HPLC-UV analysis of phenolic compounds and biological activities of Padina pavonica and Zanardinia typus marine macroalgae species

The marine macroalgae species are recognized as the food of the future with excellent bioactive properties. This study aimed to investigate phenolic compounds; cytotoxic, antibacterial, and antioxidant activities; total phenolic (TPC) and flavonoid (TFC) contents of the methanol, ethanol, and water extracts of Padina pavonica (PP) and Zanardinia typus (ZT). To the best of our knowledge, this is the first report in which ZT was evaluated in terms of phenolic content, antioxidant, antibacterial, and cytotoxic activities. The HPLC analysis allowed the identification of five phenolic compounds containing rutin (0.31 ± 0.04 – 3.00 ± 0.21 ppm) in all extracts and trans-p-coumaric acid (0.15 ± 0.02 – 3.95 ± 0.02 ppm) in MPP, EPP, MZT, EZT, WZT as the major compounds. TPC and TFC of the extracts were calculated as 11.78 ± 0.75 – 76.78 ± 0.54 µg GAEs/mg extract and 6.78 ± 0.17 – 29.50 ± 2.23 µg QEs/mg extract, respectively. The highest cytotoxicity was observed in EZT (CC50:132.3 ± 22.4 µg/mL) against MCF-7 and MZT (CC50: 91.4 ± 20.9 µg/mL) against MIA PaCa-2. Among the studied extracts, EPP showed the best antibacterial activity against all test pathogens. Also, EPP indicated superior antibacterial activity against Plesiomonas shigelloides (MIC: 1.25 mg/mL) and Staphylococcus aureus (MIC: 1.25 mg/mL). EZT displayed the highest antioxidant activity in DPPH• (IC50: 49.03 ± 0.28 µg/mL), CUPRAC (A0.50: 15.20 ± 0.14 µg/mL), and ABTS•+ (IC50: 18.86 ± 0.74 µg/mL) assays. The results approved that P. pavonica and Z. typus marine macroalgae species could be valued as natural sources of bioactive agents for food and pharmacology applications.