mass obtained was 17 mg for P. rigida and10 mg for P. gonoacantha. After that, the solutions were filtrated and concentrated.

Supercritical fluid extraction
The extraction of P. rigida and P. gonoacantha with supercritical carbon dioxide was performed at Applied Thermodynamics and Biofuel Laboratory (DEQ/UFRRJ). The experimental apparatus consists of a stainless steel 316S extractor with 42 mL of capacity. The extractor contains two canvas of 260 meshes to prevent the entrainment of material. A high-pressure pump (Palm model G100), specific for pumping CO2, was responsible for feeding the solvent into the extractor. A thermostatic bath (model Haake K15) was coupled to the extractor to control the temperature and a manometer was installed on line for controlling the pressure.

About 4.5 g of vegetable material was fed into the extractor and then the thermostatic bath was turned on, reaching the desired temperature. The experiments were performed under the operational conditions of 100, 150 and 200 bar for pressure and 40, 60 and 80°C for temperature. The maximum time of extraction was 80 min, when it was observed the saturation of the extraction curve. Sampling occurred at a maximum flow of 16.45 mL/min, controlled by a rotameter, and was performed at each 5 min using the technique of decompression through the valve. With the pressure reduction, the sample is recovered in a polypropylene tube. The yield was calculated as a ratio between the extracted oil mass and the initial plant mass fed into the extractor.

Chromatographic analysis
All samples obtained from hydrodistillation and supercritical fluid extraction, were analyzed by gas chromatograph coupled to a mass spectrometer (GC-MS) using a Shimadzu equipment (model QP 2010), with helium as a carrier gas. A Factor Four/VF-5 ms capillary column with 30 m of length, 0.25 mm of inner diameter and 0.25 µm of thickness were used. The flow rate of helium was 1 mL/min and the temperature programmer used was an increasing step of 10ºC/min from 100 to 290 ºC. The injector temperature was 250ºC, the detector temperature was 310ºC and split was the injection mode at ratio 1:20 with an injection volume of 2 µL at 10% in dichloromethane. The mass spectra were produced through electronic impact (70 eV). The database in the NIST08 library was used to compare and identify the components.

Results and discussion

Analysis of the experimental operational conditions

For determination of yield the processes were performed in triplicate and the average results are shown in TABLE 1, for the two species.

TABLE 1. Yields of the extract of Parapiptadenia rigida and Piptadenia gonoacantha with supercritical CO2.
Pressure(Bar) Temperature (°C)
40 60 80
Parapiptadenia rigida
100 0.44 + 0.11* 0.40 + 0.07  0.54 + 0.12
150 0.60 + 0.17 0.57 + 0.03 0.79 + 0.18
200 0.64 + 0.21 0.73 + 0.12 0.75 + 0.05
Piptadenia gonoacantha
100 0.31 + 0.21 0.42 + 0.13  0.65 + 0.04
150 0.68 + 0.22 0.56 + 0.10 1.05 + 0.13
200 0.85 + 0.24 0.67 + 0.08 1.31 + 0.15
* standard deviation

According to the results, the best extraction conditions were obtained at 60 °C and under pressure of 200 bar with the yield of 0.73%, for P. rigida leaves. For Piptadenia gonoacantha, the best result was obtained at 80 ºC and 200 bar (1.13%).

For the two species, at 60ºC, the yield decreases when compared the experimental results at constant pressure. This behavior has been observed for many raw materials studied involving plants and seeds, like macadamia nuts (SILVA et al., 2008).

In all experiments, the best yield results were obtained at higher pressures maintaining the temperature constant. The increase in pressure, at constant temperature, caused an increase in the density of the solvent. Moreover, the increase in the solvency power results in an increase in yield.

The accumulated yield of the extracts in function of the extraction time, for all the pressures studied, can be seen in FIGURES 1 and 2, respectively for P. rigida at 60ºC and for P. gonoacantha at 80ºC.

