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GC-MS Analysis of Phytochemical Compounds in Syzygium polyanthum Leaves Extracted using Ultrasound-Assisted Method

Abd Rahim, Ismail, Omar, Rahmat, and Wan Ahmad: GC-MS Analysis of Phytochemical Compounds in Syzygium polyanthum Leaves Extracted using Ultrasound-Assisted Method

Authors

INTRODUCTION

Syzygium polyanthum (Wight) Walp. or in Malay known as ‘salam’ or ‘serai kayu’ is an ethnomedicinal plant commonly used among Malay folks as fresh salad or as flavour enhancer in cuisines.1 Other than that, the leaves are traditionally consumed for treating hypertension, diabetes mellitus, diarrhea, rheumatism, hypercholesterolemia, gastritis and hyperuricemia.2 Few studies have discussed on the phytochemical constituents of S. polyanthum leaves. Amalina et al3 reported the presence of α-pinene (30.88%) as the major compound, followed by octanal (18.30%) and α-caryophyllene (6.22%) while Hamad et al 4 reported another major compound which is cis-4-decanal (43.49%) in essential oil of S. polyanthum leaves. The later study also stated that the essential oil were mainly composed of aldehyde, hydrocarbons and some bioactive compounds such as β-caryophyllene, α-humulene, caryophyllene oxide, α-copaene, α-selinene and α-zingiberene.4 Other than studies on the leaves essential oil, there were few studies which focused on the leaves crude extracts. Preliminary phytochemical screening analysis of crude methanolic S. polyanthum leaves extract showed the presence of tannins, flavonoids, glycosides, alkaloids, carbohydrates, steroids, triterpenoids and flavonoids.5,6 Phenolic compounds such as caffeic acid and gallic acid were previously identified in crude macerated methanolic extract of S. polyanthum leaves by high performance liquid chromatography and liquid chromatography mass spectrometry analyses.7 Analysis on the crude macerated methanolic extract of S. polyanthum leaves has detected squalene as the major compound.5,8 Another analysis on the macerated n-hexane extract similarly found squalene as the major compound (30.45%) followed by n-hentriacontane (6.57%).8

Most phytochemicals previously studied were extracted using solvent maceration and steam distillation methods, however, the use of ultrasound-assisted extraction (UAE) method is not well-documented. The present study has utilized UAE method, a different extraction method from the other previous studies. Basically, UAE method enhances solvent penetration through plant cell with the aid of sound wave.9 Its mechanistic action includes fragmentation, erosion, and destruction-detexturation of plant structures, thus, this will enhance the diffusion process by increasing the solute transfer rate.10,11 This method is usually employed for its higher extraction efficiency and its shorter extraction time as compared to maceration and soaking with the less amount of solvent application.9,10 Recently, UAE method was applied in many researches to enhance extractability of phenolic, thermo-labile and unstable compounds.12,13 A recent study by Ramli et al 13 has utilized this method for extraction of S. polyanthum leaves, and has proven that the extract possess significant renal protective effect in Spontaneously Hypertensive Rats. Thus, this study aims to extract the phytochemical compounds in S. polyanthum leaves using ultrasound-assisted method and to analyse the phytochemical compounds using GC-MS analysis.

MATERIAL AND METHODS

Materials and Reagents

Ethyl acetate, n-hexane and methanol were purchased from Merck (Germany). S. polyanthum leaves were collected from the District of Ketereh, Kelantan, Malaysia in May 2016. The leaves (1.3 kg) were dried for a week at room temperature in the laboratory. The herbal specimen was authenticated and deposited into Forest Research Institute Malaysia herbarium (Specimen voucher number: PID-171011-10). The dried leaves were then ground into fine powder and kept in temperature of 1-5°C for further analysis.

Preparation of Extract

Preparation of extract was carried out based on ultrasound-assisted extraction (UAE) method previously reported by Ramli et al.13 Briefly, 250 g of powdered S. polyanthum leaves were soaked in n-hexane (100 mL) and then sonicated at 24°C for 30 min using a sonicator (Sonicor SC221, USA). After filtration with Whatmann filter paper No. 1, the hexane layer was evaporated using a rotary evaporator (Buchi R-200, Switzerland) to afford the hexane extract (HSP). Similarly, the experiment was repeated by using the residue from the previous extraction, soaked and sonicated in ethyl acetate (100 mL) and finally repeated three times in methanol (3 × 100 mL), respectively. After filtration and evaporation, the ethyl acetate and methanol extracts afforded the extract of ethyl extract (EASP) and methanol (MSP), respectively. The crude extracts were stored at -20°C prior to further analyses.

