Isolation of 2,4-Di-tert-butylphenol and Butyrospermol 3-?-O-palmitate from Syzygium aqueum stem bark

doi:10.15406/mojes.2020.05.00193

MOJ

eISSN: 2573-2919

Ecology & Environmental Sciences

Research Article Volume 5 Issue 4

Isolation of 2,4-Di-tert-butylphenol and Butyrospermol 3-?-O-palmitate from Syzygium aqueum stem bark

Ei Ei Aung,^1,2 Alfinda Novi Kristanti,^3,4

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Nanik Siti Aminah,^3,4 Yoshiaki Takaya,⁵ Rico Ramadhan³

¹PhD Student of Mathematics and Natural Sciences, Faculty of Science and Technology, Universitas Airlangga, Indonesia
²Department of Chemistry, Yadanarbon University, Amarapura-05063, Mandalay, Myanmar
³Department of Chemistry, Faculty of Science and Technology, Universitas Airlangga, Indonesia
⁴Biotechnology of Tropical Medicinal Plants Research Group, Universitas Airlangga, Surabaya, Indonesia
⁵Faculty of Pharmacy, Meijo University, Tempaku-468-8502, Nagoya, Japan, Department of Chemistry, University of Mandalay, Myanmar

Correspondence: Alfinda Novi Kristanti, Department of Chemistry, Faculty of Science and Technology, Universitas Airlangga, Komplek Kampus C Unair, Jl. Mulyorejo-60115, Surabaya, Indonesia, Tel 62-31-5936501, Fax 62-31-5936502

Received: August 14, 2020 | Published: August 31, 2020

Citation: Aung EE, Kristanti AN, Aminah NS, et al. Isolation of 2,4-Di-tert-butylphenol and Butyrospermol 3-?-O-palmitate from Syzygium aqueum stem bark. MOJ Eco Environ Sci. 2020;5(4):193-197. DOI: 10.15406/mojes.2020.05.00193

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Abstract

Syzygium genus in Myrtaceae family is a rich source of phytochemical constituents that possess various bioactivities. One of well-known species of this genus, Syzygium aqueum, has been already utilized as traditional medicine. This plant is cultivated in countries of tropical regions of the world such as Malaysia and Indonesia. The aim of this study was intended to isolate phytochemical constituents from the stem bark of S. aqueum. To date, there have been no reports of chemical substances isolated from the stem bark of this plant. The powder of the stem bark was extracted followed by partitioned in order to obtain n-hexane extract which then was separated using silica gel column chromatographic several times until the pure compounds were resulted. The isolated compounds were identified by spectroscopie method including Fouirer Transform Infrared (FTIR) and nuclear magnetic resonance (NMR) and were known as 2,4-Di-tert-butylphenol & butyrospermol 3-β-O-palmitate, respectively. The spectoscopie data of those compounds were compared with references.

Keywords: Myrtaceae, Syzygium aqueum, phytochemical constituents, phenolic, ester of fatty acid, 2,4-di-tert-butylphenol and butyrospermol 3-β-O-palmitate

Introduction

Myrtaceae is an enormous family of wood flowering plants with 155 genera and around about 4000 species. The species are cultivated in South America, Southeast Asia, and Australia, but few species are found in Africa.^1,2 Tropical regions, such as Malaysia and Indonesia, are native regions for one species of this family which is Syzygium aqueum.^3,4 S. aqueum has the local name water jambu or water apple. The whole parts of the tree have been applied as traditional medicine such as for relieving child birth pains (bark), treating a cracked tongue (leaves), relieving itching and reducing swelling (roots)^5–7 Moreover, the previous researchers have been tested leaves and fruits for antioxidant, anti-inflammatory, and anticancer (MCF-7 and MDA-MB-231 cell lines) activities.^8–11 In recent, there are some reports about the phytochemicals constituents isolated from leaves such as flavonoid and tannin and some of these flavonoids have been determined the antidiabetic and antioxidant activities.^1,6,12 The phytochemical compounds of stem bark of S. aqueum have never been reported by any researchers. Therefore, the present study was carried out to collect the phytochemicals compounds isolated from stem bark of this plant.

Material and method

General experimental procedure

FT-IR spectra (Fouirer Transform Infrared spectroscopy) were determined on Tracer-100 spectrophotometer (Shimadzu) and the spectra showed in cm^-1.¹H NMR,¹³C NMR (Nuclear Magnetic Resonance) and 2D NMR (HSQC, HMBC and COSY) were recorded on BRUKER 600 Hz using Tetramethylsilane (TMS). Chemical shifts of carbon and proton NMR were given in d (ppm).