In order to evaluate the effect of pressure and temperature in the efficiency of the oil extraction, statistic tests were performed using the triplicate measurements obtained for each operational condition. The main parameters of the analysis of variance (ANOVA) P. gonoacantha and P. rigida are shown in TABLES 2 and 3, respectively.

TABLE 2. Analysis of variance of experimental data of Parapiptadenia rigida oil extraction (Fcritical = 3.1789).
T P CV Fcalc p-valor
40 100 0.024 41.51 2×10-11
150
200
60 100 0.029 9.13 0.000408
150
200
80 100 0.029 7.38 0.00152
150
200
T is the temperature, P is the pressure, and CV is the variation coefficient, while Fcalc and Fcritical are the calculated and critical F-values, respectively.
TABLE 3. Analysis of variance of experimental data of Piptadenia gonoacantha oil extraction (Fcritical = 3.1789).
T P CV Fcalc p-valor
40 100 2.64×10-7 5.41 0.007212
150
200
60 100 1.00×10-6 9.35 0.000326
150
200
80 100 7.82×10-6 8.11 0.000832
150
200
T is the temperature, P is the pressure, and CV is the variation coefficient, while Fcalc and Fcritical are the calculated and critical F-values, respectively.

Based on the ANOVA results exhibited in TABLES 2 and 3, the low values obtained for standard deviations (less than 3%), as well as for all coefficient of variations (less than 5%), indicate the good reproducibility of the experimental procedure, which means that the results presented in this work are reliable.

It can be observed that, when the pressure increased, the efficiency also increased at constant temperature, for the two plants studied. This feature was already expected since as the pressure increases the carbon dioxide density increases as well.

Considering the experimental apparatus used, and the operational conditions investigated in this work, the calculated F-values and p-values indicate that the values of temperature and pressure were effective, meaning that the combination of them produced a high content oil of bioactive components.

FIGURE 1. Extraction curve of Parapiptadenia rigida at 60°C and at pressures of 100, 150 and 200 bar.
FIGURE 2. Extraction curve of Piptadenia gonoacantha at 80°C and at pressures of 100,150 and 200 bar.

For results at 60 and 80ºC, the yield increased with the increase in temperature, for P. rigida extraction. This occurred because the vapor pressure of the solutes increased, favoring the extraction process.

At 80ºC, it was observed a crossover behavior between the curves of 100 and 200 bar, showing the effects of density and vapor pressure of the solute in the extraction efficiency.

TABLE 4. show the experimental results of solubility of the extract of P. rigida and P. gonoacantha. The results show that the solubility ranged from 0.0109 to 0.0357 (g extract/L CO2) for the first one and from 0.0095 to 0.0422 (g extract/L CO2) for the P. gonoacantha. It was observed that the solubility increases with increasing pressure, at constant temperature, except at 80°C at pressures of 150 and 200 bar, for the P. rigida. The solubility behavior was in an opposite way when compared with others results (STAHL, QUIRIN; and GERARD, 1987). The increase in temperature, at constant pressure, leads to an increase in solubility, except at 200 bar. This may be related to the competitive effects of the vapor pressure of the solute and solvent density. The combined effect of both will determine the behavior of the variation of solubility with the operational conditions.

TABLE 4. Experimental solubilities (g extract/L CO2) of extracts of Parapiptadenia rigida and Piptadenia gonoacantha with supercritical CO2.
Pressure (bar) Temperature (ºC)
40 60 80
Parapiptadenia rigida
100 0.0109 0.0150 0.0161
150 0.0179 0.0214 0.0259
200 0.0357 0.0259 0.0211
Piptadenia gonoacantha
100 0.0095 0.0140 0.0204
150 0.0209 0.0181 0.0335
200 0.0261 0.0205 0.0422

Identification of bioactive substances
By GC-MS, TABLES 5 and 6 show the identified components and the relative integrated areas of each component, in percentage, in the extracts obtained from the different operational conditions, for P. rigida and P. gonoacantha, respectively, using supercritical fluid.