Instrumentation

The GC-MS instrument (Shimadzu GCMS-QP2010 Ultra, Australia) with chromatographic system of GC-2010 was utilized in this analysis. All the three extracts were analysed on capillary column (BPX5-5% phenyl (equivalent)/95% methyl polysilphenylene/siloxane phase, 30 m × 0.25 μm x 0.25 μm, Shimadzu).

GC condition

The injector temperature was set at 250°C, column temperature program was set at 50°C (0 min) with an increasing rate of 3°C/min to 300°C (10 min). The carrier gas used was pure helium gas (99.999%) with its flow rate of 0.8mL/min. The split ratio used was 1:10.

MS condition

The ion source and ionization voltage used was electron ionization (EI) and 70eV respectively. The ion source temperature was set as 200°C and the detection voltage at 0.87kV. The interface temperature was 250°C with its solvent cut-off time of 2.0 min. The start time was set at 2.5 min and the end time was set at 93 min.

Identification of components

Compounds were identified based on molecular structure, molecular mass, and calculated fragments. Interpretation of data was based on mass spectral matching with standard compounds in Wiley 229, NIST11 (National Institute of Standards and Technology) and FFNSC1.3 (Flavour and Fragrance Natural and Synthetic Compounds) libraries. The retention time was matched, and the relative amounts of individual components were shown as the percentage peak areas relative to the total peak area. Only selected peaks with similarity index of 70% and above with Wiley, NIST or FFNSC libraries were chosen and identified.

RESULTS

Percentage yield

The percentage yield for HSP, EASP and MSP were tabulated in Table 1. Mean percentage yields were obtained for two batches of each extract. Among the three extracts, methanol extract gave the highest percentage yield while hexane extract gave the lowest yield.

GC-MS analysis for n-hexane extract of S. polyanthum leaves

A total of 21 peaks were identified in GC-MS chromatogram of HSP (Figure 1). Upon comparing of their mass-spectral databases with Wiley, NIST and FFNSC libraries, these phytochemical compounds were identified and characterized as listed in Table 2. There were five major compounds identified from the HSP chromatogram. The most abundant compound in HSP was an unknown compound with retention time of 62.093 min (31.912%), followed by squalene (8.776%), phytol (8.409%), α-pinene (4.921%) and lastly α-tocopherol (4.900%). The rest of compounds were present by the amount of less than 4%.

GC-MS analysis for ethyl acetate extract of S. polyanthum leaves

There were 27 peaks identified in GC-MS chromatogram of EASP (Figure 2). Upon comparing of their mass-spectral databases with the Wiley, NIST and FFNSC libraries, these phytochemical compounds were identified and characterized in Table 3. EASP extract was mainly composed of an unknown compound found at retention time of 62.290 min (27.042%), followed by squalene (8.345%), another unknown compound at retention time of 67.797 min (5.747%), phytol (5.715%) and lastly β-sitosterol (4.959%). Other than these five main compounds, the rest of compounds were found in a relatively low amount of less than 4%.

Table 1

Percentage yield of n-hexane, ethyl acetate and methanol extracts of S. polyanthum leaves.

  Yields After DryingFinal Yield
  
Batch No.Fresh weight (kg)Dry Weight (kg)% (Wet basis)HSPEASPMSP

Weight (g)% (Dry basis)Weight (g)% (Dry basis)Weight (g)% (Dry basis)
10.70.3042.863.391.136.652.2216.495.50
20.60.3050.006.892.3015.035.0121.817.27
 Total  1.72 ± 0.83 3.62 ± 1.97 6.39 ± 1.25

[i] Note: Final yield was expressed as mean percentage ± standard deviation. HSP: n-Hexane extract of S. polyanthum leaves, EASP: Ethyl acetate extract of S. polyanthum leaves and MSP: Methanol extract of S. polyanthum leaves.

Figure 1

GC-MS chromatogram of n-hexane extract of S. polyanthum leaves.

