F1000ResearchF1000Research2046-1402F1000 Research LimitedLondon, UK10.12688/f1000research.16643.1Research ArticleArticlesPhytochemical and antioxidant activity evaluation of the bark of Tampoi (
Baccaurea macrocarpa)
[version 1; peer review: 3 approved with reservations, 1 not approved]
ErwinErwinConceptualizationData CurationFormal AnalysisMethodologyWriting – Original Draft Preparationhttps://orcid.org/0000-0001-7050-7243a1PusparohmanaWidar RistiyaniFormal AnalysisInvestigationMethodology1SariIndah PermataFormal AnalysisInvestigationMethodology1HairaniRitaInvestigationMethodologyWriting – Original Draft Preparation1UsmanUsmanConceptualizationFormal AnalysisInvestigationMethodologyhttps://orcid.org/0000-0001-8155-63582
Department of Chemistry, Faculty of Mathematics and Natural Sciences Mulawarman University, Samarinda, East Kalimantan, 75123, Indonesia
Study Program of Chemical Education, Faculty of Teacher Trainer and Education, Samarinda, East Kalimantan, 75242, Indonesiawinulica@yahoo.co.id
Background: Tampoi (
Baccaurea macrocarpa) is a tropical rainforest plant that produces edible fruit and is native to Southeast Asia, especially East Kalimantan, Indonesia. Previous research showed that Tampoi potentially can be developed as a drug. It was reported that the extract of Tampoi fruit displayed antioxidant activity, which was correlated with its phenolic and flavonoid substances. There is no information about the antioxidant activity of other parts of this plant, such as the bark, which might also have this kind of activity. Therefore, the aim of this study was to evaluate the phytochemical, toxicity, and antioxidant activity of the bark of Tampoi.
Methods: The bark of Tampoi was extracted with methanol and concentrated using rotary evaporator to obtain the methanol extract of the bark. Secondary metabolites of this extract was determined using phytochemical analysis. Afterward, the methanol extract was tested for its toxicity using brine shrimp lethality test and antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl method.
Results: Phytochemical evaluation results showed that the methanol extract of bark of this plant contains several secondary metabolites including alkaloids, flavonoids, phenolics, steroids, and triterpenoids. The toxicity test displayed no toxic property due to a LC
50 value above 1000 ppm. For antioxidant activity, the result exhibited that the methanol extract of bark of this plant could be categorized as an active extract with IC
50 value of 11.15 ppm. Moreover, based on gas chromatography-mass spectrometer analysis, there are 37 isolated compounds from the bark, one of which is methylparaben, a phenolic predicted to act as an antioxidant.
Conclusion: The results obtained in this research demonstrated that the bark of Tampoi (
B. macrocarpa) has potential as an antioxidant.
TampoiBaccaurea macrocarpatoxicityBSLTantioxidantDPPHIslamic Development Bank2248/UN17.11/PL/2018The authors acknowledge funding from the Islamic Development Bank (IsDB) project in the frame of Hibah Penelitian PIU IDB for Lecturer Mulawarman University 2018 Number: 2248/UN17.11/PL/2018.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Introduction
Indonesia is a mega-diverse country in terms of biodiversity that is flanked by the Indian and Pacific Oceans. Indonesia's biodiversity encompasses the diversity of living things both on land and sea
1. Indonesia, especially East Kalimantan, has very extensive tropical rainforest, which is a habitat for much biodiversity. Various types of plants have long been utilized by the community as traditional medicines. The utilization of natural products as an alternative medicine is increasing because natural ingredients are believed to be safer than synthetic substances, i.e. do not contain chemicals that only can be found in modern medicines, which are linked to toxicity
2.
Among plants, the genus of
Baccaurea have interesting biological activities. For example,
B. angulata has been reported as a potential functional food with effective antioxidant
3, anti-inflammatory, anti-atherogenic, and hypocholesteromia activities
4. Other research has also investigated the biological activity of other species of this genus, i.e.
B. lanceolata and
B. macrocarpa. It was reported that the fruits of
B. macrocarpa exhibited the highest antioxidant activity compared with
B. lanceolata, which significantly correlated with the phenolic and flavonoid contents
5.
