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Clinical Safety of a High Dose of Enriched Phycocyanin Aqueous Extract from Arthrospira (Spirulina) platensis --Part1

- May 09, 2018 -

Clinical Safety of a High Dose of Enriched Phycocyanin  Aqueous Extract from Arthrospira (Spirulina) platensis: Results from a Randomized, Double-Blind, Placebo-Controlled Study with a Focus on Anticoagulant Activity and Platelet Activation


Part 1

Gitte S. Jensen,0,1 Cassandra Drapeau,Miki Lenninger,1 and Kathleen F. Benson1

1NIS Labs, Klamath Falls, Oregon, USA.

2Cerule LLC, Klamath Falls, Oregon, USA.

0Corresponding author.


The goal for this study was to evaluate safety regarding anticoagulant activity and platelet activation during daily consumption of an aqueous cyanophyta extract (ACE), containing a high dose of phycocyanin. Using a randomized, double-blind, placebo-controlled study design, 24 men and women were enrolled after informed consent, and consumed either ACE (2.3 g/day) or placebo daily for 2 weeks. The ACE dose was equivalent to ∼1 g phycocyanin per day, chosen based on the highest dose Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. Consuming ACE did not alter markers for platelet activation (P-selectin expression) or serum P-selectin levels. No changes were seen for activated partial thromboplastin time, thrombin clotting time, or fibrinogen activity. Serum levels of aspartate transaminase (AST) showed a significant reduction after 2 weeks of ACE consumption (P < .001), in contrast to placebo where no changes were seen; the difference in AST levels between the two groups was significant at 2 weeks (P < .02). Reduced levels of alanine transaminase (ALT) were also seen in the group consuming ACE (P < .08). Previous studies showed reduction of chronic pain when consuming 1 g ACE per day. The higher dose of 2.3 g/day in this study was associated with significant reduction of chronic pain at rest and when physically active (P < .05). Consumption of ACE showed safety regarding markers pertaining to anticoagulant activity and platelet activation status, in conjunction with rapid and robust relief of chronic pain. Reduction in AST and ALT suggested improvement in liver function and metabolism.

Key Words: :  phycocyanin, anticoagulant activity, blood pressure, chronic pain, liver enzymes, platelet, P-selectin


Cyanobacteria, or blue-green algae(spirulina), have survived and evolved over the last 3.5 billion years and are considered the evolutionary bridge between bacteria and green plants. Their adaptive ability to harvest sunlight through a broader light spectrum than most green plants, as well as their ability to utilize other forms of energy, has made these organisms well adapted to survive and inhabit diverse habitats hostile to other life forms.1,2 Edible cyanobacteria, including Spirulina platensis, Spirulina maxima, and Aphanizomenon flos-aquae, were introduced to the health food market in the late 1970s and have gained considerable popularity in the health food industry. The bright blue light-harvesting pigment phycocyanin, unique to cyanobacteria, is a known antioxidant and anti-inflammatory compound, in part, due to its ability to inhibit the inflammatory enzyme, cyclooxygenase-2 (COX-2).

3–5 Pharmaceutical inhibitors of COX enzymes, nonsteroidal anti-inflammatory drugs (NSAIDs), are commonly used anti-inflammatory medications for pain relief; however, their use is associated with side effects, including gastrointestinal discomfort and mucosal ulceration,6 and long-term use poses a risk for kidney disease especially in the hypertensive population.7 In contrast to the acute damage associated with NSAID intake, anti-inflammatory effects seem to provide a mild long-term benefit in the prevention of colorectal cancer.8 Some NSAIDs such as aspirin and ibuprofen, both nonspecific COX inhibitors, also have anticoagulant effects, which depending on dosage can be used prophylactically in the prevention of coagulopathy,9 or at higher doses are used for reducing pain and inflammation but can contribute significant gastrointestinal risks.6 Furthermore, conflicting evidence exists regarding whether the intake of NSAIDs is beneficial or detrimental to different types of bone- and joint-related diseases.10 An association has been suggested between intake of aspirin and the prevention of the progression of nontraumatic necrotic bone disease in young adults.11 In contrast, intake of NSAIDs in adults with different types of arthritis has been associated with negative impact on bone metabolism.12,13 Recent research warns that certain NSAID medications affect the gut–brain axis, triggering broad systemic, endocrine, and behavioral changes, including disturbances in heart rate, body temperature, and anxiety-like behavior.14

