Antifungal activity of Piper diospyrifolium Kunth (Piperaceae) essential oil

Vieira, Silvia Cristina Heredia; Paulo, Luis Fernando de; Svidzinski, Terezinha Inez Estivaleti; Dias Filho, Benedito Prado; Nakamura, Celso Vataru; Souza, Amanda de; Young, Maria Cláudia Marx; Cortez, Diógenes Aparício Garcia

doi:10.1590/S1517-83822011000300020

Abstract

In vitro activity of the essential oil from Piper diospyrifolium leaves was tested using disk diffusion techniques. The antifungal assay showed significant potencial antifungal activity: the oil was effective against several clinical fungal strains. The majority compounds in the essential oil were identified as sesquiterpenoids by GC-MS and GC-FID techniques.

Piper diospyrifolium; essential oil; antifungal activity

MEDICAL MICROBIOLOGY

Antifungal activity of Piper diospyrifolium Kunth (Piperaceae) essential oil

Silvia Cristina Heredia Vieira^I; Luis Fernando de Paulo^II; Terezinha Inez Estivaleti Svidzinski^II; Benedito Prado Dias Filho^II; Celso Vataru Nakamura^II; Amanda de Souza^III; Maria Cláudia Marx Young^III; Diógenes Aparício Garcia Cortez^I,^* * Corresponding Author. Mailing address: Departamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brasil.; E-mail: dagcortez@uem.br

^IDepartamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brasil

^IIDepartamento de Análises Clínicas, Universidade Estadual de Maringá, PR, Brasil

^IIIInstituto de Botânica de São Paulo, São Paulo, SP, Brasil

ABSTRACT

In vitro activity of the essential oil from Piper diospyrifolium leaves was tested using disk diffusion techniques. The antifungal assay showed significant potencial antifungal activity: the oil was effective against several clinical fungal strains. The majority compounds in the essential oil were identified as sesquiterpenoids by GC-MS and GC-FID techniques.

Key words:Piper diospyrifolium; essential oil; antifungal activity

The family Piperaceae is pantropical in distribution. In Brazil, it is represented by five genera (Piper, Peperomia, Potomorphe, Ottonia, and Sarcorhachis) and about 500 species, which are quite common in forests, particularly in the Atlantic Tropical Forest (24, 26). known for the aromatic properties of many members, the family's best-know representatives belong to the genus Piper, including species that are currently used as producers of essential oils, such as Piper arboreum, P. hispidum, P. crassinervium, P. lanceaefolium, and P. auritum (4, 13, 14, 16, 17, 19, 25). Studies by Fazolin et al. (5) gave promising results for the use of essencial oils from P. hispidinervum and P. aduncum as insecticides, at concentrations above 3.0% (v/v) and 2.5% (v/v), respectively. Species of Piperaceae are widely used in folk medicine, and their essential oils have high economic and commercial importance (2). The aim of this study was to determine the potential antifungal activity, in vitro, of the essential oil obtained from leaves of P. diospyrifolium. The composition of the oil was determined by GC-MS and GC-FID techniques.

Fresh leaves of native P. diospyrifolium were collected at Maringá, state of PR, southeastern Brazil, in March 2009, from Horto Florestal Dr. Luis Teixeira Mendes (51º30'54W and 22º30'30S), urban zone of Maringá, 556m altitude and 37ha of land. A voucher specimen, HUEM 9392, was deposited in the Herbarium of State University of Maringá.

The essential oil was obtained in a Clevenger apparatus by steam distillation. After 4 h of distillation, 300 g of fresh leaves was extracted with 2.5 l water. The oil was separated from the water and stored in a freezer at - 20ºC.

The essential oil was diluted in acetone 1:10 (v/v) and 1 µL of the sample was analyzed by GC-MS, performed using an Agilent GC (6890 Series) - quadrupole MS system (5973), with a fused silica capillary column (30 m x 0.25 mm i.d. x 0.25 µm film, coated with DB-5), operating at 70 eV. The injection port and detector temperatures were set at 250ºC (1:20 division ratio). The oven temperature program was 40ºC for 1 min and 40-240ºC at 3ºC/min, and helium was employed as the carrier gas (1 mL min^-1), with a total analysis time of 78 min.

The compounds were identified based on comparison of the calculated retention index (Kovats Index (KI)), and the mass spectra with literature data (1), or by comparison with mass spectra recorded in a database (Wiley 275).