B. macrocarpa is one of the typical plants of East Kalimantan, Indonesia and the edible fruits is a source of additional nutrients and known as Tampoi. Until now, the information about the antioxidant activity of other parts of this plant such as the bark of Tampoi has not been reported yet. Hence, the present research was conducted to investigate the phytochemical, toxicity, and antioxidant activity of the bark of Tampoi (
B. macrocarpa). Furthermore, the gas chromatography-mass spectrometer (GC-MS) analysis was performed to obtain information about the kinds of isolated compounds contained.
MethodsExtraction
Extraction was carried out as described previously by Erwin
et al. (2014)
6. The bark of Tampoi (
B. macrocarpa) was dried for 1 week at room temperature and ground to a powder. The powder was extracted using a maceration method by soaking in methanol for 24 hours at room temperature, which was repeated three times. Afterwards, the extract solution was filtered by filter paper and the solvent was evaporated under vacuum using a rotary evaporator (Buchi R II) at 45°C and 1 atm, to obtain the methanol extract of bark of Tampoi.
Phytochemical evaluation
Phytochemical evaluation was performed to investigate the secondary metabolites contents of the methanol extract of bark of Tampoi (
B. macrocarpa), including alkaloids, flavonoids, phenolics, steroids, triterpenoids, and saponins, as described previously
7. The presence of secondary metabolites were identified by observing the changing color of the extract. These evaluations were performed as follows:
Alkaloids. 1 mg of extract was inserted into a test tube and then diluted in 1 mL methanol. Then a few drops of H
2SO
4 1M was added. Afterwards, a few drops of Dragendorff reagent was added into the mixture. The formation of orange on filter paper indicated the presence of alkaloids.
Flavonoids. 1 mg of extract was inserted into a test tube and diluted in 1 mL methanol. A few 2 mg of Magnesium powder was added followed by a few drops of concentrated HCl. The presence of flavonoids was identified by the formation of pink or red color.
Phenolics. 1 mg of extract was introduced into a test tube and dissolved in methanol. Then a few drops of 1% FeCl
3 were inserted. The formation of green, red, purple, dark blue or black indicated the presence of phenolics.
Steroids and triterpenoids. 1 mL of methanol and 1 mg of extract were inserted into a test tube, stirred until homogeneous, then 2 drops of anhydride acetate and 1 drop of H
2SO
4 were added (Liebermann Burchard reagent). The formation of green or purple precipitation showed a sample containing steroids, and red precipitation displayed the presence of terpenoids.
Saponins. 1 mg extract was put into a test tube and then dissolved in distilled water, and shaken strongly. The presence of saponins is characterized by the formation of durable foam on the surface of the liquid. Foam that remains stable after the addition of a few drops of concentrated HCl indicated the presence of saponins.
Toxicity test
The toxicity test of extract was performed using brine shrimp lethality test (BSLT), as described previously
8. Methanol extract of bark of Tampoi (
B. macrocarpa) (1 mg) was dissolved using 100 µL of 1% DMSO (dimethyl sulfoxide) and homogenized. The samples were diluted using 150 µL of distilled water until the total of volume reached 250 µL, and then pipetted 200 µL and diluted again using 600 µL of distilled water until the total of volume was 800 µL, so that the sample concentration was 1000 ppm. Samples with a concentration of 500, 250, 125, 62.5, 31.2, 15.6, and 7.8 ppm were made from sample dilutions of a concentration of 1000 ppm. The control solution was made with the same treatment as the sample without the addition of extract.
The toxicity test was carried out using several standard micro plates. About 100 µL seawater containing 8-13 shrimp larvae was added to each diluted sample so that the sample volume was 200 µL (with a concentration of 500, 250, 125, 62.5, 31.2, 15.6, and 7.8 ppm). The number of dead shrimp larvae was calculated for 24 hours after treatment. Each sample was treated in triplicate. The data obtained was recorded and the value of LC
50 calculated (Lethal Concentration 50%) using SAS Probit analysis.