Seeking nonpharmaceutical interventions for chronic pain has led to an increasing attractiveness of natural products with COX-2 inhibiting properties.15–17 Spirulina's safety as a food has been established through centuries of human use, as well as through numerous toxicology studies.18,19 However, such safety data do not automatically vouch for the safety of extracts and purified compounds from Spirulina, and hence, further safety documentation is needed for such extracts.

There is a potential for natural compounds to provide more multifaceted biological effects. As an example, phycocyanin's bioactivity extends beyond its COX-2 inhibiting properties. Phycocyanin has been shown to activate Nrf2,20 and this may account for its effect on heme oxygenase-1 (HO-1).21 The activation of HO-1 may be secondary to Nrf2 activation, and Nrf2 activation could also contribute to activation of phase II enzymes in the liver and decreased liver enzymes.22 Phycocyanin contains an open-chain tetrapyrrole chromophore known as phycocyanobilin (PCB), with a chemical structure similar to that of biliverdin, susceptible to biliverdin reductase, giving rise to phycocyanorubin, an analog of bilirubin.23 PCB constitutes up to 1% of the dry weight of Spirulina, with higher free radical scavenging properties than intact phycocyanin,24 and strong protective properties in ischemia-induced inflammation,25 as well as in diabetic nephropathy.26 Consumed PCB may have a considerable potential for preventing or slowing the progression of a wide range of neurodegenerative disorders.27 These bioactivities of PCB may, in part, be explained by its potent inhibition of NADPH oxidase,23 which plays a key role in the generation of superoxide during the respiratory burst in neutrophils. Due to the inflammatory generation of free radicals by NADPH oxidase, it is a major cause of atherosclerosis, and NADPH oxidase inhibitors may reverse atherosclerosis.28 PCB also activates atheroprotective heme oxygenase-1 (HMOX1) in endothelial cells, and its multifaceted effects may represent an important mechanism of this food supplement for the reduction of atherosclerotic disease.29 The ability of HO-1 to catabolize free heme and produce carbon monoxide (CO) suggests that its anti-inflammatory properties involve upregulation of IL-10 and IL-1R antagonist expression.30

Specifically, due to the COX-2 inhibiting properties of phycocyanin, it may potentially interfere with blood clotting, at least when pure phycocyanin is introduced to molecular and cellular components of the blood clotting machinery in vitro. Purified phycocyanin from Spirulina fusiformis was tested for its effect on the fibrinolytic system in vascular endothelial cells in vitro, where phycocyanin increased the fibrinolytic activity in a dose-dependent manner.31 Purified phycocyanin is used for injection in medical imaging due to its fluorescent properties, and injectable phycocyanin may represent a potential pharmaceutical agent for the treatment of thrombosis due to its potent effects on multiple aspects of platelet activation, causing a reduction of platelet aggregation at nanomolar concentrations.32,33 In contrast, using the euglobulin fibrinolytic assay, we have previously reported that phycocyanin did not inhibit blood clotting in vitro, where clot formation and subsequent fibrinolysis were monitored in the absence versus presence of phycocyanin. Our data showed that phycocyanin contributed to the antioxidant properties and anti-inflammatory effects, without a negative impact on blood clotting in vitro; the time for clot formation and lysis was not affected.34

Whether the consumption of phycocyanin results in a measurable effect on components of the blood clotting molecular machinery in humans remained a pertinent safety question, and was the motivation for conducting the study reported here. Previous pilot studies on the phycocyanin-rich aqueous cyanophyta extract (ACE) used for the current study showed that the consumption of ACE at a dose of 0.25–1.0 g/day was associated with relief of chronic pain.35 In light of conflicting data from laboratory tests and the question of whether consumed phycocyanin could lead to anticoagulant effects in vivo, the goal for the study reported here was to document important safety parameters specifically pertaining to blood coagulation and platelet activation in a human population when ingesting a higher dose of 2.3 g ACE per day, corresponding to ∼1 g of phycocyanin per day.

