## 3 Results and Discussion  
### Antioxidant Contents  
Natural antioxidant compounds such as phenolic compounds, flavonoids, alkaloids, and vitamin C are not only found on land sources; reports show that algae are also rich in these natural antioxidants [31]. By scavenging ROS and free radicals, these antioxidants aid in the treatment of a variety of severe illnesses, including cancer, cardiovascular disease, and aging disorders [32]. Phenol is a compound widely present in almost all algae species and has a wide range of biological activities, including antioxidant properties [33].  
Figure 2 shows the total phenolic compound (TPC) and flavonoid contents of the four studied seaweeds. The _T. ornata_ showed the maximum value total phenols and flavonoid contents (14.14 \(\pm\) 0.1 mg GA/g DW and 9.98 \(\pm\) 0. 09 mg CE/g DW, respectively) while the red alga (_L. obtusa_) recorded the lowest value total phenols and flavonoid contents (7.83 \(\pm\) 0.14 mg GA/g DW and 4.78 \(\pm\) 0.05 mg CE/g DW, respectively). These results are consistent with those of [PERSON] and [PERSON] [34], who reported that total phenol and flavonoid contents of brown seaweeds _Colomenia sinuosa_ were high (56.45 and 12.13 mg/g DW, respectively) as compared to red seaweeds _Halymenia porphyoides_ (9.02 and 4.43 mg/g DW, respectively).  
Flavonoids are antioxidants, ROS scavengers, and lipid peroxidation inhibitors, as well as potential therapeutic agents for a wide range of illnesses. [35]. [PERSON] and [PERSON] [36] detailed that flavonoids have antihepatotoxic, mitigating, and antiulcer impacts other than ensuring against cardiovascular mortality.  
Red seaweeds _L. obtusa_ showed the highest ascorbic acid content (4.58 \(\pm\) 0.07 mg/100 g), followed by _S. scinaioides, P. indica_, and _T. ornata_ (3.25 \(\pm\) 0.02, 3.12 \(\pm\) 0.04, and 2.49 \(\pm\) 0.04 mg/100 g, respectively) (Figure 3). These results are in agreement with those of [PERSON] and [PERSON] [34], who proposed that red seaweed, _Halymenia porphyoides_, has a higher concentration of vitamin C (8.33 \(\mu\)g/g DW) than brown seaweed, _Colomenia sinuosa_ (0.0145 \(\mu\)g/g DW). The maximum content of \(\beta\)-carotene was detected in _T. ornata_ (2.1 \(\pm\) 0.06 mg/100 g) and the minimum content in _L. obtusa_ (0.51\(\pm\) 0.05 mg/100 g) (Figure 3). Similarly, [PERSON] et al. [37] found that \(\beta\)-carotene contents of brown seaweeds _Detyota dichotomous_ and _Turbinaria decurrens_ (1146.6 and 117.0 \(\mu\)g/g DW) were higher than those in red seaweed _Laurencia obtusa_ (45.5 \(\mu\)g/g DW).  
Figure 2: Total phenol compound (mg GA/g DW, (**A**)) and flavonoid content (mg CE/g DW, (**B**)) for studied seaweeds. Values are the mean of three replicates \(\pm\) standard deviations (SD). Different letters refer to significant differences between species (\(p<0.05\)).  
Vitamin C is a significant cancer prevention agent that aids in the development and fix of an assortment of body tissues, including ligaments, bones, ligaments, tendons, and teeth. Normal cancer prevention agents present in higher plants, such as nutrients, polyphenols, and \(\beta\)-carotene, were used to trap receptive oxygen species (ROS) that cause lipid peroxidation. These substances are now employed in the food industry to protect the human body from free radicals and to prevent a variety of chronic diseases.  
Many studies have found that natural beta caroten sources should be used to reduce free radical damage, which contributes to reducing the effects of aging and prevents cancer [12].