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The brown macroalgae Sargassum has been reported for its anti-UV and photoprotective potential for industrial applications. This study evaluated the melanin inhibition activity of Sargassum cristaefolium (SCE) ethanol extract. Melanogenesis inhibition by SCE was assessed in vitro with B16-F10 melanoma cell models and in silico against melanin regulatory proteins Tyrosinase (TYR) and Melanocortin 1 Receptor (MC1R). The regulatory properties evaluated were the melanin content, intracellular tyrosinase activity and cellular antioxidant activities. In addition, the bioactive compounds detected in SCE were subjected to molecular docking against TYR and MC1R. Based on the results, 150 µg/mL SCE effectively inhibited the production of melanin content and intracellular tyrosinase activity. Cellular tyrosinase activity was reduced by SCE-treated cells in a concentration-dependent manner. The results were comparable to the standard tyrosinase inhibitor kojic acid. In addition, SCE effectively decreased the intracellular reactive oxygen species (ROS) levels in B16-F10 cells. The antioxidant properties may also contribute to the inhibition of melanogenesis. In addition, LCMS UHPLC-HR-ESI-MS profiling detected 33 major compounds. The results based on in silico study revealed that the bioactive compound putative kaurenoic acid showed a strong binding affinity against TYR (-6.5 kcal/mol) and MC1R (-8.6 kcal/mol). However, further molecular analyses are needed to confirm the mechanism of SCE on melanin inhibition. Nevertheless, SCE is proposed as an anti-melanogenic and antioxidant agent, which could be further developed into cosmetic skin care products.

The red macroalga Gelidium latifolium is widely distributed in the coastal areas of Indonesia. However, current knowledge on its potential biological activities is still limited. In this study, we investigated the potential bioactive compounds in Gelidium latifolium ethanol extract (GLE), and its cytotoxic effects against the murine B16-F10 melanoma cell line. GLE shows high total phenolic content (107.06 ± 17.42 mg GAE/g) and total flavonoid content (151.77 ± 3.45 mg QE/g), which potentially contribute to its potential antioxidant activity (DPPH = 650.42 ± 2.01 µg/mL; ABTS = 557.01 ± 1.94 µg/mL). ESI-HR-TOF-MS analysis revealed large absorption in the [M-H] - of 327.2339 m/z, corresponding to the monoisotopic molecular mass of brassicolene. The presence of this compound potentially contributes to GLE's cytotoxic activity (IC 50 = 84.29 ± 1.93 µg/mL). Furthermore, GLE significantly increased the number of apoptotic cells (66.83 ± 3.06%) compared to controls (18.83 ± 3.76%). Apoptosis was also confirmed by changes in the expression levels of apoptosis-related genes (i.e., p53 , Bax , Bak , and Bcl2 ). Downregulated expression of Bcl2 indicates an intrinsic apoptotic pathway. Current results suggest that components of Gelidium latifolium should be further investigated as possible sources of novel antitumor drugs.

The frequent use of chemical fertilizers in agricultural practices has developed into a serious environmental concern which urgently needs a solution to restrain their use in agricultural systems. Hence, there is an urgent need to investigate potential organic fertilizers from various natural resources to decrease the use of chemical fertilizers. Seaweed is among the natural resources with potential sustainability value. Our previous work has shown the effectiveness of seaweed fertilizer for increasing plant growth and soil beneficial microbiota. This study aims to evaluate the functional genes present in the soil of rice plants treated with seaweed fertilization. It involves amendments with reduced concentrations of chemical fertilizer in three groups: CF (only chemical fertilizer), CFSF1 (50% dose of CF + seaweed fertilizer 1 ton/ha), and CFSF2 (50% dose of CF + seaweed fertilizer 2 ton/ha). The rice plants supplemented with CFSF1 and CFSF2 were taller and faster to mature compared to CF. In addition, the primary macronutrients nitrogen (N), phosphorus (P), and potassium (K) were also significantly higher in soil supplemented with SF. Our findings showed increased ammonia-oxidizing archaea Crenarchaeota abundance in increasing SF treatments. The PICRUSt analyses indicated enriched functional genes and proteins in relation to amino acid, nucleotide, protein, and carbohydrate metabolism based on the KEGG, BioCyc, and PFAM databases. The current outcomes enhanced our understanding regarding the importance of microbial community for soil quality. Furthermore, seaweed supplementation has shown improvement in soil fertility, which significantly increases rice plant growth and productivity. [ABSTRACT FROM AUTHOR]

