Characterization of Curcumin from Curcuma purpurascens Blume and Its Activity Test as Antioxidant and Antilipase
Abstract
Curcuma purpurascens Blume is a plant in the Zingiberaceae family and known as temu blenyeh. This plant has been used as a medicinal plant but there is still little research and not much has been reported about its chemical components. The research aimed to isolate and characterize the chemical components of the rhizomes of C. purpurascens and test its activity as an antioxidant and antilipase. The ethanol extract of temu blenyeh (Curcuma purpurascens Blume) underwent antioxidant activity-guided purification using vacuum liquid chromatography to obtain pure compounds. The antioxidant activity test used the DPPH (2,2-diphenyl-1picrylhydrazyl) method, while the antilipase activity test performed inhibition of pancreatic lipase enzyme activity. The results showed that the ethanol extract had antioxidant activity with an IC50 value of 55.501±0.361µg/mL with the positive control Vitamin C having an IC50 of 5.843±0.181µg/mL. The antilipase activity of the ethanol extract had an IC50 value of 117.863 ± µg/mL. The antilipase activity of orlistat as a positive control had an IC50 value of 12.265 ± µg/mL. The ethylacetate fraction activated the lipase enzyme with the highest inhibition of 70.33%. Curcumin was isolated from the ethyl acetate fraction of C. purpurascens rhizomes in the form of a yellow-orange powder with antioxidant activity of IC50 71.305±0.215µg/mL and was found to be an active lipase inhibitor with an IC50 of 54.786±5.588µg/mL. The structure was identified using UV-Vis, IR, UPLC-MSMS, 1D-NMR, and 2D-NMR analysis.
References
Ahmed, M., Abdul Qadir, M., Imtiaz Shafiq, M., Muddassar, M., Hameed, A., Nadeem Arshad, M., & Asiri, A. M. (2017). Curcumin: Synthesis optimization and in silico interaction with cyclin dependent kinase. Acta Pharmaceutica, 67(3), 385–395. https://doi.org/10.1515/acph-2017-0023
Akter, J., Hossain, M. A., Takara, K., Islam, M. Z., & Hou, D. X. (2019). Antioxidant activity of different species and varieties of turmeric (Curcuma spp): Isolation of active compounds. Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology, 215(September 2018), 9–17. https://doi.org/10.1016/j.cbpc.2018.09.002
Alawiyah, A. L., & Senania, A. (2022). Antioxidant Activity and Bioactive Compounds of Ethyl Acetate Fractions from Syzygium cumini Wood Stem. ALKIMIA : Jurnal Ilmu Kimia Dan Terapan, 5(1), 93–101. https://doi.org/10.19109/alkimia.v5i1.7143
Alekhya, V., Deepan, T., & Ganapaty, S. (2022). Phytochemical Screening And Pharmacological Evaluation Of Tecoma Gaudichaudi. Bulletin of Pharmaceutical Sciences, 45(2), 585–592. https://doi.org/https://doi.org/10.21608/bfsa.2022.271489
Alias, N., Leow, C. T., Ali, M. S. M., Tajudin, A. A., Salleh, B. A., & Rahman, A. R. Z. N. R. (2017). Anti-obesity Potential of Selected Tropical Plants via Pancreatic Lipase Inhibition. Advances in Obesity, Weight Management & Control, 6(4). https://doi.org/10.15406/aowmc.2017.06.00163
Atun, S., Aznam, N., Arianingrum, R., Senam, Naila, B. I. A., Lestari, A., & Purnamaningsih, N. A. (2020). Characterization of curcuminoid from curcuma xanthorrhiza and its activity test as antioxidant and antibacterial. Molekul, 15(2), 79–87. https://doi.org/10.20884/1.jm.2020.15.2.540
Ayati, Z., Ramezani, M., Amiri, M. S., Moghadam, A. T., Rahimi, H., Abdollahzade, A., Sahebkar, A., & Emami, S. A. (2019). Ethnobotany, Phytochemistry and Traditional Uses of Curcuma spp. and Pharmacological Profile of Two Important Species (C. longa and C. zedoaria): A Review. Current Pharmaceutical Design, 25(8), 871–935. https://doi.org/10.2174/1381612825666190402163940