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Table 2

Phytochemical compounds in n-hexane extract of S. polyanthum leaves.

NamePeak %Chemical ClassesMolecular FormulaRetention Time (min)
α-Pipene4.921MonoterpeneC10H168.072
Octanal0.573AldehydeC8H16011.083
Linalool0.448Oxygenated monoterpeneC10H18O15.366
α-Cubebene3.633SesquiterpeneC15H2428.330
2-Isopropenyl-4a,8-dimethyl-1,2,3,4,4a,5,6,7-octahydronaphthalene0.558-C15H2433.258
Azulene1.255Sesquiterpene derivativesC15H2433.538
Valencene1.097SesquiterpeneC15H2433.620
β-Panasinsene3.990Volatile compoundsC15H2433.892
δ-Cadinene0.737Bicyclic sesquiterpeneC15H2434.670
α-Panasinsen1.515Sesquiterpene,C15H2434.848
Nerolidol2.845SesquiterpeneC15H26O36.417
Humulene epoxide II2.060PeroxideC15H24O38.772
Caryophyllene oxide0.846Oxygenated terpenoid/ sesquiterpeneC15H24O39.679
Farnesol0.715Acyclic alcoholic sisquiterpeneC15H26O42.619
Phytol8.409Diterpene alcoholC20H40O56.147
RT:62.09331.912--62.091
Squalene8.776TriterpeneC30H5075.442
β-Tocopherol0.934Tocopherol (methylated phenols)C28H48O280.906
γ-Tocopherol0.934Tocopherol (methylated phenols)C28H48O281.301
α-Tocopherol0.340Tocopherol (methylated phenols)C29H50O283.063
β-Sitosterol0.676SteroidalC29H50O87.992
 Total = 77.174 %  

[i] : No data described for the section

Figure 2

GC-MS chromatogram of ethyl acetate extract of S. polyanthum. Leaves.

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Table 3

Phytochemical compounds in ethyl acetate extract of S. polyanthum leaves.

NamePeak %Chemical ClassesMolecular FormulaRetention Time (min)
Propylene glycol0.144DiolC3H8O23.521
n-Heptanal0.317AldehydeC7H14O7.207
α-Pinene1.068MonoterpeneC10H168.076
Heptane0.389AlkaneC7H169.992
Octanal0.563AldehydeC8H16O11.093
β-linalool0.468Terpene alcoholC10H18O15.373
α-Cubebene1.690SesquiterpeneC15H2428.333
α-Humulene0.504Monocyclic sesquiterpeneC15H2432.023
β-Selinene0.735SesquiterpeneC15H2433.545
Valencene0.548SesquirterpeneC15H2433.620
1H-Cyclopropa[a]naphthalene2.226Acyclic alkeneC15H2433.894
α-Panasinsen0.887SesquirterpeneC15H2434.843
Nerolidol3.085Sesquiterpene alcoholC15H26O36.423
Humulene epoxide II1.557SesquiterpeneC15H24O38.782
Caryophyllene oxide0.824Oxygenated terpenoidC15H24O39.688
Farnesol0.645Acyclic alcoholic sisquiterpeneC15H26O42.628
Neophytadiene1.347TerpenoidC20H3846.723
Phytol5.715Diterpene alcoholC20H40O56.151
9,12,15-Octadecatrien-1-ol1.037Unsaturated alcoholic compound (Lignan)C18H32O57.341
Hentriacontane0.303Long chain alkaneC31H6458.758
RT:62.29027.042--62.291
2-Cyclohexen-3-ol-1-one, 2-[1-iminoethyl]-0.107--62.658
n-Pentacosane0.472Aliphatic hydrocarbon alkaneC25H5264.611
Squalene8.345Teriterpene hydrocarbonC30H6275.455
β-Tocopherol0.693Tocopherol (methylated phenols)C28H48O280.916
α-Tocopherol4.660Tocopherol (methylated phenols)C29H50O283.081
β-Sitosterol4.959SteroidalC29H50O88.038
 Total = 70.330 %  

[i] : No data described for the section

Figure 3

GC-MS chromatogram of methanol extract of Syzygium polyanthum leaves.