Seaweed has often been reported on for it potential bioresources for fertilizers to improve crop productivity and reduce the use of chemical fertilizers (CF). However, little is known about the nutritional status of the crop grown with the implementation of seaweed fertilizers (SF). In this study, the amino acid content of rice produced by SF implementation was evaluated. Furthermore, the rhizosphere bacterial community was also investigated. The paddy seedlings were divided into five groups, control (C0), chemical fertilizer (CF), seaweed fertilizer (SF), chemical and seaweed fertilizer combination 25:75 (CFSF1), and chemical and fertilizer combination 50:50 (CFSF2). The CFSF2 group shown significantly better growth characteristics compared to other groups. Based on the concentration of macronutrients (N, P, K) in paddy leaf, CFSF2 also shown the best results. This also correlates with the abundant amino acid composition in CFSF2 in almost all tested amino acids, namely, serine, phenylalanine, isoleucine, valine, glycine, tyrosine, proline, threonine, histidine, and arginine. Interestingly, beneficial bacteria Rhizobiales were significantly higher in CFSF2-treated soil (58%) compared to CF (29%). Another important group, Vicinamibacterales, was also significantly higher in CFSF2 (58%) compared to CF (7%). Hence, these potentially contributed to the high rice amino acid content and yield in the CFSF2-treated paddy. However, further field-scale studies are needed to confirm the bioindustrial application of seaweed in agricultural systems. [ABSTRACT FROM AUTHOR]

Excessive use of chemical fertilizer could potentially decrease soil productivity by decreasing soil microbiome diversity. In this study, we evaluated the effects of fermented seaweed fertilizer in the soil microbial community of paddy plants (Oryza sativa L.). The paddy seedlings were divided into five groups, control (C0), chemical fertilizer (CF), seaweed fertilizer (SF), chemical and seaweed fertilizer combination 50:50 (CFSF1), and chemical and fertilizer combination 75:25 (CFSF2). The CFSF1 combination showed to be the most effective in inducing plant height (83.99 ± 3.70 cm) and number of tillers (24.20 ± 4.08). After 8 weeks after transplantation, the isolated DNA from each soil treatment were subjected to 16S rRNA (v3–v4 region) next-generation sequencing. The beneficial Acidobacteriota was most abundant in CFSF1. At genus level, the nitrifying bacteria MND1 was seen to be abundant in CFSF1 and also present in other SF treatments. The genus Chujaibacter is highly abundant in CF, which potentially plays a role in denitrification resulting in soil degradation. In addition, the CFSF1-treated soils show significantly higher diversity of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). The current results could potentially contribute to the utilization of SF as a bioremediator and promoting green agriculture practice by reducing the amount of CF usage. [ABSTRACT FROM AUTHOR]

Many studies have evidenced the negative effects of synthetic fertilizers toward the environment and also the crop products itself. Hence, the improvement of organic fertilizers is necessary to resolve this problem. Seaweeds or marine macroalgae are considered to be an excellent natural resource in different aspects of agricultural fields. Brown macroalgae Turbinaria murayana (TM) is often found in Indonesian coastal areas with high bioavailability throughout the year. This study evaluated the potentials of TM as biofertilizer in tomato plants (Lycopersicum esculentum Mill.). Evaluation of phytohormones present in TM crude extract was conducted with high performance liquid chromatography (HPLC). Macro and micronutrients available in TM crude extract were determined by atomic absorbance spectroscopy (AAS). A concentration of 4% TM crude extract was applied to tomato plants. The vegetative properties of the treated tomatoes were observed such as growth and yield. Current results evidenced the presence of growth-promoting factors (kinetin, gibberellin and ABA) and essential elements (N, P, K, Ca, Fe and Mn) in TM crude extract. Application of 4% TM extract to tomato plants significantly increased vegetative growth compared to untreated plants; plant height, leaf number and branch number, approximately 58.4%, 87.5% and 200%, respectively. Similar results were also found in the response of generative growth. Application of 4% liquid extract significantly improved flower and fruit number compared to control; 53.6% and 125%, respectively. These results suggest that TM crude extract is a potential source for developing organic fertilizers. [ABSTRACT FROM AUTHOR]