Babu, K. N., Divakaran, M., Pillai, G. S., Sumathi, V., Praveen, K., Raj, R. P., Akshita, H. J., Ravindran, P. N., & Peter, K. V. (2016). Protocols for In Vitro Propagation , Conservation , Synthetic Seed Production , Microrhizome Production , and Molecular Profi ling in Turmeric ( Curcuma longa L .) (Vol. 1391). https://doi.org/10.1007/978-1-4939-3332-7
Caiqin, L., Weiqing, C., Nan, W., & Jianchang, J. (2018). Optimization of extraction of antioxidants from turmeric (Curcuma longa L.) using response surface methodology. Wuhan University Journal of Natural Sciences, 23(1), 63–69. https://doi.org/10.1007/s11859-018-1295-0
Cucuzza, L. S., Motta, M., Miretti, S., Accornero, P., & Baratta, M. (2008). Curcuminoid-phospholipid complex induces apoptosis in mammary epithelial cells by STAT-3 signaling. Experimental and Molecular Medicine, 40(6), 647–657. https://doi.org/10.3858/emm.2008.40.6.647
Diastuti, H., Asnani, A., & Chasani, M. (2019). Antifungal activity of curcuma xanthorrhiza and curcuma soloensis extracts and fractions. IOP Conference Series: Materials Science and Engineering, 509, 1–5. https://doi.org/10.1088/1757-899X/509/1/012047
Hadváry, P., Sidler, W., Meister, W., Vetter, W., & Wolfer, H. (1991). The lipase inhibitor tetrahydrolipstatin binds covalently to the putative active site serine of pancreatic lipase. Journal of Biological Chemistry, 266(4), 2021–2027. https://doi.org/10.1016/s0021-9258(18)52203-1
Halim, A. R. M., Tan, Z. M. S. M., Ismail, S., & Mahmud, R. (2012). Standardization and Phytochemical Studies Of Curcuma Xanthorrhiza Roxb. International Journal of Pharmacy and Pharmaceutical Sciences, 4(3), 6060–6610.
Hamdi, A. A. O. (2015). Chemical Constituents From The Rhizomes Of Curcuma zedoria And Curcuma purpurascens and Assessment of Their Biological Activities. University of Malaya.
Hidayat, M., Soeng, S., & Prahastuti, S. (2014). Pengujian Aktivitas Inhibitor Lipase Ekstrak Etanol Dan Hasil Fraksionasi Dari Kedelai Detam 1 Dan Daun Jati Belanda. Chimica et Natura Acta, 2(1), 76–82. https://doi.org/10.24198/cna.v2.n1.9146
Hong, S. L., Lee, G. S., Syed Abdul Rahman, S. N., Ahmed Hamdi, O. A., Awang, K., Aznam Nugroho, N., & Abd Malek, S. N. (2014). Essential oil content of the rhizome of curcuma purpurascens Bl. (Temu Tis) and its antiproliferative effect on selected human carcinoma cell lines. The Scientific World Journal, 2014, 1–7. https://doi.org/10.1155/2014/397430
Istyastono, E. P., Martono, S., Pranowo, H. D., & Tahir, I. (2003). Quantitative Structure-Activity Relationship Analysis of Curcumin and Its Derivatives As Gst Inhibitors Based on Computational Chemistry Calculation. Indonesian Journal of Chemistry, 3(3), 179–186. https://doi.org/10.22146/ijc.21886
Jalip, I. S., Suprihatin, Ida, W., & Ernawati, S. (2013). Antioxidant Activity and Total Flavanoid Content of Curcuma Rhizome Extract. Proceeding International Conference, 2013 , The 4th Green Technology Faculty of Science and Technology Islamic of University State Maulana Malik Ibrahim Malang, 93.
Jantan, I., Saputri, F. C., Qaisar, M. N., & Buang, F. (2012). Correlation between chemical composition of curcuma domestica and curcuma xanthorrhiza and their antioxidant effect on human low-density lipoprotein oxidation. Evidence-Based Complementary and Alternative Medicine, 2012(Ldl). https://doi.org/10.1155/2012/438356
Jeon, W., Lee, M., Shin, I., Jin, S. E., & Ha, H. (2015). Curcuma aromatica Water Extract Attenuates Ethanol-Induced Gastritis via Enhancement of Antioxidant Status. 2015, 1–7. https://doi.org/10.1155/2015/582496
Jovanovic, S. V, Steenken, S., Boone, C. W., & Simic, M. G. (1999). H-Atom Transfer Is A Preferred Antioxidant Mechanism of Curcumin. J. Am. Chem. Soc, 121(14), 9677–9681.