The chromatographic conditions from GC-FID analyses were identical to those used for GC-MS.

Yeast strain patterns of Candida albicans ATCC-90028, C. parapsilosis ATCC-22019 and C. tropicalis ATCC-28707 were used. From C. Albicans yeast, isolates from urine, catheter and blood culture were used; from C. parapsilosis, isolates from catheter and blood culture and, from C. tropicalis, clinical samples isolates from urine, blood culture and oro-tracheal tube. Samples were donated by the Santa Casa de Maringá-PR or by the Hospital Universitário de Maringá-PR, and grown at 37ºC in Sabouraud broth.

In vitro antifungal activity of the P. diospyrifolium essential oil was determined by the agar disk diffusion method according to Rubio et al. (21). Yeasts suspensions with turbidity equivalent of the McFarland 0.5 standard were poured on Petri plates containing solid Sabouraud agar. Sterile filter-paper discs (Whatman No. 1, 6.0 mm diameter) were impregnated with 20 µl of the oil and placed on the inoculated plates. Nystatin (Sensifungidisc, Cecon) (100 U.I.) was used as a positive control. These plates were allowed to dry at room temperature for 2 h, and were incubated at 37ºC for 24 to 48 h. After the incubation, the presence or absence of inhibition zones was checked. The diameters of the inhibition zones were measured in millimeters, and their means were calculated (12). All the tests were performed in triplicate.

The essential oil from P. diospyrifolium leaves afforded 0.1%, similar to other Piper species (P. arboreum, P. crassinervium, P. dilatatum and P. tuberculatum) tested by Cysne et al. (4).

The main compounds were sesquiterpenoid hydrocarbons (68.21%) and monoterpene hydrocarbons (19.41%). The majority compounds were eudesmane-type compounds including (E)-eudesma-6,11-diene (21.12%) and y-muurolene (10.57%) and caryophyllene-type (E)-caryophyllene (16.76%) (Table 1).

Thumbnail

Mesquita et al. (11) found a similar predominance of sesquiterpenoids in other species (P. aduncum, P. amalago, P. arboreum, P. cernuum, P. hispidum, P. regnelii, P. submarginalum, P. vicosanum and Pothomorphe umbellate). Three species of Piper from gallery forests of the Cerrado (P. arboreum subsp arboreum, P. dilatatum and, P. hispidum) also showed a predominance of sesquiterpenoids (18).

Yeats are emerging as an important cause of diseases, not only because of their commensal nature but especially due to their implication as important agents of infections. Candidiases primarily infect immunocompromised patients or hospitalized patients with serious underlying diseases (3, 10, 15). Many antifungal agents are available for the treatment of candidal infections, such as polyenes (amphotericin B and nystatin) and azoles (itraconazole and fluconazole). However, due to the occurrence of undesirable outcomes, such as the unpredictable resistance to recently developed antifungal agents, mainly in immunodepressed individuals, as well as their toxic effects, further studies are needed to develop new, more effective antifungal medicines with fewer disadvantages (23, 6, 7, 8).

The essential oil was effective against several clinical isolates and for standard samples of C. albicans (Table 2). The essential oil was more effective against C. parapsilosis (ATCC 22019), with an inhibition zone of 15.0 ± 1.0 mm.

Thumbnail

Rodrigues-Silva et al. (20) reported that essential oil extracted from P. ovatum leaves showed an effect against C. tropicalis ATCC 28707 and C. tropicalis from urine clinical isolates (22.6±3.1 and 18.7 ±2.1 mm respectively. The main constituents found in the oil were δ-amorphene (16.5%), cis-muurola-4(14%),5-diene (14.29%) and γ-muurolene (13.26%).

Eudesmane-type sesquiterpenoids from Asteraceae exhibit a wide range of biological activities, and include compounds that are plant-growth regulators, insect antifeedants, antifungals, anti-tumor compounds and antibacterials (27, 9). The derivative from (E)-caryophyllene like caryophyllene oxide, used as preservative in food, drugs, and cosmetics, has been tested in vitro as an antifungal against dermatophytes. Its antifungal activity has been compared to ciclopirox olamine and sulconazole, wich are commonly used to treat onychomycosis (28).

In conclusion, the essential oil of P. diospyrifolium, under the test conditions, showed interesting antifungal properties. This activity merits further study of this drug as a possible new phytotherapeutic or natural fungicide.