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GC-MS analysis for methanol extract of S. polyanthum leaves

GC-MS chromatogram of MSP showed presence of 31 peaks (Figure 3). These peaks which were identified and characterized by comparing their mass-spectral databases with the Wiley, NIST and FFNSC libraries was tabulated in Table 4. Similarly, the most abundant compound was an unknown compound with retention time of 61.98 min (22.386%); these was followed by squalene (10.913%), β-sitosterol (5.560%), pyrogallol (5.247%) and phytol (4.952%). The rest of the compounds were also not abundant with the amount of less than 4%.

DISCUSSION

Organic crude extracts from S. polyanthum leaves (hexane-HSP, ethyl acetate-EASP and methanol-MSP) were sequentially extracted using ultrasound-assisted extraction (UAE) method. Gas Chromatography–Mass Spectrometry (GC-MS) analyses on HSP, EASP and MSP showed that each crude extract was composed of different phytochemical compositions. Overall, they were basically composed of hydrocarbons, aldehydes, terpenoids, phenolics, fatty acids, monoterpenes, diterpenes, triterpenes and sesquiterpenes. Sesquiterpenes were found as highest in composition in which they have contributed to the total amount of 41.63%, 31.32 % and 22.58 % in HSP, EASP and MSP, respectively. There were 21, 27, and 31 compounds identified in the GC-MS chromatograms for HSP, EASP, and MSP, respectively. Nine compounds (nerolidol, caryophyllene oxide, farnesol, phytol, squalene, β-tocopherol, γ-tocopherol, α-tocopherol and β-sitosterol) were present in all three extracts. Certain compounds such as α-pinene and linalool co-exist in both HSP and EASP while α-humulene, β-selinene, 9,12,15-Octadecatrien-1-ol, hentriacontane, pentacosane, and octanal co-exist in both EASP and MSP.

The major compound in HSP, EASP and MSP was an unknown compound, each detected at retention time of 62.093, 62.2290 and 61.980 min, respectively. This may have suggested that this unknown compound might be the same compound, however, this will require further analysis for characterization. Terpenes, such as squalene (an isoprenoid compound) and phytol (a cyclic diterpene alcohol) were observed as among the next major components in all extracts. This finding was in agreement with previous studies that also found squalene as their major compound in macerated methanolic 5 and hexane 8 extracts of S. polyanthum leaves. Besides squalene, phytol was also identified as the most abundant compound in the macerated ethanolic extract of S. polyanthum leaves.14 These findings have greatly supported our finding in which squalene and phytol are the main volatile compounds in S. polyanthum leaves. On contrary, n-hexatriacontane and n-triacontane which were reported by Hamad et al 8 in macerated hexane extract were not found in this study. Other than that, the unknown major compound which were detected in all three extracts in this study was not detected in these previous studies. Even so, these few differences in phytochemical composition might be contributed by the dissimilarities in the employed extraction method. Our study utilized sequential UAE method while the other previous studies utilized direct maceration method. In terms of geographic location, the plant materials used in this study was obtained from S. polyanthum leaves grown in Malaysia, while the other previous studies mainly harvested the leaves from S. polyanthum plant grown in Indonesia. Other than these major compounds, the rest of compounds only showed relative amount of less than 4%.

There were 20 bioactive compounds detected in HSP, EASP and MSP as summarized in Table 5. Few known antidiabetic compounds such as linalool15 and β-sitosterol16 were identified in the present study. As such, S. polyanthum leaves extracts were previously shown to exhibit anti-diabetic properties on alloxan-induced17 and on streptozotocin-induced5 diabetic rats. Antibacterial compounds identified in this present study include α-pinene which was active against Staphylococcus aureus;18 linalool which was active against Escherichia coli;19 and palmitic acid (n-hexadecanoic acid) which was active against Salmonella typhii20 With relation to that, previous study also found that S. polyanthum leaves extracts possessed antibacterial activity against Staphylococcus aureus,21 Bacillus cereus 6 and Bacillus subtilis.22 Asides from antibacterial compounds, there were also some antifungal compounds found in the present study. This include nerolidolx23 and caryophyllene oxide24 which were active against Trichophyton mentagrophytes; and farnesol which was active against Candida albicans.25 Accordingly, S. polyanthum leaves extract has exhibited some antifungal activity, but against Alternaria alternate and Colletotrichum capsicii.26

Other than that, this study also found few cytotoxic compounds such as linalool and octanal;19 α-humulene;27 and pyrogallol (1,2,3-benzenetriol).28 S. polyanthum leaves extract has also exhibited cytotoxic effect on HB4C5 human hybridoma and mouse colon 26 adenocarcinoma cells;29 and on 3T3-L1 cell lines proliferation.30 Some anti-tumour compounds such as farnesol31 and squalene32 were also found in this study. Previously, S. polyanthum leaves extract were reported to exhibit some anti-tumour promoting activity, but against Raji cells.33 Moreover, an anticancer compound, phytol34 and the anti-proliferative and pro-apototic compound, 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one35 were also found in this study.

