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Natural Product Research: Formerly Natural Product Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gnpl20
Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana a
b
c
Joseph T. Ndongo , Mark E. Issa , Angelique N. Messi , Joséphine c
b
c
Ngo Mbing , Muriel Cuendet , Dieudonné E. Pegnyemb & Christian G. Bochet
d
a
Department of Chemistry, Higher Teacher Training College, University of Yaoundé 1, P.O. Box 47, Yaoundé, Cameroon b
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School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Switzerland c
Department of Organic Chemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon d
Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland Published online: 02 Jan 2015.
To cite this article: Joseph T. Ndongo, Mark E. Issa, Angelique N. Messi, Joséphine Ngo Mbing, Muriel Cuendet, Dieudonné E. Pegnyemb & Christian G. Bochet (2015): Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana, Natural Product Research: Formerly Natural Product Letters, DOI: 10.1080/14786419.2014.991321 To link to this article: http://dx.doi.org/10.1080/14786419.2014.991321
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
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Natural Product Research, 2015 http://dx.doi.org/10.1080/14786419.2014.991321
SHORT COMMUNICATION Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana Joseph T. Ndongoa, Mark E. Issab, Angelique N. Messic, Jose´phine Ngo Mbingc*, Muriel Cuendetb, Dieudonne´ E. Pegnyembc and Christian G. Bochetd
Downloaded by [University of Bristol] at 22:53 26 February 2015
a
Department of Chemistry, Higher Teacher Training College, University of Yaounde´ 1, P.O. Box 47, Yaounde´, Cameroon; bSchool of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Gene`ve 4, Switzerland; cDepartment of Organic Chemistry, Faculty of Science, University of Yaounde´ 1, P.O. Box 812, Yaounde´, Cameroon; dDepartment of Chemistry, University of Fribourg, Chemin du Muse´e 9, CH-1700 Fribourg, Switzerland (Received 25 August 2014; final version received 16 November 2014) OH OH
O HO
O
OH OH
O OH
O
HO
O HO
OH
OH
O
HO O
O
OH 4
6
Seven flavonoids, hemerocallone (1), 6,7-dimethoxy-30 ,40 -dimethoxyisoflavone (2), amentoflavone (4), agathisflavone (6), cupressuflavone (8), robustaflavone (9) and epicatechin (10), together with three other compounds, lithospermoside (3), b-D fructofuranosyl-a-D -glucopyranoside (5) and 3b-O-D -glucopyranosyl-b-stigmasterol (7), were isolated from the ethyl acetate extract of the stem bark of Ochna schweinfurthiana F. Hoffm. All the compounds were characterised by spectroscopic and mass spectrometric methods, and by comparison with literature data. Cytotoxicity of the extracts and compounds against cervical adenocarcinoma (HeLa) cells was evaluated by MTT assay. Compounds 4 and 6 exhibited good cytotoxic activity, with IC50 values of 20.7 and 10.0 mM, respectively. Keywords: Ochna schweinfurthiana; Ochnaceae; flavonoids; cytotoxic activity
1. Introduction Ochna schweinfurthiana F. Hoffm. belongs to the Ochnaceae family and is widely distributed in African woodlands. The plant grows into a decorative shrub bearing bright-yellow flowers (Burkill 1997). In the north of Cameroon, the powdered bark is traditionally used as antimalarial and anthelmintic, and the decoction of the root, leaves or bark is used in wound dressing (Abdullahi et al. 2010). Previous phytochemical studies of the leaves and roots of this plant reported the isolation of quercetin 3-O-b-D -glucopyranosyl (1 ! 6)-a-rhamnoside and tri-
*Corresponding author. Email: [email protected] q 2015 Taylor & Francis
Downloaded by [University of Bristol] at 22:53 26 February 2015
2 J.T. Ndongo et al.
Figure 1. Structures of compounds 1 – 10.
Natural Product Research
3
methoxy lophirone A (Abdullahi et al. 2011, 2014). In this study, the chemical constituents of an ethyl acetate extract of the stem bark of O. schweinfurthiana were examined and 10 known compounds were obtained. The methanolic and ethyl acetate extracts displayed a moderate cytotoxic activity on cervical adenocarcinoma (HeLa) cells, while compounds 4 and 6 exhibited good cytotoxic activity on the same cell line.
