Multifunctionality of Clausena harmandiana Extract and Its Active Constituents against Alzheimer’s Disease

Round 1

Reviewer 1 Report

In the present study, the authors investigated the effects of Clausena harmandiana (CH) and their constituents on anti-oxidative and anti-acetylcholinesterase, and the effects to improve memory deficient induced by scopolamine. The present study showed that CH shows multimodal actions relevant to the AD pathological cascade including antioxidant effects, the inhibition of Aβ aggregation, and neuroprotection against oxidative stress and Aβ toxicity. In addition, CH improved both the short- and long-term memory deficits induced by scopolamine. Although I think that topic of this study is interesting, there are some flaws in this manuscript.

 Comments:

1.      Abstract: There is a rule that the abstract should be a total of about 200 words maximum. However, the abstract of this manuscript has about 300 words. The authors have to revise it.

2.      The composition of CH should be summarized in Table.

3.      The sources of cell lines used in this study is missing.

4.      Statistical analysis: Post-hoc multiple comparisons should be performed.

5.      The authors mention that “the improvement of memory deficit of the CH extract might be mediated by anti-oxidant and anti-acetylcholinesterase actions”. If so, I wonder that curcumin alone or combination of curcumin and Trolox can improve memory deficient. What do the authors think about it?

6.      Discussion: Discussion should be improved. For example, the authors have to discuss how nordentatin shows anti-oxidant action.

7.    There are some careless mistakes such as [33] in Line 196. The authors have to check the manuscript carefully.

Author Response

Dear Reviewer I,

Thank you for your comments on the manuscript entitled “Multifunctionality of Clausena harmandiana extract and its active constituents against Alzheimer’s disease” submitted online for publication in Current Issues in Molecular Biology (CIMB). The manuscript has been revised as follows:

In the present study, the authors investigated the effects of Clausena harmandiana (CH) and their constituents on anti-oxidative and anti-acetylcholinesterase, and the effects to improve memory deficient induced by scopolamine. The present study showed that CH shows multimodal actions relevant to the AD pathological cascade including antioxidant effects, the inhibition of Aβ aggregation, and neuroprotection against oxidative stress and Aβ toxicity. In addition, CH improved both the short- and long-term memory deficits induced by scopolamine. Although I think that topic of this study is interesting, there are some flaws in this manuscript.

1. Abstract: There is a rule that the abstract should be a total of about 200 words maximum. However, the abstract of this manuscript has about 300 words. The authors have to revise it.

The abstract has been revised following the reviewer’s suggestion.

2. The composition of CH should be summarized in Table.

The composition of CH has been summarized in Table 1

3. The sources of cell lines used in this study is missing.

The sources of cell lines used have been included in 5.7 and 5.8.

4. Statistical analysis: Post-hoc multiple comparisons should be performed.

For all the statistical analyses, statistical significance was determined by a one-way analysis of variance (ANOVA) followed with Tukey post hoc test.

5. The authors mention that “the improvement of memory deficit of the CH extract might be mediated by anti-oxidant and anti-acetylcholinesterase actions”. If so, I wonder that curcumin alone or combination of curcumin and Trolox can improve memory deficient. What do the authors think about it?

Due to the multi-pathogenesis of AD, the classical approach modulating at one target may be inadequate in this complex disease. Therefore, searching the candidates acting at multiple sites of pathologic cascade has become a new strategy for the design of new drugs for AD. Currently, there are several strategies to develop drugs with multi-target action. The combination therapy is one of the strategies for muti-target drug development. The combination therapy is a combination of ≥2 agents that target separate pathways such as a fixed-dose combination with donepezil (AChE inhibitor) and memantine (NMDA antagonist) (NAMZARIC®). Combining therapeutic agents may offer synergistic effects, allow for lower doses of the individual agents, reducing side effects. However, inflexible fixed dose ratio, incompatible pharmacokinetics and the interaction between the different agents must be concern. For the combination of curcumin and Trolox, theoretically sounds well but there will have to be further studies on the concern issues before further development as a drug.

6. Discussion: Discussion should be improved. For example, the authors have to discuss how nordentatin shows antioxidant action.

