Dear Prachi,

You can use the protocol described in the following publication:

 High-Yield RNA-Extraction Method for Saliva

Pratibala Pandit1, Justin Cooper-White1,2 and Chamindie Punyadeera1,2,*

Abstract

BACKGROUND: The use of salivary diagnostics is increasing because of its noninvasiveness, ease of sampling, and the relatively low risk of contracting infectious organisms. Saliva has been used as a biological fluid to identify and validate RNA targets in head and neck cancer patients. The goal of this study was to develop a robust, easy, and cost-effective method for isolating high yields of total RNA from saliva for downstream expression studies.

METHODS: Oral whole saliva (200 μL) was collected from healthy controls (n = 6) and from patients with head and neck cancer (n = 8). The method developed in-house used QIAzol lysis reagent (Qiagen) to extract RNA from saliva (both cell-free supernatants and cell pellets), followed by isopropyl alcohol precipitation, cDNA synthesis, and real-time PCR analyses for the genes encoding β-actin (“housekeeping” gene) and histatin (a salivary gland–specific gene).

RESULTS: The in-house QIAzol lysis reagent produced a high yield of total RNA (0.89–7.1 μg) from saliva (cell-free saliva and cell pellet) after DNase treatment. The ratio of the absorbance measured at 260 nm to that at 280 nm ranged from 1.6 to 1.9. The commercial kit produced a 10-fold lower RNA yield. Using our method with the QIAzol lysis reagent, we were also able to isolate RNA from archived saliva samples that had been stored without RNase inhibitors at −80 °C for >2 years.

CONCLUSIONS: Our in-house QIAzol method is robust, is simple, provides RNA at high yields, and can be implemented to allow saliva transcriptomic studies to be translated into a clinical setting.

http://www.clinchem.org/content/59/7/1118.full

Hoping this will be helpful,

Rafik

Thank you sir.

But i have checked the product detail of qiazol and trizol.Both are based on phenol and quanidine iso thiocyanate.In research gate forum, they told it is same. Could you please let me know if there is a difference between trizol and qiazol?

Dear Prachi Kochhar 

please check the links

www.protocol-online.org/biology-forums/RNA.html

www.protocol-online.org/biology-forums-2/DNA.html

Dear Prachi,

They both are composed of the same two compounds: phenol & quanidine thiocyanate, however, they may differ in the percentage of each component in the mixture. They both are used for for RNA & DNA extraction, however, they are slightly different reagents and thus they might give different yields.

QIAzol Lysis Reagent:

Composition:

Phenol 25-50%

Quanidine thiocyanate 10-25%

For efficient lysis of fatty and standard tissues before RNA isolation. Optimized lysis conditions to purify RNA for gene expression analysis. High yields of RNA from fatty tissues. Easy-to-follow protocol for lysis and homogenization. Integration with RNeasy cleanup to prevent phenol carryover. Compatibility with a variety of tissue types.

QIAzol Lysis Reagent is optimized for lysis of fatty tissues. The standard QIAzol protocol provides an easy-to-follow procedure, combining QIAzol lysis with standard homogenization methods and isopropanol precipitation.

Triazol:

Composition:

Phenol & quanidine thiocyanate (the percentage of each component in the mixture is not known).

Hoping this will be helpful,

Rafik

Thank you..