Thua-nao, or Thai fermented soybeans, is a traditional Lanna fermented food in Northern Thailand. It is produced by using a specific bacterial species called Bacillus subtilis var. Thua-nao. We investigated the antioxidant activity and cytotoxic effect of isoflavones from Thua-nao. The phenolic compound contents and total flavonoid contents were determined by spectrophotometry. The antioxidant activity was examined using the ABTS, FRAP, and DPPH assays. The isoflavone contents and phenolic compositions were examined by the high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) techniques. The ability of isoflavones to inhibit human cancer cell growth was assessed by the MTT assay. The total phenolic content, total flavonoid content, and antioxidant activities of the isoflavones were 49.00 ± 0.51 mg GAE/g of dry extract (DE), 10.76 ± 0.82 mg QE/g of DE, 61.03 ± 0.97 µmol Trolox/g of DE, 66.54 ± 3.97 µM FeSO₄/g of DE, and 22.47 ± 1.92% of DPPH inhibition, respectively. Additionally, the isoflavone extracts from Thua-nao had high isoflavone contents and polyphenolic compound compositions, especially daidzein and genistein. The isoflavone demonstrated a weak inhibition of MCF-7 and HEK293 cancer cell growth. It has a high antioxidant component, which is beneficial and can be developed for new therapeutic uses. However, further studies on the benefits of Thua-nao should be performed for realizing better and more effective uses soon.

Objective: To investigate anti-hemolytic, antibacterial and anti-cancer activities of leaf and stem extracts from Polygonum odoratum. Methods: Leaves and stems of Polygonum odoratum were extracted using methanol and their anti-hemolytic activity was assessed using 2, 2′-Azobis (2-methylpropionamidine) dihydrochloride which is known to generate free radical damage on cell membranes of red blood cells. This damage, represented by hemolysis, was measured using spectrophotometry. Antibacterial activity was tested by using a broth microdilution method to find minimal inhibitory concentrations against eight bacterial strains. Anti-cancer activity of the extracts was evaluated against a human promyelocytic leukemic cell line (HL- 60) by using MTT assay for cell viability and flow cytometry for apoptosis induction and cell cycle analysis. Results: Both leaf and stem extracts have anti-hemolytic activity. The results showed a significantly increased percentage of inhibition in a concentration-dependent manner. Interestingly, the leaf extract showed anti-hemolytic activity to a greater extent than the stem extract. Antibacterial activity of the extracts, as indicated by their minimal inhibitory concentration, using 12.5, 50, 25, 25 μg/mL, was measured against Staphylococcus epidermidis, Enterococcus faecium, Enterococcus faecalis and Staphylococcus aureus. The leaf extracts also exhibited anti-cancer activity, demonstrated by significantly decreased cell viability of human promyelocytic cells (HL-60), with an IC₅₀ of (350.00±1.85) μg/mL for 48 h and (38.00±0.92) μg/mL for 72 h. Additionally, HL-60 became apoptotic and accumulated in G₁–phase after 48 hours of treatment. Conclusions: The extracts of Polygonum odoratum exhibit potential anti-hemolytic activity. They also have antibacterial activity by inhibiting growth of Gram-positive bacteria. The leaf extract shows anti-cancer activity against HL-60 to a greater extent than the stem extract, causing decreased viability, increased G₁-phase accumulation and apoptosis induction.

Polygonum odoratum var. Pakphai has been used in traditional Thai medicine for the treatment of flatulence and constipation and to relieve the inflammation caused by insect bites. Quercetin (Q), which is abundant in plant-based foods, has been found to exert anti-inflammatory properties. This study evaluated the anti-inflammatory activity of P. odoratum ethanolic extract in RAW264.7 macrophage cells. Leaves were extracted with 50% ethanol, phenolics and flavonoids were then analyzed using UHPLC-QTOF-MS and HPLC-DAD. RAW264.7 cells were induced with lipopolysaccharides (LPSs). They were then treated with the extract and prostaglandin E₂ (PGE₂), and interleukin-6 (IL-6) and tumor necrotic factor-alpha (TNF-α) concentrations were determined. Levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), IL-6 and TNF-α mRNAs were analyzed using qRT-PCR. Chemical analysis demonstrated that the extract was abundant with Q while also containing catechin, gallic acid, epicatechin gallate and coumarin. The extract increased the viability of RAW264.7 cells and dose-dependently decreased nitric oxide production, PGE₂, IL-6 and TNF-α levels in the medium from the LPS-induced RAW264.7 cell culture. Consistently, COX-2, iNOS, IL-6 and TNF-α mRNA levels were decreased in a concentration-dependent manner (p < 0.05). Thus, the quercetin-rich ethanolic extract derived from P. odoratum var Pakphai leaves can exert anti-inflammatory activity in LPS-induced RAW264.7 cells through a reduction of the pro-inflammatory mediator response.

Particulate matter-10 (PM10) can penetrate the lungs, leading to increased lung cell injury and inflammation. The leaf extract of Polygonum odoratum Lour. (PO) is rich in quercetin, a compound known for its antioxidant and anti-inflammatory properties. This study aimed to evaluate the protective effect of PO in a PM10-induced human lung cell model. PM10 samples were collected in Chiang Rai, Thailand, and tested for cytotoxicity in the human lung epithelial cell line (A549). To assess the protective effect, cells were pre-treated with PO and subsequently exposed to PM10 (100 µg/mL) for 24 hours. Cell viability and lactate dehydrogenase (LDH) activity were measured, and the expression of pro-inflammatory genes, including interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-13 (IL-13), and interleukin-17 (IL-17), was analyzed using quantitative real-time polymerase chain reaction (RT-qPCR). The results demonstrated that PO attenuated PM10-induced lung cell injury in a dose-dependent manner and downregulated the mRNA expression of pro-inflammatory cytokines. In conclusion, PO shows potential as an alternative treatment for mitigating PM10-induced lung damage.