Analysis of total flavonoids and phenolics in different fractions of bark and needle extracts of Pinus roxburghii and Pinus wallichiana

Abstract

Total flavonoid and phenolic content was estimated quantitatively by using colorimetric method in various fractions of bark and needle extracts of Pinus roxburghii and Pinus wallichiana. Flavonoids may exist as free aglycone, but usually they are bound to sugar as glycosides and any one aglycone may occur in single plant in several combinations. For the measurement of total flavonoid content, original plant extract was hydrolysed and aglycone was measured before and after hydrolysis to calculate the presence of free aglycone content. Flavonoid contents (aglycone) of the extracts, in terms of quercetin equivalent (the standard curve equation: y = 0.0877x -0.0595, r2 = 0.9981), were in the range of 60.1 ± 4.5 to 484 ± 2.5 before and after hydrolysis. As such, the values fell in the range of 76.9 ± 3.2 to 943 ± 2.6. The total phenol varied from 394 + 0.03 to 1331 + 0.24 measured in terms of gallic acid equivalent (with standard equation: y = 0.0197x-0.0076, r2 = 0.9997). Key words: Flavonoid, phenolics, aglycone, Pinus wallichiana, Pinus roxburghii.