Downloaded by [University of Bristol] at 22:53 26 February 2015
2. Results and discussion The ethyl acetate extract, obtained from partition of methanolic crude extract of the stem bark of O. schweinfurthiana resuspended in water, was separated using various chromatographic techniques to afford hemerocallone (1), 6,7-dimethoxy-30 ,40 -dimethoxyisoflavone (2), lithospermoside (3), amentoflavone (4), b-D -fructofuranosyl-a-D -glucopyranoside (5), agathisflavone (6), 3-b-O-D -glucopyranosyl-b-stigmasterol (7), cupressuflavone (8), robustaflavone (9) and epicatechin (10). The chemical structure of each isolated compound (Figure 1) was elucidated on the basis of spectroscopic methods, including 2D NMR experiments, and confirmed by comparison with the literature. To the best of our knowledge, there are no published reports on these compounds in the plant. The extracts and compounds 3 –6, 8 and 9 were evaluated for their cytotoxicity against HeLa cells using the MTT assay. The measurement of cell viability showed that both the methanolic and ethyl acetate crude extracts had a moderate cytotoxic activity on the tested human cancer cell line, and amentoflavone (4) and agathisflavone (6) exhibited a good activity (Table 1). However, compounds 3, 5, 8 and 9 were inactive. Compounds 1, 2, 7 and 10 were obtained in too low quantity and could not be tested. Amentoflavone and agathisflavone were previously isolated from Selaginella tamariscina (Selaginellaceae) and Rhus parviflora (Anacardiaceae), respectively. Both compounds showed good cytotoxicity against HeLa cancer cell lines with IC50 values of 20.0 and 15.2 mM, respectively (Ying et al. 2010; Shrestha et al. 2012). Amentoflavone has previously shown antiviral activity (Lin et al. 1999). It also induced apoptosis in MCF-7 breast cancer cells (Pei et al. 2012), and inhibited the proliferation of human promyelocytic leucaemia (HL-60), MCF-7, HeLa and human hepatocellular carcinoma BEL-7402 cells with IC50 values between 47 and 77 mM (Ying et al. 2010). Agathisflavone inhibited b-secretase at a 10 mM concentration (Shrestha et al. 2012). Although the methanolic and ethyl acetate extracts showed a moderate cytotoxic activity on HeLa cells, this study indicated that O. schweinfurthiana can be considered as a possible source of secondary metabolites exhibiting a cytotoxic activity on HeLa cells. It would be worthwhile to Table 1. Cytotoxic activity of the extracts and compounds 3– 6, 8 and 9 in HeLa cellsa. Extracts and compounds MeOH extract EtOAc extract Lithospermoside (3) Amentoflavone (4) Saccharose (5) Agathisflavone (6) Cupressuflavone (8) Robustaflavone (9) Mitoxantronec Vehicle a
% Viability at 20 mg/mL 13.9 9.4 70.5 1.9 75.5 1.5 67.6 69.0 0.0 100.0
IC50 (mM)b
20.7 ^ 1.58 10.0 ^ 0.88 0.2 ^ 0.05
Extracts and compounds were evaluated for cytotoxicity by standard procedures as described in the Experimental section. HeLa (cervical cancer) human cell lines were used. Results are shown as % viability and IC50 values (mM). Results are the means of at least three independent determinations ^SD. c Positive control. b
4
J.T. Ndongo et al.
establish structure –activity relationships in order to highlight the functional groups important for the activity of the isolated compounds. 3. Conclusions We report the phytochemical study of O. schweinfurthiana and demonstrated the cytotoxic activity of the methanolic and ethyl acetate extracts, as well as of some isolated compounds. Flavonoids, cyanoglycoside, saccharose and sterol glycoside were identified from the ethyl acetate extract for the first time. The results of the bioassay confirmed the effects of amentoflavone and agathisflavone in HeLa cells as demonstrated by Ying et al. (2010) and Shrestha et al. (2012).
Downloaded by [University of Bristol] at 22:53 26 February 2015
Supplementary material Experimental details relating to this article are available online. Acknowledgements The authors thank Mr F. Fehr and Mr F. Nydegger for NMR and mass spectrometry measurements, and Mr Fawa Guidawa (University of Ngaounde´re´) for the collection of plant material.
Funding The authors wish to thank the Swiss National Science Foundation [grant number IZK0Z2__145075] for the financial support.