Following reviewer’s comment, we have included the concerned points in the discussion section.

7. There are some careless mistakes such as [33] in Line 196. The authors have to check the manuscript carefully.

Thank you for your suggestion. The manuscript has been checked and edited.

Yours sincerely,

Pornthip Waiwut

Author Response File: Author Response.pdf

Reviewer 2 Report

In this study, the authors suggest Clausena harmandiana (CH) as a potential candidate for further development as a drug for AD therapy. They show CH’s neuroprotective effects through various experiments that target the AD pathological cascade. Overall, this review supports existing evidence and is unique. However, its statements may be too generalized as further studies should be done to elucidate further the molecular effect of CH on the AD pathological cascade. There are several comments and suggestions below for the authors’ review to be made prior to publication. Major comments are those that need to be addressed; while minor comments are suggestions that will improve the quality of the paper.

Comment 1 [Major]: Statistics. There should be an indication of the number of trials and repeats for each type of method and what was taken into consideration for it. This only exists for two of the methods.  

Comment 2 [Major]: Overstating Conclusions; No Future Research / Discussion. I am concerned with the confidence in which the authors present their conclusions, leading towards further development as a drug for AD therapy. For example, in Lines 229-231, they state that “Our results suggest that the CH extract has the ability to improve or ameliorate the dysfunction of spatial long-term and working memory, in part, by enhancing the activity of the cholinergic nervous system.” Instead of having a one-sided statement for CH can only improve and fix an issue, it is better to be cautious and state that there is a noticeable effect that has positive ramifications for ameliorating memory dysfunctions (etc.) and further studies must be performed.” There will have to be further studies before further development is done. These should all be added to the paper. After that, the final statement/recommendation will need to change as well to reflect observed effects.

Comment 3 [Major] Figure Labelling. Figure 1 is extremely small and blurry. This must be enhanced prior to publication. The figure caption should also be more detailed.

Author Response

Dear Reviewer 2,

Thank you for your comments on the manuscript entitled “Multifunctionality of Clausena harmandiana extract and its active constituents against Alzheimer’s disease” submitted online for publication in Current Issues in Molecular Biology (CIMB). The manuscript has been revised as follows:

In this study, the authors suggest Clausena harmandiana (CH) as a potential candidate for further development as a drug for AD therapy. They show CH’s neuroprotective effects through various experiments that target the AD pathological cascade. Overall, this review supports existing evidence and is unique. However, its statements may be too generalized as further studies should be done to elucidate further the molecular effect of CH on the AD pathological cascade. There are several comments and suggestions below for the authors’ review to be made prior to publication. Major comments are those that need to be addressed; while minor comments are suggestions that will improve the quality of the paper.

Comment 1 [Major]: Statistics. There should be an indication of the number of trials and repeats for each type of method and what was taken into consideration for it. This only exists for two of the methods. 

The number of trials and repeats of each experiment have been included in “5. Materials and Methods” and “2. Result”.

Comment 2 [Major]: Overstating Conclusions; No Future Research / Discussion. I am concerned with the confidence in which the authors present their conclusions, leading towards further development as a drug for AD therapy. For example, in Lines 229-231, they state that “Our results suggest that the CH extract has the ability to improve or ameliorate the dysfunction of spatial long-term and working memory, in part, by enhancing the activity of the cholinergic nervous system.” Instead of having a one-sided statement for CH can only improve and fix an issue, it is better to be cautious and state that there is a noticeable effect that has positive ramifications for ameliorating memory dysfunctions (etc.) and further studies must be performed.” There will have to be further studies before further development is done. These should all be added to the paper. After that, the final statement/recommendation will need to change as well to reflect observed effects.

Following reviewer’s comment, the conclusion and discussion sections have been revised.

Comment 3 [Major] Figure Labelling. Figure 1 is extremely small and blurry. This must be enhanced prior to publication. The figure caption should also be more detailed.

Figure 1 has been edited and the figure caption has been revised following the reviewer’s suggestion.

Yours sincerely,

Pornthip Waiwut

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for responding to my comments.

I am satisfied with the authors' responses.