Quantification of Procyanidin B₂ in Bark and Leaves of Saraca Asoca (Roxb.) Willd: Pharmacognostic Profiling, TLC And HPLC Approaches

Abstract

Saraca asoca (Roxb. Willd.; Sita-ashok) is a medicinal tree of high ethnopharmacological importance. Overharvesting of its bark for therapeutic use has contributed to IUCN listing as a threatened taxon; therefore, replacement of destructive harvest (bark) with sustainable plant parts (leaves) is an urgent conservation priority. Procyanidin B₂ (a B-type proanthocyanidin) is a pharmaceutically valuable flavonoid dimer reported from S. asoca and implicated in anti-inflammatory and neuroprotective activity. In the present study, a pharmacognostic and chromatographic instrumental TLC and HPLC evaluation was conducted for the qualitative and quantitative profiling of Procyanidin B₂ in methanolic extracts of Saraca asoca bark and leaves. Macroscopic and microscopic features, physicochemical constants, Instrumental TLC fingerprinting, and an HPLC method (C18 column; gradient elution; detection 290 nm; RT ≈ 2.8 min) were developed and applied. Yields of methanolic maceration (1 kg starting material each) were 54.0 g (bark) and 48.8 g (leaves). Using the in-house developed HPLC method, Procyanidin B₂ was detected in both bark and leaf extracts; assay values were 444 ppm for bark and 509 ppm for leaves, corresponding to the reported assay percentages of 22.2% w/w (bark) and 25.5% w/w (leaves). These preliminary data support the feasibility of leaf substitution as a conservation-oriented strategy while retaining the target marker Procyanidin B₂.