Julianti, T. B., Bakar, M. F. A., & Wikantyasning, E. R. (2022). Phytochemical, Antioxidant Analysis and In Vitro Xanthine Oxidase Inhibitory Activity of Kaempferia parviflora and Kaempferia galanga. Tropical Journal of Natural Product Research, 6(12), 1981–1985. https://doi.org/10.26538/tjnpr/v6i12.14
Kato, A. M., Nishikawa, S., Ikehata, A., Tani, T., Takahashi, T., Imaizumi, A., & Tsuda, T. (2016). Curcumin improves glucose tolerance via stimulation of glucagon-like peptide-1 secretion. Molecular Nutrition & Food Research, 61(3), 1–20. https://doi.org/10.1002/mnfr.201600471.This
Katz, D. L., Doughty, K., & Ali, A. (2011). Cocoa and chocolate in human health and disease. Antioxidants and Redox Signaling, 15(10), 2779–2811. https://doi.org/10.1089/ars.2010.3697
Khan, I., Jan, A. S., Shinwari, K. Z., Ali, M., Khan, Y., & Kumar, T. (2017). Ethnobotany and Medicinal Uses of Folklore Medicinal Plants Belonging to Family Acanthaceae: An Updated Review. MOJ Biology and Medicine, 1(2), 34–38. https://doi.org/10.15406/mojbm.2017.01.00009
Kim, Y. S., Lee, Y. M., Kim, H., Kim, J., Jang, D. S., Kim, J. H., & Kim, J. S. (2010). Anti-obesity effect of Morus bombycis root extract: Anti-lipase activity and lipolytic effect. Journal of Ethnopharmacology, 130(3), 621–624. https://doi.org/10.1016/j.jep.2010.05.053
Kodjio, N., Atsafack, S., Fodouop, S., Kuiate, J.-R., & Gatsing, D. (2016). In vitro Antisalmonellal and Antioxidant Activities of Extracts and Fractions of Curcuma longa L. Rhizomes (Zingiberaceae). International Journal of Biochemistry Research & Review, 11(3), 1–14. https://doi.org/10.9734/ijbcrr/2016/25106
Li, W., Wang, S., Feng, J., Xiao, Y., Xue, X., Zhang, H., Wang, Y., & Liang, X. (2009). Structure elucidation and NMR assignments for curcuminoids from the rhizomes of Curcuma longa. Magnetic Resonance in Chemistry, 47(10), 902–908. https://doi.org/10.1002/mrc.2478
Liu, T. T., Liu, X. T., Chen, Q. X., & Shi, Y. (2020). Lipase Inhibitors for Obesity: A Review. Biomedicine and Pharmacotherapy, 128(May). https://doi.org/10.1016/j.biopha.2020.110314
Malik, P., & Mukherjee, T. K. (2014). Structure-Function Elucidation of Antioxidative and Prooxidative Activities of the Polyphenolic Compound Curcumin. Chinese Journal of Biology, 2014, 1–8. https://doi.org/10.1155/2014/396708
Mangunwardoyo, W., Deasywaty, & Usia, T. (2012). Antimicrobial and identification of active compound Curcuma xanthorrhiza Roxb. International Journal of Basic & Applied Sciences - IJBAS-IJENS, 12(1), 69–78.