Submitted: May 11, 2010; Returned to authors for corrections: December 13, 2010; Approved: January 31, 2011.

1. Adams, R.P. (2001) Identification of essential oil components by gas chromatography/quadrupole mass spectroscopy Illinois, Allured Pub. Corporation.
2. Albiero, A.L.M; Souza, L.A.; Mourão, K.S.M.; Almeida, O.J.G.; Lopes, W.A.L. (2005). Morfo-anatomia do caule de Piper gaudichaudianum Kuntze (Piperaceae). Acta Farm. Bonaerense 24(4),550-554.
3. Cavassani, V.G.S.; Sobrinho, J.A.; Homem, M.G.N.; Rapoport, A. (2002). Candidíase oral como marcador de prognóstico em pacientes portadores do HIV. Rev. Bras. Otorrinol 68(5),630-4.
4. Cysne, J.B.; Canuto, K.M.; Pessoa, O.D.L.; Nunes, E.P.; Silveira, E.R. (2005). Leaf essential oils of four piper species from the State of Ceara Northeast of Brazil. J. Braz. Chem. Soc 16(6B),1378-1381.
5. Fazolin, M.; Estrela, J.L.V.; Catani, V.; Alécios, M.R.; Lima, M.S. (2007). Propriedade inseticida dos óleos essenciais de Piper hispidinervum C. DC.; Piper aduncum L. e Tanaecium nocturnum (Barb. Rodr.) Bur. & K. Shum sobre Tenebrio molitor L., 1758. Ciênc. Agrotec. 31(1),113-120.
6. Fenner, R.; Betti, A.H.; Mentz, L.A.; Rates, S.M.K. (2006). Plantas utilizadas na medicina popular brasileira com potencial atividade antifúngica. Rev. Bras. Cienc. Farm 42(3),369-394.
7. Gazim, Z.C.; Rezende, C.M.; Fraga, S.R.; Svidzinski, T.I.E.; Cortez, D.A.G. (2008). Antifungal activity of the essential oil from Calendula officinalis L. (Asteraceae) growing in Brazil. Braz. J. Microbiol. 39,61-63.
8. Lima, I.O.; Oliveira, R.A.G.; Lima, E.O.; Farias, N.M.P.; Souza, E.L. (2006). Atividade antifúngica de óleos essenciais sobre espécies de Candida. Rev. Bras. de Farmacogn. 16(2),197-201.
9. Maatooq, G.T.; Stumpf, D.K.; Hoffmann, J.J.; Hutter, L.K.;Timmermann, B.N. (1996). Antifungal eudesmanoids from Parthenium argentatum x P. tomentosa. Phytochemistry 41(2),519-524.
10. Menezes, T.O.A.; Alves, A.C.B.A.; Vieira, J.M.S. Menezes, S.A.F.; Alves, B.P.; Mendonça, L.C.V. (2009). Avaliação in vitro da atividade antifúngica de óleos essenciais e extratos de plantas da região amazônica sobre cepa de Candida albicans. Rev Odontol. UNESP 38(3),184-91.
11. Mesquita, J.M.O.; Cavaleiro, C.; Cunha, A.P.; Lombardi, J.A.; Oliveira, A.B. (2005). Estudo comparativo dos óleos voláteis de algumas espécies de Piperaceae. Rev. bras. de farmacogn. 15(1),6-12.
12. Nascimento, P.F.C.; Nascimento, A.C.; Rodrigues, C.S.; Antoniolli, A.R.; Santos, P.O.; Júnior, A.M.B.; Trindade, R.C. (2007). Atividade antimicrobiana dos óleos essenciais: uma abordagem multifatorial dos métodos. Rev. Bras. de Farmacogn 17(1),108-113.
13. Packer, J.F.; Luz, M.M.S. (2007). Método para avaliação e pesquisa da atividade antimicrobiana de produtos de origem natural. Rev. Bras. de Farmacogn. 17(1),102-107.
14. Parmar, V.S.; Jain, S.C.; Bisht, K.S.; Jain, R.; Taneja, P.; Jha, A.; Tyagi, O.D.; Prasad, A.K.; Wengel, J.; Olsen, C.E.; Boll, P.M. (1997). Phytochemistry of the genus Piper. Phytochemistry 46(4),597-673.
