Ulva sp. is a well-known green seaweed containing bioactive metabolites such as polyphenols, flavonoids, alkaloids, terpenoids, and carotenoids, making it a potential bioresource for pharmaceutical and biomedical applications. Recently, algal blooms have increased due to various environmental changes. However, Ulva sp. remains underutilized as a beneficial ingredient. Thus, fundamental research and biological efficacy evaluations of Ulva sp. are essential. This study evaluated the chemical composition and biological activities of 70% ethanol, hot water, and water extracts of Ulva sp. collected from Seongsan, Jeju Island, over a one-year period. Carbohydrate content was the highest among the proximate components of Ulva sp., while protein content was notably high in December 2023, January 2023, and February 2023. The study also assessed the antioxidant activities of Ulva sp. extracts, revealing potent activity in ethanol extracts from March 2023 and October 2023. These findings suggest that Ulva sp. extracts possess bioactive potential for pharmaceutical and nutraceutical applications.

Methane emissions play a significant role in climate change, second only to carbon dioxide. Although methane's atmospheric concentration is lower than that of carbon dioxide, its radiation absorption capacity is significantly higher. Other than natural sources such as wetlands and organic matter degradation, most methane emissions come from agriculture, primarily through ruminants like cows. Scientists have identified the mechanisms of methane production in cow rumen during digestion, leading to efforts aimed at reducing these emissions. One promising ap- proach is the inclusion of red seaweed species, particularly Asparagopsis, into animal feed. Asparagopsis contains bromoforms that can inhibit methane production. Remarkably, even a small proportion, approximately 0.5% of dried Asparagopsis in feed, can reduce methane emissions from the rumen by up to 95%. This discovery presents a new opportunity for seaweed cultivation. Given the high global population of cows and other ruminants, the demand for Asparagopsis is substantial and requires international cooperation. Asia-Pacific countries have significant advantages in developing Asparagopsis cultivation. Nations such as Japan, Korea, Vietnam, Indonesia, and the Philippines have long-standing traditions of seaweed production, processing, and use. Additionally, the region's climate is well-suited for seaweed cultivation. Coastal fishing communities are experienced in aquaculture, both in ponds and in open seas. Therefore, despite the remaining challenges related to Asparagopsis cultivation, the industry shows great potential for growth.

The productivity of microalgal biomass in ocean floating ponds (OFPs) is highly dependent on the energy from irregular ocean waves for algae mixing. This study aimed to enhance the biomass productivity and photosynthetic efficiency (PE) of the green microalga Tetraselmis sp. KCTC12429BP by improving the mixing efficiency of cultures in OFPs. Thus, we installed solar cell-powered mixers (SCPMs; 10 W) at the center of a 4-ton OFP on the coast of Young-Heung Island (Korea) and evaluated the improvement in microalgal biomass productivity, PE, and mixing efficiency by varying the number of SCPMs. SCPM use increased the mixing efficiency and PE by 2.2 and 1.6 times, respectively, compared with the control (wave mixing only). Moreover, the biomass productivity using SCPMs reached 6.0 ± 0.1 g/m²/day, whereas that of the control was 4.4 ± 0.4 g/m²/day. The installation of two SCPMs increased the PE by 133% (4.0% PE) compared with the control. Our findings demonstrate a new approach to enhancing algal biomass productivity in OFPs by integrating natural energy sources (solar energy and wave energy) into microalgal cultures.

Haematococcus pluvialis reportedly exhibits various beneficial effects, such as anti-oxidant and anti-obesity properties. However, its anti-melanogenic effect, particularly that of red-stage H. pluvialis ethanol extract (HPEE), has not yet been investigated in B16F10 melanoma cells or in a zebrafish model. Therefore, this study aimed to investigate the anti-melanogenic activity of HPEE. The results showed that HPEE strongly inhibited Tyrosinase (TYR) activity. In addition, HPEE treatment significantly reduced cellular tyrosinase activity and melanin content in a dose-dependent manner in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells without inducing cytotoxicity. HPEE also downregulated the expression of melanogenesis-related proteins, including TYR, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2), by suppressing the microphthalmia-associated transcription factor in α-MSH-stimulated B16F10 melanoma cells. In an in vivo zebrafish model, HPEE significantly inhibited melanin synthesis in a dose-dependent manner without inducing developmental toxicity. These findings indicate that HPEE exhibits anti-melanogenic activity in vitro and in vivo, and may serve as a potential skin-whitening agent in pharmaceutical and cosmeceutical applications.

