Abstract
Abstract In the present study, the optimized solvent extraction conditions with regards to the total polyphenol content (TPC) and antioxidant capacity of rosemary leaf extract (RLE) were determined. The one-factor-at-a-time method was used to independently investigate the effect of several extraction parameters, including ethanol concentration (0–100% v/v), extraction temperature (50–80°C), extraction period (15–60 min), material–solvent ratio (1:5–1:10 g/mL), and extraction cycles (1, 2, and 3 times) on polyphenol content. Response surface methodology (RSM), in combination with a central composite design, was used to perform optimization. The following optimal conditions that gave maximal TPC were determined and experimentally verified: ethanol concentration of 65% (v/v), extraction temperature of 65°C, material–solvent ratio of 1:7.5 g/mL, extraction time of 15 min, and 2 cycles of extraction. These parameters corresponded with the TPC yield of 87.42 ± 0.25 mg gallic acid equivalent/g dried feed material (mg GAE/g DW). The optimal conditions gave a high extraction yield (337 ± 6 mg dried extract/g dried feed material) with 197.28 ± 3.11 mg GAE/g dried extract. The estimated models were strongly significant (p < 0.05) for TPC values with significant regression coefficients (R 2) of 0.9979. The obtained RLE was supposed to be the top grade of natural antioxidant with the IC50 (DPPH assays) value of 9.4 ± 0.1 μg/mL, which is higher than that of the vitamin C by just three times (IC50 = 3.2 ± 0.1 μg/mL). Current results justify RLE as a potential agent in food preservation applications.
Highlights
Various examinations have shown that herbs have powerful antioxidant properties, because of the amount and nature of phenolic compounds present in them [1]
A total of 20 combinations consisting of eight factorial points, six axial points, and six center points were generated by central composite design (CCD)
Recovered from the extract at 60% of ethanol (56.5 mg gallic acid equivalent (GAE)/g DW) was significantly higher than those obtained at lower ethanol concentrations (30 and 0%)
Summary
Various examinations have shown that herbs have powerful antioxidant properties, because of the amount and nature of phenolic compounds present in them [1]. Rosemary has been acknowledged as the most noteworthy cancer prevention plant [2]. These antioxidant properties were identified with the presence of phenolic contents, accounting for the most majority rosmarinic acid (RA), carnosic acid (CA), and carnosol (COH) [3,4]. RLE has been proved to exhibit hepato-protective properties, suggesting the potential use in medicinal applications for treatment of maladies [6], Alzheimer’s malady [7], and angiogenesis-related diseases [8]. This work is licensed under the Creative Commons Attribution
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