Although fish are good sources of selenium (Se), an essential trace element for the human body, very limited data exist on Se content in commonly consumed fish in Thailand. Consequently, this study investigated selenium content and the effect of cooking among 10 fish species (5 freshwater and 5 marine) most-commonly consumed by the Thai people. The fish were purchased from three representative wholesale markets within or nearby to Bangkok. All fish species were prepared to determine their edible portions (EP) and moisture contents. Total Se in fresh, boiled, and fried fish were analysed using Inductively Coupled Plasma-Triple Quadrupole-Mass Spectrometry (ICP-QQQ-MS). In general, higher levels of Se were found in marine fish (37.1–198.5 µg/100 g EP in fresh fish, 48.0–154.4 µg/100 g EP in boiled fish, and 52.9–262.4 µg/100 g EP in fried fish) compared to freshwater fish (6.9–29.4 µg/100 g EP in fresh fish, 10.1–26.5 µg/100 g EP in boiled fish, and 13.7–43.8 µg/100 g EP in fried fish). While Longtail tuna showed significantly higher Se content than other fish (p < 0.05), boiled Longtail tuna had significantly lower true retention of Se than the other fish (p < 0.05). Most fish species retained a high level of selenium (ranged 64.1–100.0% true retention in boiling and frying). Longtail tuna, Short-bodied mackerel, Indo-pacific Spanish mackerel, Nile tilapia, and red Nile tilapia–cooked by boiling and frying–are recommended for consumption as excellent sources of selenium.

Selenium (Se), abundantly obtained in fish, is a crucial trace element for human health. Since there are no data on Se bioaccessibility from commonly consumed fish in Thailand, this study assessed the in vitro bioaccessibility of Se using the equilibrium dialyzability method. The five fish species most commonly consumed in Thailand were selected to determine total Se content using several preparation methods (fresh, boiling, and frying). Equilibrium dialyzability was used to perform in vitro bioaccessibility using enzymatic treatment to simulate gastrointestinal digestion for all boiled and fried fish as well as measuring Se using inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ-MS). Two-way ANOVA with interaction followed by Tukey’s honestly significant difference (HSD) post hoc test revealed that boiled Indo-Pacific Spanish mackerel, longtail tuna, and short-bodied mackerel were significantly higher in Se content than striped snakehead and giant sea perch (p < 0.05). For fried fish, longtail tuna showed the highest Se content (262.4 µg/100 g of product) and was significantly different compared to the other fish (p < 0.05, estimated marginal means was 43.8–115.6 µg/100 g of product). Se bioaccessibilities from striped snakehead (70.0%) and Indo-Pacific Spanish mackerel (64.6%) were significantly higher than for longtail tuna (p < 0.05). No significant difference in bioaccessibility was found in terms of preparation method (i.e., boiling and frying). In conclusion, the fish included in this study, either boiled or fried, have high Se content and are good sources of Se due to high bioaccessibility.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is linked to choline metabolism. The present study investigated the effect of holy basil (Ocimum sanctum L.) flower water extract (OSLY) on MASLD with choline metabolism as an underlying mechanism. Rats with high-fat diet (HFD)-induced MASLD received 250–1000 mg/kg bw of OSLY, fenofibrate, or fenofibrate + 1000 mg/kg OSLY combination. Biochemical parameters, choline metabolites, and one-carbon gene transcription were analyzed. OSLY and fenofibrate independently reduced serum LDL cholesterol (p < 0.02), liver cholesterol (p < 0.001), and liver triglyceride levels (p < 0.001) in HFD-fed rats. Only OSLY reduced signs of liver injury and increased serum HDL. Fenofibrate influenced choline metabolism by decreasing liver glycerophosphocholine (GPC; p = 0.04), as well as increasing betaine (p < 0.001) and the betaine:choline ratio (p = 0.02) in HFD-fed rats. Fenofibrate (vs. HFD) increased the expression of one-carbon metabolism genes Mthfd1l, Pemt, Smpd3, and Chka (p < 0.04). The OSLY treatment decreased liver GPC (500 mg dose; p = 0.03) and increased Smpd3 expression (1000 mg dose; p = 0.04). OSLY and fenofibrate showed weak synergistic effects on lipid and choline metabolism. Collectively, OSLY and fenofibrate independently improve lipid profiles in MASLD rats. The benefits of fenofibrate are partially mediated by choline/one-carbon metabolism, while those of OSLY are not mediated by this pathway. Holy basil flower extract merits further development as an alternative medicine for MASLD.