Summary This study revealed that the ethanolic bran extracts of 11 Thai pigmented (red and purple) and 2 nonpigmented rice varieties exerted scavenging activity against DPPH and ABTS radicals and ROS in HL‐60 cells in the following order: red > purple > nonpigmented rice. These rice extracts also showed the same order of phenolic and flavonoid contents, which were strongly correlated with their scavenging activity. Phenolic subtype analysis further indicated that proanthocyanidins as well as anthocyanins and protocatechuic acid contributed directly to antioxidant capacity in red and purple rice bran, respectively. In contrast, these pigmented rice bran extracts possessed moderate chelating activity partly attributed to their contents of phenolics and flavonoids, especially proanthocyanidins in red rice bran. Moreover, rice bran extracts significantly restored SOD and CAT activities in oxidative stress‐induced A549 cells. This study provides new insights on the intracellular potent antioxidant capacity of pigmented rice bran extracts in the cell‐based systems.

Royal jelly (RJ) is widely used as a food supplement for anti-aging and beauty. However, its use has been linked to asthma and hemorrhagic colitis. Since its mechanisms of toxicity have not been fully identified, we conducted an investigation to elucidate its molecular and cytogenetic effects. Using human lymphocytes in vitro, treatments with RJ (0.0005-5 mg/ml) for 3 h did not induce sister chromatid exchanges until 5 mg/ml was used. Treatments for 24 h showed a dose-dependent reduction in BCL2/BAX, c-MYC/BAX and HO-1/BAX ratios. The exception was the NRF2/BAX ratio, showing a dose-dependent reduction at low doses, but a marked increase at the highest dose. The hTERT/BAX ratio was maintained at approximately a 1.2-fold increase but decreased to nearly normal at the highest dose. Our findings indicated that the lowest dose of RJ treatment provided maximum benefits, mainly through hTERT activation relating to prolonged lifespan. The highest dose of RJ inhibited cell survival, cell proliferation and an antioxidative enzyme; nevertheless, it still activated an antioxidative response through NRF2 and maintained telomeres during cell crisis. RJ treatment at 0.05 mg/ml increased cyclin E, BCL2 and BAX to maximum levels indicating that throughout the active cell cycle, both cell survival and cell apoptosis increased. Using the gene expression ratios over BAX, similar to BCL2/BAX, provided more informative data than using individual protein levels alone. With these informative ratios, our results confirm the potential benefits of RJ in enhancing lifespan and activation antioxidative power. Further, in vivo mechanistic studies will be useful in validating these results.

Mentha cordifolia (MC) is a popular herb used to flavor food in Thailand that exhibits several biological effects. The present study aimed to determine the role of MC in regulating glucose and lipid metabolism in mice fed a high-fat diet (HFD). ICR obese mice were fed an HFD (45 kcal% lard fat) for 12 weeks, with MC (100 and 200 mg/kg/d) treatment from Week 7. After treatment with MC for 6 weeks, mice showed significantly lower rates of hyperglycemia, hyperinsulinemia, hyperleptinemia, and hyperlipidemia, and increased amounts of serum adiponectin. Furthermore, in mice treated with MC, serum interleukin-6 and tumor necrosis factor alpha were significantly inhibited and liver histology results showed decreased lipid accumulation and liver triglyceride content vs. untreated mice. In addition, MC treatment was associated with smaller fat cells and lower gene expression of liver sterol regulatory element binding protein 1c, acetyl-CoA carboxylase, and fatty acid synthase. However, MC treatment was associated with higher carnitine palmitoyltransferase 1a gene expression and significantly higher rates of adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in liver, but lower levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. These results indicate MC regulates glucose and lipid metabolism in a HFD-induced obese mouse model, possibly via activation of AMPK signaling pathway.

Genoprotective effects of royal jelly (RJ) treatments against doxorubicin (DXR), a potent genotoxic chemotherapeutic compound in human lymphocytes were investigated using the sister chromatid exchange (SCE) assay, and their molecular mechanisms were examined by Western blot. Results showed that RJ pretreatments at 0.005 and 0.05 mg/mL significantly decreased DXR-induced SCE levels by 1.2-fold (p<0.05), compared to DXR treatment alone. Co-treatment of RJ (5 mg/mL) with DXR (0.2 µg/mL) increased the ratios of BCL2/BAX (1.5-fold), NRF2/BAX (1.3-fold), and hTERT/BAX (1.1-fold) compared to the DXR alone, suggesting its power in enhancing cell survival, antioxidative potentials, and longevity over cell death. The study suggested that RJ protected human cells from DXR-induced genotoxicity, possibly mediated through anti-apoptotic, anti-oxidative, and anti-aging properties of RJ. However, lower doses of RJ co-treatments enhanced DXR toxicity. Further, in vivo molecular study is required to validate this in vitro study.

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