From the TABLES it can be seen that the extracts are characterized by complex mixtures. The majority components identified in the P. rigida extract, using carbon dioxide, according to the peak area, are: 4,6-dimethyl-dodecane, N-butyl-benzene-sulfonamide (NBBS), Bis(2-ethyl-hexyl) hexadecanoate, 2-hydroxy-1-(hydroxy-methyl)ethyl hexadecanoate, 2,3-dihydroxy-propyl octadecanoate and sitostenone.

In the extract of P. gonoacantha,there were identified as majorities the NBBS, 2-hydroxy-1-(hydroxy-methyl) ethyl hexadecanoate, N-(2-ethoxy-phenyl)-N'-(1-phenyl-ethyl)-oxalamide, 2,3-dihydroxy-propyl octadecanoate, squalene, nonacosane, 1,30-triacontanediol and 1-heptacosanol.

The high content of NBBS in the P. rigida extract makes an interesting characteristic of the oil due to the antifungal activity against plant pathogens. The NBBS isolated from Pseudomonas sp. AB2, an antifungal bacteria family, showed ED50 (effective dosage) of 33, 41, 73 and 102 ppm against Rhizoctonia solani, Phytophthora capsici, Pythium ultimum and Botrytis cinerea, respectively. This effect generated by NBBS can effort that the species P. rigida produces this metabolite to defend against these types of plant pathogens (KIM et al., 2000).

The NBBS was also extracted from Angelica sinensis (Oliv.) Diels (DENG et al., 2006). The same component isolated from the kernel of Prunus africana (Hook.f.) Kalkman (synonym Pygeum africanum Hook.f.) presented an elevated antiandrogenic activity, inhibiting the cells growing responsible for the prostate cancer, due to the fact that they do not accept the treatment with hydroxyflutamide (PAPAIOANNOU et al., 2010; ROELL; and BANIAHMAD, 2011).

In this study, it was observed that the NBBS content decreased with the pressure increasing when compared from 40 to 60ºC. The total yield using supercritical fluid increases with the pressure increasing. For the temperature of 80°C, the NBBS content and the yield increased with the increase in pressure. In the P. gonoacantha extract,the main component is the NBBS derivative with a molecular weight of 290 g/mol. It was observed in the extracts obtained at 150 bar and 60°C, with the highest concentration (53.70%). At 40°C, the highest content of NBBS derivative was found in the oil extracted at 100 bar; it was observed a decreasing at 150 bar and a slight increasing at 200 bar. At 80°C, only at 150 bar it was observed the presence of NBBS derivative in the extracts (see TABLES 5 and 6). For P. rigida, higher contents of NBBS derivative were obtained at 80ºC and 200 bar.

The NBBS was also found in other natural raw materials, as in the orange pomace oil extracted using supercritical fluids, with concentrations of 88.8 and 91.4% at 40°C and 200 bar and at 40°C and 300 bar, respectively (BENELLI et al., 2010). The NBBS derivative was also observed in the peach almond oil, extracted using supercritical fluid, with the concentrations of 97.0 and 98.8% at 50°C and 300 bar and at 40°C and 300 bar, respectively (MEZZOMO, MANTÍNEZ; and FERREIRA , 2009).

The compositions of P. rigida and P. gonoacantha extracts, respectively, by hydrodistillation, were apparently different, as showed in TABLE 7. The majority components present in the extracts using supercritical fluid were not observed in the extracts obtained by hydrodistillation, with the exception of hexadecanoic acid. The composition of the oil obtained by hydrodistillation is characterized by the presence of low molecular weight compounds commonly present in essential oils, like m-cumenol, cis-pulegol and ionones, beyond volatile compounds such as aldehydes, ketones, alcohols, acids and sesquiterpene.

