The current study estimated the antioxidant activity and biochemical composition of four seaweeds; Toania atomaria (Phaeophyta), Padina pavonia (Phaeophyta), Jania rubens (Rhodophyta) and Corallina elongate (Rhodophyta). The highest total antioxidant activity was observed with ethanol extract of T. atomaria (44.6 ± 1.6 mg ascorbic acid equivalents/g crude extract). Among the four seaweeds, ethanol extract of T. atomaria has recorded the highest value in ferric reducing antioxidant power (FRAP) assay (32.3 ± 0.0 mg ascorbic acid equivalents/g crude extract). The uppermost level of carbohydrates was (20.4% ± 0.4 and 19.5% ± 0.7 dry wt.) in P. pavonia and T. atomaria. Proteins were maximum (10.5% ± 0.6 and 8.0% ± 0.0 dry wt.) in P. pavonia and T. atomaria. The results detected that T. atomaria had the largest amounts of lipids (5.92% ± 0.09 dry wt.). The polyunsaturated ω6 essential fatty acids were recorded in T.atomaria, P. pavonia, and J. rubens (11.39%, 8.09%, and 6.28%), and ω3 essential fatty acids were recorded in T. atomaria and P. pavonia (0.65% and 0.97%). The seaweeds are interesting candidates for medicinal, pharmaceutical, and nutritional applications owing to their antioxidant activities, biochemical composition; they are not widespread in the coastal waters of Egypt and has few studies, especially T. atomaria.

This study aims to evaluate the secondary metabolites, cytotoxicity, antioxidant, antidiabetic, anti-inflammatory, and anticancer activities of four selected seaweeds Padina pavonica, Taonia atomaria, Jania rubens, and Corallina elongata. The maximum value of phenolic content (176.7 ± 6.9 mg gallic acid equivalents/g crude extract) and tannin content (26.5 ± 4.3 mg tannic acid equivalents/g crude extract), was shown in the methanol extract of J. rubens and P. pavonica, respectively. While the ethanol extract of T. atomaria recorded the highest values of total flavonoid content (374.1 ±27.4 mg quercetin equivalents/g crude extract) and total saponins content (30.2 ± 0.7 mg cholesterol equivalents/g crude extract, respectively) compared to other seaweeds. Methanol extract of J. rubens and C. elongata exhibited the greatest content of alkaloids (25.8 ± 4.4 and 22.7 ± 2.6 mg/g d wt.). The methanol extract of P. pavonica established the highest DPPH radical scavenging activity (55.7% ± 0.1) at 50 μg/mL. Among the selected seaweed extracts, the ethanol extract of T. atomaria demonstrated the maximum α-amylase inhibition capacity (66.3% ± 0.0). Methanol extract of J. rubens and P. pavonica species effectively prevented the hypotonicity-induced haemolysis in a concentration-dependent manner compared with the diclofenac potassium as a standard anti-inflammatory drug. In vitro, the reported results also supported the safety and non-toxicity of the four seaweed extracts on WI-38 cell line at lower concentrations. J. rubens and P. pavonica methanol extracts recorded the highest cell growth inhibition of the HeLa Cancer Cell Lines compared to other seaweed extracts and the standard drug Cisplatin.

Marine seaweeds are important sources of drugs with several pharmacological characteristics. The present study aims to evaluate the antitumor and antitumor immunological potentials of the extracts from the brown alga Padinapavonica and the red alga Janiarubens, inhibiting the Egyptian marine coasts. Hep-G2 cell lines were used for assessment of the antitumor efficacy of Padinapavonica and Janiarubens extracts in vitro, while Ehrlich ascites carcinoma (EAC) cells were applied to gain more antitumor immunity and antitumor insights of P.pavonica and J.rubens extracts in vivo. In vitro antitumor potentials of P.pavonica and J.rubens extracts were analyzed against human liver cancer Hep-G2 cells by MTT and trypan blue exclusion assays. In vivo antitumor immunological potentials of P.pavonica and J.rubens extracts at low, high, and prophylactic doses were analyzed by blood counting and flow cytometry in mice challenged with Ehrlich ascites carcinoma (EAC) cells. In vitro results revealed that P.pavonica and J.rubens extracts caused significant decreases in the number and viability of Hep-G2 cells in a dose-dependent manner as compared to untreated Hep-G2 cells or Cisplatin®-treated Hep-G2 cells. In vivo findings showed that P.pavonica and J.rubens extracts at low, high, and prophylactic doses significantly reduced the number and viability of EAC tumor cells accompanied by increases in EAC apoptosis compared to naïve EAC mouse. Additionally, P.pavonica and J.rubens extracts at low and prophylactic doses remarkably increased both the total WBC count and the relative numbers of lymphocytes and decreased the relative numbers of neutrophils and monocytes. Flow cytometric analysis showed that P.pavonica and J.rubens extracts at the treatment and the prophylactic doses resulted in a significant increase in the phenotypic expressions of CD4+ T, CD8+ T, and CD335 cells compared to naïve EAC mouse. Overall, both extracts P.pavonica and J.rubens possess potential antitumor and antitumor immunological effects with less toxicity, opening new approaches for further studies of the chemical and biological mechanisms behind these effects.

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