Isolation and Characterization of Two Coumarin Compounds from the Chloroform Fraction of Scadoxus multiflorus (Martyn) Raf. (Amaryllidaceae) †
by
Olaiya Akeem Ayodele
*, 
Tijani Tawakaltu Omolara
,
Abdullahi Sakynah Musa
and
Sule Mohammed Ibrahim
Department of Pharmaceutical and Medicinal Chemistry, Ahmadu Bello University, Zaria 810107, Nigeria
*
Author to whom correspondence should be addressed.
†
Presented at the 28th International Electronic Conference on Synthetic Organic Chemistry (ECSOC-28), 15–30 November 2024; Available online: https://sciforum.net/event/ecsoc-28.
Chem. Proc. 2024, 16(1), 89; https://doi.org/10.3390/ecsoc-28-20184
Published: 18 February 2025
(This article belongs to the Proceedings of The 28th International Electronic Conference on Synthetic Organic Chemistry)
Abstract
:In this study, the aerial parts of Scadoxus multiflorus were extracted using methanol through a maceration process. The resulting methanol crude extract was subsequently partitioned with solvents including n-hexane, chloroform, ethyl acetate, and n-butanol. Extensive column chromatography separation of the chloroform fraction, followed by isocratic elution of two pooled fractions, led to the isolation of two coumarin derivatives: 2-methyl-2H-chromen-7-ol and 7-methoxy-2H-chromen-2-one. These compounds underwent various physicochemical analyses, such as chemical tests, melting point determination, and solubility assessments. Structural elucidation of the isolated compounds was conducted using UV spectroscopy, FT-IR, and 1D/2D NMR techniques. The final molecular structures were confirmed and named using ChemDraw.
1. Introduction
Plants have thrived on Earth for hundreds of millions of years, evolving sophisticated biochemical systems to withstand both external and internal stresses [1]. These chemicals, referred to as secondary metabolites or natural products, are produced by plants to adapt to environmental fluctuations while minimally affecting their cellular and developmental physiological processes [2]. Some key secondary metabolites include alkaloids, coumarins, flavonoids, steroids, tannins, anthraquinones, and saponins, among others.
Coumarins represent a large and diverse class of compounds widely distributed in the plant kingdom. They are predominantly found in higher plants, with the compound umbelliferone being a particularly rich source. Although coumarins can be found throughout various plant tissues, they are most concentrated in the fruits, followed by the roots, stems, and leaves. In recent years, coumarin compounds have gained increasing attention due to their medicinal properties, particularly for their significant roles in disease prevention and treatment, including bacteriostatic effects and anti-tumour activities [3,4].
Scadoxus multiflorus, a member of the Amaryllidaceae family, is a flowering plant first described by Thomas Martyn in 1795 as Haemanthus multiflorus. In 1838, Constantine Samuel Rafinesque reclassified it into the new genus Scadoxus. Commonly known as fire-ball lily, African blood lily, powderpuff lily, and pincushion flower, S. multiflorus is primarily native to the tropical regions of Africa [5,6] and is cultivated globally for both ornamental and medicinal purposes. The species is widely distributed across northern and southern Nigeria, where it is traditionally used by the Fulani to demarcate farm plot boundaries. Additionally, in various parts of Nigeria, it serves as an ointment for treating ulcers, as an antimalarial agent, a cardiotonic, and as a stimulant for alleviating debility [7,8].
The objective of this study is to isolate and characterize coumarin compounds from the chloroform fraction of the methanolic extract of the aerial parts of Scadoxus multiflorus.
2. Material and Methods
2.1. Plant Material
S. multiflorus aerial parts, which comprises the flower, leaves and stem were collected from Kundugi Village, Sabon Gari Local Government, Kaduna State Nigeria, on September 2022. The plant material was identified by Mr. Namadi Sanusi of Herbarium unit, Department of Botany, Ahmadu Bello University, Zaria Kaduna State Nigeria, by comparing them with existing voucher specimen number (ABU019006). The aerial parts were shade-dried at room temperature to a constant weight and pounded. A 800 kg of the powdered plant sample was stored at room temperature for use.
