Chemical constituents from Casearia spp. (Flacourtiaceae/Salicaceae sensu lato)

ABSTRACT

Chemical investigation of the leaves of Casearia gossypiosperma Briq., Salicaceae, led to the isolation of two known flavonoids, (+)-taxifolin and quercetin, the leaves of Casearia decandra Jacq. have afforded hydroquinone, the leaves of Casearia rupestris Eichler and Casearia lasiophylla Eichler have afforded a diterpene, (E)-phytol, and the leaves of C. rupestris and Casearia obliqua Spreng. have afforded sitosterol. The twigs of Casearia lasiophylla Eichler led to the isolation of two compounds (+)-pinoresinol, and N-trans-feruloyltyramine, and the twigs of C. obliqua have afforded N-trans-feruloyltyramine, N-trans-cumaroyltyramine, and cinamic acid. This is the first report of the compounds (+)-taxifolin, quercetin, hydroquinone, (+)-pinoresinol and N-trans-cumaroyltyramine from the Casearia genus.

Keywords:
Phenolic compounds; Chemical constituents; Salicaceae sensu lato

Introduction

Recent phylogenetic and chemical studies, besides ecological and morphological observations from the Angiosperm Phylogeny Group (APG) showed that the Flacourtiaceae family was separated into two clades (Achariaceae and Salicaceae), with the genus Casearia belonging to the Salicaceae (APG, 2003). Casearia genus is found in Brazil and contains ca. of 180 species, 70 belonging to the American continent and 37 present in Brazil (Shen et al., 2004). No chemical studies have been previously reported for C. gossypiosperma Briq. and C. decandra Jacq. However, previous studies of our group with C. sylvestris Sw. (Santos et al., 2010), C. obliqua Spreng. (Vieira-Júnior et al., 2009), and C. rupestris Eichler (Vieira-Júnior et al., 2011) related the presence of clerodane diterpenes as well as in many other Casearia species (Kanokmedhakul et al., 2007). Previous studies of the C. lasiopylla Eichler species described the chemical composition of the essential oils from leaves (Salvador et al., 2011). In the present short communication, the occurrence of nine known compounds from Casearia spp. is described.

