Biology, Medicine, & Natural Product Chemistry ISSN 2089-6514 (paper) Volume 14, Number 1, April 2025 | Pages: 323-326 | DOI: 10.14421/biomedich.2025.141.323-326 ISSN 2540-9328 (online) Isolation and Characterization of Constituents from The Extracts of Momordica angustisepala Aerial Parts Abdulmumeen Amao Hamid1,2,*, Godshelp Osas Egharevba3,4,**, Shuab Bolaji Issa1,5, Oluwafeyikemi Mercy Olalere1, Bukunmi Temitope Akinloye1, Yakub Tunde Yakub1 1Department of Chemistry, University of Ilorin, Kwara State, Nigeria. 2Department of Pharmaceutical Chemistry and Pharmacognosy, School of Pharmacy, Kampala International University, Western Campus, Uganda. 3Chemistry Unit, Landmark University, Omu Aran, Kwara State, Nigeria. 4Indian Institute of Chemical Technology (IICT), Hyderaba, India. 5Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim, Norway. Corresponding author hamid.aa@unilorin.edu.ng; hamid@kiu.ac.ug; hamidmemo@gmail.com*, egharevb.godshelp@lmu.edu.ng; godhelpeghas@gmail.com** Manuscript received: 07 March, 2025. Revision accepted: 20 May, 2025. Published: 30 June, 2025. Abstract N-hexane, ethyl acetate and methanol extracts of Momordica angustisepala were screened for the presence of metabolites, using column and thin-layer chromatographic techniques. Octadecane (1), tetradec-5-enoic acid (2), 1,2,3-propanetriyl (8Z,11’Z,14”Z)tris(-8,11,14- eicostrienoate) (3), methyl oleana-5,12,15-trienoate-3β-acetate (4) and 1,2,3-propanetriyl (9Z,12’Z,15”Z)tris(-9,12,15-uneicostrienooate) (5) are the compounds obtained from the extracts of M. angustisepala aerial parts using proton and 13C Nuclear Magnetic Resonance Spectroscopy (NMR). Keywords: Momordica angustisepala aerial parts; 1,2,3-propanetriyl (8Z,11’Z,14”Z)tris(-8,11.14-eicostrienoate); 1,2,3-propanetriyl (9Z,12’Z,15”Z)tris(-9,12,15-uneicostrienooate); methyl oleana-5,12,15-trienoate-3β-acetate; Proton and Carbon-13 Nuclear Magnetic Resonance Spectroscopy; Column Chromatography; Thin-Layer Chromatography. INTRODUCTION Momordica angustisepala belongs to the family Cucurbitaceae and is a large climbing plant with stout stems attaching themselves into the surrounding vegetation by means of tendrils. The plant, also known as “Ejirin nla” in Yoruba and “bitter gourd” in English, is mostly found in West Tropical Africa (such as Nigeria, Côte D’Ivoire, and Cameroon), mostly in deciduous or semi-deciduous forest. It can also be found at the road side, old plantation, or filthy areas. M. angustisepala is used in making sponges due to its fibre-forming polymeric activity (Biswas et al., 2011). This plant is used in herbal medicine to treat tumors, malaria and diabetes, and as abortifacient to guard against unwanted pregnancy (Burkill, 1997; Shehu et al., 2019). Despite the ethnomedicinal uses of this plant, less attention has been paid to its exploitation. This study was designed to isolate (using chromatography) and to characterize the constituents of M. angustisepala extracts using 1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy. MATERIALS AND METHODS Plant Materials Fresh aerial parts of M. angustisepala were collected in Ilorin, Kwara State, Nigeria. The plants were identified and