References Abdullahi MI, Iliya I, Haruna AK, Sule MI, Musa AM, Abdullahi MS. 2010. Preliminary phytochemical and antimicrobial investigations of leaf extracts of Ochna schweinfurthiana (Ochnaceae). Afr J Pharm Pharmacol. 4:83–86. Abdullahi MI, Musa AM, Haruna AK, Pateh UU, Sule MI, Abdulmalik IA, Abdullahi MS, Abimiku AG, Iliya I. 2014. Isolation and characterization of an anti-microbial biflavonoid from the chloroform-soluble fraction of methanolic root extract of Ochna schweinfurthiana (Ochnaceae). Afr J Pharm Pharmacol. 8:93–99. Abdullahi MI, Musa AM, Haruna AK, Sule MI, Abdullahi MS, Abdulmalik MI, Akinwande Y, Abimiku AG, Iliya I. 2011. Antimicrobial flavonoid diglycoside from the leaves of Ochna schweinfurthiana F. Hoffm. (Ochnaceae). Niger J Pharm Sci. 10:1–7. Burkill HM. 1997. The useful plants of West Tropical Africa. Families M–R. Vol. 4 2nd ed. Kew: Royal Botanic Gardens. Lin YM, Flavin MT, Schure R, Chen FC, Sidwell R, Barnard DL, Huffman JH, Kern ER. 1999. Antiviral activities of biflavonoids. Planta Med. 65:120–125. Pei JS, Liu CC, Hsu YN, Lin LL, Wang SC, Chung JG, Bau DT, Lin SS. 2012. Amentoflavone induces cell-cycle arrest and apoptosis in MCF-7 human breast cancer cells via mitochondria-dependent pathway. In Vivo. 26:963–970. Shrestha S, Park JH, Lee DY, Cho JG, Seo WD, Kang HC, Yoo KH, Chung IS, Jeon YJ, Yeon SW, Baek NI. 2012. Cytotoxic and neuroprotective biflavonoids from the fruit of Rhus parviflora. J Korean Soc Appl Biol Chem. 55:557–562. Ying J, Guogang Z, Enlong M, Hongmei Z, Jin G, Jie H. 2010. Amentoflavone and the extracts from Selaginella tamariscina and their anticancer activity. Asian J Tradit Med. 5:226–229.
Natural Product Research: Formerly Natural Product Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gnpl20
Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana a
b
c
Joseph T. Ndongo , Mark E. Issa , Angelique N. Messi , Joséphine c
b
c
Ngo Mbing , Muriel Cuendet , Dieudonné E. Pegnyemb & Christian G. Bochet
d
a
Department of Chemistry, Higher Teacher Training College, University of Yaoundé 1, P.O. Box 47, Yaoundé, Cameroon b
Click for updates
School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Switzerland c
Department of Organic Chemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon d
Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland Published online: 02 Jan 2015.
To cite this article: Joseph T. Ndongo, Mark E. Issa, Angelique N. Messi, Joséphine Ngo Mbing, Muriel Cuendet, Dieudonné E. Pegnyemb & Christian G. Bochet (2015): Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana, Natural Product Research: Formerly Natural Product Letters, DOI: 10.1080/14786419.2014.991321 To link to this article: http://dx.doi.org/10.1080/14786419.2014.991321
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.