TABLE 5. Chemical composition of Parapiptadenia rigida extracts using supercritical fluid.
Compounds RT
(min)		 Relative area (%)
Extraction conditionsa
1A 1B 1C 2A 2B 2C 3A 3B 3C
5,6,7,7a-Tetrahydro-4,4,7a-trimethyl-,(R)-2(4H)-benzofuranone 9.68 - - - - - - - - 1.05
3-Methyl-5-propylnonane 10.23 - - - - 1.36 0.89 - - -
2,6,10-Trimethyl-dodecane, 10.78 - - - 1.58 1.54 1.38 - - -
Nonanedioic acid 10.90 - - - - - - - - 1.57
4,6-Dimethyl-dodecane 11.45 - - - 10.43 6.49 6.08 - - -
10-Methyl-nonadecane 11.92 - - - 1.06 0.92 0.93 - - -
Isotridecanol 12.08 - - - - - - - 0.91 -
4-(2,4-Dimethylcyclohex-3-enyl)but-3-en-2-one 12.55 - - - - - - - 0.87 -
n-Octadecane 12.59 - - - 5.00 3.69 3.48 - - -
N-Butyl-benzenesulfonamide  12.66 19.92 17.24 - 10.79 10.86 7.93 2.84 13.86 22.53
N-Butyl-benzenesulfonamide derivative (m/z 290) 12.96 - - 16.89 - - - - - -
Hexahydrofarnesyl acetone 13.07 - 1.24 - 3.28 2.55 1.76 - 1.50 2.35
7,9-Di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione 13.89 - - - - - - - 0.86 -
Phytol 13.93 - - 0.81 - - - - - 1.14
n-Hexadecanoic acid 14.35 - - 5.74 - - - 4.33 4.16 7.48
2-Hexyl-1-decanol 14.73 - - - - - - - - 0.95
cis-13-Octadecenal 16.17 - - 0.96 - - - - - 1.16
n-Octadecanoic acid 16.35 - - 5.15 - - - 3.45 2.73 5.44
Ethyl 9-hexadecenoate 16.61 - - 1.12 - - - - - 1.20
Linoleic acid 16.96 - - - - - - - - 0.84
4,8,12,16-Tetramethylheptadecan-4-olide 18.13 - - 1.63 - 0.87 0.65 - - -
Bis(2-ethylhexyl) hexanedionate 18.38 3.68 4.89 - 12.03 5.40 3.60 - - -
Eicosyl 2-ethylbutyrate 19.25 - - - - - - - 1.23 -
2-Hydroxy-1-(hydroxymethyl)ethyl hexadecanoate 19.54 - - 4.94 - - - 27.93 15.24 4.14
2,3-Bis[(trimethylsilyl)oxy]propyl eicosanoate 20.78 - - - - - - - - 1.65
2-Deoxy-bis(thiononyl)-dithioacetal d-ribose 20.99 - - - - - - 1.33 1.50 -
2,3-Dihydroxypropyl octadecanoate 21.33 - - 3.36 - - - 24.89 13.74 2.61
Nonacosane 23.01 - - - 1.24 2.80 2.19 - - -
Triacontane 25.85 0.63 2.13 0.75 0.67 3.30 2.39 - - -
Stigmasterol acetate 26.04 - - 2.08 - - - 1.61 1.12 2.34
1,30 Triacontanediol 28.88 2.16 3.00 5.49 - 4.06 4.19 7.81 3.38 4.94
1-Heptacosanol 30.53 - - 3.76 - - - 5.65 - 1.44
Sitosterol 31.24 2.01 3.94 1.07 - 2.16 2.33 - - -
4,22-Stigmastadiene-3-one 33.15 8.78 6.84 4.09 3.45 5.15 4.81 - 1.19 3.87
Lupeol 34.04 3.29 2.72 1.21 - - - - - 1.44
Sitostenone 35.25 36.22 29.63 14.95 15.18 20.27 19.60 - 6.98 13.98
Friedeline 38.75 4.51 6.94 5.35 - 5.59 4.05 - - 3.94
4-tert-Butylcalix[4]arene 39.38 - - 1.70 - - - 6.22 4.27 1.65
Stigmastane-3,6-dione 41.33 - - 2.18 - - - - - -
Extraction conditionsa: 1A (40°C/100 bar); 1B (40°C/150 bar); 1C (40°C/200 bar); 2A (60°C/100 bar); 2B (60°C/150 bar); 2C (60°C/200 bar); 3A (80°C/100 bar); 3B (80°C/150 bar); 3C (80°C/200 bar).