Plant material

The stem bark of S. aquem was collected form Wage, Taman, Sidoarjo, East Java, Indonesia. This our sample had brown color and cracked. Department of Biology, Faculty of Science and Technology, Universitas Airlangga was identified and determined the scientific name. The stem bark obtained was crushed to form a powder and then was extracted using a general protocol.¹³

Extraction and isolation

The powdered of stem bark of S. aqueum (1kg) was macerated with 40L of methanol at room temperature for 3 days. The methanol extract (450g) was partitioned with n-hexane. n-hexane fraction obtained (50g) was then separated using silica gel 60 (700-200 mesh ASTM) in gravity column chromatographic method (GCC) with n-hexane: ethyl acetate (9:1) as eluent.¹³The similar fractions were combined to yield 19 fractions (SA- 1 to SA-19). Fraction-1 (SA-1) was re-chromatographed by eluting with n-hexane: ethyl acetate (95:5), yielding 5 fractions (SA-1-1 to SA-1-5). One spot was found in SA-1-1 fraction and was named as Compound-1. Moreover, fraction-2 (SA-2) was also separated more through GCC using hexane: ethyl acetate (9:1) eluent to give 6 fractions (SA-2-1 to SA-2-6). One spot was discovered form fraction-1 (SA-2-1) and was marked as Compound-2. Hereinafter, Compound-1 and Compound-2 were elucidated by spectroscopie method in an attempt to determine their stucture.

Result and discussion

Compound-1 (2mg) was collected as yellow oil. ¹H NMR d_H: 1.29 (9H, s), 1.34 (9H, s), 7.13 (1H, dd, J= 2.5 and 8.7Hz), 7.36 (1H, d, J= 2.5Hz), 7.54 (1H, d, J= 8.7Hz). Three protons (d_H: 7.13, 7.36, 7.54) showed in aromatic protons region. The remaining 18 protons (d_H: 1.29 & 1.34) supposed to be six methyls. And then, COSY (¹H-¹H) and HMBC correlations (¹H-¹³C) were joined for confirmation of the structure. The NMR spectra were also compared to previous literature data.¹⁴ From these data Compound-1 was determined as 2,4-di-tert-butylphenol and the molecular formula was C₁₄H₂₂O.

Compound-2 was obtained as pale yellow oil. FTIR spectra showed at 2926-2854 cm^-1 (sp³ C-H stretching), 1708 cm^-1 (C=O).¹H NMR d_H: 0.77 (3H, s), 0.81 (3H, s), 0.86 (3H, s), 0.89 (6H, m), 0.94 (3H, s), 0.98 (3H,s), 1.19 (1H, m), 1.26 (24H, m), 1.42 (3H, m), 1.50 ( 4H, m), 1.61 (3H,s), 1.65 (3H, m), 1.67 (3H, m), 1.69 (3H, s), 1.78 ( 1H, m), 1.93 (2H, m), 1.98 (3H, m), 2.04 (2H, m), 2.13 (1H, m), 2.23 (1H, m), 2.30 (2H, t, J=7.5 Hz), 4.53 (1H, dd, J=3.9, 11.5Hz), 5.12 (1H, t, J=7.1Hz), 5.25 (1H, m). The proton signal at d_H: 4.53ppm (C-3) belonged to the proton attached to the carbon that binds the ester group (C-3). The proton signal of 5.25 (1H, m) and 5.12 (1H, t, J= 7.1 Hz) linked to sp² hybridized carbons (C-7 and C-24 respectively). COSY (¹H-¹H) and HMBC correlations (¹H-¹³C) were joined for confirmation of structure. NMR spectra also compared to previous literature data.^15,16 From these data Compound 2 was identified as Butyrospermol 3-β-O-palmitate and molecular formula was C₄₆H₈₀O₂(Figure 1) (Figure 2) (Table 1) (Table 2).

Figure 1 Chemical structure of 2,4-di-tert-butylphenol and butyrospermol 3-β-O-palmitate.

Figure 2 Selected () HMBC, () COSY of 2,4-di-tert-butylphenol and butyrospermol 3-β-O-palmitate.

