# Green extraction approach for green microalga Tetraselmis tetrahele: Enhanced phenolic yield and bioactivity via Ultrasound-Assisted extraction **Authors:** Tao Mai, Norazira Abdu Rahman, Swee Yun Pang, Jian Ping Tan, Sook Chin Chew PMC · DOI: 10.1016/j.ultsonch.2026.107774 · Ultrasonics Sonochemistry · 2026-02-12 ## TL;DR This study shows that using ultrasound-assisted extraction improves the yield and bioactivity of phenolic compounds from a green microalga, making it a promising method for producing high-value natural products. ## Contribution The study introduces ultrasound-assisted extraction as a green and scalable method for maximizing phenolic compound yield from Tetraselmis tetrahele. ## Key findings - Ultrasound-assisted extraction significantly increased phenolic and flavonoid content compared to maceration. - The UAE method enhanced anti-collagenase activity and photosynthesis pigment levels in microalgal extracts. - Extraction parameters like solvent composition and time were optimized for maximum bioactive yield. ## Abstract Microalgae are gaining attention as promising natural sources of bioactives due to their rich nutrient content. This study investigates the effects of ultrasound-assisted extraction (UAE) parameters (i.e., solvent composition, temperature, solid-to-solvent ratio, and time) on the extraction of phenolic compounds from Tetraselmis tetrahele. The UAE parameters were determined at a solid-to-solvent ratio of 1:75, a temperature of 25 °C, and an extraction time of 15 min with 75% ethanol as the solvent. Phenolic profile, total phenolic content, total flavonoid content, radical scavenging activity of DPPH and ABTS, photosynthesis pigment (chlorophyll a, b, and total carotenoid), anti-collagenase activity, and metabolic profile of Tetraselmis tetrahele extract obtained using UAE were determined. Tetraselmis tetrahele extracts obtained using the selected UAE method demonstrated significantly higher (p < 0.05) levels in gallic acid (1.81%), 4-hydroxybenzoic acid (7.0%), total phenolic content (84.0%), total flavonoid content (56.2%), ABTS (101.3%), chlorophyll a (119.4%), chlorophyll b (174.3%), total carotenoids (173.2%) and anti-collagenase activity (15.9%) compared to the maceration method. These findings provide UAE as a green and scalable method for maximizing the phenolic yield and support the application of Tetraselmis tetrahele in the development of high-value products across pharmaceutical, cosmetic, and functional food industries. ## Linked entities - **Chemicals:** gallic acid (PubChem CID 370), 4-hydroxybenzoic acid (PubChem CID 135), ethanol (PubChem CID 702) ## Full-text entities - **Diseases:** ND (MESH:C537849), cancer (MESH:D009369), inflammation (MESH:D007249) - **Chemicals:** oleamide (MESH:C029407), 4-hydroxybenzoic acid (MESH:C038193), essential amino acids (MESH:D000601), 1,10-phenanthroline (MESH:C025205), acetic acid (MESH:D019342), vitamin C (MESH:D001205), phytosphingosine (MESH:C012491), ethanol (MESH:D000431), hydroxyl radicals (MESH:D017665), water (MESH:D014867), EPA (MESH:D015118), carotenoid (MESH:D002338), alpha-linolenic acid (MESH:D017962), kaempferol (MESH:C006552), ferulic acid (MESH:C004999), catechin (MESH:D002392), terpenoid (MESH:D013729), polysaccharides (MESH:D011134), omega-3 fatty acids (MESH:D015525), quercetin (MESH:D011794), nitrogen (MESH:D009584), acetonitrile (MESH:C032159), DPPH (MESH:C004931), chlorophyll (MESH:D002734), Ala (MESH:D000409), methanol (MESH:D000432), silicate (MESH:D017640), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (MESH:C010643), Potassium acetate (MESH:D019347), embelin (MESH:C010945), glycerophospholipids (MESH:D020404), oxygen (MESH:D010100), vanillic acid (MESH:D014641), Gallic acid (MESH:D005707), Campesteryl ferulate (MESH:C584530), chlorophyll b (MESH:C037184), PVDF (MESH:C024865), tryptophan (MESH:D014364), caffeic acid (MESH:C040048), hydrogen (MESH:D006859), chlorogenic acid (MESH:D002726), flavonoid (MESH:D005419), protocatechuic acid (MESH:C009091), AlCl3 (MESH:D000077410), astaxanthin (MESH:C005948), DHA (MESH:D004281), lipid (MESH:D008055), lactone (MESH:D007783), beta-carotene (MESH:D019207), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (MESH:C002502), Sodium carbonate (MESH:C005686), p-coumaric acid (MESH:C495469), triterpenoid (MESH:D014315), lutein (MESH:D014975), carbohydrates (MESH:D002241), fatty acids (MESH:D005227), Arginine (MESH:D001120), DL-2-Aminooctanoic acid (-), Polyunsaturated fatty acids (MESH:D005231) - **Species:** Vitis vinifera (wine grape, species) [taxon 29760], Chlorella vulgaris (species) [taxon 3077], Asparagopsis taxiformis (species) [taxon 260499], Limnospira platensis (species) [taxon 118562], Tetraselmis sp. (species) [taxon 2812566], Spirogyra sp. (species) [taxon 3181], Graesiella emersonii (species) [taxon 95581], Tetraselmis tetrathele (species) [taxon 445571], Fucus vesiculosus (species) [taxon 49266], Homo sapiens (human, species) [taxon 9606] ## Full text _Full body text omitted from this summary view._ Fetch the complete paper as Markdown: https://tomesphere.com/paper/PMC12945581/full.md ## Figures 2 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12945581/full.md ## References 62 references — full list in the complete paper: https://tomesphere.com/paper/PMC12945581/full.md --- Source: https://tomesphere.com/paper/PMC12945581