15. Passos, X.S; Santos, S.C; Ferri, P.H; Fernandes, O.F.L; Paula, T.F; Garcia, A.C.F; Silva, M.R.R. (2002). Atividade antifúngica de Caryocar brasiliensis (Caryocaceae) sobre Cryptococcus neoformans. Rev. Soc. Bras. Med. Trop 35(4),623-627.
16. Pino Benítez, N.; Melendez, E.; Stashenko, E.E. (2009). Composición química y actividad antibacteriana del aceite esencial de hojas de Piper lanceaefolium, planta usada tradicionalmente en Colombia. Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas 8(4),301-304.
17. Potzernheim, M.C.L.; Bizzo, H.R.; Agostini-Costa, T.S.; Vieira, R.F.; Carvalho-Silva, M.; Gracindo, L.A.M.B. (2006a). Chemical characterization of seven Piper species (Piperaceae) from Federal District, Brazil, based on volatile oil constituents. Rev. Bras. Pl. Med. 8 (esp), 10-12.
18. Potzernheim, M.C.L; Bizzo, H.R.; Agostini-Costa, T.S.; Vieira, R.F. (2006b). Análise dos óleos essenciais de três espécies de Piper coletadas na região do Distrito Federal (Cerrado) e comparação com óleos de plantas procedentes da região de Paraty, RJ (Mata Atlântica). Rev. Bras. de Farmacogn 16(2),246-251.
19. Rios, A.G.; Leyva, M.A.; Martinez, J.R.; Stashenko, E.E. (2007). Determinación de la composición química y actividad antioxidante in vitro del aceite esencial de Piper auritum Kunth (Piperaceae) difundida en la Costa Colombiana. Scientia Et Technica 8(33),439-442.
20. Rodrigues-Silva, D.; endo, E.H.; Filho, B.P.D.; Nakamura, C.V.; Svidzinski, T.I.E.; Souza, A.; Young, M.C.M.; Ueda-Nakamura, T.; Cortez, D.A.G. (2009). Chemical composition and antimicrobial properties of Piper ovatum Vahl. Molecules 14(3),1171-1182.
21. Rubio, M.C.; Gil, J.; de Ocariz, I.R.; Benito, R.; Rezusta, A. (2003). Comparison of Results Obtained by Testing with Three Different Agar Media and by the NCCLS M27-A Method for In Vitro Testing of Fluconazole against Candida spp. J. Clin. Microbiol. 41(6),2665-2668.
22. SAHM, D.F.; WASHINGTON, J.A. (1992). Antimicrobial susceptibility tests: dilution methods. In: Ballows A. Manual of clinical microbiology. Washington: American Society for Microbiology. 1105-1125.
23. Souza, L.K.H.; Oliveira, C.M.A.; Ferri, P.H.; Santos, S.C.; Oliveira Júnior, J.G; Miranda, A.T.B.; Lião, L.M.; Silva, M.R.R. (2002). Antifungical properties of brazilian cerrado plants. Braz. J. Microbiol 33(2),247-249.
24. Souza, V.C.; Lorenzi, H. (2005). Botânica sistemática - guia ilustrado para identificação das famílias de Angiospermas da flora brasileira, baseado em APG II Instituto Plantarum, Nova Odessa, SP.
25. Sousa, P.J.C.; Barros, C.A.L.; Rocha, J.C.S.; Lira, D.S.; Monteiro, G.M.; Maia, J.G.S. (2008). Avaliação toxicológica do óleo essencial de Piper aduncum L. Rev. Bras. de Farmacogn. 18(2),217-221.
26. Teixeira, S.D. (2003). Estudo fitoquímico de Piper gaudichaudianum e sua interação com morcegos frugívoros Curitiba, Brasil, 164p. (D.S. Tesis. Programa de Pós-graduação em Química. UFPR).
27. Wu, Q.X.; Shi, Y.P.; Jia, Z.J. (2006). Eudesmane sesquiterpenoids from the Asteraceae family. Nat. Prod. Rep 23(5),699-734.
28. Yang, D.; Michel, L.; Chaumont, J.P.; Millet-Clerc, J. (1999). Use of caryophyllene oxide as an antifungal agent in an in vitro experimental model of onychomycosis. Mycopathologia 148(2),79-82.

