Korean red ginseng is a traditional health food frequently used to prevent or treat various diseases worldwide. In this study, we evaluated the immunomodulatory activities of eleven compounds (1-11) isolated from Korean red ginseng, focusing on T cell function. First, the effects of the eleven compounds were studied on the regulation of IL-2, a potent T cell growth factor. Compounds 5, 7, and 9 significantly increased IL-2 secretion in phorbol 12-myristate 13-acetate (PMA)/ionomycin (Io)-induced EL-4 T cells. Next, we examined the effects of compounds 5, 7, and 9 on the regulation of transcription factors related to IL-2 production in T cells. Compound 9 significantly increased the PMA/Io-induced promoter activity of nuclear factor of activated T cells (NF-AT) in EL-4 T cells, but did not have any significant effects on the promoters of NF-jB. These results suggest that compound 9 activates T cell function via the regulation of NF-AT-mediated IL-2 production.

Sargassum is a genus of brown macroalgae in the class Phaeophyta, distributed widely in all oceans, including those of Vietnam. Species of this genus have been proven to possess diverse biological activities, such as antioxidant, anti-fungal, and anti-inflammatory, along with many benefits and applications for human health, including anti-diabetic, obesity, and thrombosis. These benefits arise from a diverse chemical composition, with compounds such as fucoidan, mannitol, and especially phlorotannin—a group of phenolic derivatives found predominantly in brown algae. In this study, we evaluated and optimized the factors that affected the extraction process of phlorotannins from Sargassum swartzii (Turn.) C. Ag., a common species of brown macroalgae in Vietnam. The process utilized ethanol and water as the solvent system, and the extraction process was assisted with the use of microwaves. To carry out optimization studies, Response Surface Methodology (RSM) was adopted according to a Central Composite Desisgn (CCD), taking four processing factors into consideration, ethanol concentration (%, v/v), extraction time (minutes), solvent/material ratio (v/w), and microwave output power (W) as independent variables. Phlorotannin concentration (mgPhE/g) and extract mass (mg) were regarded as optimization outcomes. Experimental conditions that produced the highest phlorotannin yield from 10 g of S. swartzii are as follows: Extraction time of 65 minutes, ethanol concentration of 52%, microwave output power of 613 W, and solvent/material ratio of 33/1 (v/w). These conditions corresponded to a phlorotannin concentration of 5.59 ± 0.11 mg PhE/g, and a total extract content of 27.88 ± 0.13 mg/g.

Nine bioactive compounds, including one new dihydroisocoumarin glycoside, 3Sthunberginol C 6-O-β-D-glucopyranoside (1a/1b), were isolated by chromatographic separation from the fruits of the Vietnamese medicinal plant Docynia indica (Wall.) Decne. 3S-thunberginol C 6-Oβ-D-glucopyranoside was determined as a mixture of boat-like conformers based on NMR evidence and density functional theory (DFT) calculations. The in vitro inhibition of soluble epoxide hydrolase (sEH) by the isolated compounds was comparable to that of AUDA (positive control), yielding IC50 values ranging from 10.0 ± 0.6 to 88.4 ± 0.2 µM. Among isolated compounds, 3methoxy-4-hydroxy-benzoic acid (7) and 2′,6′-dihydroxy 3′,4′-dimethoxychalcone (9) were identified as a potent inhibitor of sEH, with IC50 values of 19.3 ± 2.2 and 10.0 ± 0.6 mM, respectively. These results suggest that the fruits of D. indica may be useful as daily supplements for the prevention of cardiovascular and other sEH-related diseases.

(1) Background: Hedera nepalensis (Araliaceae) is a recognized medicinal plant founded in Asia that has been reported to work in antioxidant, antifungal, antimicrobial, and antitumor capacities. (2) Methods: The subcritical fluid extraction of saponin from Hedera nepalensis leaves and the optimum of the extraction process based on yield of saponin contents (by calculating the hederacoside C contents in dried Hedera nepalensis leaves) are examined by response surface methodology (RSM). Furthermore, the antimicrobial activity of the extract is tested for potential drug applications in the future. (3) Results: Based upon RSM data, the following parameters are optimal: extraction time of 3 min, extraction temperature of 150 °C, and a sample/solvent ratio of 1:55 g/mL. Under such circumstances, the achieved yield of saponin is 1.879%. Moreover, the extracts inhibit the growth of some bacterial strains (Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenza) at a moderate to strong level with inhibition zone diameter values ranging from 12.63 to 19.50 mm. (4) Conclusions: The development of such a model provides a robust experimental process for optimizing the extraction factors of saponin contents from Hedera nepalensis extract using subcritical fluid extraction and RSM. Moreover, the current work reveals that saponin extracts of Hedera nepalensis leaves exhibit a potential antimicrobial activity, which can be used as scientific evidence for further study.