Materials and Methods

Study design

A randomized, double-blind, placebo-controlled study design was used for this clinical study. Twenty-four people qualified for enrollment in the 2-week study on signing written informed consent, as approved by the Sky Lakes Institutional Review Board. The inclusion and exclusion criteria are shown in Table 1. The participants were randomized to receive either product or placebo for the 2-week study. The prescreening involved an interview to document gender, age, body mass index (BMI), medical/surgical history, diet/lifestyle, current health issues, medication, and supplement use. If subjects met these criteria, they were scheduled for a screening visit to evaluate electrocardiogram (ECG) and blood chemistry. Subjects who passed the prescreening interview and met the screening criteria were invited to participate and after signing an informed consent were enrolled in the study. The study was carried out during 2014/2015 through NIS Labs located in southern Oregon (United States), where study participants live and work at an elevation of 1200–1500 m above sea level.

Table 1. Phycocyanin Inclusion and Exclusion Criteria for the Study.jpg 


Consumable test products

The active consumable product for this study is an ACE, Cyactiv®, and is based on proprietary aqueous processing of Arthrospira platensis biomass, produced at Cerule LLC (Klamath Falls, OR, USA). Phycocyanin factory Zhejiang Binmei Biotechnology Co.,Ltd(Linhai, Zhejiang, China). The lot used for this study was obtained from Cerule LLC, where the extract Cyactiv is produced using a proprietary process involving aqueous extraction technology. The lot had ∼40% phycocyanin by weight, and also contained nonphycocyanin bioactive anti-inflammatory compounds.31 A color-matched placebo powder was made from rice flour. The ACE and placebo were encapsulated in vegetarian cellulose capsules and bottled in similar bottles. Subjects were instructed to return bottles with unused capsules at the study exit visit, and remaining capsules were used to document compliance.

Blood pressure

Blood pressure readings were performed using an Omron 741 or 742 monitor, and were scheduled at the same time of the day for each subject. At each study visit, blood pressure was measured two or three times at a sitting position after a 5-min rest, with at least a 3-min interval between each measurement. Subjects were asked not to smoke, eat, or exercise 1 h before their appointment, and all study participants adhered to the requirements of abstinence from exercise and nicotine and caffeine use for 1 h before a study visit.


At screening and the 2-week follow-up, a three-lead ECG was performed.

Blood collection

On each of the two study visits (baseline, 2 weeks), a blood sample was drawn. A complete blood count with differential count was performed, as well as blood chemistry. Additional serum samples were used for testing for activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen activity.

Platelet P-selectin expression

The level of platelet activation was evaluated by dual staining with the platelet marker CD42a (glycoprotein IX, which together with glycoprotein Ib, forms the receptor for von Willebrand factor) and CD62P. The CD62P selectin is a selectin-type cell adhesion molecule, residing in intraplatelet vacuoles until platelets are activated, after which CD62P is rapidly expressed on the platelet surface. Whole blood samples were stained with fluorescent anti-CD42a and anti-CD62P monoclonal antibodies (BD Biosciences, San Jose, CA, USA) and incubated for 20 min in the dark. Red blood cells were lysed using High-Yield Lyse (Life Technologies, Grand Island, NY, USA), vortexed, and incubated for 10 min. All samples were stained and analyzed in triplicate. Samples were acquired within 2 h using the acoustic aligning Attune® flow cytometer. Platelets and platelet-bound leukocytes were identified as CD42a-positive particles, and electronic gating on CD42a-positive particles was used to analyze platelets for CD62P fluorescence intensity.

