Characterization and anti-oxidant potential of polyphenolic biomarker compounds of Indian propolis: a multivariate and ANN-based approach

The current investigation emphasizes the characterization of polyphenolic compounds, antioxidant potential, and mapping of biomarkers in propolis samples acquired from India. LC-ESI-QTOF-MS discovered 67 phytocompounds, including 39 flavonoids, 20 phenolic acids and their derivatives, along with carotenoids and phytosterols in northern Indian propolis. Compounds like: proanthocyanidins, iso-flavonoids, carotenoids, and phytosterols were only detected in particular region samples, recognized as biomarker compounds of specific locations. The spectrophotometric analysis quantified a higher concentration of total flavonoids (TFC) than total phenolic content (TPC) in propolis samples ranging from 228.76 and 214.62 mg QU/g and 137.02–122.13 mg GAE/g, respectively. In addition, antioxidant potential was confirmed highest in Himachal Pradesh propolis (HPP). Total antioxidant capacity (64.91 ± 0.27 mg Vit C/g), DPPH radical scavenging activity (94.76 ± 0.88 %), and FRAP (2.25 ± 0.05 mmol Fe 2+ /g) but lowest in Rajasthan propolis (RP). Further, HPLC estimated the highest concentration of beta-carotene (217.44 ± 0.58 mg/g) and galangin (184.63 ± 0.75 mg/g) in RP, whereas caffeic acid phenethyl ester (CAPE, 174.65 ± 0.84 mg/g) was highest in HPP samples. Moreover, the antioxidant potency of extracts was efficiently forecasted with TPC, TFC, CAPE, galangin, and beta-carotene concentration using the artificial neural network. Furthermore, principal component analysis recognized three principal components, revealed 98.1% of the variation and well established the dissimilarities in Indian propolis.