Extraction of natural drugs

Sure. In fact, since not all glycoside V in momordica was extracted, the calculated extraction rate is only slightly higher. I don’t know the equipment and methods for extraction. If the extract contains only glycoside V and solvent, the refractometry method can be considered for detecting the concentration of glycoside V.

Are there any authoritative papers that use similar methods to determine the content of a certain substance? I searched for a long time but couldn’t find it. The detection method I use here is high-performance liquid chromatography, HPLC

This post was last edited by qugd on 2018-10-19 at 11:11. I don’t know what literature the original poster has consulted; there seems to be no solution to such a problem. Presumably, the original poster is engaged in research in this field or in the techniques for extracting such substances; one can simply consider extraction methods based on the physicochemical properties of these substances. Starting with the CAS code, it is possible to determine the structure of the substance, and its physicochemical properties can be inferred; in particular, its solubility is likely to be high in water, making the use of water as a solvent for extraction the most convenient option. To control the amount of the extract, it is possible to use a Soxhlet extractor with a slightly larger capacity, which eliminates the need to add the solvent repeatedly and thus improves efficiency. If the extraction in one attempt does not seem complete, the residue can be extracted a second time. The ingredients can be chopped appropriately. Additionally, trying to add methanol or ethanol can roughly increase the extraction speed. The attached figure shows its structural formula; the original poster can take a look at it and estimate the physical and chemical properties of this substance. Chinese name: Mogroside V, derived from Momordica grosvenori; English name: Mogroside V, from Fructus Momordicae; CAS number: 88901-36-4. A method for determining the content of Mogroside V in Momordica grosvenori herbal materials using RP-HPLC. Method: A Lailtma-C column (4.6 mm x 250 mm, 5 μm) was used, with acetonitrile-water (23:77) as the mobile phase, a flow rate of 1.0 mL·min⁻¹, a detection wavelength of 203 nm, and a column temperature of 32°C. Results: The linear range of momordicoside V was 0.17–4.2 μg, with an average recovery rate of 99.05% (RSD = 0.78%, n = 9).

Bro Qugd is a pro. I learned before that there are so-called ‘pilot-scale’ or ‘production-scale’ HPLC systems available on the market; for example, in Beijing there is a equipment manufacturer named ‘Innovation Tongheng’ that specializes in services related to extraction.

I’m a first-year undergraduate who is new to research, and there are many things I don’t quite understand. Thank you all for your thorough explanations. Because it is impossible to extract all mogroside V from momordica fruit no matter what method is used, it is questionable whether using the amount of glycoside V extracted by a certain method as the actual content of glycoside V in momordica fruit is reasonable. I’m quite puzzled by this, as there are basically no national standards in this area, nor is it mentioned in any papers. :lol

This post was last edited by qugd on 2020-3-31 09:21. How do you understand the concepts of extraction efficiency and complete extraction? No matter how it’s extracted, it’s impossible to get momordica fruit… You’re just being argumentative. When extracting a certain component, by using an appropriate solvent to extract the majority of that component, and leaving behind in the original sample an amount that is insufficient to affect the efficiency of the extraction process, it can be considered that the extraction is complete. Continuous extraction can be carried out using a Soxhlet extractor, or extraction can be performed in stages with a solvent; both methods yield good extraction results. I’ve checked the information; the content of mogroside V is about 1%. After extraction, when the residue contains less than 0.001% of it, it can be considered that the extraction is complete, as the extraction efficiency has reached 99%. You’re in graduate school and don’t even know such basic common sense. Besides, not every method requires **standards**; there are already ready-made standards, so there’s no need for you to go to the trouble of researching them. The fact that this is not mentioned in the paper indicates that you did not conduct a thorough enough search of the relevant literature; I was able to find two papers with conclusions regarding both the methods and the concentrations used. I feel you’re not suited for graduate school, because you don’t use your brain at all. If no literature can be found, don’t you have a CAS number? Search in CA; there, you can find many documents related to the extraction, analysis, structure, etc. of such chemical substances, along with their abstracts. Then you can use those abstracts to locate the original sources. I guess you don’t know what kind of treasure guide CA is. Looking at this link, there are just two papers: https://wenku.baidu.com/view/51a6517831b765ce050814bd.html, https://wenku.baidu.com/view/193216110c22590103029d00.html. If there is no authoritative literature on the topic, then if you do it well, you become the authority.

I’ve heard of CAS numbers, but I don’t know how to use them; it seems that they can’t be searched directly on CNKI

You’re already in graduate school, and you’ve only heard of CAS; so you probably haven’t used CA at all. For those studying chemistry, if they can’t use CA, then graduating from undergraduate level is more or less sufficient; but what about during postgraduate studies? How can they conduct literature searches or check for recent research? Find some time to learn how to use a CA. Avoid browsing useless websites; it’s better to work on mastering the basics.

Does CA refer to the American Chemical Abstracts? Even through the school network, you need an account and password to log in. Could you tell me roughly how to use this thing?