The extensive use of glyphosate (N-(phosphonomethyl) glycine) herbicide in agriculture is accompanied by the risk of environmental contamination of aquatic ecosystems. In this study, the effects of glyphosate at different concentrations (50–500 µg ml-1) on three Chlorella species including Chlorella ellipsoidea, Chlorella sorokiniana and Chlorella vulgaris especially in relation to the biomass, pigment contents and photosynthetic efficiency were assessed. After treatment for 24 hr, the acute toxicity results showed that C. vulgaris (IC50 = 449.34 ± 6.20 µg ml-1) was more tolerant to glyphosate than C. ellipsoidea (IC50 = 288.23 ± 23.53 µg ml-1) and C. sorokiniana (IC50 = 174.28 ± 0.50 µg ml-1). After a 72-hr chronic toxicity treatment with glyphosate, glyphosate concentrations decreased to 400–500 µg ml-1 in C. ellipsoidea, 200–300 µg ml-1 in C. sorokiniana and 200–500 µg ml-1 in C. vulgaris respectively. During 24-hr acute toxicity exposure to glyphosate, the pigment contents and maximum quantum efficiency of photosystem II (Fv/Fm) decreased as the concentration of glyphosate increased. Overall, the biomass, pigment contents and photosynthetic efficiency presented a high positive correlation. It is worthwhile to mention that our study provides detailed information on the toxicity and sensitivity of these Chlorella species to glyphosate.

Microalgae represent promising biotechnological platforms for bioactive compound production with pharmaceutical applications. This study investigated the phytochemical composition and biological activities of lipid extracts from three Chlorella species to evaluate their potential as antioxidant and antidiabetic sources. Lipid extraction using chloroform–methanol (2:1) followed by GC–MS analysis revealed distinct compound distributions: 29 compounds in C. ellipsoidea, 33 in C. sorokiniana, and 19 in C. vulgaris. Major bioactive compounds included 2-hexanol, 1,3,6-heptatriene, 4-(2,3-dimethyl-2-cyclopenten-1-yl)-4-methylpentanal, n-hexadecanoic acid, and octadecanoic acid. Biological activity screening encompassed antioxidant assessment through DPPH• and •NO radical scavenging assays and FRAP analysis, while antidiabetic potential was evaluated using α-glucosidase and α-amylase inhibition assays. C. sorokiniana exhibited superior bioactivity with the highest antioxidant capacity (DPPH• IC₅₀ = 329.03 ± 4.30 µg/mL; •NO IC₅₀ = 435.53 ± 10.20 µg/mL; FRAP = 94.74 ± 5.72 mg TE/g) and strongest enzyme inhibition (α-glucosidase IC₅₀ = 752.75 ± 57.95 µg/mL; α-amylase IC₅₀ = 3458.50 ± 104.01 µg/mL). This is the first report on C. sorokiniana strain KU.B2′s biological properties and phytochemical profile. These findings establish C. sorokiniana as a valuable biotechnological platform for pharmaceutical bioactive compound development.

Microalgae are a potentially valuable source in the food, pharmaceutical and nutraceutical sectors. While biological activities surveys have investigated the pharmaceutical properties of a few microalgae species, there are not many reports covering biological activity studies. This study was carried out to identify the metabolites by gas chromatography-mass spectrometry and evaluate the anti-oxidant, anti-diabetic properties of green algae extracts, Chlorella sorokiniana (KU.B2) and Scenedesmus falcatus (KU.B1). A total of 51 different chemical constituents were detected and tentatively identified. The primary compounds in both microalgae extracts included (R)-2-hexanol (38.67% in C. sorokiniana and 23.53% in S. falcatus), n-hexadecanoic acid (13.58% in C. sorokiniana and 18.94% in S. falcatus) and octadecanoic acid (22.30% in C. sorokiniana and 32.67% in S. falcatus). According to the profiling results, the C. sorokiniana extract exhibited greater anti-oxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC50 = 480.30 ±?14.85 µg ml-1), nitric oxide (NO) radical scavenging (562.73 ±?3.52 µg mL-1) and ferric reducing anti-oxidant power (FRAP) of 58.51 ± 2.42 mgTE g-1. Comparatively, the C. sorokiniana extract had higher contents of alpha-glucosidase and alpha-amylase (IC50 = 491.22 ± 78.41 and 2,817.00 ±143.04 µg mL-1, respectively) than the S. falcatus extract. This first report demonstrated anti-diabetic effect of both extracts on diabetic enzymes. The results confirm microalgae's anti-oxidant and anti-diabetic properties and suggest their potential benefits in cosmeceutical, nutraceutical and pharmaceutical applications.