Antioxidant assay
The antioxidant activity of the extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method, as described previously
7,
9–
11. Briefly, the extract of bark of Tampoi (
B. macrocarpa) was prepared in a solution with a concentration of 25, 50, 75 and 100 ppm, respectively. 1 mL of extract and 1 mL of DPPH (0.024 mg/mL) were put into a test tube, which was incubated for 30 min at 37°C before being measured by Spectrophotometer UV Thermo Scientific Evolution 201 (measurements were carried out at a wavelength of 515 nm). Vitamin C was used as a positive control with variations in concentration were 2, 4, 6, and 8 ppm, respectively. Determination of antioxidant activity or DPPH scavenging effect (%) of extract and vitamin C were carried out in triplicate using equation as follow.
Then, the value of IC
50 (Inhibitory Concentration 50%) was determined using linear regression.
GC-MS analysis
In order to obtain the information of the kinds of compounds in methanol extract of bark of Tampoi, an analysis using GC-MS 5977 was performed. Specification of column that used in this research was HP-5MS with length 30 m, diameter 0.25 mm, thick of film 0.25 µm. The identification of the compound was compared to NIST standard data (
https://webbook.nist.gov).
Results
The secondary metabolites found in the methanol extract of the bark of Tampoi (
B. macrocarpa) are presented in
Table 1.
Phytochemical evaluation of the methanol extract of bark of Tampoi (
<italic toggle="yes">Baccaurea macrocarpa</italic>).
Secondary metabolites
Bark
Alkaloids
+
Steroids
+
Triterpenoids
+
Flavonoids
+
Phenolics
+
Saponins
˗
(+): Presence; (-): Absence
To evaluate the antioxidant activity of the methanol extract of the bark, DPPH method was performed. The results of the antioxidant test can be seen in
Table 2.
Antioxidant activity of the methanol extract of bark of
<italic toggle="yes">Tampoi</italic> (
<italic toggle="yes">Baccaurea macrocarpa</italic>).
Average of three replicates performed for each concentration.
Sample
Concentration (ppm)
Absorbance
Inhibition
Percentage of inhibition (%)
IC
50 (ppm)
Sample
Blank
Bark
20
0.2190
0.4150
0.47229
47.229
11.15
40
0.0560
0.88193
88.193
60
0.0490
0.86506
86.506
75
0.0305
0.92651
92.651
Vitamin C
2
0.5470
0.6700
0.18360
18.360
3.28
4
0.1530
0.77160
77.160
6
0.0450
0.93280
93.280
8
0.0340
0.94930
94.930
Furthermore, the methanol extract was analyzed using GC-MS analysis. The chromatogram and it compound contents of this extract is shown in
Figure 1 and
Table 3, respectively.
GC chromatogram of methanol extract of bark of
<italic toggle="yes">Tampoi</italic> (
<italic toggle="yes">Baccaurea macrocarpa</italic>).
Composition of compounds from methanol extract of bark of
<italic toggle="yes">Tampoi</italic> (
<italic toggle="yes">B. macrocarpa</italic>).
Peak
Retention
Time (min)
% Peak
Area
Molecule
Formula
Molecular
Weight
Compounds
1
9.467
0.76
C
8H
8O
3
152
Methylparaben
2
14.877
1.32
C
14H
26
194
Cyclohexane, 1-(cyclohexylmethyl)-2-methyl-, cis
3
19.329
0.91
C
17H
34O
2
270.
Methyl palmitate
4
20.034
16.14
C
16H
32O
2
256
palmitic acid
5
20.227
0.72
C
16H
32O
2
256
palmitic acid
6
20.300
3.08
C
34H
65F
3O
2
562
Dotriacontyl trifluoroacetate
7
20.432
3.18
C
34H
65F
3O
2
562
Tricosyl trifluoroacetate
8
21.234
1.40
C
18H
36O
2
284
Methyl 7-methylhexadecanoate
9
22.479
0.04
C
19H
34O
2
294
9,12-Octadecadienoic acid (Z,Z)-, methyl ester
10
22.597
8.46
C
19H
36O
2
296
9-Octadecenoic acid, methyl ester
11
22.811
0.62
C
29H
60O
424
Eicosyl nonyl ether
12
23.069
7.05
C
19H
38O
2
298
Heptadecanoic acid, 16-methyl, methyl ester
13
23.334
3.34
336
Undec-10-ynoic acid, undecyl ester
14
23.431
0.29
C
18H
32O
264
9,17-Octadecadienal, (Z)-
15
23.485
0.07
C
24H
48O
2Si
396
cis-Vaccenic acid
16
23.730
1.19
C
18H
34O
2
282
Oleic Acid
17
23.774
1.15
C
15H
24O
220
(2S,3S,6S)-6-Isopropyl-3-methyl-2-(prop-1-en-2-
yl)-3-vinylcyclohexan one
Based on the phytochemical evaluation, the results showed that the methanol extract of bark of Tampoi (
B. macrocarpa) contains several secondary metabolites including alkaloids, flavonoids, phenolics, steroids, and triterpenoids. Several secondary metabolites including alkaloids, steroids, triterpenoids, flavonoids, and phenolics are known to have antioxidant properties. These antioxidant compounds wield their activities through different mechanisms, for example by inhibiting hydrogen abstraction, radical scavenging, binding transition metal ions, disintegrating peroxides
12,
13, and one of the most important factors influencing antioxidant activity is the ability of the compounds to donate electrons.
