Chlorella Microalgae: A Green Treasure to Fight Oxidative Stress and Diabetes?

Microalgae are emerging as biotech stars, and Chlorella takes the spotlight in a recent study. Researchers extracted lipids from three species – C. ellipsoidea, C. sorokiniana and C. vulgaris – using a chloroform‑methanol mix, then analyzed them by GC‑MS. They identified 29, 33 and 19 compounds respectively, including 2‑hexanol, 1,3,6‑heptatriene, n‑hexadecanoic acid and octadecanoic acid, known for bioactive properties.\n\nTo test antioxidant effects, they performed DPPH•, •NO and FRAP assays. C. sorokiniana stood out, showing the highest radical‑scavenging capacity (IC50 DPPH• = 329 µg/mL, IC50 •NO = 436 µg/mL) and the highest FRAP value (94.7 mg TE/g).\n\nAntidiabetic activity was assessed with α‑glucosidase and α‑amylase inhibitors. Again, C. sorokiniana delivered the best results (IC50 α‑glucosidase = 753 µg/mL, α‑amylase = 3459 µg/mL). These data suggest that its lipids can modulate enzymes involved in carbohydrate digestion, offering potential support for glucose management.\n\nIn short, the research confirms that Chlorella, especially C. sorokiniana, is a promising platform for natural compounds with antioxidant and antidiabetic properties, paving the way for new ingredients in supplements or medicines.

Lipid extraction using the chloroform‑methanol (2:1) method is a classic approach to recover both phospholipids and triglycerides from microalgal cells. Subsequent GC‑MS analysis separates volatile compounds and identifies them by matching mass spectra libraries. Among the 29‑33 detected compounds, saturated fatty acids (n‑hexadecanoic, octadecanoic) and short‑chain alcohols (2‑hexanol) stand out, known for their electron‑donating ability to interrupt free‑radical chains.\n\nThe antioxidant mechanism of Chlorella lipids primarily involves neutralizing DPPH• and •NO radicals, two highly reactive species that, in excess, damage proteins, DNA, and cellular membranes. FRAP (Ferric Reducing Antioxidant Power) assays measure the capacity of compounds to reduce Fe³⁺ to Fe²⁺, an overall reducing‑power indicator. The high FRAP values observed for C. sorokiniana indicate a rich presence of molecules with –OH or –COOH functional groups capable of electron donation.\n\nRegarding antidiabetic activity, α‑glucosidase and α‑amylase inhibitors interfere with polysaccharide breakdown into glucose, slowing post‑prandial glycemic absorption. Certain medium‑chain fatty acids, such as capric acid, can bind to the enzymes' active sites, altering their conformation. The presence of unsaturated compounds and terpenes (e.g., 1,3,6‑heptatriene) may increase affinity for the enzymes' hydrophobic regions, enhancing inhibition.\n\nFrom a biotechnological perspective, cultivating C. sorokiniana in photobioreactors allows optimization of lipid production by adjusting light, nutrients, and temperature. Using genetically engineered strains or applying controlled stress conditions (e.g., nitrogen limitation) can boost synthesis of specific fatty acids or terpenes, further improving bioactivity. These strategies enable scalable industrial processes with potential applications in nutraceutical, cosmetic, or pharmaceutical formulations, where product naturalness and sustainability are increasingly demanded.\n\nIn summary, the combination of a rich, diversified lipid profile together with proven antioxidant and digestive‑enzyme‑inhibiting activities makes C. sorokiniana an ideal platform for developing new functional ingredients, offering potential benefits for human health and the environment.