Dear Nawraj,

Opposite to flavonoids and phenolics, terpenoids are commonly not aromatic and hence are difficult to quantify by UV detection. If you want to use HPLC, using a diode array or MS detector is a possible approach. The most precise and widely used method to analyze and quantify terpenoids is by GC/MS, since terpenoids can be distinguished from other metabolites based on their mass spectra and, with exception of higher molecular weight non-volatile compounds, separate well on the GC. Alternatively, you can use a GC-FID system provided that you have an appropriate standard for the terpenoid class you are seeking to study. There is a large body of literature available on the analysis of terpenoids by GC/MS.

Also keep in mind that prior to your analysis, terpenoids will extract at different levels depending on which solvent you use. This can alter your total terpenoid content significantly; again depending on the organism, tissue etc. that you study.

Hope this helps.

Best wishes,

Philipp

Before the wide spread use of GC-FID and GC-MS, colourimetric procedures were employed to detect adulterants in essential oils (composed of mono and sesquiterpenes, their oxygenated compounds, phenylpropanoids etc.). However, total terpenoids were not analysed by these methods. Literature search may yield useful leads for developing a new analytical method.

See this: Phytochemical Characteristics, Free Radical Scavenging Activities, and Neuroprotection of Five Medicinal Plant Extracts

http://www.hindawi.com/journals/ecam/2012/984295/

Thank you Zulane Sousa. Will surely try carry out  this protocol