Furthermore, in the present study the antioxidant activity of the Tampoi extract was determined by DPPH method. This method was used because it is simple, efficient, quick, more practical, and relatively inexpensive
14. Based on
Table 2, it is known that the methanol extract of bark of Tampoi (
B. macrocarpa) can be categorized as an active extract in an antioxidant assay with IC
50 value of 11.15 ppm. In addition, the results of the toxicity test using the BSLT method showed that the extract was toxic because it displayed LC
50 value above 1000 ppm.
According to the results of GC-MS analysis, the chromatogram showed 37 peaks (compounds). The profile of the compounds showed that the main components were fatty acids and fatty acid esters. Total content of unsaturated fatty acids and esters with a peak area of 12.15% including 9,12-octadecadienoic acid (Z,Z)-, methyl ester (peak area 0.04), 9-octadecenoic acid, methyl ester (peak area 8.46), undec-10-ynoic acid, undecyl ester (peak area 3.58), undec-10-ynoic acid, undecyl ester (peak area 3.346), cis-vaccenic acid (peak area 0.07), and oleic acid (peak area 0.19). It was been reported that unsaturated fatty acid compounds and unsaturated fatty acid esters have significant antioxidant properties
15–
17.
It can be seen that only a small part of those are aromatic compounds. However, aromatic compounds are compounds that have the ability to stabilize high free radicals. The mechanism of phenolics as antioxidants is started by the formation a bond between free radical (DPPH radical) and hydrogen atom from OH-phenolics (ArOH) to form ArO
. radical. Hydrogen atom will easier to be released because of the presence of electron withdrawing group which is bound at
ortho- or
para- positions
18. Furthermore, ArO will react with a radical (ArO
. or other radical) to form a stable compound
19,
20.
DPPH
. + AOH → DPPH-H + ArO
.
DPPH
. + ArO
. → DPPH-OAr or DPPH
. + R
. → DPPH-R
According to identification of the compound in the methanol extract of bark of
Tampoi (
B. macrocarpa) using
NIST database (DRUGBANK accession number,
DB14212), it is known that the compound is identified as methylparaben. Based on the NIST database, peak at retention time at 9.467 min and peak area of 0.76% showed the characteristic of methylparaben (Molecular formula=C
8H
8O
3; Molecular weight=152).
It has been reported that methylparaben does not show negative effects on male mouse reproduction
21. Methylparaben is widely used as a preservative in cosmetic products, medicines or pharmaceutical products and food ingredients
22,
23, and the antibacterial activity of methylparaben is stronger than benzoate acid
24.
Methylparaben is a phenolic group that can reduce free radicals because it contains aromatic groups, -OH clusters and carbonyl groups. The presence of –COOCH
3 substituent at
para- position in methylparaben makes this compound act as an electron withdrawing group. The bond dissociation energy (BDE) of the O–H bond is a main factor to investigate the action of antioxidant, due to the weaker OH bond the reaction of the free radical will be easier
19. As the prediction of the previous reaction mechanism
7,
19, the prediction of the reaction mechanism between DPPH radical and methyl paraben can be seen in
Figure 2.
Prediction of DPPH radical scavenging mechanism by methylparaben.
Conclusion
The results of the study showed that the bark of Tampoi (
Baccaurea macrocarpa) has antioxidant activity with an IC
50 value of 11.15 ppm.