Materials and methods

The aerial parts, twigs and leaves of the Casearia species were collected in May 2007 at Campinas municipality, São Paulo State, Brazil. The plant material was identified by Dr. Roseli B. Torres, Instituto Agronômico de Campinas, Brazil. A voucher specimens [IAC38438 (C. gossypiosperma Briq.), IAC42645 (C. decandra Jacq.), IAC41542 (C. rupestris Eichler), IAC42645 (C. lasiophylla Eichler), and IAC46529 (C. obliqua Spreng.)] have been deposited in the herbarium of the Instituto Agronômico de Campinas (São Paulo State, Brazil). Optical rotation was measured on a Perkin-Elmer 341 LC polarimeter. IR spectra was measured on a Nicolet Impact 400 spectrometer, using KBr disks. The 1D and 2D NMR experiments were recorded on a Varian INOVA 500 spectrometer (11.7 T) at 500 MHz (¹H) and 125 MHz (¹³C) with pulse field gradient and a Varian INOVA 300 spectrometer (7.4 T) at 300 MHz (¹H) and 75 MHz (¹³C), using CD₃OD, DMSO-d₆ or CDCl₃. Positive-ion HRMS spectra were recorded on an UltrOTOFq (Bruker Daltonics) ESI-qTOF mass spectrometer, using TFANa as the internal standard. Open column chromatography was performed over silica gel (40–63 µm, Merck), silica C18 (40 µm, J. T. Baker), or on Sephadex LH-20 (Pharmacia Biotech). TLC was performed using Merck silica gel 60 (>230 mesh) and precoated silica gel 60 PF₂₅₄ plates. Spots on TLC plates were observed under UV light and by spraying the plates with anisaldehyde-H₂SO₄ reagent, followed by heating at 120 ºC. All solvents were purchased from Sigma–Aldrich (St. Louis, MO, USA). The air-dried and powdered aerial parts of C. gossypiosperma (leaves 1.4 kg), C. decandra (leaves 0.3 kg), C. rupestris (leaves 0.4 kg), C. lasiophylla (leaves 0.6 kg, and twigs 1.1 kg), and C. obliqua (twigs 0.5 kg) were exhaustively extracted by maceration successively with hexane, ethanol and water (3 l × 3) at room temperature. The aqueous extract (20 g) of the leaves from C. gossypiosperma was subjected to chromatographic column on Amberlite XAD-4 using water, water/MeOH (1:1) and MeOH, to afford (+)-taxifolin (1, 581.0 mg, 0.04% – eluted with MeOH). The hexane extract (4 g) of the leaves from C. lasiophylla was chromatographed over silica gel using hexane containing increasing amounts of EtOAc. The subfraction 3 (223 mg) was subjected to thin-layer preparative chromatography with hexane/EtOAc (7:3), resulting in the isolation of (E)-phytol (13 mg, 0.002%). The hexane extract (14 g) of the leaves from C. rupestris was chromatographed over silica gel using hexane containing increasing amounts of EtOAc. The subfraction 3 (1 g) was rechromatographed in a C-18 column using water containing increasing amounts of MeOH afforded a mixture of (E)-phytol + sitosterol (362 mg, 0.09%, eluted with MeOH). The hexane extract (1.5 g) of the leaves from C. obliqua was chromatographed over silica gel using hexane containing increasing amounts of EtOAc and MeOH. The subfraction 3 (350 mg) was rechromatographed over silica gel using hexane containing increasing amounts of EtOAc afforded sitosterol (27.2 mg, 0.005%), eluted with hexane/EtOAc (9:1). All ethanolic extracts were diluted with MeOH/H₂O (3:1) and partitioned with hexane, Et₂O, and EtOAc, successively. The MeOH–H₂O phase (7.7 g) of the leaves from C. gossypiosperma was subjected to chromatographic column on silica gel using hexane containing increasing amounts of EtOAc to afford (+)-taxifolin (1, 1 g, 0.07%), eluted with hexane/EtOAc (1:1). The Et₂O phase (9.6 g) of the leaves from C. gossypiosperma was subjected to gel filtration (Sephadex LH-20 with MeOH) to afford (+)-taxifolin (1, 2.8 g, 0.2%) and quercetin (37.4 mg, 0.002%). The EtOAc phase (6.1 g) of the leaves from C. decandra was subjected to chromatographic column on silica gel using hexane containing increasing amounts of EtOAc, the subfraction 21 (146.1 mg) was subjected to gel filtration (Sephadex LH-20 with MeOH). The subfraction 21–4 (115 mg) was rechromatographed in EFS-C18 (reverse phase) column using MeOH afforded hydroquinone (110.5 mg, 0.03%). The EtOAc phase (6 g) of the twigs from C. lasiophylla was subjected to gel filtration (Sephadex LH-20 with MeOH). The subfraction 20 (332 mg) was chromatographed over silica gel using hexane containing increasing amounts of EtOAc to provide N-trans-feruloyltyramine (2, 19.5 mg, 0.001%), eluted with hexane/EtOAc (3:7). The subfraction 20–10 (41 mg) was rechromatographed over silica gel using hexane containing increasing amounts of AcOEt to provide (+)-pinoresinol (3 19 mg, 0.001%), eluted with hexane/EtOAc (5:5). The EtO₂ phase (1 g) of the leaves from C. obliqua was subjected to gel filtration (Sephadex LH-20 with MeOH). The subfraction 60 (32 mg) was submited to preparative RP-HPLC on a C18 column eluted with H₂O/MeOH 20:80 (v/v) at a flow rate of 15 ml/min and UV detection at 254 nm, affording the cinnamic acid (9 mg, 0.001%). The subfraction 73 (11 mg) was submitted to preparative RP-HPLC on a C18 column eluted with H₂O/MeOH/HOAc 33:67:0.01 (v/v/v) at a flow rate of 11 ml/min and UV detection at 254 nm, affording the N-trans-cumaroyltyramine (4, 2.2 mg, 0.0004%), and N-trans-feruloyltyramine (2, 4.5 mg, 0.0009%).

