Bioavailability of carotenoids from chlorella powder in healthy subjects: A comparison with marigold petal extract

In Vitro α-Amylase and α-Glucosidase Inhibitory Effects, Antioxidant Activities, and Lutein Content of Nine Different Cultivars of Marigold Flowers (Tagetes spp.)

Marigolds (Tagetes spp.) are major sources of bioactive compounds. The flowers are used to treat a variety of illnesses and have both antioxidant and antidiabetic effects. However, marigolds exhibit a wide range of genetic variations. Because of this, both the bioactive compounds and biological activities of the plants differ between cultivars. In the present study, nine marigold cultivars grown in Thailand were evaluated for their bioactive compound content, as well as for their antioxidant and antidiabetic activities, using spectrophotometric methods. The results showed that the Sara Orange cultivar possessed the highest total carotenoid content (431.63 mg/100 g). However, Nata 001 (NT1) had the highest amount of total phenolic compounds (161.17 mg GAE/g), flavonoids (20.05 mg QE/g), and lutein (7.83 mg/g), respectively. NT1 exhibited strong activities against the DPPH radical and ABTS radical cation, and had the highest FRAP value as well. Moreover, NT1 demonstrated the most significant (p < 0.05) α-amylase and α-glucosidase inhibitory effects (IC₅₀ values of 2.57 and 3.12 mg/mL, respectively). The nine marigold cultivars had reasonable correlations between lutein content and the capacity to inhibit α-amylase and α-glucosidase activities. Hence, NT1 may be a good source of lutein; it may also be beneficial in both functional food production and medical applications.

A Single Dose of Marine Chlorella vulgaris Increases Plasma Concentrations of Lutein, β-Carotene and Zeaxanthin in Healthy Male Volunteers

The beneficial health effects of Chlorella vulgaris have been associated with the presence of several nutrients and antioxidants, including carotenoids. However, the in vivo bioavailability of Chlorella is still poorly evaluated. In this work, a human intervention study was conducted in 11 healthy men to evaluate the bioavailability of carotenoids within 3 days after the intake of a single dose (6 g) of dried marine Chlorella vulgaris containing lutein (7.08 mg), β-carotene (1.88 mg) and zeaxanthin (1.47 mg). Subjects were instructed to follow a low carotenoid diet during the experimental phase, starting 1 week earlier. On the day of the experiment, dried microalgae formulated in vegetarian hard capsules were ingested, and blood samples were collected up to 72 h for the analysis of plasma carotenoids concentration by high-performance liquid chromatography with diode-array detection. For all carotenoids, the estimated AUC and C_max values were significantly different from zero (p < 0.05), indicating that a single dose of marine Chlorella vulgaris increased plasma concentrations of lutein (C_min-corrected AUC = 1002 µg·h/L, C_max = 20.4 µg/L), β-carotene (AUC = 1302 µg·h/L, C_max = 34.9 µg/L) and zeaxanthin (AUC = 122.2 µg·h/L, C_max = 3.4 µg/L). The bioavailability of other compounds, namely, polyunsaturated fatty acids and trace elements, was also assessed post-prandial for the first time, showing that linoleic acid, docosahexaenoic acid and iodine were absorbed after microalgae intake. These findings support the use of Chlorella vulgaris as a source of carotenoids, PUFA and essential trace elements with associated health benefits.

Nano based lutein extraction from marigold petals: optimization using different surfactants and co-surfactants

Nanotechnology has high potential in processing of industrial crops and by-products in order to extract valuable biological active compounds. The present study endeavored to take advantage of nanotech approach (i.e microemulsion, ME), as a novel green technique, for lutein extraction from marigold (Tagetes erecta) as an industrial crop. The pseudo-ternary phase diagrams confirmed the effect of surfactant type on the formation of mono-phasic lutein MEs. The combination of sucrose monopalmitate:1-poropanol (1:5) showed the highest efficiency in the presence of marigold petal powder (MPP, 18%) and water (42%). In addition, the efficiency of primitive MEs (without co-surfactants) was outstandingly increased as MPP was moistened by co-surfactants. Furthermore, different MEs resulted in various droplet size (14–250nm), PDI (0.05–0.32) and zeta potential (−1.96 to −38.50 mV). These findings revealed the outstanding importance of the surfactants and co-surfactants and their ratio on the extraction capability of MEs. These findings also proved the capability of microemulsion technique (MET) as a potential alternative to conventional solvent with possible applicability for extraction of lutein and other industrial plant based bio-compounds.

A dietary cholesterol challenge study to assess Chlorella supplementation in maintaining healthy lipid levels in adults: a double-blinded, randomized, placebo-controlled study

Background

Previous animal studies suggested that Chlorella, a unicellular green alga, has a preventive role in maintaining serum cholesterol levels against excess dietary cholesterol intake. This study aimed to conduct a pioneering investigation to clarify this issue in healthy subjects by adopting a dietary cholesterol challenge, which has not been used previously in similar studies of Chlorella in hypercholesterolemia.

Methods

In this double blind, randomized, placebo-controlled study, 34 participants ingested 510 mg of dietary cholesterol from three eggs concomitantly with a usual dose of Chlorella (5 g/d) or a matched placebo for 4 weeks.

Results

The dietary cholesterol challenge induced consistently higher concentrations of serum total cholesterol (TC, P < 0.001), LDL-C (P = 0.004), and HDL-C (P = 0.010) compared with baseline values, suggesting that the challenge was reliable. Thus, we observed a preventive action of Chlorella in maintaining serum TC versus placebo levels (3.5 % versus 9.8 %, respectively; P = 0.037) and LDL-C versus placebo levels (1.7 % versus 14.3 %, respectively; P = 0.012) against excessive dietary cholesterol intake and in augmenting HDL-C versus placebo levels (8.3 % versus 3.8 %, respectively). Furthermore, serum α-carotene showed the best separation between the placebo and Chlorella groups (R²X and R²Y > 0.5; Q² > 0.4).

Conclusion

The results suggest that a fully replicated dietary cholesterol challenge may be useful in assessing the effectiveness of dietary supplements in maintaining the serum lipid profiles of adults whose habitual diets are high in cholesterol.

Trial registration

WHO International Clinical Trials Registry Platform (KCT0000258)