2.2. Extraction and Partitioning
The pulverized plant material (800 kg) of S. multiflorus was extracted with 15 L of methanol using maceration method for four days with occasional shaking and swirling. The extract was concentrated in-vacuo using a rotary evaporator at 40 °C to afford a greenish-brown crude methanol extract. The concentrated methanol extract (97 g) was then subjected to successive fractionation with different solvents in sequence and the yields were n-hexane-18.28 g, chloroform- 10.19 g ethylacetate-5.88 g, and n-butanol-25.57 g [9].
2.3. Isolation and Characterization of Compound B12 and C11 from Chloroform Fraction
The chloroform fraction (10.19 g) was chromatographed over silica gel of 60–120 μm mesh size in a glass column of 75 cm by 3.5 cm and eluted sequentially with an n-hexane/ethyl acetate solvent system in respect to others of polarity from the nonpolar to polar region. The fractions were monitored by thin layer chromatography (TLC). The TLC plates were sprayed with dilute sulfuric acid followed by heating at 100 °C and viewed under UV light. Similar fractions were grouped according to their TLC profile. The two fractions B and C that were purified using a small column of 25 mL with n-hexane: ethyl acetate (50:50) as a solvent system using isocratic elusion techniques yielded compound B12 (10 mg) and C11 (13.5 mg). The two compounds were subjected to physicochemical studies (solubility, melting point, and chemical test) and the spectral analysis was carried out using UV, IR and NMR analysis [10].
3. Results and Discussion
Column chromatographic separation of the chloroform fraction followed by purification of the pooled fraction B led to the isolation of a white solid material coded B12 which gave a single homogenous spot on TLC using two different solvent systems with an Rf value of 0.78 using HEX: EA (1:1) and an Rf value of 0.63 using DCM: EA (9.5:0.5). The compound was only visible under UV and showed a violet colour. B12 was completely soluble in chloroform and melted at 122–124 °C. The appearance of a greenish colour with FeCl3 solution suggests that compound B12 might be a phenolic compound. The UV spectrum of compound B12 recorded in methanol showed absorption maxima at 200.11 nm and an absorbance of 3.939, indicating the presence of absorbing chromophore. The IR spectrum of B12 showed characteristics absorption frequencies at 3428.2cm−1 typical of the O-H stretching; stretching vibrations due to asymmetric and symmetric C-H were represented by the bands at 2926.0cm−1 and 2855.1cm−1, respectively. A measurement of 1602.8 cm−1 and 1509.6 cm−1 were due to the aromatic ring C=C in plane-stretching vibrations, 1461.1cm−1 band was due to aliphatic C-H bending, 1312.0 cm−1 was due to C-O-C stretching band of ether, and 820.0 cm−1 was due to olefinic C-H bending.
The 1H- NMR revealed a singlet at 0.86 assigned to the methyl group at position two. The singlet, doublet, and triplet peaks at 6.89, 8.05, 7.95, 7.46, and 7.75 are assigned protons at 3rd, 4th, 5th, 6th and 8th position protons, which showed meta and ortho coupling to each other. C-NMR spectrum showed the presence of 10 carbon atoms. The peak at 18.08 is assigned to the methyl group. The peak at 56.79, 108.15, 124.68, 118.73, 110.45, 129.32, 111.42, 116.42, and 151.16 were assigned to C-2, C-3, C-4, C-5, C-6, C-7, C-8, C-9, and C-10, respectively. The COSY spectral shows the correlations of protons H-3 with H-4, H-4 with H-3 and H-5, H-5 with H-4 and H-6, and H-6 with H-5. The complete assignment of the signals of compound B12 was based on proton, 13C-NMR H-H COSY and HSQC. All the data of 1H, 13C, COSY NMR of compound B12 are shown in Table 1. Therefore, the proposed structure of B12 was suggested to be 2-methyl-2H-chromen-7-ol, as shown in Figure 1.
Column chromatographic separation of the chloroform fraction followed by column chromatography of column fraction C led to the isolation of a white solid material coded C11, which gave a single homogenous spot on TLC using two different solvent systems with Rf value of 0.78 using HEX: EA (1:1) and Rf value of 0.63 using DCM: EA (9.5:0.5). The compound was only visible under UV and appeared violet. C11 was completely soluble in chloroform and melted at 120–123 °C. The appearance of a greenish colour with FeCl3 solution suggests that compound C11 might be a phenolic compound. The UV spectra of compound C11 recorded in methanol showed absorption maxima at 205.13 nm and absorbance of 3.939, indicating the presence of absorbing chromophore. The IR spectrum of C11 showed characteristics absorption frequencies at 2922.2cm−1 and 2851.4cm−1 stretching vibrations due to asymmetric and symmetric C-H. 1673.6cm−1 was due to stretching vibration of carbonyl group. The measurement of 1509.6 cm−1 was due to the aromatic ring C=C in plane stretching vibrations, 1457.4 was due to aliphatic C-H bending vibration, 1315.8 cm−1 was due to C-O-C stretching band of ether, and 805.1cm−1 was due to olefinic C-H bending vibration.
