Background: Extracellular metabolites of short chain fatty acids (SCFA) excreted by gut microbiota have been reported to play an important role in the regulation of intestinal homeostasis. Apart from supplying energy, SCFA also elicit immune stimulation in animal and human cells. Therefore, an attempt was conducted to isolate SCFA producing bacteria from healthy human microbiota. The anti-cancer and anti-inflammatory effects of extracellular metabolites and individual SFCA were further investigated by using breast, colon cancer and macrophage cells. Toxin, inflammatory and anti-inflammatory cytokine gene expressions were investigated by RT-qPCR analyses in this study. Results: Escherichia coli KUB-36 was selected in this study since it has the capability to produce seven SCFA extracellularly. It produced acetic acid as the main SCFA. It is a non-exotoxin producer and hence, it is a safe gut microbiota. The IC₅₀ values indicated that the E. coli KUB-36 metabolites treatment elicited more potent cytotoxicity effect on MCF7 breast cancer cell as compared to colon cancer and leukemia cancer cells but exhibited little cytotoxic effects on normal breast cell. Furthermore, E. coli KUB-36 metabolites and individual SCFA could affect inflammatory responses in lipopolysaccharide-induced THP-1 macrophage cells since they suppressed inflammatory cytokines IL-1β, IL-6, IL-8 and TNF-α well as compared to the control, whilst inducing anti-inflammatory cytokine IL-10 expression. Conclusion: SCFA producing E. coli KUB-36 possessed vast potential as a beneficial gut microbe since it is a non-exotoxin producer that exhibited beneficial cytotoxic effects on cancer cells and elicited anti-inflammatory activity simultaneously. However, the probiotic characteristic of E. coli KUB-36 should be further elucidated using in vivo animal models.

Thunbergia laurifolia leaf is used in Thai herbal medicine to moderate alcohol, food poisoning, and other health-related diseases mainly due to its overwhelming phytochemical compounds which exert several biological functions such as antioxidant, and anti-inflammatory properties, among others. This study investigated the potential effects of hot air-drying conditions (TL-D80°C, TL-D90°C, and TL -D100°C) of T. laurifolia tea leaves on phenolic compounds, total flavonoid content (TFC), total phenolic content (TPC), and antioxidant activities (AOA) of the infused teas. The results show that an increase in drying temperature significantly improved TPC (709.7 ± 1.36–744.8 ± 5.79 mg GAE/) and TFC (198.98 ± 7.59–207.16 ± 4.10 mg RE/L) of infused teas. TL-D80°C (69.9 ± 0.95%) and TL-D90°C (69.3 ± 0.7%) infused teas showed significantly higher DPPH inhibitory effect compared to TL-D100°C. Treatment had no effects on ABTS^.+ scavenging activity. The phenolic compounds detected in infused teas were rosmarinic acid, caffeic acid, gallic acid, catechin, rutin, and quercetin. Regarding, the cumulative phenolic compounds TL-D100°C infused teas were significantly higher compared to TL-D90°C and TL-D80°C. The results suggest that drying conditions (i.e., TL-D100°C within 30 min) could be used to achieve appropriate moisture content of T. laurifolia tea leaves without compromising the phytochemical compositions and antioxidant potentials of the resulting infused teas.

This study highlights the dynamics of phenolic acids, antioxidation, and 4-vinylguaiacol in beer produced with dark purple rice malt, also known as Riceberry rice malt, as an adjunct and base malt. Riceberry rice malt substituted barley malt at 40% (w/w), 60% (w/w), 80% (w/w), and 100% (w/w) with 100% (w/w) barley malt as the control. Two types of ale beer were produced with two yeasts, designated as POF⁻ and POF⁺. The wort produced with the Riceberry rice malt had higher anthocyanin and vanillic acids relative to all barley malt wort. Fermentation and beer maturation reduced phenolic acids and antioxidant activity in all treatment. Nevertheless, beer produced from 40% (w/w)–80% (w/w) Riceberry rice malt maintained higher p-coumaric acid, vanillic acid, anthocyanin, and antioxidant activity in beers with lower 4-vinylguaiacol relative to all barley malt beer, which also had higher ferulic acid and sinapic acid contents. The beers made from POF⁺ yeast contained more 4-vinylguaiacol contents than those found in beers made from POF⁻ yeasts. This study suggests that Riceberry rice malt or POF⁻ yeast are suitable raw materials for phenolic acid off-flavour reduction and the stabilisation of antioxidant activity in beer.