*

Corresponding Author. Mailing address: Departamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brasil.; E-mail:

dagcortez@uem.br

Publication Dates

Publication in this collection
21 Dec 2011
Date of issue
Sept 2011

History

Reviewed
13 Dec 2010
Received
11 May 2010
Accepted
31 Jan 2011

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Adams, R.P. (2001) Identification of essential oil components by gas chromatography/quadrupole mass spectroscopy Illinois, Allured Pub. Corporation.

[2] 2. Albiero, A.L.M; Souza, L.A.; Mourão, K.S.M.; Almeida, O.J.G.; Lopes, W.A.L. (2005). Morfo-anatomia do caule de Piper gaudichaudianum Kuntze (Piperaceae). Acta Farm. Bonaerense 24(4),550-554.

[3] 3. Cavassani, V.G.S.; Sobrinho, J.A.; Homem, M.G.N.; Rapoport, A. (2002). Candidíase oral como marcador de prognóstico em pacientes portadores do HIV. Rev. Bras. Otorrinol 68(5),630-4.

[4] 4. Cysne, J.B.; Canuto, K.M.; Pessoa, O.D.L.; Nunes, E.P.; Silveira, E.R. (2005). Leaf essential oils of four piper species from the State of Ceara Northeast of Brazil. J. Braz. Chem. Soc 16(6B),1378-1381.

[5] 5. Fazolin, M.; Estrela, J.L.V.; Catani, V.; Alécios, M.R.; Lima, M.S. (2007). Propriedade inseticida dos óleos essenciais de Piper hispidinervum C. DC.; Piper aduncum L. e Tanaecium nocturnum (Barb. Rodr.) Bur. & K. Shum sobre Tenebrio molitor L., 1758. Ciênc. Agrotec. 31(1),113-120.

[6] 6. Fenner, R.; Betti, A.H.; Mentz, L.A.; Rates, S.M.K. (2006). Plantas utilizadas na medicina popular brasileira com potencial atividade antifúngica. Rev. Bras. Cienc. Farm 42(3),369-394.

[7] 7. Gazim, Z.C.; Rezende, C.M.; Fraga, S.R.; Svidzinski, T.I.E.; Cortez, D.A.G. (2008). Antifungal activity of the essential oil from Calendula officinalis L. (Asteraceae) growing in Brazil. Braz. J. Microbiol. 39,61-63.

[8] 8. Lima, I.O.; Oliveira, R.A.G.; Lima, E.O.; Farias, N.M.P.; Souza, E.L. (2006). Atividade antifúngica de óleos essenciais sobre espécies de Candida. Rev. Bras. de Farmacogn. 16(2),197-201.

[9] 9. Maatooq, G.T.; Stumpf, D.K.; Hoffmann, J.J.; Hutter, L.K.;Timmermann, B.N. (1996). Antifungal eudesmanoids from Parthenium argentatum x P. tomentosa. Phytochemistry 41(2),519-524.

[10] 10. Menezes, T.O.A.; Alves, A.C.B.A.; Vieira, J.M.S. Menezes, S.A.F.; Alves, B.P.; Mendonça, L.C.V. (2009). Avaliação in vitro da atividade antifúngica de óleos essenciais e extratos de plantas da região amazônica sobre cepa de Candida albicans. Rev Odontol. UNESP 38(3),184-91.

[11] 11. Mesquita, J.M.O.; Cavaleiro, C.; Cunha, A.P.; Lombardi, J.A.; Oliveira, A.B. (2005). Estudo comparativo dos óleos voláteis de algumas espécies de Piperaceae. Rev. bras. de farmacogn. 15(1),6-12.

[12] 12. Nascimento, P.F.C.; Nascimento, A.C.; Rodrigues, C.S.; Antoniolli, A.R.; Santos, P.O.; Júnior, A.M.B.; Trindade, R.C. (2007). Atividade antimicrobiana dos óleos essenciais: uma abordagem multifatorial dos métodos. Rev. Bras. de Farmacogn 17(1),108-113.

[13] 13. Packer, J.F.; Luz, M.M.S. (2007). Método para avaliação e pesquisa da atividade antimicrobiana de produtos de origem natural. Rev. Bras. de Farmacogn. 17(1),102-107.

[14] 14. Parmar, V.S.; Jain, S.C.; Bisht, K.S.; Jain, R.; Taneja, P.; Jha, A.; Tyagi, O.D.; Prasad, A.K.; Wengel, J.; Olsen, C.E.; Boll, P.M. (1997). Phytochemistry of the genus Piper. Phytochemistry 46(4),597-673.

