i thinch the HPLC methods can help you to isolate the terponoids components

I have not used this particular plant but have purified diterpenoids from other plants.  They often exist as very complex mixtures with variable substitution patterns.  I found a mixture of techniques which utilised different properties was the best.  So I used LH20 column chromatography for initial shape separation, then reverse phase HPLC then normal phase chromatography using either high performance TLC (using Merck HPTLC plates) or you could use normal phase HPLC.  Alternatively, you could reverse these last two and do the normal phase first and the reverse phase second.  The difference between TLC plates and HPTLC plates is significant, but HPTLC plates are not cheap.

Please refer to the MUST HAVE BOOK on Phytochemicals from JB Harbourne from a library or e-copy. Immensely helpful. Big topic to explain- esp. without knowing your resources and objectives ! Best wishes.

Depending on your objective you can use both HPLC or Column Chromatography. HPLC can be used at analytical scale to just identify the different compounds present  using external standard and sample can be obtained at microgram to milligram levels by collecting the resolved peaks. The column chromatography (preparative scale) can be done to obtain the sample in larger amount. The column chromatography can be performed on silica or reversed phase resin.