Phytochemical Extract from Syzygium cumini Leaf: Maximization of Compound Extraction, Chemical Characterization, Antidiabetic and Antibacterial Activity, and Cell Viability
, Jaqueline Hoscheid 2, Vitor Augusto dos Santos Garcia 3, Oscar de Oliveira Santos Junior 4 and Camila da Silva 1,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsRequires minor revision.
Comments for author File: 
Comments.pdf
Author Response
Review 1
- Abstract should include the results of the biological studies as weel, not just conclusive remarks.
Answer: Based on the reviewer's comment, the abstract has been modified.
- Title should reflect the entire work reported.
Answer: Based on the reviewer's comment, the title has been modified.
- Line 23: extracts were studied for antidiabetic, antimicrobial, and cell viability, whereas Line 28: states antioxidants, but did not specify cell viability results.
Answer: Based on the reviewer's comment, the abstract has been modified.
- Line 72: EAU?
Answer: The correct spelling UAE. The correction was made in the revised version of the manuscript.
- Line 81: It should be antibacterial, not antimicrobial activity, as only three bacteria were used.
Answer: The revised version of the manuscript presents antibacterial activity and not antimicrobial activity.
- Methodology of antibacterial was not included.
Answer: The test methodology is presented in detail in previous work by the research group (as cited). I believe it is not feasible to describe the methodology again in this manuscript.
- Figure 2: What was the control used? Why standard was not included?
Answer: We appreciate the reviewer's comments. Three controls were used to perform the cell viability test: the positive control with hydrogen peroxide, the vehicle control with the solvent used, and the negative control without the extract. The information was added to the manuscript and in Figure 2 we included the vehicle data.
- Figure 2: Statistical significance with what? Viability is more or less similar?
Answer: We appreciate the reviewer's comments. Statistical analysis was performed between the different extracts (AE, 75E 3 50E), so the text was changed and added to the manuscript.
- More discussion with relevant literature is needed w,r,t, to the biological experiments.
Answer: We appreciate the reviewer's comments. The information was added to the manuscript.
- Suplementay data is not provided.
Answer: The supplementary material is again attached in the revised version of the manuscript.
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors,
Please revise the manuscript considering the following comments:
L36-37 - Explain the importance of this crop (production/consumption/why should be worthy of being studied); include the types of phenolics recently found.
L72 - Explain the acronym first before mentioning the abbreviation.
L100/L95 - ''Ethanol..'' -Avoid unnecessary repetition throughout the text.
L116-144 - Include the equipment used for UAE. Include the power used. For how long were the extractions conducted?
One observation: the authors mentioned in introduction that US brings cavitation. However, the authors are analyzing effect of temperature - make sure if use of temperature is detrimental to understand the sonication phenomena throughout the extraction.
L172-180 - Please mention how these were calculated/how results were expressed.
l183 - From where did authors get the cell lines?
L184-190/L431-438/Fig2 - Why did authors evaluated just one concentration of extract? Result part: What is the ideal? For all extracts to be next to the control/higher than 70% ?
Table 1 - Please include the statistical differences of EY and TPC.
Table 3/ - Please use the term: antioxidant potential. The authors did not measure activity.
Author Response
Review 2
- L36-37 - Explain the importance of this crop (production/consumption/why should be worthy of being studied); include the types of phenolics recently found.
Answer: Jambolan is not yet produced on a commercial scale (information added in the revised manuscript) and the present work aims to contribute to increasing interest in this crop. Information on phenolics recently reported in the leaves was added in the revised version of the manuscript.
- L72 - Explain the acronym first before mentioning the abbreviation.
Answer: The acronym was wrong, it is mentioned previously in L51. The correction was made in the revised version of the manuscript.
- L100/L95 - ''Ethanol..'' -Avoid unnecessary repetition throughout the text.
Answer: The correction was made in the revised version of the manuscript.
- L116-144 - Include the equipment used for UAE. Include the power used. For how long were the extractions conducted?
Answer: Based on the reviewer's comments, the information of the equipment was added to the revised version of the manuscript.
The reaction time was in accordance with the experimental planning (Table 1).
- One observation: the authors mentioned in introduction that US brings cavitation. However, the authors are analyzing effect of temperature - make sure if use of temperature is detrimental to understand the sonication phenomena throughout the extraction.
Answer: In the investigated temperature values the vapor pressure in the solvent is low, allowing cavitation bubbles to collapse violently, inducing matrix bonds to break, disrupting cell tissues (Tiwari, 2015). On the other hand, higher temperatures can have a negative effect on the cavitation phenomenon, which can cause a reduction in the extraction yield or even, degradation of the compounds obtained. In this case, the disruption of the solute-matrix interaction promotes the filling of voids with solvent vapors, resulting from the reduction in the intensity of cavitation (Tiwari, 2015), resulting in a decrease in the extraction rate.
Tiwari, B.K., 2015. Ultrasound: A clean, green extraction technology. Trac Trend Anal. Chem. 71, 100-109. https://doi.org/10.1016/j.trac.2015.04.013
- L172-180 - Please mention how these were calculated/how results were expressed.
Answer: The information was added in the revised version of the manuscript.
- L183 - From where did authors get the cell lines?
Answer: We appreciate the reviewer's comments. The cell lines used were immortalized HaCat cells, a human keratinocyte line. The information has been added to the manuscript.
- L184-190/L431-438/Fig2 - Why did authors evaluated just one concentration of extract? Result part: What is the ideal? For all extracts to be next to the control/higher than 70%?
Answer: We appreciate the reviewer’s comments. The choice to test only one concentration of extract was based on previous experiments. We agree with the reviewer that it is necessary to conduct tests with different concentrations; however, due to financial limitations, this was not possible. Nonetheless, we believe that the results obtained still provide a basis for future investigations. As all tested extracts showed cell viability above 70%, none of them are considered toxic. Adjustments have been made to the manuscript.
- Table 1 - Please include the statistical differences of EY and TPC.
Answer: The statistical difference is not presented in Table 1 because these data are used to generate the ANOVA presented in Table 2.
- Table 3/ - Please use the term: antioxidant potential. The authors did not measure activity.
Answer: The revised version of the manuscript presents antioxidant potential and not antioxidant activity.