Data availability
The data referenced by this article are under copyright with the following copyright statement: Copyright: � 2018 Erwin E et al.
Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).
F1000Research: Dataset 1. Sheet 1, raw data of the results of phytochemical evaluation for alkaloids, flavonoids, phenolics, steroids, triterpenoids, and saponins by observing the changing of colors; Sheet 2, raw data of the observation of the mortality numbers of Artemia salina Leach and calculation of LC50 value in toxicity test using brine shrimp lethality test; Sheet 3, raw data for antioxidant activity by DPPH method, including the measurement of absorbance using spectrophotometer in triplicate, the calculation of percentage of antioxidant activity, and the value of IC50; Sheet 4, raw data of GC-MS analysis.,
https://doi.org/10.5256/f1000research.16643.d22722225
Acknowledgements
The authors would like to thank the IsDB project for providing financial support and Head of Plant Anatomy and Systematic Laboratory of Biology Department, Faculty of Mathematics and Natural Sciences of Mulawarman University for identification the specimen.
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http://www.doi.org/10.5256/f1000research.16643.d22722210.5256/f1000research.18189.r56216Reviewer response for version 1ChaicharoenpongChanya1Referee
Institute of Biotechnology and Genetic Engineering, Molecular Crop Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
Competing interests: No competing interests were disclosed.
This manuscript reported the new information of phytochemical and antioxidant activity of barks of
Baccaurea macrocarpa.
The authors used only DPPH assay to evaluate antioxidant activity. Antioxidant activity should be investigated using various assays to present antioxidant capacity of the extracts.
The results of evaluation on phytochemicals of barks of
B. macrocarpa showed that the methanol extract consisted of alkaloids, steroids, triterpenoids, flavonoids and phenolic compounds. But the profile of GC-MS showed only fatty acids, fatty acid esters and methyl paraben. The authors should use LC-MS to investigate chemical constituents of methanol extract instead of GC-MS.
In results section, the authors did not mention on the toxicity test of the extract using brine shrimp lethality test. And the results should express yours statistical analysis.
In discussion section, the third paragraph, the authors need to rewrite the total content and composition of fatty acids. GC chromatogram in Figure 1 was not related to the data of composition of compounds in Table 3 such as retention time, % peak area. For example, peak at retention time 19.329 showed high intensity on GC chromatogram but it expressed low % peak area just 0.91. The peak at retention time 14.877 showed low intensity on GC chromatogram but it expressed % peak area 1.32. Moreover, some compounds presented low matching percentage from the library searching. In Figure 2, structure of methyl paraben was wrong.
Is the work clearly and accurately presented and does it cite the current literature?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
Not applicable
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Is the study design appropriate and is the work technically sound?
Partly
Are the conclusions drawn adequately supported by the results?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
Reviewer Expertise:
Natural Product Chemistry.
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
erwinerwinmulawarman university, Indonesia
Competing interests: no competing interests
21112019
Reviewer comment #1
The authors used only DPPH assay to evaluate antioxidant activity. The antioxidant activity should be investigated using various assays to present antioxidant capacity of the extracts. The results of evaluation on phytochemical of barks of
B. macrocarpa showed that the methanol extract consisted of alkaloids, steroids, triterpenoids, flavonoids and phenolic compounds. But the profile of GC-MS showed only fatty acids, fatty acid esters and methyl paraben. The authors should use LC-MS to investigate chemical constituents of methanol extract instead of GC-MS.
Author response #1
This study is an initial screening of the antioxidant activity of Tampoi bark. The next project if we get the funding, we will use another antioxidant test and other instruments as you suggest. We will also carry out isolation and purification to obtain active compounds from Tampoi bark. Thank you for your valuable suggestion
Reviewer comment #2
In the results section, the authors did not mention on the toxicity test of the extract using brine shrimp lethality test. And the results should express your statistical analysis
Author response #2
Toxicity test data have been added in the revised article
Reviewer comment #3
some compounds presented low matching percentage from the library searching
Author response #3
It has been fixed
Reviewer comment #4
In Figure 2, the structure of methylparaben was wrong.
