Acute myeloid leukemia is a horrible hematological disorder. Although many patients with AML receive common remedies, their side effects might impress survival chances (
Degos et al., 1990). In decades, brown algae have been used in the health and production of medicines (
Fitton et al., 2015;
Choo et al., 2016;
Nagamine et al., 2009;
Yuan et al., 2015). Fucoidan is a sulfated polysaccharide extracted from brown algae and has been recognized as a promising medicine for preventing and treating diseases like cancer (
Wei et al., 2015). First, the present study investigated the anti-cancer property extracted from native Persian Gulf algae,
Sargassum angustifolium. The previous studies have been shown the effects of standard fucoidan inhibition activities on PC-3 cell line at a concentration of 10 μg/mL to 100 μg/mL (
Boo et al., 2013), MCF-7 cell line at a concentration of 80 μg/mL to 820 μg/mL (
Zhang et al., 2011) and U937 cells at a concentration of 20 μg/mL to 100 μg/mL (
Park et al., 2013). The FSA extracted from the native species of
Sargassum angustifolium had an inhibitory effect at concentrations of 62.5 μg/mL, 125 μg/mL, 250 μg/mL, 500 μg/mL, 1 000 μg/mL, and 2 000 μg/mL on the proliferation of NB4 cells. This was similar to the effects of the fucoidan inhibitors of other species. Based on the obtained results, FSA acted in a dose and time-dependent manner, inhibiting growth and inducing apoptosis. The greatest inhibitory effect of FSA was observed at a concentration of 2 000 μg/mL at 72 h when cell growth was zero. With concentration reduction, the inhibitory effect of FSA decreased. Therefore at concentration of 62 µg/mL, IC
50 was (40±0.023 9) μg/mL and (37±0.116 1) μg/mL within 48 h and 72 h, respectively. In comparison to
Jin et al. (2010), fucoidan at a concentration of 62 µg/mL caused cell death, while in the study of Jin, the concentration of 150 µg/mL resulted in cell cycle arrest within 48 h. However, the cell death rate in this study was similar to those reported by
Jin et al. (2010). In the meantime, multiple gene families play a role in maintaining or induction of apoptosis (
Saitoh et al., 2009). Fucoidan, as previously described, induces apoptosis by various mechanisms, including activation of caspases and activation of mitochondrial signaling pathways (
Park et al., 2013,
2015). In this study, the effect of fucoidan on the expression of
p53, p21, and
p15 pro-apoptotic genes showed that fucoidan at 62 µg/mL increased
p53,
p21, and
p15 genes expression within 24 h. Also, in this concentration, the expression of the
Bcl-2 gene decreased, which is an apoptotic inhibitor gene. The results indicated that the treatment of NB4 cells with FSA increased the expression of
p53 and
p21 genes that activated the mitochondrial pathway of apoptosis, and this was similar to the results of the work by
Jin et al. (2010). Also, they indicated that in the NB4 cell line, fucoidan has a strong apoptotic effect. By increasing
p15 expression, cellular arrest in the G
0/G
1 phases increases, and
Bcl-2 expression reduction happens, which prevents its anti-apoptotic effect (
Jin et al., 2010). In this study, the expression level of the
Dnmt1, the responsible gene for DNA methylation, decreased, which also has an inhibitory effect on tumor suppressor genes.
Yan et al. (2015) have also reported that fucoidan might suppress the expression of methylation genes. The correlation analysis of the present study showed an inverse relationship between the expression of
Dnmt1 and
p53 under the influence of FSA. In the study conducted by Wong et al., the oncogenic effect of the
Dnmt1 gene on inhibition of tumor suppressor genes in AML has been described (
Wong et al., 2019). According to
Fig. 3, it seems that diminished expression of
Dnmt1 treated with FSA increased
p53 gene expression and downstream of the
p21 gene. Due to the assessment of the FSA effect on PBMC, it was found that FSA had no effect on normal cells and even stimulated normal cell growth. A study by Dinesh et al. had not reported any adverse effects of fucoidan on PBMC (
Wong et al., 2019). It has also been reported by Yang and colleagues that fucoidan induced mononuclear cell maturation (
Yang et al., 2008). Irhimeh indicated that oral use of fucoidan increased CD
34+ as a marker of T-cell growth (
Irhimeh et al., 2007). Since the hemolysis rate should be in the range of 10% to 100% (
Devi et al.,2014), the study of the effect of fucoidan on RBC lyses of fucoidan did not cause in the specified concentrations. Further study by
Veena et al. (2007) explained increasing RBC unity and decreased membrane damage due to increased oxalate. Activation and enhancement in
p53 expression indicate that fucoidan is an apoptotic component through mitochondrial pathways. Some investigations have reported the independent relation of
p53 mediated apoptosis, but as shown in the present study, fucoidan increased the expression level of
p53 in cancer cells. However, it has to be determined whether the fucoidan directly induces DNA damage in the S phase, leading to cell arrest, or whether it interferes with DNA regeneration by destroying the replication. These data indicated that the anti-cancer activity of fucoidan occurs through multiple pathways. Therefore, the fucoidan of
Sargassum angustifolium, native to the Persian Gulf, could be suggested as a promising treatment for APL. It can be concluded that FSA was a complex molecule with a similar structure to the standard fucoidan and was capable of absorbing free radicals comparing to ascorbic acid. For the first time, the present study elucidated the anti-cholinesterase properties of the Persian Gulf brown seaweed
Sargassum angustifolium. This study suggested that FSA had powerful AChE inhibitory activity, which may help prevent or slow down AD progress. The reason for their potential ChEI activity was plastoquinones and farnesylacetone derivatives (
Choi et al., 2007;
Natarajan et al., 2009). However, further research is underway to isolate the active compounds responsible for different biological activities of the native Persian Gulf
Sargassum angustifolium.