Cancer
A considerable amount of research has been undertaken on various types of fucoidan and cancer (Lin, 2020, Jin, 2021). Some researchers have proposed that certain fucoidans not only increase patient wellbeing, but may also assist in the treatment of disease. The potential for some fucoidans as an anti-cancer agent is explored in several review publications, including those by Fitton (2015), Kwak (2014) and Lowenthal (2014).
Cancer cell cycles
Research confirms that some fucoidans have direct in vitro effects on cancer cells. Studies have shown that some cancer cells apoptose in the presence of fucoidan and may also enter a cell cycle arrest, making them unable to multiply (Chen, 2014). Immune cells also clear cancer cells and some fucoidans have been shown to enhance this effect in vitro (Jin, 2014). Whilst apoptosis pathways are not always identified, there is evidence to support the induction of both intrinsic and extrinsic apoptosis pathways. Studies have demonstrated the induction of these apoptosis pathways can be via the activation of ERK1/2 MAPK, the down-regulation of Wnt/beta-catenin signalling (Boo, 2013), the induction of caspase 8 in breast cancer cells (Yamasaki, 2012) and/or the induction of endoplasmic reticulum stress cascades (Chen, 2014). A fucoidan extract has also been shown to enhance the activity of chemotherapeutic agents against breast cancer cells (Zhang, 2013).
Tumour growth
A variety of animal models have demonstrated reductions in tumour growth when certain fucoidans have been administered orally, intravenously or intraperitoneally. The models have included blood, ovarian, breast, prostate, liver and head and neck cancers, as reviewed by Kwak (2014) and Fitton (2015). These studies have shown marked differences in the rate of growth of tumours when fucoidan extracts have been administered either intraperitoneally or orally. In one colon cancer model (Azuma, 2012), tumour weights were up to 6 times lower in fucoidan groups than the control group, and life span increased by up to 100%. Aside from direct inhibition and immune clearance of cancer cells, studies have also indicated that fucoidan extracted from Undaria pinnatifida inhibited angiogenesis (Yang, 2016), and that some fucoidan extracts can inhibit metastasis (Gassmann, 2010).
Quality of life
There is increasing interest in the potential of various fucoidans to improve quality of life and ameliorate the side effects of conventional cancer treatments. Research in this area has included pre-clinical studies involving the co-administration of fucoidan with common chemotherapies. Amongst these studies, high purity fucoidan from Marinova was shown to enhance anti-tumour activity of treatments using certain common chemotherapy agents in the models studied (Mathew, 2016). Both in vitro testing and human clinical studies have explored the pharmacokinetics of fucoidan produced by Marinova with common chemotherapies to establish the safety of these combined treatments (Tocaciu, 2016). In some patients, reduced side effects were also noted. In another study, colon cancer patients undergoing chemotherapy experienced reduced fatigue when taking a fucoidan extract and were able to tolerate more rounds of therapy (Ikeguchi, 2011). Ingesting certain fucoidan has also been shown to reduce cachexia in an animal model, the debilitating muscle wasting and fat loss that can often occur during cancer (Chen, 2016).
Research shows that fucoidan extracts may have the potential to assist in alleviating side effects that are common during chemotherapy treatment. In a clinical trial where fucoidan was administered to 20 patients with advanced cancer, proinflammatory cytokines, including interleukin-1β (IL-1β), interleukin- 6 (IL-6) and tumour necrosis factor-α (TNF-α) were significantly reduced (Takahashi, 2017). Fucoidan extracts have also been shown to reduce fatigue, both in a clinical study (Ikeguchi, 2011) and in a mouse model (Chen, 2015).
In a clinical study involving osteoarthritis patients, Marinova's Fucus vesiculosus fucoidan was shown to reduce joint pain (Myers, 2010). In a clinical breast cancer study, Marinova's Undaria pinnatifida fucoidan was also shown to reduce pain (Tocaciu, 2016). Animal studies have shown that various fucoidan extracts produced by Marinova were effective in reducing inflammation in the gut (Lean, 2015), addressing appetite reduction, skeletal muscle atrophy and systemic inflammation (Chen, 2016).