TABLE 6. Chemical composition of Piptadenia gonoacantha extracts using supercritical fluid
Compounds RT
(min)		 Relative area (%)
Extraction conditionsa
1A 1B 1C 2A 2B 2C 3A 3B 3C
n-Tetradecane 11.45 - - - 0.85 - - - - -
4-Methyl-tetradecane 12.11 - - - 1.20 - - - - -
n-Octadecane 12.58 - - - 1.48 - - - - -
n-Methyl-benzenesulfonamide 12.63 - 0.80 1.34 - - - - - -
n-Butyl-benzenesulfonamide 12.66 20.38 - - - - - - 1.72 -
n-Butyl-benzenesulfonamide derivative (m/z 290) 12.96 - - - 35.44 53.7 47.24 - - -
Hexahydrofarnesyl acetone 13.08 0.82 - - 2.97 - - -
n-Nonadecane 13.96 - - - 2.04 - - -
n-Hexadecanoic acid 14.33 - 0.62 - 2.82 6.89 5.42 0.62 0.54 -
cis-9-Hexadecenal 16.20 - - - - 2.19 1.34 - - -
n-Octadecanoic acid 16.36 - - - 1.54 3.03 2.96 - - -
n-Eicosane 16.66 2.04 1.20 5.64 - - - - - -
2,7,10-Trimethyldodecane 16.68 0.78 0.52 - - - - - - -
2,6,10,15-Tetramethylheptadecane 17.58 0.65 0.39 - - - - - - -
Heptadecane 17.64 - 2.34 - - - - - - -
n-Heneicosane 17.83 - - 0.76 - - - - - -
4,8,12,16-Tetramethylheptadecan-4-olide 18.13 0.67 0.71 1.23 - - - 0.98 0.44 -
Bis(2-ethylhexyl) hexanedionate 18.40 2.83 - 1.45 - - - 3.22 3.01 -
n-Docosane 18.45 - - - - - - 1.49 0.85 -
n-Tricosane 19.29 - - - - - - 1.75 1.27 -
2-Ethylhexyl octadecyl oxalate 19.31 3.26 1.45 4.23 - - - - - -
2-Hydroxy-1-(hydroxymethyl)ethyl   hexadecanoate 19.56 - - - 13.86 4.37 2.68 - - -
Oxalic acid diamide N,N'-bis(2-ethylphenyl)- 19.61 - 0.79 - - - - - - -
N-(2-Ethoxy-phenyl)-N'-(1-phenyl-ethyl)-oxalamide 20.66 6.74 12.48 4.25 0.90 1.86 1.86 - 4.10 7.19
n-Tetracosane 20.95 4.21 5.07 9.04 - - - 1.91 2.06 1.35
2,3-Dihydroxypropyl octadecanoate 21.36 - - - 12.37 2.90 2.38 - - -
n-Pentacosane 21.90 - - - - - - 1.42 2.68 -
Squalene 22.13 - - - - - - - - 22.91
Nonacosane 23.03 11.67 14.25 11.68 - 1.80 1.95 3.49 16.93 13.49
2,2-Dimethyl-3-(3,7,16,20-tetramethyl-heneicosa-3,7,11,15,19-pentaenyl)-oxirane 23.55 - - - - - - - - 1.61
n-Dotriacontane 24.32 2.94 3.90 2.62 - - - 0.68 3.25 2.42
n-Triacontane 25.84 7.70 10.14 6.25 - 1.33 1.41 1.32 8.29 6.02
1-Heptatriacotanol 26.39 - - - - - - 1.38 - 1.28
Vitamin E 26.75 - - - - - 0.83 - - 2.00
n-Tritetracontane 27.76 - 0.89 0.80 - - - - 0.79 -
Octadecanal 28.90 10.31 9.22 8.38 2.60 3.17 4.49 13.98 12.86 5.25
1-Heptacosanol 30.51 - - - - 2.61 5.05 53.98 - -
2-Nonadecanone 30.82 - 4.99 2.19 - - - - - 1.49
Sitosterol 31.30 - - - - 2.12 1.90 - - -
Lupeone 33.19 - - - - 3.17 2.46 - - -
Lupeol 34.04 - - - - 2.17 1.82 - - -
Pentadecanal 34.61 2.10 3.40 4.62 - - - 2.52 2.09 -
1,2-Epoxy-3-(hexadecyloxy)-propane 37.61 - - - - - - - - 2.50
Extraction conditionsa: 1A (40°C/100 bar); 1B (40°C/150 bar); 1C (40°C/200 bar); 2A (60°C/100 bar); 2B (60°C/150 bar); 2C (60°C/200 bar); 3A (80°C/100 bar); 3B (80°C/150 bar); 3C (80°C/200 bar).