The 1H- NMR revealed a singlet at 3.69 assigned to the methoxy group at the 7th position. The singlet, doublet, and triplet peaks at 6.90, 8.02, 7.93, 7.49, and 7.72 are assigned protons at the 3rd, 4th, 5th, 6th and 8th position protons, which showed meta and ortho coupling to each other. The C-NMR spectrum showed the presence of 10 carbon atoms. The peak at 55.14 is assigned to the methoxy group. The peak at 167.04, 118.73, 124.01, 130.28, 110.45, 160.11, 111.43, 116.43, and 152.16 were assigned to C-2, C-3, C-4, C-5, C-6, C-7, C-8, C-9, and C-10, respectively. The COSY spectral shows the correlations of protons H-3 with H-4, H-4 with H-3 and H-5, H-5 with H-4 and H-6, and H-6 with H-5. The complete assignment of the signals of compound C11 was based on proton, 13C-NMR, H-H COSY, and HSQC. All the data of 1H, 13C, and COSY NMR of compound C11 are shown in Table 1. These data were compared with that of the literature reported by [10,11,12,13] which shows a uniformity with the isolated herniarin from Eupatorium plants. Therefore, the proposed structure of C11 was suggested to be 7-methoxy-2H-chromen-2-one as shown in Figure 2.
Benzopyran, commonly referred to as chromene, is a crucial compound in organic chemistry. Both natural and synthetic benzopyran derivatives exhibit a wide range of biological activities, including anti-inflammatory, anticancer, anti-arthritic, antibacterial, anti-Alzheimer’s, antiviral, and anti-skin disease properties, as well as potential therapeutic effects for autosomal dominant polycystic kidney disease (ADPKD) [14]. The two compounds, B12 and C11, feature a benzopyran ring structure similar to coumarins. Coumarins are known to be slightly soluble in water and ethanol, but highly soluble in solvents such as chloroform, diethyl ether, and pyridine [15,16,17]. Coumarins possess an extended π-π conjugated system with electron-rich and charge-transfer properties, making them useful as fluorescent sensors in biological applications. Notably, substitution at the 7 position with electron-donating groups significantly enhances their fluorescence [18]. The fact that compounds B12 and C11 were isolated from the chloroform fraction and exhibited fluorescence, as observed under UV light during thin-layer chromatography experiments, strongly suggests they belong to the coumarin class. Furthermore, the biosynthetic intermediate of coumarins derived from polycerasoidol and tocopherol in plants [19] bears structural similarity to compound B12, further supporting the hypothesis that B12 is a coumarin derivative.
4. Conclusions
This work revealed the isolation and characterization of 2-methyl-2H-chromen-7-ol (B12) and 7-methoxy-2H-chromen-2-one (C11) from the chloroform fraction. With extensive literature research, it has been concluded that this is the first report on the isolation of these two compounds from chloroform fraction of the methanol aerial parts extracted from Scadoxus multiflorus.
Author Contributions
O.A.A.: Conceptualization, Formal Analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Writing original draft, Writing review & editing. T.T.O.: Formal Analysis, Project administration, Resources, Software, Visualization. A.S.M.: Methodology, Supervision, Visualization, Validation, Writing—original draft, Writing—review & editing. S.M.I.: Investigation, Project administration, Resources, Supervision, Validation. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
The raw data supporting the conclusions of this article will be made available by the authors on request.
Conflicts of Interest
The authors declare no conflicts of interest.