authenticated at the Department of Plant Biology, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria by Mr Bolu Ajayi (a botanist), and voucher specimens of the plants were deposited in the Herbarium of the department. Extraction and Isolation Procedures Momordica angustisepala aerial parts were air-dried for three weeks and ground into powdery form with the machine. The weights obtained after grinding were 530.51 g. The ground sample was soaked with n-hexane, ethyl acetate and methanol successively for 10 days each in the order of their polarity, for complete extraction. The extracts were filtered separately with Whatmann No1 filter paper and concentrated at 45 oC using rotatory evaporator and then freeze-dried to remove trace solvents. The dried extracts were subjected to column chromatography to obtain pure isolates, and thin layer chromatography and recrystallization were carried out on the isolates to affirm their purity. https://doi.org/10.14421/biomedich.2025.141.323-326 mailto:hamidmemo@gmail.com* 324 Biology, Medicine, & Natural Product Chemistry 14 (1), 2025: 323-326 Extraction of M. angustisepala aerial parts with n- hexane, ethyl acetate and methanol gave 22 g, 11.8 g and 5 g extracts respectively. The methanol extract was not reckoned with due to its small quantity. The ethyl acetate-hexane extract (33.8 g) of Momordica angustisepala aerial parts (MAEH) was pre-adsorbed on silica gel (60-200 mesh size) (60 g) to form powdered homogeneous slurry. The slurry was then subjected to column chromatography, packed using the slurry method (silica gel 700 g, 60-120 mesh size) and eluted with various solvent systems, starting with 100% of Hexane; then using Hexane: CHCl3 (49:1, 100 mL); (19:1, 100 mL); (23:2, 100 mL); (9:1, 100 mL); (17:3, 100 mL); (4:1, 100 mL); (3:1, 100 mL); (7:3, 100 mL); (3:2, 100 mL); (11:9, 100 mL); and (1:1, 100 mL) separately. A total of 75 fractions (100 mL each) were collected and pooled to five pure fractions, coded MAEH-1–MAEH-5, based on TLC analysis, with masses 20 mg, 15 mg, 24 mg, 15 mg, and 42 mg respectively; and found to be a pure compound each on characterization using 1H NMR and 13C NMR. Characterization of Octadecane, C18H38, white solid (20 mg); 1H NMR (CDCl3, 300 MHz): δ 0.88 (6H, t, 2 × CH3), 1.10–1.28 (32H, m, 16 × CH2); 13C NMR (CDCl3, 75 MHz): δ 14.25 (C-1), 29.62 (C-2–16), 31.8 (C-17), 22.68 (C-18). Characterization of Tetradec-5-emoic acid, C14H25O, yellow viscous oily liquid (15 mg); 1H NMR (CDCl3, 300 MHz): δ 1.85–2.40 (4H, H-2 (t) & H-3 (m)), 1.48– 1.68 (4H, m, H-4 & 7), 5.11–5.36 (2H, m, H-5 & 6), 1.14– 1.41 (12H, m, H-8–13), 0.89 (3H, t, H-14); 13C NMR (CDCl3, 75 MHz): δ 182.05 (C=O, C-1), 29.73 (C-3 & 4), 137.50 (C-5), 128.00 (C-6), 31.95 (C-7), 39.40 (C-8), 37.28 (C-9), 32.83 (C-10), 22.72 (C-11), 19.78 (C-12), 16.04 (C-13), 14.15 (C-14). Characterization of 1,2,3-Propanetriyl (8Z,11’Z,14”Z)tris(-8,11,14-eicostrienoate), C63H101O6, creamy solid (24 mg); 1H NMR (CDCl3, 300 MHz): δ 0.86–0.88 (9H, t, 3 × CH3), 1.25–1.41 (3 × 6H, m, 3 × 3CH2), 1.94–2.45 (3 × 18H, m, 3 x 9CH2), 4.89–6.19 (3 × 6H, m, 3 × 6CH), 3.43–4.28 (4H, d, 2 × OCH2 & 1H, m, OCH); 13C NMR (CDCl3, 75 MHz): δ 173.37 (C=O, C-1), 29.29 (C-2–7), 139.53 (C-8), 132.56 (C-9), 52.03 (C- 10), 131.73 (C-11), 129.72 (C-12), 37.18 (C-13), 127.93 (C- 14), 125.30 (C-15), 34.07 (C-16), 31.94 (C-17), 24.87 (C-18), 23.96 (C-19), 14.14 (C-20), 62.12 (OCH2 of fatty triester, C-1), 68.93 (OCH of fatty triester, C-2), 65.06 (OCH2 of fatty triester, C-3). Characterization of Methyl Oleana-5,12,15-trienoate- 3β-acetate, C33H48O4, yellow solid (15 mg); 1H NMR (CDCl3, 300 MHz): δ 1.06–1.40 (10H, H-1, H-21 & 22 (t); H-2 (m); H-19 (d) 5 × R2CH2,), 1.63–1.79 (4H, H-7 (d) & H-11 (q), 2 × R2CH2), 1.48–1.55 (2H, t, H-9 & H-18, 2 × R3CH); 5.08–5.25 (1H, t, H-6, R2C=CHR), 5.30–5.35 (1H, t, H-12, RCH=CR2), 5.65–6.50 (2H, d, H-15 &16, RCH=CHR), 0.81–0.91 (21H, s, H-23–27, 29 & 30, 7 × RCH3), 4.5 (1H, t, H-3, O-CHR2), 2.05–2.37 (3H, s, ROOCCH3), 3.62 (3H, s, OCH3); 13C NMR (CDCl3, 75 MHz): δ 39.74 (C-1 & 2), 51.45 (C-3), 29.14 (C-4), 125.03 (C-5), 119.37 (C-6), 29.72 (C-7), 32.22 (C-8), 27.22 (C-9), 29.54 (C-10), 22.71 (C-11), 124.25 (C-12), 142.35 (C-13), 29.54 (C-14), 130.05 (C-15), 135.22 (C-16), 29.37 (C-17), 31.94 (C-18), 29.14 (C-19), 29.54 (C-20), 26.43 (C-21), 25.71 (C-22), 25.71 (C-23), 16.02 (C-24), 14.14 (C-25), 22.65 (C-26), 23.45 (C-27), 174.33 (C=O, C-28), 29.14 (C- 29), 24.96 (C-30), 51.45 (ROOCCH3), 60.90 (OCH3). Characterization of 1,2,3-Propanetriyl (9Z,12’Z,15’’Z)tris(-9,12,15-uneicostrienoate), C66H107O6, creamy solid (42 mg). 1H NMR (CDCl3, 300 MHz): δ 1.83–2.42 (42H, H-2 (t); H-3-8 (m), 3 × 7R2CH2), 4.56–6.46 (18H, m, H-9, 10, 12, 13, 15 & 16, 3 × 3RCH=CHR), 1.25 – 1.75 (36H, m, H-11, 14 & 17, 3 × 3RCH=CH-CH2 & H-18–20, 3 x 3R2CH2), 0.88–0.97 (9H, t, 3 × 3RCH3), 3.41–3.94 (4H, d, 2 × OCH2 & 1H, m, OCH); 13C NMR (CDCl3, 75 MHz): δ 173.07 (C=O, C- 1), 29.70 (C-2–8), 135.10 (C-9), 132.81 (C-10), 39.72 (C-11), 130.13 (C-12), 128.77 (C-13), 34.15 (C-14), 125.90 (C-15), 124.24 (C-16), 32.75 (C-17), 27.78 (C-18), 26.41 (C-19), 24.85 (C-20), 14.11 (C-21), 62.07 (2 × O-CH2R of fatty triester C-1 & 3), 68.89 (O-CHR2 of fatty triester, C-2) RESULTS AND DISCUSSION Characterization of the Isolated Compounds The isolates from the plant extracts were characterized using 1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy. The 1H and 13C NMR analyses on the isolates obtained from the ethyl acetate-hexane extracts of M. angustisepala aerial parts gave compounds 1–5. The structures of these compounds are shown in Figure 1. Compound 1 (20 mg) was isolated as white crystals. The 1H NMR spectrum showed peaks at δH 0.88 (6H, t, H-1 and H-18) corresponding to the terminal methyl hydrogen atoms. The peak at δH 1.10–1.28 was assigned to the cluster of methylene (CH2) hydrogen atoms at 2–17 positions. The 13C NMR spectrum displayed eighteen carbon resonances and was sorted out to contain sixteen methylene carbons (δc 29.62–31.8) and two methyl carbons (δc 14.25 (C-1) and 22.68 (C-18)). The spectroscopic data of compound 1 were similar to those reported on octadecane in the literature (Lide & Milne, 1994). Hence, the structure of compound 1 was established as octadecane (Figure 1). Hamid et al. – Isolation and Characterization of Constituents from The Extracts … 325 Figure 1. Octadecane. Compound 