Marliyana, S. D., Wartono, M. W., Wibowo, F. R., & Munasah, G. (2018). Isolasi dan Identifikasi Senyawa Seskuiterpen dari Curcuma soloensis Val. (Temu Glenyeh). Jurnal Kimia VALENSI, 4(2), 137–142. https://doi.org/10.15408/jkv.v4i2.7443
Naksuriya, O., Okonogi, S., Schiffelers, R. M., & Hennink, W. E. (2014). Curcumin nanoformulations: A review of pharmaceutical properties and preclinical studies and clinical data related to cancer treatment. Biomaterials, 35(10), 3365–3383. https://doi.org/10.1016/j.biomaterials.2013.12.090
Nandiyanto, D. B. A., Wiryani, S. A., Rusli, A., Purnamasari, A., Abdullah, G. A., Ana, A., Widiaty, I., & Hurriyati, R. (2017). Extraction of Curcumin Pigment from Indonesian Local Turmeric with Its Infrared Spectra and Thermal Decomposition PropertiesPreface: International Conference on Recent Trends in Physics (ICRTP 2016). IOP Conf. Series: Materials Science and Engineering, 180(1). https://doi.org/10.1088/1742-6596/755/1/10.1088/1757-899X/180/1/012136011001
Nelson, K. M., Dahlin, J. L., Bisson, J., Graham, J., Pauli, G. F., & Walters, M. A. (2017). The Essential Medicinal Chemistry of Curcumin. Journal of Medicinal Chemistry, 60(5), 1620–1637. https://doi.org/10.1021/acs.jmedchem.6b00975
Nuri, N., Puspitasari, E., Hidayat, M. A., Ningsih, I. Y., Triatmoko, B., & Dianasari, D. (2020). Pengaruh Metode Ekstraksi terhadap Kadar Fenol dan Flavonoid Total, Aktivitas Antioksidan serta Antilipase Daun Jati Belanda (Guazuma ulmifolia). Jurnal Sains Farmasi & Klinis, 7(2), 143. https://doi.org/10.25077/jsfk.7.2.143-150.2020
Padalia, R. C., Verma, R. S., Sundaresan, V., Chauhan, A., Chanotiya, S., & Yadav, A. (2014). Volatile terpenoid compositions of leaf and rhizome of Curcuma amada Roxb . from Northern India. Journal of Essential Oil Research, 25(1), 17–22. https://doi.org/10.1080/10412905.2012.747271
Policegoudra, R. S., Abiraj, K., Gowda, D. C., & Aradhya, S. M. (2007). Isolation and characterization of antioxidant and antibacterial compound from mango ginger (Curcuma amada Roxb.) rhizome. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 852(1–2), 40–48. https://doi.org/10.1016/j.jchromb.2006.12.036
Policegoudra, R. S., Rehna, K., Rao, L. J., & Aradhya, and S. M. (2010). Antimicrobial , antioxidant , cytotoxicity and platelet aggregation inhibitory activity of a novel molecule isolated and characterized from mango ginger ( Curcuma amada Roxb .) rhizome. 35(June), 231–240. https://doi.org/10.1007/s12038-010-0027-1
Pramiastuti, O., Kartika Murti, F., Mulyati, S., Khasanah, U., Atqiya, A. H., Afifah, Ainun, A. K. N., Sundawa, A. K. N., & Nandayani, ElaPamungkas, Y. (2021). Aktivitas Antioksidan Ekstrak Etanol Temu Blenyeh (Curcuma Purpurascens Blumae) Dengan Metode Dpph (1,1 Diphenyl-2-Picrylhydrazyl). Prosiding Seminar Nasional Kesehatan 2021 Lembaga Penelitian Dan Pengabdian Masyarakat Universitas Muhammadiyah Pekajangan Pekalongan, 29–37.
Pramiastuti, O., Wahyuono, S., Fakhrudin, N., & Astuti, P. (2023). Phytochemical and Pharmacological Activities of Curcuma purpurascens Blume, A Review. Journal of Tropical Biodiversity and Biotechnology, 8(1), 1–14. https://doi.org/10.22146/jtbb.75891
Pulido-Moran, M., Moreno-Fernandez, J., Ramirez-Tortosa, C., & Ramirez-Tortosa, M. C. (2016). Curcumin and health. Molecules, 21(3), 1–22. https://doi.org/10.3390/molecules21030264
Purwanti, L., Dasuki, U. A., & Imawan, A. R. (2019). Comparison of antioxidant activity of steeping 3 brands of black tea (Camellia Sinensis (L.) Kuntze) with steeping method based on SNI 01-1902-1995. Scientific Journal of Pharmacy, 2(1), 19–25. https://doi.org/10.29313/jiff.v2i1.4207.