References
- Zaynab, M.; Fatima, M.; Abbas, S.; Sharif, Y.; Umair, M.; Zafar, M.H.; Bahadar, K. Role of Secondary Metabolites in Plant Defense Against Pathogens. Microb. Pathog. 2018, 124, 198–202. [Google Scholar] [CrossRef] [PubMed]
- Adedeji, A.A.; Babalola, O.O. Secondary Metabolites as Plant Defensive Strategy: A Large Role for Small Molecules in the Near Root Region. Planta 2020, 252, 61. [Google Scholar] [CrossRef]
- Jain, P.K.; Joshi, H. Coumarin: Chemical and Pharmacological Profile. J. Appl. Pharm. Sci. 2012, 2, 236–240. [Google Scholar] [CrossRef]
- Matos, M.J.; Santana, L.; Uriarte, E.; Abreu, O.A.; Molina, E.; Yordi, E.M.A.E.G. Coumarins—An Important Class of Phytochemicals. In Phytochemicals—Isolation, Characterisation and Role in Human Health; IntechOpen: London, UK, 2015; pp. 113–140. [Google Scholar] [CrossRef]
- Mim, B.A.; Md Mashrur, C.; Rajib, H.; Tania, P.; Fatema, K.; Anzuman, A.; Islam, M.T.; Razina, R. Phyto-pharmacological Investigation of Aqueous Crude Extract of Scadoxus multiflorus. World J. Pharm. Pharm. Sci. 2021, 10, 154–173. [Google Scholar] [CrossRef]
- Yokosuka, A.; Suzuki, N.; Mimaki, Y. Chemical constituents of the bulbs of Haemanthus multiflorus. Phytochem. Lett. 2017, 21, 6–10. [Google Scholar] [CrossRef]
- Burkill, H.M. The Useful Plants of West Tropical Africa; Royal Botanical Gardens: Kew, UK, 1985; Volume 1, p. 319. [Google Scholar]
- Tsukamoto, K. Juveniles Released with Fluorescent Otolith Tags. News Bay 1989, 35, 59–69. [Google Scholar]
- Alhakmani, F.; Kumar, S.; Alam Khan, S. Estimation of Total Phenolic Content, In-Vitro Antioxidant and Anti–Inflammatory Activity of Flowers of Moringa Oleifera. Asian Pac. J. Trop. Biomed. 2013, 3, 623–627. [Google Scholar] [CrossRef] [PubMed]
- Cheriyan, B.V.; Kadhirvelu, P.; Nadipelly, J.; Shanmugasundaram, J.; Sayeli, V.; Subramanian, V. Anti-nociceptive Effect of 7-methoxy Coumarin from Eupatorium triplinerve vahl (Asteraceae). Pharmacogn Mag. 2017, 13, 81–84. [Google Scholar] [CrossRef] [PubMed]
- Silva, J.L.; Chai, H.; Farnsworth, N.I.; Gupta, M.P. Natural Product Isolation; Carnell, R., Ed.; Humana Press Publication: Clifton, NJ, USA, 1998; pp. 349–359. [Google Scholar]
- Bose, P.K.; Roy, A.C. The Constitution of Ayapanin. J. Indian Chem. Soc. 1936, 13, 586–587. [Google Scholar]
- Natarajan, R.K.; Natarajan, M.J. Phytochemical Investigation of Eupatorium Ayapana. J. Res. Indian Med. Yoga Homeopat. 1979, 14, 155–156. [Google Scholar]
- Xiu, C.; Hua, Z.; Xiao, B.; Tang, W.J.; Zhou, H.P.; Liu, X.H. Expert Opinion on Therapeutic Patents Novel Benzopyran Derivatives and their Therapeutic Applications: A Patent Review. Expert Opin. Ther. Pat. 2017, 00, 1–15. [Google Scholar] [CrossRef]
- Budavári, T.; Szalay, A.S.; Charlot, S.; Seibert, M.; Wyder, T.K.; Arnouts, S.; Barlow, T.A.; Bianchi, L.; Byun, Y.-I.; Donas, J.; et al. The Ultraviolet Luminosity Function of Galex Galaxies at Photometric Redshifts between 0.07 and 0.25. Astrophys. J. 2005, 619, L31–L34. [Google Scholar] [CrossRef]
- Lide, D.R.; Milne, G.W. Properties of Organic Compounds. Pure Appl. Chem. 1996, 55, 221–228. [Google Scholar]
- Netea, M.G.; Demacker, P.N.; Kullberg, B.J.; Boerman, O.C.; Verschueren, I.; Stalenhoef, A.F.; van der Meer, J.W. Low-Density Lipoprotein Receptor-Deficient Mice Are Protected Against Lethal Endotoxemia and Severe Gram-Negative Infections. J. Clin. Investig. 1996, 97, 1366–1372. [Google Scholar] [CrossRef] [PubMed]
- Raunio, H.; Pentikäinen, O.; Juvonen, R.O. Coumarin-Based Profluorescent and Fluorescent Substrates for Determining Xenobiotic-Metabolizing Enzyme Activities In Vitro. Int. J. Mol. Sci. 2020, 21, 4708. [Google Scholar] [CrossRef] [PubMed]
- Bermejo, A.; Barrachina, I.; El Aouad, N.; Franck, X.; Chahboune, N.; Andreu, I.; Figadère, B.; Vila, L.; Hennuyer, N.; Staels, B.; et al. Synthesis of Benzopyran Derivatives as PPARα and/or PPARγ activators. Bioorg. Med. Chem. 2019, 27, 115162. [Google Scholar] [CrossRef] [PubMed]
Figure 1.