2 (15 mg) was obtained as a light yellow viscous oily liquid. The 1H NMR spectrum showed signals at δH 0.89 (3H, t, H-14) corresponding to the terminal methyl hydrogen atoms. The multiplet peaks at δH 1.14–1.41 were attributed to the cluster of methylene hydrogen atoms (CH2) at 8–13 positions. Allylic hydrogen atoms (-CH=CH-CH2) were shown by δH 1.48– 1.68 at 4 and 7 positions. The signal δH 1.85–2.40 corresponds to the α- and β- carbon hydrogen atoms to the carbonyl at positions 2 and 3 respectively. The peaks at δH 5.11 – 5.36 represent the olefinic hydrogen atoms (CH=CH) at positions 5 and 6. The 13C NMR spectrum indicated fourteen carbon resonances and was sorted out as two olefinic carbons (δc 128.0, C-6– 137.5, C-5); one carbonyl carbon (δc 182.05, C-1); ten methylene carbons (δc 19.78–39.40); and one methyl carbon (δc 14.15, C-14). The spectroscopic data of compound 2 were similar to those reported on tetradec-5-enoic acid in the literature (Ogunleye et al., 1991; Lie Ken Jie & Lam, 1995). Therefore, compound 2 was established as tetradec-5- enoic acid (Figure 2). Figure 2. Tetradec-5-enoic acid. Compound 3 (24 mg) was isolated as a creamy solid. The 1H NMR spectrum signals at δH 0.86–0.88 (9H, t, 3 × CH3) correspond to the cluster of methyl hydrogen atoms. The peaks at δH 1.25–1.41 shows the cluster of methylene hydrogen atoms; δH 1.94–2.45 corresponds to the cluster of allylic hydrogen atoms and methylene hydrogen atoms immediate to the carbonyl; δH 3.43–4.28 indicates oxymethylene hydrogen atoms; and δH 4.89– 6.19 shows the olefinic hydrogen atoms. The 13C NMR spectrum indicated 23 resonances corresponding to 63 carbons with the carbons assigned positions 1–20 occurring three times. The peak at δc 173.37 represents carbonyl carbon; δc 62.12–65.06 shows oxymethylene carbons; δc 125.30–139.53 indicates olefinic carbons; δc 22.71–52.03 represents the methylene carbons; and the peak at δc 14.14 corresponds to the methyl carbon. The spectroscopic data of compound 3 were similar to those reported on 1,2,3-Propanetriyl (8Z,11’Z,14”Z)tris(- 8,11,14-eicostrienoate) in the literature (Hamid et al., 2017; Lie Ken Jie & Lam, 1995). Hence, the structure of compound 3 was established as 1,2,3-Propanetriyl (8Z,11’Z,14”Z)tris(-8,11,14-eicostrienoate (Figure 3). Figure 3. 1,2,3-Propanetriyl (8Z,11'Z,14"Z)tris(-8,11,14-eicostrienoate. Compound 4 (15 mg) was isolated as a yellow solid. The 1H NMR spectrum signals at δH 5.08–6.5 correspond to olefinic hydrogen atoms. The peaks δH 0.81–0.91 correspond to the cluster of methyl hydrogen atoms. The peaks at δH 3.62 and 4.5 show the oxymethine hydrogen atoms; δH 2.05–2.37 corresponds to α- hydrogen atoms to the carbonyl. The peaks at δH 1.06–1.55 corresponds to the cluster of methylene hydrogen atoms. The 13C NMR spectrum indicated 31 resonances. The peaks at δc 14.14, 16.02, 22.65, 23.45, 24.19, 29.14 correspond to methyl carbons. The signals at δc 51.45 and 60.90 represent the oxymethine carbons. δc 119.37–142.35 correspond to the olefinic carbons. The spectroscopic data of compound 4 were similar to those reported on oleana-12,15-diene and oleana-5,12-diene in the literature (Bhattacharyya & Cunja, 