[15] 15. Passos, X.S; Santos, S.C; Ferri, P.H; Fernandes, O.F.L; Paula, T.F; Garcia, A.C.F; Silva, M.R.R. (2002). Atividade antifúngica de Caryocar brasiliensis (Caryocaceae) sobre Cryptococcus neoformans. Rev. Soc. Bras. Med. Trop 35(4),623-627.

[16] 16. Pino Benítez, N.; Melendez, E.; Stashenko, E.E. (2009). Composición química y actividad antibacteriana del aceite esencial de hojas de Piper lanceaefolium, planta usada tradicionalmente en Colombia. Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas 8(4),301-304.

[17] 17. Potzernheim, M.C.L.; Bizzo, H.R.; Agostini-Costa, T.S.; Vieira, R.F.; Carvalho-Silva, M.; Gracindo, L.A.M.B. (2006a). Chemical characterization of seven Piper species (Piperaceae) from Federal District, Brazil, based on volatile oil constituents. Rev. Bras. Pl. Med. 8 (esp), 10-12.

[18] 18. Potzernheim, M.C.L; Bizzo, H.R.; Agostini-Costa, T.S.; Vieira, R.F. (2006b). Análise dos óleos essenciais de três espécies de Piper coletadas na região do Distrito Federal (Cerrado) e comparação com óleos de plantas procedentes da região de Paraty, RJ (Mata Atlântica). Rev. Bras. de Farmacogn 16(2),246-251.

[19] 19. Rios, A.G.; Leyva, M.A.; Martinez, J.R.; Stashenko, E.E. (2007). Determinación de la composición química y actividad antioxidante in vitro del aceite esencial de Piper auritum Kunth (Piperaceae) difundida en la Costa Colombiana. Scientia Et Technica 8(33),439-442.

[20] 20. Rodrigues-Silva, D.; endo, E.H.; Filho, B.P.D.; Nakamura, C.V.; Svidzinski, T.I.E.; Souza, A.; Young, M.C.M.; Ueda-Nakamura, T.; Cortez, D.A.G. (2009). Chemical composition and antimicrobial properties of Piper ovatum Vahl. Molecules 14(3),1171-1182.

[21] 21. Rubio, M.C.; Gil, J.; de Ocariz, I.R.; Benito, R.; Rezusta, A. (2003). Comparison of Results Obtained by Testing with Three Different Agar Media and by the NCCLS M27-A Method for In Vitro Testing of Fluconazole against Candida spp. J. Clin. Microbiol. 41(6),2665-2668.

[22] 22. SAHM, D.F.; WASHINGTON, J.A. (1992). Antimicrobial susceptibility tests: dilution methods. In: Ballows A. Manual of clinical microbiology. Washington: American Society for Microbiology. 1105-1125.

[23] 23. Souza, L.K.H.; Oliveira, C.M.A.; Ferri, P.H.; Santos, S.C.; Oliveira Júnior, J.G; Miranda, A.T.B.; Lião, L.M.; Silva, M.R.R. (2002). Antifungical properties of brazilian cerrado plants. Braz. J. Microbiol 33(2),247-249.

[24] 24. Souza, V.C.; Lorenzi, H. (2005). Botânica sistemática - guia ilustrado para identificação das famílias de Angiospermas da flora brasileira, baseado em APG II Instituto Plantarum, Nova Odessa, SP.

[25] 25. Sousa, P.J.C.; Barros, C.A.L.; Rocha, J.C.S.; Lira, D.S.; Monteiro, G.M.; Maia, J.G.S. (2008). Avaliação toxicológica do óleo essencial de Piper aduncum L. Rev. Bras. de Farmacogn. 18(2),217-221.

[26] 26. Teixeira, S.D. (2003). Estudo fitoquímico de Piper gaudichaudianum e sua interação com morcegos frugívoros Curitiba, Brasil, 164p. (D.S. Tesis. Programa de Pós-graduação em Química. UFPR).

[27] 27. Wu, Q.X.; Shi, Y.P.; Jia, Z.J. (2006). Eudesmane sesquiterpenoids from the Asteraceae family. Nat. Prod. Rep 23(5),699-734.

[28] 28. Yang, D.; Michel, L.; Chaumont, J.P.; Millet-Clerc, J. (1999). Use of caryophyllene oxide as an antifungal agent in an in vitro experimental model of onychomycosis. Mycopathologia 148(2),79-82.