Proposed structure of compound B12 (2-methyl-2H-chromen-7-ol).
Figure 2.
Structure of compound C11 (7-methoxy-2H-chromen-2-one) Herniarin.
Table 1.
1H and 13C NMR (CDCl3, 400 MHZ) Chemical Shifts and Coupling Constants for Compound B12 & C11.
Table 1.
1H and 13C NMR (CDCl3, 400 MHZ) Chemical Shifts and Coupling Constants for Compound B12 & C11.
| Compound B12 | Compound C11 | ||||
|---|---|---|---|---|---|
| C | δH (ppm) | δC (ppm) | C | δH (ppm) | δC (ppm) |
| 1 | ----- | ----- | 1 | ----- | ----- |
| 2 | 4.09 (s) | 56.79 | 2 | ----- | 167.04 |
| 3 | 6.89 (d, J = 4.0 Hz) | 108.15 | 3 | 6.90 (d, J = 4.0 Hz) | 118.73 |
| 4 | 8.05 (t, J = 4.0, 8.0 Hz) | 124.68 | 4 | 8.02 (t, J = 4.0, 8.0 Hz) | 124.01 |
| 5 | 7.95 (t, J = 4.0, 8.0 Hz) | 118.73 | 5 | 7.93 (t, J = 4.0, 8.0 Hz) | 130.28 |
| 6 | 7.46 (d, J = 4.0 Hz) | 110.45 | 6 | 7.49 (d, J = 4.0 Hz) | 110.45 |
| 7 | OH | 129.32 | 7 | ----- | 160.11 |
| 8 | 7.75 (s) | 111.42 | 8 | 7.72 (s) | 111.43 |
| 9 | ----- | 116.72 | 9 | ----- | 116.43 |
| 10 | ----- | 151.16 | 10 | ----- | 152.16 |
| CH3 | 0.86 (s) | 18.08 | OCH3 | 3.69 (s) | 55.14 |
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
MDPI and ACS Style
Ayodele, O.A.; Omolara, T.T.; Musa, A.S.; Ibrahim, S.M. Isolation and Characterization of Two Coumarin Compounds from the Chloroform Fraction of Scadoxus multiflorus (Martyn) Raf. (Amaryllidaceae). Chem. Proc. 2024, 16, 89. https://doi.org/10.3390/ecsoc-28-20184
AMA Style
Ayodele OA, Omolara TT, Musa AS, Ibrahim SM. Isolation and Characterization of Two Coumarin Compounds from the Chloroform Fraction of Scadoxus multiflorus (Martyn) Raf. (Amaryllidaceae). Chemistry Proceedings. 2024; 16(1):89. https://doi.org/10.3390/ecsoc-28-20184
Chicago/Turabian StyleAyodele, Olaiya Akeem, Tijani Tawakaltu Omolara, Abdullahi Sakynah Musa, and Sule Mohammed Ibrahim. 2024. "Isolation and Characterization of Two Coumarin Compounds from the Chloroform Fraction of Scadoxus multiflorus (Martyn) Raf. (Amaryllidaceae)" Chemistry Proceedings 16, no. 1: 89. https://doi.org/10.3390/ecsoc-28-20184
APA StyleAyodele, O. A., Omolara, T. T., Musa, A. S., & Ibrahim, S. M. (2024). Isolation and Characterization of Two Coumarin Compounds from the Chloroform Fraction of Scadoxus multiflorus (Martyn) Raf. (Amaryllidaceae). Chemistry Proceedings, 16(1), 89. https://doi.org/10.3390/ecsoc-28-20184
