Dear Nathipong,

First you have to be certain your extract dissolves in DMSO before making your stock. 

Also you should consider that DMSO is an oxidizing agent hence it MIGHT reduce the antioxidant activity of plant extracts. If the antioxidant activity is integral to your research you should consider other solubilizing agents (eg ethanol) 

To make your stock solution, weigh out the exact quantity of extract you have.

Assuming you have 0.20g of extract, it will be equivalent to 200mg.

To make a 100mg/ml stock you just add 1ml to each 100mg of your extract.

In case of the assumed 200mg you add 2mls of DMSO or (what ever you decide suits your experiment best).

After sorting your stock solution, as you indicated The final % of concentration you need will be 1-2% of 100mg/ml in your cell treatment meaning 1-2mg/ml of your extract. 

To get the final concentration of 1-2mg/ml in your cell culture medium, you use the formula C1 V1 = C2 V2. where C1 = the stock concentration, V1 is volume of stoc needed, C2 = concentration needed V1 = final volume of media needed.

(Assuming you are using 24 well plates with final volume of 2mg/ml(2%) in 400uL in each well)

you re arrange formula to V1 = (C2 V2)/C1 then substitute C2 = 2mg/ml, V2 = 0.4ml, C1= 100mg/ml . your voulume of  stock needed will be 8uL. To make life easier, you can make treatment media for the whole plate. Meaning 24 x 400uL = 9.6ml. substitute 9.6ml for V2 value and you will need 192uL of stock solution in 9.6ml then use a mutichannel pipette to distribute.

Hope it helps.

Dear first you have to know which solvent is better to dissolve your plant extract, because I used several plant extracts, some of them dissolved in just normal distilled water (such as morinda leaf) then no need to use DMSO, as it has little toxicity to the cells. secondly I usually prepare 10mg/ml stock from plant extract, that is why suggest u to start from 10mg and not 100mg. All the best to your research. TQ

Thank you very much Rahman. Why did you advised me to prepare in 10 mg/ml stock? 100 mg/ml is too much?

Dear Romann, I would not use DMSO, and I propose to reduce concentration of the stock among 10mg/ml or 5mg/ml. Cordially

-Stock solution : 10mg + 100 micro liter DMSO = 100mg/ml

-Working solution : 10 micro liter of stock solution + 990 micro liter of culture media= 1 mg/ml

- Final dilutions can be prepared from working solution

Dear Nithipong Mapratiep

First you have to know which extract of the sample showing the higher levels of phytochemicals when compared to the other extracts then you can go for DMSO .All the best

dear Nithipong.

I agree with Ahmed Arbab on the prep. but firstly you need to know which works better as your solvent.

Dear Nathipong,

First you have to be certain your extract dissolves in DMSO before making your stock. 

Also you should consider that DMSO is an oxidizing agent hence it MIGHT reduce the antioxidant activity of plant extracts. If the antioxidant activity is integral to your research you should consider other solubilizing agents (eg ethanol) 

To make your stock solution, weigh out the exact quantity of extract you have.

Assuming you have 0.20g of extract, it will be equivalent to 200mg.

To make a 100mg/ml stock you just add 1ml to each 100mg of your extract.

In case of the assumed 200mg you add 2mls of DMSO or (what ever you decide suits your experiment best).

After sorting your stock solution, as you indicated The final % of concentration you need will be 1-2% of 100mg/ml in your cell treatment meaning 1-2mg/ml of your extract. 

To get the final concentration of 1-2mg/ml in your cell culture medium, you use the formula C1 V1 = C2 V2. where C1 = the stock concentration, V1 is volume of stoc needed, C2 = concentration needed V1 = final volume of media needed.

(Assuming you are using 24 well plates with final volume of 2mg/ml(2%) in 400uL in each well)

you re arrange formula to V1 = (C2 V2)/C1 then substitute C2 = 2mg/ml, V2 = 0.4ml, C1= 100mg/ml . your voulume of  stock needed will be 8uL. To make life easier, you can make treatment media for the whole plate. Meaning 24 x 400uL = 9.6ml. substitute 9.6ml for V2 value and you will need 192uL of stock solution in 9.6ml then use a mutichannel pipette to distribute.

Hope it helps.

I want ask some question about my sample. I have crude extract for 3 categories of extraction which are water extract, methanol/water extract and partition extract(hexane, DCM,CHCl3,n-buoh and aq). What the suitable solution can i use to prepare my sample for cell treatment? Thanks for your advanced.

Dear  Nithipong ;

If it this extract contain high oil derived molecules, You can dissolve high rate EtOH..