Position	DEPT	HSQC (¹H-¹³C)		HMBC	COSY
Position	DEPT	dC	dH	HMBC	COSY
1	C	147.7	-	H-3	-
2	C	138.4	-	H-9, H-6	-
3	CH	124.4	7.36	H-5	-
			(d, J= 2.5 Hz)
4	C	147.1	-	H-6, H-10	-
5	CH	123.9	7.13	H-3	H-6
			(dd, J= 2.5, 8.7 Hz)
6	CH	119.1	7.54	H-5	H-5
			(d, J= 8.7 Hz)
7	C	34.8	-	H-9, H-3	-
8	C	34.5	-	H-10, H-5	-
9	3CH₃	30.2	1.34 (s)	-	-
10	3CH₃	31.4	1.29 (s)	-	-

Table 1 NMR data (CDCl₃, 600 MHz) of 2,4-di-tert-butylphenol

Position	DEPT	HSQC (¹H-¹³C)		HMBC	COSY
		13C	1H
1	CH₂	36.8	1.67(m)	H-19	H-2
			1,19(m)
2	CH₂	25.7	1.67 (m)	-	H-1, H-3
3	CH	81	4.53	H-28, H-29	H-2
			(dd, J= 3.9, 11.5 Hz)
4	C	38	-	H-29	-
5	CH	50.7	1.42 (m)	H-28, H-29	H-6
6	CH₂	23.8	2.13 (m)	-	H-5,H-7
			1.98 (m)
7	CH	117.6	5.25 (m)	-	H-6
8	C	146	-	H-30	-
9	CH	48.8	2.23 (m)	-	H-11
10	C	34.8	-	H-19,H-5	-
11	CH₂	18.2	1.50 (m)	-	H-9
12	CH₂	33.8	1.65 (m)	H-18	-
			1.78 (m)
13	C	43.6	-	H-18,H-30	-
14	C	51.9	-	H-18,H-30	-
15	CH₂	34	1.42 (m)	H-30	-
			1.50 (m)
16	CH₂	29.2	1.26 (m)	H-15	H-17
17	CH	53.2	1.50 (m)	-	H-16
18	CH₃	22.1	0.81 (s)	-	-
19	CH₃	13.1	0.77 (s)	-	-
20	CH	35.7	1.42 (m)	H-17	H-21
21	CH₃	18.2	0.89 (m)	-	H-20
22	CH₂	39.8	1.98 (m)	H-23	-
23	CH₂	26.8	2.04 (m)	H-22	H-24
24	CH	125.1	5.12	H-26, H-27	H-23
			(t, J= 7.1 Hz)
25	C	130.9	-	H-26, H-27	-
26	CH₃	17.7	1.61 (s)	H-27	-
27	CH₃	25.7	1.69 (s)	H-26	-
28	CH₃	27.7	0.86 (s)	-	-
29	CH₃	16	0.94 (s)	-	-
30	CH₃	27.3	0.98 (s)	H-15	-
1’	C	173.6	-	H-2’	-
2’	CH₂	35	2.3	-	H-3’
			(t, J= 7.5 Hz)
3’	CH₂	25.1	1.65 (m)	H-2’	H-2’
4’	CH₂	29.7	1.26 (m)	H-3’
5	CH₂	29.7	1.26 (m)	-	-
6’	CH₂	29.6	1.26 (m)	-	-
7’	CH₂	29.6	1.26 (m)	-	-
8’	CH₂	29.6	1.26 (m)	-	-
9’	CH₂	29.5	1.26 (m)	-	-
10’	CH₂	29.4	1.26 (m)	-	-
11’	CH₂	29.3	1.26 (m)	-	-
12’	CH₂	29.2	1.26 (m)	-	-
13’	CH₂	28.4	1.93 (m)	-	H-14’
14’	CH₂	31.9	1.26 (m)	H-16’	H-13’
15’	CH₂	22.7	1.26 (m)	-	H-16’
16’	CH₃	14.1	0.89 (m)	-	H-15’

Table 2 NMR data (CDCl₃, 600 MHz) of Butyrospermol 3-β-O-palmitate

The bioactivities of 2,4-Di-tert-butylphenol has been previously reported such as moderate cytotoxicity against HeLa and MCF-7, high percentage of antioxidant activity, active antibacterial against Pseudomonas aeruginosa and Staphylococcus aureus, prevention the fungal mycelial growth of Aspergillus niger, Fusarium oxysporum and Penicillium chrysogenumon.^17–19However, Butyrospermol 3-β-O-palmitate hasn’t been reported any bioactivities in literature. Therefore, we would like to recommend studying the various bioactivities of this compound for the next research.

Conclusion

In this study, 2,4-di-tert-butylphenol and Butyrospermol 3-β-O-palmitate were isolated from stem bark of S. aqueum. These phytochemical constituents are the first to be reported from the stem bark of this species.

Acknowledgments

The authors would like to special thanks Faculty of Science and Technology, Universitas Airlangga and Faculty of Pharmacy, Meijo University, Tempaku, Nagoya, Japan.

Funding

Universitas Airlangga supported the first author for the scholarship (ADS) and The Indonesian Ministry of Research, Technology, and Higher Education for research grant (Basic Research, 2020).