In vitro antioxidant and anti-inflammatory activity of the polyphenol complex from Habarlea rhodopensis

Bulgaria stands out in Europe for its abundance of resurgent plants thriving in the wild, with Haberlea rhodopensis being one such example from the Gesneriaceae family. The plant's noteworthy benefits stem from its leaf composition, particularly its polyphenolic components. To delve deeper, researchers fractionated the polyphenolic complex using solvents of varying polarity (hexane, chloroform, ethyl acetate, and butanol), and subsequently evaluated each fraction for potential biological activity.

The butanol and ethyl acetate fractions exhibited the highest concentrations of total phenols (841.12 and 797.58 mg GAE/g extract) and tannins (792.10 and 571.49 mg TAE/g extract). These fractions underwent scrutiny for antioxidant and anti-inflammatory properties, gauged through hydrogen peroxide scavenging activity and inhibition of albumin denaturation (IAD), respectively.

The antioxidant activity of the fractions ranged from 105.61 μg/mL to 486.73 μg/mL. Notably, polyphenols isolated with polar solvents (ethyl acetate, chloroform, and butanol) demonstrated significant antioxidant potential. In assessing the anti-inflammatory prowess, the inhibition of the albumin denaturation method was employed using human albumin. Standard ibuprofen and ketoprofen, known for their anti-inflammatory effects, were utilized for comparison. Their IC₅₀ values, estimated as IADs, were 81.50 μg/mL and 126.58 μg/mL, respectively. The IC₅₀ values for the H. rhodopensis fractions ranged from 143.89 to 307.87 μg/mL, indicating a comparatively lower degree of albumin protection.

Examining the polarity-based protection of albumin, the butanol, chloroform, and ethyl acetate fractions exhibited similar efficacy, surpassing that of hexane.