Author response #4
The structure of methylparaben has been fixed
Reviewer comment #5
In the discussion section, the third paragraph, the authors need to rewrite the total content and composition of fatty acids. GC chromatogram in Figure 1 was not related to the data of composition of compounds in Table 3 such as retention time, % peak area. For example, peak at retention time 19.329 showed high intensity on GC chromatogram but it expressed a low % peak area just 0.91. The peak at retention time 14.877 showed low intensity on GC chromatogram but it expressed % peak area 1.32.
Author response #5
The percentage (%) peak area of GC chromatogram has been fixed
10.5256/f1000research.18189.r56219Reviewer response for version 1WibowoAgustono1Refereehttps://orcid.org/0000-0001-6588-9507
Faculty Applied Science, Universiti Putra Malaysia, Pahang Darul Makmur, Malaysia
Competing interests: No competing interests were disclosed.
In first paragraph line 5, please correct your statement on natural ingredients “
do not contain chemicals” that only can be found in modern medicines, as all things in this world is formed from chemical constituents. Please change to “contain toxic chemicals”.
Last paragraph line 5, the statement “kinds of isolated compounds contained” are not correct as you don’t isolate the compound. Please remove the word “isolated”.
Methods:
DDPH assay alone can’t express the antioxidant properties of sample, so we suggest you to add other antioxidant assay such as ABTS and FRAP.
Discussion:
GCMS result indicated that the main constituent in
Baccaurea macrocarpa extract is fatty acid, this is because the GCMS can only detect the volatile compounds. To identify other compounds that are responsible in the antioxidant activity of
Baccaurea macrocarpa, we suggest you to run your sample using LCMS.
Methylparaben is familiar compound. Can you give literature which supported your claim that methylparaben is responsible to the antioxidant of
Baccaurea macrocarpa extract?
Is the work clearly and accurately presented and does it cite the current literature?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
Not applicable
Are all the source data underlying the results available to ensure full reproducibility?
Partly
Is the study design appropriate and is the work technically sound?
Partly
Are the conclusions drawn adequately supported by the results?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
Reviewer Expertise:
Natural Product Chemistry and Organic Synthesis
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
erwinerwinmulawarman university, Indonesia
Competing interests: no competing interests
21112019
Reviewer comments #1
In first paragraph line 5, please correct your statement on natural ingredients “do not contain chemicals” that only can be found in modern medicines, as all things in this world is formed from chemical constituents. Please change to “contain toxic chemicals”
Author response #1
Thank you for your suggestion, It has been fixed
Reviewer comments #2
The statement “kinds of isolated compounds contained” are not correct as you don’t isolate the compound. Please remove the word “isolated”
Author response #2
The word isolated has been removed
Reviewer comments #3
Methods:
DPPH assay alone can’t express the antioxidant properties of the sample, so we suggest you add other antioxidant assays as ABTS and FRAP
Author response #3
This study is an initial screening of the antioxidant activity of Tampoi bark.
Reviewer comments #4
Discussion:
GCMS result indicated that the main constituent in
Baccaurea macrocarpa extract is a fatty acid, this is because the GCMS can only detect the volatile compounds. To identify other compounds that are responsible for the antioxidant activity of
Baccaurea macrocarpa, we suggest you to run your sample using LCMS.
Author response #4
The next project if we get the funding, we will use another antioxidant test and other instruments as you suggest. We will also carry out isolation and purification to obtain active compounds from Tampoi bark.
Reviewer comments #5
Methylparaben is a familiar compound. Can you give literature which supported your claim that methylparaben is responsible for the antioxidant of
Baccaurea macrocarpa extract?
Author response #5
I could not find in the literature that discusses the antioxidant properties of parabens in vegetation, but methylparaben is preservative and antioxidant in cosmetic products, medicines or pharmaceutical products, and food ingredients. Based on GC-MS data, methylparaben is most likely to be antioxidants
10.5256/f1000research.18189.r56217Reviewer response for version 1WeerapreeyakulNatthida1Referee
Division of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand
Competing interests: No competing interests were disclosed.
According to the GC chromatogram the peak that was claimed to be methyl paraben was detected at 9.479 min but when identified with the MS the peak at 9.467 min was identified instead. This might be wrong interpretation.
Why the peak with high intensity detected at 19.329 min of methyl palmitate was not considered as the major compound or whether it was contributed to the antioxidant effect?