Table 4

Phytochemical compounds in methanol extract of S. polyanthum leaves.

NamePeak %Chemical ClassesMolecular FormulaRetention Time (min)
Propylene glycol0.272DiolC3H8O23.487
Octanal0.354AldehydeC8H16O11.090
2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one1.423Flavanoid fractionC6H8O417.841
α-Copaene0.636SesquiterpeneC15H2428.333
Pyrogallol5.247PhenolC6H6O328.727
α-Humulene0.576SesquiterpeneC15H2432.031
β-Panasinsene0.923SesquiterpeneC15H2433.554
Selina-4,11-diene1.519-C15H2433.896
α-Panasinsen0.677Sesquiterpene,C15H2434.848
Nerolidol2.267SesquiterpeneC15H26O36.417
β-Selinene0.321SesquiterpeneC15H2438.307
Humulene epoxide II0.910EpoxideC15H24O38.784
Caryophyllene oxide0.943Oxygenated terpenoidC15H2439.698
Pentadecane, 2,6,10,14-tetramethyl-0.386Saturated terpenoid alkaneC19H4041.659
Farnesol0.421Acyclic SesquiterpeneC15H26O42.630
Neophytadiene0.581TerpenoidC20H3846.735
Methyl palmitate0.425Palmitic acid esterC17H34O250.092
Palmitic acid2.378Fatty acidC16H32O251.507
Eicosane0.294Aliphatics alkaneC20H4252.398
Methyl oleate0.343Unsaturated fatty acid Methyl esterC19H36O255.887
Phytol4.952Diterpene alcoholC20H40O56.137
9,12,15-Octadecatrien-1-ol1.783Unsaturated alcoholic compoundC18H32O57.317
Stearic acid0.604Stearic acid Saturated fatty acidC18H36O257.963
Hentriacontane0.674AlkaneC31H6455.647
RT:61.98022.386--61.975
Pentacosane1.282Aliphatic hydrocarbonC31H6458.758
Hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)0.525Fatty acidC19H38O468.232
Squalene10.913TriterpeneC30H5075.440
β-Tocopherol0.548Tocopherol compound (methylated phenols)C28H48O280.903
α-Tocopherol4.933Tocopherol (methylated phenols)C29H50O283.048
β-Sitosterol5.560SteroidalC29H50O87.988
 Total = 75.056 %   

[i] : No data described for the section

Table 5

Bioactive compounds in n-hexane, ethyl acetate and methanol extracts of S. polyanthum leaves.