Gloiopeltis furcata J. Agardh, a red alga widely distributed along the North Pacific coast, including Korea, has traditionally been used for various health-promoting purposes. Previous studies have reported that extracts from this alga possess diverse biological and pharmacological activities, including antioxidant, anti-inflammatory, antidiabetic, anti-obesity, and antitumor effects. However, its potential skin-whitening effects have not yet been explored. Therefore, in this study, we investigated the anti-melanogenic effects and underlying mechanisms of an ethanol extract of G. furcata (EEGF) using an α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cell model. Within a non-cytotoxic concentration range, EEGF significantly reduced α-MSH-induced intracellular tyrosinase activity and melanin content. EEGF also downregulated the expression of key melanogenic enzymes, including tyrosinase, tyrosinase-related protein 1 (TRP-1), and TRP-2. Mechanistically, EEGF inhibited melanogenesis through the suppression of the cAMP-dependent protein kinase A (PKA)/cAMP response element-binding protein (CREB) signaling pathway, leading to reduced expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis. Furthermore, EEGF inhibited α-MSH-induced activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, further contributing to MITF downregulation. Collectively, these findings suggest that EEGF inhibits melanogenesis by targeting both the PKA/CREB and PI3K/Akt signaling pathways, resulting in decreased MITF activity. G. furcata extract and its bioactive components thus hold promise as skin-whitening agents for potential application in cosmetic and pharmaceutical formulations.

Marine macroalgal biodiversity and community structure were investigated in the intertidal bedrock zones and tidal pools of Jeongdo-ri, Wando-gun, Jeollanam-do, Korea (34°17'45.98"N, 126°42'05.26"E) from February to November 2020. A total of 135 macroalgal species were identified, with peak diversity recorded in spring (86 species). Species richness declined sharply during the summer and rose again in autumn. The average values of C/P (0.7), R/P (5.8), and (C+R)/P (6.5)-indices that reflect the geographical affinity of macroalgae-indicate a shift toward tropical and temperate elements, suggesting an overall trend of tropicalization compared with previous studies. Among the six functional form groups of macroalgae, coarsely branched forms were the most prevalent (39.3%), while crustose forms were the least common (3.6%). Furthermore, 71.8% of the identified species belonged to Ecological Status Group II (ESG II), indicating that the marine environment in Jeongdo-ri is frequently exposed to disturbances and pollution. Seasonal variation was observed in dominant species based on Importance Value (IV): Monostroma nitidum in winter, Corallina pilulifera in spring, Ulva australis in summer, and Chondria crassicaulis in autumn. These findings highlight the need for ongoing research and monitoring to track temporal changes in macroalgal diversity and biomass, thereby supporting ecosystem conservation and informed responses to environmental changes in the coastal waters of Jeongdo-ri, Wando.

Hair loss is a common condition influenced by various physiological and environmental factors, including oxidative stress, inflammation, and hormonal dysregulation in hair follicle cells. In this study, we investigated the hair growth promoting effects of Spirulina maxima extract on human dermal papilla cells (HDPCs) and elucidated the underlying mechanisms focusing on mTOR/Akt and Wnt/β-catenin signaling pathways. The results demonstrated that S. maxima extract significantly enhanced the proliferation and alkaline phosphatase (ALP) activity of HDPCs. Moreover, the extract increased both the expression levels of mammalian target of rapamycin (mTOR), β-catenin, Cyclin D1, and proliferating cell nuclear antigen (PCNA), and the phosphorylation levels of protein kinase B (Akt) and glycogen synthase kinase 3β (GSK3β), which are crucial for hair follicle development and regeneration. These findings suggest that S. maxima extract can promote hair growth by modulating mTOR/Akt and Wnt/β-catenin signaling pathways, indicating the potential application of S. maxima as a marine-derived natural resource for hair loss therapeutic agents.