Due to there are many antioxidant mechanisms, therefore, only DPPH scavenging activity is not sufficient.
Cytotoxicity result was not shown and sufficiently discussed in correlation with the antioxidant activity.
The statistical analysis should be mentioned in the method section.
Based on the insufficient information and evidence, this manuscript needs more experimentation and well written regarding the method, results and discussion.
Is the work clearly and accurately presented and does it cite the current literature?
No
If applicable, is the statistical analysis and its interpretation appropriate?
I cannot comment. A qualified statistician is required.
Are all the source data underlying the results available to ensure full reproducibility?
No
Is the study design appropriate and is the work technically sound?
No
Are the conclusions drawn adequately supported by the results?
No
Are sufficient details of methods and analysis provided to allow replication by others?
Partly
Reviewer Expertise:
Pharmacology, Biomedical sciences
I confirm that I have read this submission and believe that I have an appropriate level of expertise to state that I do not consider it to be of an acceptable scientific standard, for reasons outlined above.
10.5256/f1000research.18189.r44034Reviewer response for version 1SelvarajChinnadurai Immanuel1Refereehttps://orcid.org/0000-0001-5292-0122
Department of Biotechnology, School of Biosciences and Technology,, VIT University, Vellore, Tamil Nadu, India
Competing interests: No competing interests were disclosed.
The study design and the methodology sounds good. Still more details on the plant
B. macrocarpa need to be included in the introduction. Even though the authors try to substantiate Methyl paraben as a non-toxic compound, it is a universally known fact usage of Methyl paraben is strongly discouraged in all human usage food and cosmetics as preservative. The Environmental Working Group (EWG) lists methylparaben as being a low to moderate Health Hazard. Parabens are potential endocrine disruptors due to their ability to mimic estrogen. Studies demonstrate that at sufficient concentrations, parabens can increase cell proliferation in human breast cancer MCF-7 cells, which are often used as a sensitive measure of estrogenic activity. Applying personal care product containing parabens—especially methylparaben—can lead to UV-induced damage of skin cells and disruption of cell proliferation (cell growth rate). These are evidenced reports on the Methyl paraben. Nevertheless, it is available in the natural source from the plant in meagre quantity. The authors can check for other compounds in GC-MS and state its importance in the manuscript. The GC-MS can be repeated. or HPLC can be performed using an aqueous extract. A simple TLC becomes handy for compound prediction, Then a column chromatography will be useful to check if there are any useful compounds.
The authors fail to include the ill effects of Methyl paraben in the literature. Is there any reason for avoiding such inclusions? The authors should weigh the importance of other compounds in the plant. Is there any traditional/ancient usage of the fruit mentioned in literature must be included in Introduction section.
Is the work clearly and accurately presented and does it cite the current literature?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
Not applicable
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Is the study design appropriate and is the work technically sound?
Partly
Are the conclusions drawn adequately supported by the results?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Partly
Reviewer Expertise:
Plant Phyto chemistry
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
erwinerwinmulawarman university, Indonesia
Competing interests: no competing interests
21112019
Reviewer comment #1
The authors can check for other compounds in GC-MS and state its importance in the manuscript
Author response #1
We have re-checked the 37 peaks which appeared to be methylparaben most likely to be antioxidants
Reviewer comment #2
The GC-MS can be repeated or HPLC can be performed using an aqueous extract. A simple TLC becomes handy for compound prediction, Then a column chromatography will be useful to check if there are any useful compounds.
Author response #2
This study is an initial screening of the antioxidant activity of Tampoi bark. The next project if we get the funding, we will use other instruments as you suggested. We will also carry out isolation and purification to obtain active compounds from Tampoi bark. We appreciated your suggestion
Reviewer comment #3
The authors fail to include the ill effects of Methyl paraben in the literature
Author response #3
We have added additional literature about the side effects of methyl paraben. Ref. no: 27
Reviewer comment #4
Is there any traditional/ancient usage of the fruit mentioned in literature must be included in the Introduction section
Author response #4
We did not find any use of tampoi as traditional medicine, but several other species of the genus
Baccuarea were used as traditional medicine. In addition, there are several preliminary studies on Tampoi's bio-activity. Ref. no: 3,4,8, and 9