Bioactive compoundsHSPEASPMSPBiological Activity
α-pinene+ (4.921%)+ (1.068 %)-Anti-inflammatory43
Antibacterial18, 44
Hypotensive45
Linalool+ (0.448%)+ (0.468%)-Antibacterial46
Hepatoprotective47
Anti-inflammatory48
Antidiabetic15
Cytotoxicity19
Azulene+ (1.255%)--Anti-inflammatory49
Nerolidol+ (2.845%)+ (3.085 %)+ (2.267 %)Antinociceptive50
Anti-inflammatory50
Antifungal23
Antiulcer51
Caryophyllene oxide+ (0.846%)+ (0.824 %)+ (0.943 %)Analgesic52
Anti-inflammatory52
Antifungal24
Farnesol+ (0.715%)+ (0.645%)+ (0.421%)Anti-tumor31
Antifungal25
Antinociceptive53
Anti-inflammatory54
Antioxidant55
Antimicrobial56
Phytol+ (8.409%)+ (5.715%)+ (4.952 %)Antimicrobial57
Anti-inflammatory34
Anti-cancer58
Antinociceptive59
Antioxidant60
Squalene+ (8.776 %)+ (8.345%)+ (10.913 %)Antioxidant32
Antitumor32
Chemopreventive effect61
β-Tocopherol+ (0.934%)+ (0.693 %)+ (0.5485 %)Antioxidant41
γ-Tocopherol+ (0.340%)--Antineoplastic62
Anti-carcinogenesis63
Anti-inflammatory64
Antioxidant41
α-Tocopherol+ (4.900%)+ (4.660 %)+ (4.933%)Antioxidant41, 42
β-Sitosterol+ (0.676%)+ (4.959%)+ (5.560 %)Antidiabetic16
α-Humulene-+ (0.504 %)+ (0.576%)Antifungal65
Cytotoxicity27
Anti-inflammatory66
Neophytadiene-+ (1.347 %)-Anti-inflammatory67
Hentriacontane-+ (0.303 %)+ (0.361 %)Anti-inflammatory68
Octanal-+ (0.563%)+ (0.354%)Cytotoxicity19
2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one--+ (1.423 %)Antiproliferative35 Antioxidant39, 40
Pyrogallol--+ (5.247 %)Antioxidant28
Cytotoxicity28
Antiproliferative28
Methyl palmitate--+ (0.425%)Phagocytosis inhibitor69
Palmitic acid--+ (2.378 %)Anti-inflammatory70 Antibacterial20

S.polyanthum leaves extract was also known for their anti-inflammatory property.36 Nerolidol, α-humulene, phytol, farnesol, azulene, caryophyllene oxide, neophytadiene and α-pipene were among the known terpenoids with anti-inflammatory properties found to be present in this study. A hypotensive compound α-pinene was found in HSP extract in this study. In agreement with that, S. polyanthum leaves extract was previously reported to reduce blood pressure of normotensive and hypertensive rats.1 S. polyanthum leaves extract also possessed antioxidant properties.14,37,38 Accordingly, this study has found some known phenolic compounds with anti-oxidant property such as 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one,39,40 β-tocopherol,41 pyrogallol (1,2,3,-benzenetriol)28 and α-tocopherol.41,42

CONCLUSION

GC-MS analyses of n-hexane (HSP), ethyl acetate (EASP), and methanol (MSP) of S. polyanthum leaves extracted using ultrasound-assisted method have revealed the presence of few major compounds such as phytol, squalene and an unknown compound that requires further characterization. Some of the identified compounds in S. polyanthum leaves extract in this study are known bioactive compounds with therapeutic importance. Even though the association between these structure-activity relationships was not directly being proven yet, this study may serve as a basis for further investigation.

GRAPHICAL ABSTRACT

https://s3-us-west-2.amazonaws.com/jourdata/pj/PharmacognJ-10-110-g004.jpg

SUMMARY

  • Phytol and squalene were among the major compounds in Syzygium polyanthum leaves which were extracted by using ultrasound-assisted extraction (UAE) method.

  • Few known bioactive compounds were found in S. polyanthum leaves extracts. This has shown that this plant has vast pharma-therapeutic importance.

ACKNOWLEDGEMENT

We are thankful to International Islamic University Malaysia who have provided financial support for this research project through Research Initiative Grant Scheme (RIGS 15-039-0039).

ABOUT AUTHORS

Erlena Nor Asmira Abdul Rahim is currently an MSc (Biotechnology) student at Kulliyyah of Science, International Islamic University Malaysia.

Azlini Ismail is currently an Assistant Professor at Department of Fundamental Dental & Medical Sciences, Kulliyyah of Dentistry, International Islamic University Malaysia.

Umi Nadhirah Rahmat is an MSc (Biomedicine) graduate from Universiti Sains Malaysia.

Muhammad Nor Omar is a Professor at Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia.

Wan Amir Nizam Wan Ahmad is currently holding a post as a senior medical lecturer at School of Health Sciences, Universiti Sains Malaysia

Notes

[5] Conflicts of interest CONFLICT OF INTEREST There is no conflict of interest.

ABBREVIATION USED

EASP

Ethyl acetate extract of Syzygium polyanthum leaves

GC-MS

Gas chromatography-mass spectrophotometry

HSP

n-Hexane extract of Syzygium polyanthum leaves

MSP

Methanol extract of Syzygium polyanthum leaves

RT

Retention time

UAE

Ultrasound-assisted extraction

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