Abstract

Background:
Crocus sativus L., globally recognized as saffron, transcends its traditional culinary utility to emerge as a cornerstone of contemporary pharmacological research. Recent scientific inquiry has pivoted toward its intricate profile of bioactive secondary metabolites, which are increasingly scrutinized for their robust therapeutic potential and their role as pivotal agents in neutralizing oxidative stress.

Aim:
The primary objective of this investigation was to systematically evaluate the antioxidant efficacy of saffron stigma extracts while providing a rigorous quantitative assessment of total phenolic content (TPC) and total flavonoid content (TFC) as a function of diverse solvent polarities.

Methods:
Crocus sativus L. stigmas were subjected to solid-liquid extraction employing a polarity-based gradient consisting of four solvent systems: aqueous methanol (50% v/v), aqueous propanol (50% v/v), ethyl acetate, and chloroform. The radical scavenging potential of the resulting extracts was evaluated via the 2,2-diphenyl-1-picrylhydrazyl assay. Furthermore, the quantitative determination of TPC and TFC was conducted using the Folin-Ciocalteu and aluminum chloride colorimetric protocols, respectively.

Results:
The results indicated that the extraction efficiency of bioactive metabolites from C. sativus L. was significantly influenced by solvent polarity. The 50% methanolic extract demonstrated the highest phytochemical recovery, yielding a maximum mean TPC of 4,822.6 ± 145.2a μg GAE/g and a TFC of 2,210.0 ± 88.4a μg QE/g, with an extraction yield of 1.50%. In stark contrast, the chloroform extract exhibited the lowest extraction yields, with 1,411.9 ± 56.5 d μg GAE/g for TPC and 271.1 ± 10.8 μg QE/g for flavonoid content, alongside the minimum overall yield (0.53%). This quantitative superiority was directly reflected in the antioxidant capacity of the extracts. Specifically, the 50% methanolic extract displayed the most potent radical scavenging activity, characterized by the minimum IC50 value of 6.98 ± 0.3a μg/ml. Conversely, the chloroform extract demonstrated the weakest antioxidant potential, recording the maximum IC50 value of 10.20 ± 0.6c μg/ml. These findings substantiate a robust linear correlation between the recovery of polar phenolic fractions and the resultant antioxidant potency, indicating that phenolic concentration is a primary determinant of radical scavenging efficiency.

Conclusion:
These findings validate the intrinsic dependency of antioxidant potency on phenolic density, demonstrating that the scavenging efficiency is a direct function of the successful recovery of polar secondary metabolites during the extraction process.

Key words: Crocus sativus L.; DPPH assay; Total phenolic content; Total flavonoid content; Solvent polarity; IC50.