Results and discussion

The structures of the nine compounds were identified by comparison of their optical rotation, spectroscopic and spectrometric data (UV, IR, HRESIMS or ESIMS and ¹H and ¹³C NMR) with those reported in the literature (see Supporting Information).

This work reported the isolation of two flavonoids ((+)-taxifolin (1) and quercetin), one simple phenolic compound (hydroquinone), one diterpene ((E)-phytol), one steroid (sitosterol), one lignan ((+)-pinoresinol (3)), two amides (N-trans-feruloyltyramine (2) and N-trans-cumaroyltyramine (4)), and cinnamic acid from five Casearia species. All compounds were isolated from these species for the first time. Except for (E)-phytol, sitosterol, N-trans-feruloyltyramine (2), and cinnamic acid, all other compounds were isolated from the genus Casearia for the first time. Sitosterol has been isolated previously from C. grewiifolia (Rayanil et al., 2012), C. sylvestris (Wang et al., 2009), C. membranacea (Chang et al., 2003), and C. graveolens (Talapatra et al., 1983), N-trans-feruloyltyramine (2) from C. membranacea (Chang et al., 2003) and C. grewiifolia (Rayanil et al., 2012), (E)-phytol from C. balansae (Wang et al., 2013), and cinnamic acid from C. sylvestris (Wang et al., 2009). Casearia species contains flavonoids (Raslan et al., 2002), lignans (Wang et al., 2010), steroids (Wang et al., 2009; Chang et al., 2003), coumarins (Talapatra et al., 1983), amides (Chang et al., 2003), terpenoids (Bou et al., 2014), phenolic compounds (Chai et al., 2010), and mainly clerodane diterpenes (Vieira-Júnior et al., 2009; Vieira-Júnior et al., 2011; Bou et al., 2014).

The compound (+)-taxifolin (1) was isolated in a significant amount (3.8 g) from leaves of C. gossypiosperma, but it can be found in larger quantities in conifers, e.g., the Siberian larch, Larix sibirica, Pinus roxburghii and Cedrus deodara (Willför et al., 2009). The clerodane diterpenes are considered chemosystematic markers of this genus, but the literature does not describe the presence of these substances in C. lasiophylla, C. gossypiosperma and C. decandra.

The best of our knowledge, this is the first report of the chemical constituents of C. gossypiosperma and C. decandra. The compounds (+)-taxifolin (1), quercetin, hydroquinone, (+)-pinoresinol (3) and N-trans-cumaroyltyramine (4) are reported for the first time in the Casearia genus. From 1.4 kg of dried leaves from C. gossypiosperma, an amount of 3.8 g of (+)-taxifolin (1) was obtained. This extract is a rich source of (+)-taxifolin (1), which may offer interesting potential applications in the food, cosmetic and/or pharmaceutical industries.

Acknowledgments

The authors are grateful to Fundação de Amparo à Pesquisa do Estado de São Paulo and Biota Instituto Virtual da Biodiversidade for financial support of the Project no. 03/02176-7. We are grateful the Prof. Dr. Norberto Peporine Lopes for use of the LC–MS.

Appendix A. Supplementary data

Supplementary data associated with this article can be found, in the online version, at doi: 10.1016/j.bjp.2017.10.003.

