Ultrasonic Extraction and Separation of Taxanes from Taxus cuspidata Optimized by Response Surface Methodology

Round 1

Reviewer 1 Report

The manuscript entitled "Ultrasonic extraction and separation of taxanes from Taxus cuspidata and optimization of response methodology" is well constructed and written piece of scientific reaserch.

The design of experiment and optimization procedure is well done and described - single factor revealed the importance of independent variables and allowed to determine by BB design the most desirable conditions of UAE extraction in order to maximize the yield of taxanes. 

Statistical calculations and further experiments proves that the applied approach in optimization of the process was accurate and reliable resulting in retrieval of taxanes with high yield and no loss due to degradation, what further was confirmed by analytical chemistry.

I have got only three issues with the reviewed article:

1) English language and writing should be improved - I recommend revision by the native speaker, qualified in scientific papers proofreading.

For example: the experimental section, especially points 2.3 to 2.5 and 2.7-2.8 is written in present tense and sounds like laboratory instruction rather than description of methods employed. Moreover, it is inconsistent with the rest of the style used in manuscript (vide Introduction section, which is well presented). I have faced this issue several times while reading the paper. Improving the English language will for sure bring wider audience.

2) Quality of the figure 5 - unfortunately the presented response surface graphs are very blurry and hard to read - especially the bottom axes, a one can hardly read anything. The results presented are very important and proves the quality of optimization model applied. Without appropriate graphical representation, potential readers may not be able to notice the actual influence of process parameters on the yield of extraction. I recommend to enlarge the graphs, change the perspective angle in order to improve the visibility of response surfaces, as well as the axes values. Moreover, higher resolution and better color selection for sure will improve the perception of the graphs.

3) Title - in present version it may suggest that you are optimizing the response surface methodology, rather than the extraction process. If I may recommend, I would change the title into:

Ultrasonic extraction and separation of taxanes from Taxus cuspidata optimized by response surface methodology.

To conclude, I am very satisfied in general by the quality of the paper and careful development of the conclusions in discussion section, strongly supported by accurate optimization results.

Reviewer 2 Report

In this study, Taxanes were extracted from Taxus cuspidate using ethanol solution. Then, the extraction process was optimized by RSM. Although the work is not very innovative, this work is systematacially studied. So I suggest some revisions for this work.

1. The main processes are extraction other than separation for this work, so you can emphasize the separation process.

2. How to isolate the eight taxanes after extraction? If this work is added, I think this work will be more attractive.

3. Figure 2. The HPLC chromatograms for the standards and real sample should be compared.

3. Some minor revisions.

Some spaces are missing, Line 10, 16, 20, 81, 200

The points are missing, Line 131.

The symbol of temperature is wrong.

Table 2. Regression equation, the special characters use italic

Reviewer 3 Report

Dear Authors 

After reviewing your manuscript, I can say that it is interesting and contains novel information and work. 

I have the following comments and suggestions: 

1. The Introduction is OK, but at the end, (page 2 lines 70-88) where you give the aim of the work, it contains detailed information that probably need to be in the Materials and Methods section, especially when describing the compounds used in HPLC. Usually, the aim is a shorter statement that describes the general intended work. 

2. The first sentence of the Materials and Methods is not complete, please rephrase it so as to be understood well.

3. In page 3 line 19, you mention that the explants were washed with running water for 3-4 HOURS? 

3. Sections 2.3.1 to 2.5 please be consistent in writing the methods: Do not write in "order form" like "soak it in 0.1% ....." but use "it was soaked ... the cell growth was observed..... and so on. Additionally, r/min (page 4 line 46) should be rpm, and the "± " symbol to temperature and humidity in the same page. 

4. At the end of section 3.2.1. where you say that " These results are consistent with other reports" please add reference to those reports.

5. In section 3.2.4. lines 89-90: This is not an explanation why 90% ethanol is the best solvent. Please consider "swelling of the matrix of the plants" as well. 

6. Section 2.4, the figure should be Figure 6 NOT figure 5. 

7. There are minor English mistakes that do not bother the reader, but try to correct. Some examples: Page 1 line 21, for the rapid and effective ..... should be for rapid and effective; line 12 in the same page (Abstract): to optimize the optimum extraction ... Please delete "optimum".... 

8. Nothing is mentioned about Figure 3 in the text. Please add a sentence for figure 3. 

9. In table 2, you use the term "structural formula" it might be better using "molecular formula" instead. 

Nevertheless, the research is good and well-planned and executed. 

Wish you all the best. 

Regards