1992). Therefore, the structure of compound 4 was established as methyl Oleana-5,12,15-trienoate-3β- acetate (Figure 4). Figure 4. Methyl Oleana-5,12,15-trienoate-3β- acetate. Compound 5 (42 mg) was obtained as a cream solid. The 1H NMR spectrum signals at δH 0.88–0.97 correspond to the methyl hydrogen atoms. The peaks at δH 1.25–2.42 correspond to the cluster of methylene hydrogen atoms. The signals at δH 4.56–6.46 indicate the olefinic hydrogen atoms and δH 3.41–3.94 represent the oxymethylene hydrogen atoms. The 13C NMR spectrum indicated 24 resonances, equivalent to 67 carbons in the compound; with carbon-assignment 1–20 occurring three times. The peak at δc 14.11 shows the methyl carbons; δc 173.07 indicates the carbonyl carbon. The olefinic carbons are shown by δc 124.24–135.10; the oxymethylene carbons are represented by δc 62.07–68.89; 326 Biology, Medicine, & Natural Product Chemistry 14 (1), 2025: 323-326 and δc 24.85–39.72 corresponds to the methylene carbons. The spectroscopic data of compound 5 were similar to those reported on 1,2,3-Propanetriyl (9Z,12’Z,15’’Z)tris(-9,12,15-uneicostrienoate) in the literature (Hamid et al., 2017; Chuah et al., 2006; Lie Ken Jie & Lam, 1995). Hence, the structure of compound 5 was established as 1,2,3-Propanetriyl (9Z,12’Z,15’’Z)tris(-9,12,15-uneicostrienoate) (Figure 5). Figure 5. 1,2,3-Propanetriyl (9Z,12'Z,15''Z)tris(-9,12,15-uneicostrienoate) CONCLUSION The authors appreciated Mr. Bolu Ajayi, Department of Plant Biology Laboratory, University of Ilorin for collection of plant and deposition at the herbarium. Competing Interests: The author declares that there are no competing interests. REFERENCES Biswas, S., Kindo, S. and Patnaik, A. (2011), Effect of fiber length on mechanical behaviour of coir fiber reinforced epoxy composites, Fiber Polymer, 12: 73–78 Burkill, H. M. (1997), The useful plants of West Tropical Africa, Vol. IV, Families M-R. Royal Botanical Gardens, Kew 8–9. Chuah, T. G., Rozanna, D., Salmiah, Y., Thomas Choong, S., Sa’ari, M. (2006), Fatty Acids used as Phase Change Materials (PCMs) for Thermal Energy Storage in Building Material Applications, University Putra Malaysia Hamid, A.A., Aiyelaagbe, O.O., Kaneez, F., Luqman, S., Negi, A.S. (2017). 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(2019), Chemical composition from the leaf extracts of Momordica angustisepala with its antibacterial, antifungal and antioxidant activities. Nigerian Journal of Chemical Research, 24 (2). N-hexane, ethyl acetate and methanol extracts of Momordica angustisepala indicated the presence of metabolites: triterpenoids, fatty acids and esters. Octadecane (1), tetradec-5-enoic acid (2), 1,2,3- propanetriyl (8Z,11’Z,14”Z)tris(-8,11.14-eicostrienoate) (3), methyl oleana-5,12,15-trienoate-3β-acetate (4) and 1,2,3-propanetriyl (9Z,12’Z,15”Z)tris(-9,12,15- uneicostrienooate) (5) were isolated from the ethyl acetate-hexane extracts of M. angustisepala aerial parts. These compounds are being reported for the first time from this plant. Acknowledgement: Authors acknowledged Indian Institute of Chemical Technology (CSIR-IICT) is highly appreciated for providing the facilities for this research.