Downloaded by [University of Bristol] at 22:53 26 February 2015
This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Natural Product Research, 2015 http://dx.doi.org/10.1080/14786419.2014.991321
SHORT COMMUNICATION Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana Joseph T. Ndongoa, Mark E. Issab, Angelique N. Messic, Jose´phine Ngo Mbingc*, Muriel Cuendetb, Dieudonne´ E. Pegnyembc and Christian G. Bochetd
Downloaded by [University of Bristol] at 22:53 26 February 2015
a
Department of Chemistry, Higher Teacher Training College, University of Yaounde´ 1, P.O. Box 47, Yaounde´, Cameroon; bSchool of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Gene`ve 4, Switzerland; cDepartment of Organic Chemistry, Faculty of Science, University of Yaounde´ 1, P.O. Box 812, Yaounde´, Cameroon; dDepartment of Chemistry, University of Fribourg, Chemin du Muse´e 9, CH-1700 Fribourg, Switzerland (Received 25 August 2014; final version received 16 November 2014) OH OH
O HO
O
OH OH
O OH
O
HO
O HO
OH
OH
O
HO O
O
OH 4
6
Seven flavonoids, hemerocallone (1), 6,7-dimethoxy-30 ,40 -dimethoxyisoflavone (2), amentoflavone (4), agathisflavone (6), cupressuflavone (8), robustaflavone (9) and epicatechin (10), together with three other compounds, lithospermoside (3), b-D fructofuranosyl-a-D -glucopyranoside (5) and 3b-O-D -glucopyranosyl-b-stigmasterol (7), were isolated from the ethyl acetate extract of the stem bark of Ochna schweinfurthiana F. Hoffm. All the compounds were characterised by spectroscopic and mass spectrometric methods, and by comparison with literature data. Cytotoxicity of the extracts and compounds against cervical adenocarcinoma (HeLa) cells was evaluated by MTT assay. Compounds 4 and 6 exhibited good cytotoxic activity, with IC50 values of 20.7 and 10.0 mM, respectively. Keywords: Ochna schweinfurthiana; Ochnaceae; flavonoids; cytotoxic activity
1. Introduction Ochna schweinfurthiana F. Hoffm. belongs to the Ochnaceae family and is widely distributed in African woodlands. The plant grows into a decorative shrub bearing bright-yellow flowers (Burkill 1997). In the north of Cameroon, the powdered bark is traditionally used as antimalarial and anthelmintic, and the decoction of the root, leaves or bark is used in wound dressing (Abdullahi et al. 2010). Previous phytochemical studies of the leaves and roots of this plant reported the isolation of quercetin 3-O-b-D -glucopyranosyl (1 ! 6)-a-rhamnoside and tri-
*Corresponding author. Email: [email protected] q 2015 Taylor & Francis
Downloaded by [University of Bristol] at 22:53 26 February 2015
2 J.T. Ndongo et al.
Figure 1. Structures of compounds 1 – 10.
Natural Product Research
3
methoxy lophirone A (Abdullahi et al. 2011, 2014). In this study, the chemical constituents of an ethyl acetate extract of the stem bark of O. schweinfurthiana were examined and 10 known compounds were obtained. The methanolic and ethyl acetate extracts displayed a moderate cytotoxic activity on cervical adenocarcinoma (HeLa) cells, while compounds 4 and 6 exhibited good cytotoxic activity on the same cell line.
Downloaded by [University of Bristol] at 22:53 26 February 2015
2. Results and discussion The ethyl acetate extract, obtained from partition of methanolic crude extract of the stem bark of O. schweinfurthiana resuspended in water, was separated using various chromatographic techniques to afford hemerocallone (1), 6,7-dimethoxy-30 ,40 -dimethoxyisoflavone (2), lithospermoside (3), amentoflavone (4), b-D -fructofuranosyl-a-D -glucopyranoside (5), agathisflavone (6), 3-b-O-D -glucopyranosyl-b-stigmasterol (7), cupressuflavone (8), robustaflavone (9) and epicatechin (10). The chemical structure of each isolated compound (Figure 1) was elucidated on the basis of spectroscopic methods, including 2D NMR experiments, and confirmed by comparison with the literature. To the best of our knowledge, there are no published reports on these compounds in the plant. The extracts and compounds 3 –6, 8 and 9 were evaluated for their cytotoxicity against HeLa cells using the MTT assay. The measurement of cell viability showed that both the methanolic and ethyl acetate crude extracts had a moderate cytotoxic activity on the tested human cancer cell line, and amentoflavone (4) and agathisflavone (6) exhibited a good activity (Table 1). However, compounds 3, 5, 8 and 9 were inactive. Compounds 1, 2, 7 and 10 were obtained in too low quantity and could not be tested. Amentoflavone and agathisflavone were previously isolated from Selaginella tamariscina (Selaginellaceae) and Rhus parviflora (Anacardiaceae), respectively. Both compounds showed good cytotoxicity against HeLa cancer cell lines with IC50 values of 20.0 and 15.2 mM, respectively (Ying et al. 2010; Shrestha et al. 2012). Amentoflavone has previously shown antiviral activity (Lin et al. 1999). It also induced apoptosis in MCF-7 breast cancer cells (Pei et al. 2012), and inhibited the proliferation of human promyelocytic leucaemia (HL-60), MCF-7, HeLa and human hepatocellular carcinoma BEL-7402 cells with IC50 values between 47 and 77 mM (Ying et al. 2010). Agathisflavone inhibited b-secretase at a 10 mM concentration (Shrestha et al. 2012). Although the methanolic and ethyl acetate extracts showed a moderate cytotoxic activity on HeLa cells, this study indicated that O. schweinfurthiana can be considered as a possible source of secondary metabolites exhibiting a cytotoxic activity on HeLa cells. It would be worthwhile to Table 1. Cytotoxic activity of the extracts and compounds 3– 6, 8 and 9 in HeLa cellsa. Extracts and compounds MeOH extract EtOAc extract Lithospermoside (3) Amentoflavone (4) Saccharose (5) Agathisflavone (6) Cupressuflavone (8) Robustaflavone (9) Mitoxantronec Vehicle a
% Viability at 20 mg/mL 13.9 9.4 70.5 1.9 75.5 1.5 67.6 69.0 0.0 100.0
IC50 (mM)b
20.7 ^ 1.58 10.0 ^ 0.88 0.2 ^ 0.05
Extracts and compounds were evaluated for cytotoxicity by standard procedures as described in the Experimental section. HeLa (cervical cancer) human cell lines were used. Results are shown as % viability and IC50 values (mM). Results are the means of at least three independent determinations ^SD. c Positive control. b
4
J.T. Ndongo et al.