Purwanto, D., Bahri, S., & Ridhay, A. (2017). Antioxidant Activity Test of Purnajiwa (Kopsia arborea Blume.) Fruit Extract With Various Solvents. KOVALEN Jurnal Riset Kimia, 3(1), 24–32. https://doi.org/https://doi.org/10.22487/J24775398.2017.V3.I1.8230
Rajkumari, S., & Sanatombi, K. (2018). Nutritional value, phytochemical composition, and biological activities of edible Curcuma species: A review. International Journal of Food Properties, 20(3), S2668–S2687. https://doi.org/10.1080/10942912.2017.1387556
Ralston, J., & Baur, L. (2023). World Obesity Atlas 2023. World Obesity Federation, March, 5–25. www.johnclarksondesign.co.uk
Regina, K. M. M., Adama, H., Jeanne, M., & Odile, N. (2015). Ethnobotany and Ethnopharmacognosy of Lamiaceae Species from Central Burkina Faso: Leucas martinicensis (Jacquin) R. Brown, Hoslundia opposita Vahl and Orthosiphon pallidus Royle Ex Benth. American Journal of Ethnomedicine, 2(4), 219–232. http://www.ajethno.com/index.php/AJETHNO/article/view/84
Riskesdas. (2018). Laporan Riskesdas 2018 Nasional. In Lembaga Penerbit Balitbangkes.
Rouhollahi, E., Moghadamtousi, S. Z., Abdulla, M. A., & Mohamed, Z. (2015). The chemopreventive potential of Curcuma purpurascens rhizome in reducing azoxymethane-induced aberrant crypt foci in rats. European Journal of Cancer, 51, e8. https://doi.org/10.1016/j.ejca.2015.06.028
Rouhollahi, Elham. (2016). Biological Activities Of Curcuma purpurascens Bl Rhizome Extract Using In Vitro and In Vivo Models. University Of Malaya Kuala Lumpur.
Rouhollahi, Elham, Moghadamtousi, S. Z., Abdalla, O., Hamdi, A., Fadaeinasab, M., Hajrezaie, M., Awang, K., Looi, C. Y., Abdulla, M. A., & Mohamed, Z. (2014). Evaluation of acute toxicity and gastroprotective activity of curcuma purpurascens BI . rhizome against ethanol-induced gastric mucosal injury in rats. BMC Complementary and Alternative Medicine, 14(378), 1–10. http://www.biomedcentral.com/1472-6882/14/378%0ARESEAR
Rouhollahi, Elham, Zorofchian Moghadamtousi, S., Hamdi, O. A. A., Fadaeinasab, M., Hajrezaie, M., Awang, K., Looi, C. Y., Abdulla, M. A., & Mohamed, Z. (2014). Evaluation of acute toxicity and gastroprotective activity of curcuma purpurascens BI. rhizome against ethanol-induced gastric mucosal injury in rats. BMC Complementary and Alternative Medicine. https://doi.org/10.1186/1472-6882-14-378
Sasikumar, B. (2005). Genetic resources of Curcuma : diversity, characterization and utilization . Plant Genetic Resources, 3(2), 230–251. https://doi.org/10.1079/pgr200574
Setyawan, A. D. (2003). Diversity of essential oils constituent of Curcuma. Biofarmasi Journal of Natural Product Biochemistry, 1(2), 44–49. https://doi.org/10.13057/biofar/f010202
Seyedan, A., Alshawsh, M. A., Alshagga, M. A., Koosha, S., & Mohamed, Z. (2015). Medicinal Plants and Their Inhibitory Activities against Pancreatic Lipase: A Review. Evidence-Based Complementary and Alternative Medicine, 2015. https://doi.org/10.1155/2015/973143
Simoh, S., & Zainal, A. (2015). Chemical profiling of Curcuma aeruginosa Roxb. rhizome using different techniques of solvent extraction. Asian Pacific Journal of Tropical Biomedicine, 5(5), 412–417. https://doi.org/10.1016/S2221-1691(15)30378-6
Sinaga, E., Suprihatin, & Rastuti, M. R. (2018). Kadar Flavonoid Total, Daya Antioksidan dan Daya Hepatoprotektif Ekstrak Etanol Rimpang Temu Tis (Curcuma purpurascens). Konggres XX Dan Pertemuan Ilmiah Tahunan Ikatan Apoteker Indonesia 2018, 13. http://repository.unas.ac.id/1570/1/B20-Prosiding-PIT-2018.pdf
Srivastava, S. (2006). Pharmacognostic Evaluation of Curcuma aeurigenosa Roxb Curcuma. AGRIS, 12(3), 162–165.