References

• APG, 2003. The Angiosperm Phylogeny Group. J. Linn. Soc. 141, 399-436.
• Bou, D.D., Tempone, A.G., Pinto, E.G., Lago, J.H.G., Sartorelli, P., 2014. Antiparasitic activity and effect of casearins isolated from Casearia sylvestris on Leishmania and Trypanosoma cruzi plasma membrane. Phytomedicine 21, 676-681.
• Chai, X.-Y., Li, F.-F., Bai, C.-C., Xu, Z.-R., Shi, H.-M., Tu, P.-F., 2010. Three new acylated glycosides from the stems of Casearia velutina and their protective effect against H₂O₂-induced impairment in PC12 cells. Planta Med. 76, 91-93.
• Chang, K.-C., Duh, C.-Y., Chen, I.-S., Tsai, I.-L., 2003. A cytotoxic butenolide, two new dolabellane diterpenoids, a chroman and a benzoquinol derivative formosan Casearia membranacea Planta Med. 69, 667-672.
• Kanokmedhakul, S., Kanokmedhakul, K., Buayairaksa, M., 2007. Cytotoxic clerodane diterpenoids from fruits of Casearia grewiifolia J. Nat. Prod. 70, 1122-1126.
• Raslan, D.S., Jamal, C.M., Duarte, D.S., Borges, M.H., Lima, M.E., 2002. Anti-PLA2 action test of Casearia sylvestris Sw. Bolletin Chimie et Farmacie 141, 457-460.
• Rayanil, K.-O., Nimnoun, C., Tuntiwachwuttikul, P., 2012. New phenolics from the wood of Casearia grewiifolia Phytochem. Lett. 5, 59-62.
• Salvador, M.J., Carvalho, J.E., Wisniewski, A., Kassuya, C.A.L., Santos, E.P., Riva, D., Stefanello, M.E.A., 2011. Chemical composition and cytotoxic activity of the essential oil from the leaves of Casearia lasiophylla Rev. Bras. Farmacogn. 21, 864-868.
• Santos, A.G., Ferreira, P.M.P., Vieira-Junior, G.M., Perez, C.C., Tininins, A.G., Silva, G.H., Bolzani, V.S., Costa-Lotufo, L.V., Pessoa, C.O., Cavalheiro, A.J., 2010. Casearin X, its degradation product and other clerodane diterpenes from leaves of Casearia sylvestris: evaluation of cytotoxicity against normal and tumor human cells. Chem. Biodivers. 7, 205-215.
• Shen, Y.-C., Wang, C.-H., Cheng, Y.-B., Wang, L.-T., Guh, J.-H., Chien, C.-T., Khalil, A.T., 2004. New cytotoxic clerodane diterpenoids from the leaves and twigs of Casearia membranacea J. Nat. Prod. 67, 316-321.
• Talapatra, S.K., Ganguly, N.C., Goswami, S., Talapatra, B., 1983. Chemical constituents of Casearia graveolens: some novel reactions and the preferred molecular conformation of the major coumarin, micromelin. J. Nat. Prod. 46, 401-408.
• Vieira-Júnior, G.M., Gonçalves, T.O., Regasini, L.O., Ferreira, P.M.P., Pessoa, C.Ó., Costa-Lotufo, L.V., Torres, R.B., Boralle, N.B., Bolzani, V.S., Cavalheiro, A.J., 2009. Cytotoxic clerodane diterpenoids from Casearia obliqua J. Nat. Prod. 72, 1847-1850.
• Vieira-Júnior, G.M., Dutra, L.A., Ferreira, P.M.P., Morais, M.O., Costa-Lotufo, L.V., Pessoa, C.Ó., Torres, R.B., Boralle, N.B., Bolzani, V.S., Cavalheiro, A.J., 2011. Cytotoxic clerodane diterpenes from Casearia rupestris J. Nat. Prod. 74, 776-781.
• Wang, W., Zhao, J., Wang, Y.-H., Smillie, T.A., Li, X.-C., Khan, I.A., 2009. Diterpenoids from Casearia sylvestris Planta Med. 75, 1436-1441.
• Wang, W., Zulfiqar, A., Li, X.C., Khan, I.A., 2010. Neolignans from the leaves of Casearia sylvestris Swartz. Helv. Chim. Acta. 93, 139-146.
• Wang, B., Wang, X.-L., Wang, S.-Q., Shen, T., Liu, Y.-Q., Yuan, H., Lou, H.-X., Wang, X.-N., 2013. Cytotoxic clerodane diterpenoids from the leaves and twigs of Casearia balansae J. Nat. Prod. 76, 1573-1579.
• Willför, S., Ali, M., Karonen, M., Reunanen, M., Arfan, M., Harlamow, R., 2009. Extractives in bark of different conifer growing in Pakistan. Holzforschung 63, 551-558.

Publication Dates

• Publication in this collection
  Nov-Dec 2017

History

• Received
  26 Sept 2017
• Accepted
  5 Oct 2017