Soluble P-selectin

Serum samples were tested in duplicate for soluble P-selectin using a Luminex magnetic bead-based kit (ProcartaPlex Human P-Selectin Simplex; Ebioscience, San Diego, CA, USA), performed according to the manufacturer's instructions. Samples were analyzed on the MAGPIX instrument (Luminex Corporation, Austin, TX, USA) using the xPONENT software (Version 4.2; Software Solution for Luminex, Hoorn, The Netherlands).

Coagulation markers

Plasma samples were tested for aPTT, TT, and fibrinogen activity at Machaon Diagnostic Laboratory (Oakland, CA, USA).

Pain assessment

The pain assessments at the baseline and the 2-week visits involved the scoring of pain levels in the areas of the body identified by each study participant as their primary and secondary area of pain limiting their daily activities. Scoring was performed using the visual analogue scales (VAS, 0–100), and subjects were asked to score their individual pain areas for pain levels when at rest and when physically active.

Statistical analysis

Average and standard deviation for each data set was calculated using Microsoft Excel. Statistical analysis of clinical data was performed as “between-group” comparison using the two-tailed, unpaired t-test. Statistical significance of changes from baseline to the 2-week assessment was evaluated by “within-subject” analysis using the two-tailed paired t-test. A trend was defined as P < .1. Statistical significance was defined as P < .05, and a high level of significance P < .01.


Demographics and compliance

The study population was predominantly female, with 19 women and 5 men distributed evenly between the placebo and ACE groups with no significant differences between the age and BMI between the two groups (Table 2). All subjects showed greater than 80% compliance, with an average compliance of 97%.


Table 2. Phycocyanin Demographics of Study Population.jpg 


Blood pressure

There were no statistically significant differences between the two groups regarding systolic and diastolic blood pressure at baseline or after 2 weeks. The consumption of ACE was associated with a mild reduction in diastolic blood pressure, but did not reach statistical significance within the 2-week study (P < .15). This effect was seen for both female and male study participants (Table 3).



Table 3.Phycoyanin Blood Pressure Results.jpg 



All study participants were screened to ensure a normal ECG before enrolling into the study. There were no changes in individual ECG readings after the 2-week study participation (data not shown).

Blood chemistry

The blood chemistry data showed a mild, but highly significant reduction in aspartate transaminase (AST) after 2 weeks of ACE consumption (P < .001), in contrast to placebo where no changes were seen; the difference in AST levels between the two groups was significant at 2 weeks (P < .02) (Fig. 1A). In addition, a reduction in alanine transaminase (ALT) was also seen in the group consuming ACE, however, the reduction did not reach statistical significance (P < .08) (Fig. 1B). A mild reduction in the A/G ratio was seen in the ACE group. A slight increase in blood CO2 was seen in the ACE group, in contrast to a slight decrease in the placebo group, resulting in a significant difference between the two groups' averages at 2 weeks; however, the changes were minor and well within the normal range. No other changes in blood chemistry were seen (Table 4).


Table 4. Phycocyanin Blood Chemistry.jpg

FIG. 1.Phycocyanin Serum levels of the two liver enzymes (A) AST and (B) ALT.jpg

FIG. 1.

Serum levels of the two liver enzymes (A) AST and (B) ALT are shown as the group averages ± standard error of the mean for baseline and 2-week samples from the group consuming the ACE (solid lines) versus placebo (dashed lines). A reduction was seen in the ACE group for both enzymes, where the change for AST reached a high level of statistical significance within the ACE group (##P < .01). The difference in AST levels between the ACE and placebo groups at 2 weeks was statistically significant (*P < .02). ACE, aqueous cyanophyta extract; ALT, alanine transaminase; AST, aspartate transaminase.

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