Subositi, D., & Wahyono, S. (2019). Study of the genus curcuma in Indonesia used as traditional herbal medicines. Biodiversitas, 20(5), 1356–1361. https://doi.org/10.13057/biodiv/d200527
Suharsanti, R., Astuti, P., Yuniarti, N., & Wahyuono, S. (2023). Isolation and Characterization of Curcumenotone, a Sesquiterpene from Curcuma aeruginosa Roxb as Antioxidant Ririn. Indonesian Journal of Pharmacu, 34(4), 592–601.
Suprihatin, Tambunan, C., & Sinaga, E. (2020). Acute and Subchronic Toxicity Of Temu Tis ( Curcuma Purpurascens Bi .) Rhizom in Mouse ( Rattus Norvegicus ). XXX(Xx), 2020.
Tanaya, V., Retnowati, R., & Suratmo. (2015). Fraksi Semi Polar dari Daun Mangga Kasturi (Mangifera casturi Kosterm). Kimia Journal, 1(1), 778–784.
Theanphong, O., Mingvanish, W., & Kirdmanee, C. (2015). Chemical Constituents and Biological Activities of Essential Oil From Curcuma Aeruginosa Roxb. Rhizome. Science and Technology BHST, 13(1), 6–16.
Utami, S., Endrini, S., Nafik, S., Lestari, I. M. T., Anindya, D., Bakar, E. A., Rozy, F., Said, F. F., Afifah, E., Arumwardana, S., Nufus, H., Rihibiha, D. D., Kusuma, H. S. W., Wibowo, S. H. B., & Widowati, W. (2019). In vitro antioxidant and anti-obesity activities of freeze-dried canarium sp., averrhoa bilimbi L. and malus domestica. Indonesian Biomedical Journal, 11(3), 320–326. https://doi.org/10.18585/inabj.v11i3.728
Vangoori, Y., Dakshinamoorthi, A., & Kavimani, S. (2019). Prominent Pancreatic Lipase Inhibition and Free Radical Scavenging Activity of a Myristica fragrans Ethanolic Extract in vitro. Potential Role in Obesity Treatment. Maedica : A Journal of Clinical Medicine, 14(3), 254–259. https://doi.org/https://doi.org/10.26574/maedica.2019.14.3.254
Vitasari, R.A., Wibowo, F.R., Marliyana, S.D., & Wartono, M. W. (2016). Isolation and Identification of Curcumin and Bisacurone from Rhizome Extract of Temu Glenyeh. IOP Conf. Series: Materials Science and Engineering, 1–5. https://doi.org/10.1088/1757-899X/107/1/012063
Wikara, T., Sulistiowaty, A., Murhandini, S., & Usia, T. (2016). Fingerprint Study of Curcuma xanthorrhiza Rhizome by High Performance Thin Layer Chromatography (HPTLC). Jurnal Jamu Indonesia, 1(2), 9–14. https://doi.org/10.29244/jjidn.v1i2.30607
World Health Organization (WHO). (2023). Obesity and Overweight, Fact sheet N°311. https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
Yokozawa, T., Chen, C. P., Dong, E., Tanaka, T., Nonaka, G. I., & Nishioka, I. (1998). Study on the inhibitory effect of tannins and flavonoids against the 1,1-diphenyl-2-picrylhydrazyl radical. Biochemical Pharmacology, 56(2), 213–222. https://doi.org/10.1016/S0006-2952(98)00128-2
Yuan, T., Zhang, C., Qiu, C., Xia, G., Wang, F., Lin, B., Li, H., & Chen, L. (2018). Chemical constituents from Curcuma longa L. and their inhibitory effects of nitric oxide production. Natural Product Research, 32(16), 1887–1892. https://doi.org/10.1080/14786419.2017.1354185
Zahran, R. F., Geba, Z. M., Tabll, A. A., & Mashaly, M. M. (2020). Therapeutic potential of a novel combination of Curcumin with Sulfamethoxazole against carbon tetrachloride-induced acute liver injury in Swiss albino mice. Journal of Genetic Engineering and Biotechnology, 18(13). https://doi.org/https://doi.org/10.1186/s43141-020-00027-9