The majority of the components of P. rigida oil were the hexadecanoic acid, phytol and the octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate and the majorities of P. gonoacantha oil were the hexadecanoic acid, phytol, and the linolenic acid.

TABLE 7. Chemical composition of Parapiptadenia rigida and Piptadenia gonoacantha extracts by hydrodistillation.
Compounds RT
(min)*		 %* RT (min)** %
**
Benzeneacetaldehyde 3.454 3.02 - -
2-pyridineacetic acid hexahydro-1-methyl - - 4.294 1.18
m-cumenol - - 5.356 0.82
cis-pulegol - - 5.543 0.66
Nonanoic acid - - 5.876 1.55
Geranic acid - - 7.136 5.51
Decanoic acid - - 7.233 1.13
m-Benzyloxybenzaldehyde 7.791 3.02 - -
trans-alpha-Ionone - - 8.119 0.99
cis-geranylacetone - - 8.352 0.69
2-Phenyl-1,3-dioxan-5-yl-(9E,12E,15E)-9,12,15-octadecatrienoate 8.498 1.44 - -
7-Methoxy-2,2,4,8-tetramethyltriciclo-undecane - - 8.534 5.05
trans-β-Ionone - - 8.867 1.67
trans-Ionone epoxide - - 9.155 6.73
2,6-Bis(1,1-dimethylethyl)-4-methyl-phenol, 9.29 1.69 9.29 1.20
Dicyclohexyl methanone, - - 9.37 0.70
5,5,8a-Trimethyl-3,5,6,7,8,8a-hexahydro-2H-chromene - - 9.45 0.53
5,6,7,7a-Tetrahydro-4,4,7a-trimethyl-(R)-2(4H)-benzofuranone,  9.679 1.69 - -
Cinnamic acid m-methyl - - 9.714 4.24
Dodecanoic acid 9.746 2.27 10.144 1.52
5,6,7,7a-Tetrahydro-4,4,7a-trimethyl 2(4H)-benzofuranone, - - 9.806 3.77
Tetradecanoic acid 12.131 1.45 12.509 1.54
1-Tetradecene - - 12.757 1.63
Hexahydrofarnesyl acetone 13.066 2.59 13.861 0.97
1-Nonadecene - - 13.069 1.65
Methyl pentadecanoate 13.951 1.79 - -
Isophytol - - 14.179 0.99
Hexadecanoic acid 14.361 9.89 14.441 13.05
Ethyl hexadecanoate - - 14.66 2.08
n-Nonadecanol-1 - - 15.621 1.07
Linoleic acid 15.696 1.65 15.7 0.67
Phytol 15.858 13.44 15.872 7.90
Octadecanoic acid 16.338 1.89 - -
1,3-Dioxolane, 2-(phenylmethyl)- 16.409 1.56 - -
Pregna-4,16-diene-3,20-dione 18.761 2.00 - -
Eicosane 19.289 1.47 - -
Heneicosane 20.947 1.62 - -
Tetracosane 23.001 2.47 - -
4-tert-Butylcalix[4]arene 23.36 3.88 - -
Octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl) propanoate 24.739 12.84 - -

*Parapiptadenia rigida
** Piptadenia gonoacantha

Acknowledgments

To CNPq, CAPES and FAPERJ, for financial support.

References