establish structure –activity relationships in order to highlight the functional groups important for the activity of the isolated compounds. 3. Conclusions We report the phytochemical study of O. schweinfurthiana and demonstrated the cytotoxic activity of the methanolic and ethyl acetate extracts, as well as of some isolated compounds. Flavonoids, cyanoglycoside, saccharose and sterol glycoside were identified from the ethyl acetate extract for the first time. The results of the bioassay confirmed the effects of amentoflavone and agathisflavone in HeLa cells as demonstrated by Ying et al. (2010) and Shrestha et al. (2012).
Downloaded by [University of Bristol] at 22:53 26 February 2015
Supplementary material Experimental details relating to this article are available online. Acknowledgements The authors thank Mr F. Fehr and Mr F. Nydegger for NMR and mass spectrometry measurements, and Mr Fawa Guidawa (University of Ngaounde´re´) for the collection of plant material.
Funding The authors wish to thank the Swiss National Science Foundation [grant number IZK0Z2__145075] for the financial support.
References Abdullahi MI, Iliya I, Haruna AK, Sule MI, Musa AM, Abdullahi MS. 2010. Preliminary phytochemical and antimicrobial investigations of leaf extracts of Ochna schweinfurthiana (Ochnaceae). Afr J Pharm Pharmacol. 4:83–86. Abdullahi MI, Musa AM, Haruna AK, Pateh UU, Sule MI, Abdulmalik IA, Abdullahi MS, Abimiku AG, Iliya I. 2014. Isolation and characterization of an anti-microbial biflavonoid from the chloroform-soluble fraction of methanolic root extract of Ochna schweinfurthiana (Ochnaceae). Afr J Pharm Pharmacol. 8:93–99. Abdullahi MI, Musa AM, Haruna AK, Sule MI, Abdullahi MS, Abdulmalik MI, Akinwande Y, Abimiku AG, Iliya I. 2011. Antimicrobial flavonoid diglycoside from the leaves of Ochna schweinfurthiana F. Hoffm. (Ochnaceae). Niger J Pharm Sci. 10:1–7. Burkill HM. 1997. The useful plants of West Tropical Africa. Families M–R. Vol. 4 2nd ed. Kew: Royal Botanic Gardens. Lin YM, Flavin MT, Schure R, Chen FC, Sidwell R, Barnard DL, Huffman JH, Kern ER. 1999. Antiviral activities of biflavonoids. Planta Med. 65:120–125. Pei JS, Liu CC, Hsu YN, Lin LL, Wang SC, Chung JG, Bau DT, Lin SS. 2012. Amentoflavone induces cell-cycle arrest and apoptosis in MCF-7 human breast cancer cells via mitochondria-dependent pathway. In Vivo. 26:963–970. Shrestha S, Park JH, Lee DY, Cho JG, Seo WD, Kang HC, Yoo KH, Chung IS, Jeon YJ, Yeon SW, Baek NI. 2012. Cytotoxic and neuroprotective biflavonoids from the fruit of Rhus parviflora. J Korean Soc Appl Biol Chem. 55:557–562. Ying J, Guogang Z, Enlong M, Hongmei Z, Jin G, Jie H. 2010. Amentoflavone and the extracts from Selaginella tamariscina and their anticancer activity. Asian J Tradit Med. 5:226–229.
