Protective Effect against Hydroxyl-induced DNA Damage and Antioxidant Activity of Radix Glycyrrhizae (Liquorice Root)

Total Flavonoids from Radix Glycyrrhiza Exert Anti-Inflammatory and Antitumorigenic Effects by Inactivating iNOS Signaling Pathways

Inducible nitric oxide synthase (iNOS) plays an important role in inflammation, which has also been considered as a major driver of breast cancer disease progression. Radix Glycyrrhiza (RG) has been broadly used for its anti-inflammatory and antitumorigenic effects. However, the mechanisms of regulation of iNOS in inflammation and cancer have not been fully explored. Total flavonoids isolated from RG (TFRG) exhibited anti-inflammatory activity through the regulation of ERK/NF-κB/miR-155 signaling and suppression of iNOS expression in LPS/IFN-γ stimulated RAW264.7 macrophages without cytotoxicity. TFRG also markedly reduced tumor mass of breast cancer cell MDA-MB-231 xenografts with suppression of iNOS expression, formation of 3-nitrotyrosine (3-NT), and inactivation of protumorigenic JAK2/STAT3 signaling pathway. These results suggested that TFRG limited the development of breast cancer and inflammation due to its property of iNOS inhibition.

Development of Simultaneous Analysis of Thirteen Bioactive Compounds in So-Cheong-Ryong-Tang Using UPLC-DAD

So-Cheong-Ryong-Tang, which is a standardized Korean medicine of the National Health Insurance, is a traditional prescription for the treatment of allergic rhinitis, bronchitis, and bronchial asthma. Simultaneous analysis and development of SCRT is essential for its stability, efficacy, and risk management. In this study, a simple, reliable, and accurate method using ultrahigh-performance liquid chromatography (UPLC) fingerprinting with a diode array detector (DAD) was developed for the simultaneous analysis. The chromatographic separation of the analytes was performed by an ACQUITY UPLC BEH C18 column (1.7 μM, 2.1 × 100 mm, Waters) with a mobile phase of water containing 0.01% (v/v) phosphoric acid and acetonitrile containing 0.01% (v/v) phosphoric acid. The flow rate and detection wavelength were set at 0.4 mL/min and 215, 230, 254, and 280 nm. All calibration curves of the thirteen components showed good linearity (R² > 0.999). The limit of detection and limit of quantification ranged 0.001-0.360 and 0.004-1.200 µg/mL, respectively. The relative standard deviation (RSD) of intra- and interday was less than 2.60%, and the recoveries were within the range 76.08-103.79% with an RSD value of 0.03-1.50%. The results showed that the developed method was simple, reliable, accurate, sensitive, and precise for the quantification of bioactive components of SCRT.

Attenuation of neuropathic pain by saikosaponin a in a rat model of chronic constriction injury

Despite immense advances in the treatment strategies, the effective treatment of patients suffering from neuropathic pain remains challenging. Saikosaponin a possesses anti-inflammatory activity. However, the role of saikosaponin a in neuropathic pain is still unclear. Therefore, the objective of this study was to investigate the effects of saikosaponin a on neuropathic pain. Neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve in rats. After CCI, rats were administered saikosaponin a (6.25, 12.50 and 25.00 mg/kg intraperitoneal, once daily) for 14 days. Mechanical withdrawal threshold and thermal withdrawal latency were assessed before surgery and on days 1, 3, 7, and 14 after CCI. Our results showed that CCI significantly decreased mechanical withdrawal threshold and thermal withdrawal latency on days 1, 3, 7 and 14, as compared with sham groups, however, saikosaponin a reversed this effects. In addition, saikosaponin a inhibited CCI-induced the levels of TNF-α, IL-1β, IL-2 in spinal cord. Western blot analysis demonstrated that saikosaponin a reduced the elevated expression of p-p38 mitogen-activated protein kinase (MAPK) and NF-κB in the spinal cord induced by CCI. These results suggest that saikosaponin a could effectively attenuate neuropathic pain in CCI rats by inhibiting the activation of p38 MAPK and NF-κB signaling pathways in spinal cord.

DNA protective effect of mangosteen xanthones: an in vitro study on possible mechanisms

PURPOSE

The aim of this study was to evaluate antioxidant ability of mangosteen shell and explore the non-enzymatic repair reaction and possible mechanism of xanthones in mangosteen shell.

METHODS

Mangosteen shell was extracted by methanol to obtain the extract of mangosteen shell. The extract was then determined by various antioxidant assays in vitro, including protection against DNA damage, •OH scavenging,DPPH• (1,1-diphenyl-2-picryl-hydrazl radical) scavenging, ABTS(+)• (2,2'-azino-bis(3-ethylbenzo- thiazoline-6-sulfonic acid diammonium) scavenging, Cu(2+)-chelating, Fe(2+)-chelatingand Fe(3+) reducing assays.

RESULTS

Mangosteen shell extract increased dose-dependently its percentages in all assays. Its IC50 values were calculated as 727.85±2.21,176.94±19.25, 453.91±6.47, 84.60±2.47, 6.81±0.28, 1.55±0.10, 3.93±0.17, and 9.52±0.53μg/mL, respectively for DNA damage assay, •OH scavenging assay, Fe(2+)-Chelating assay, Cu(2+)-Chelating assay, DPPH• scavenging assay, ABTS(+)•scavenging assay, Fe(3+) reducing assay and Cu(2+) reducing assay.

CONCLUSION

On the mechanistic analysis, it can be concluded that mangosteen shell can effectively protect against hydroxyl-induced DNA oxidative damage. The protective effect can be attributed to the xanthones. One approach for xanthones to protect against hydroxyl-induced DNA oxidative damage may be ROS scavenging. ROS scavenging may be mediated via metal-chelating, and direct radical-scavenging which is through donating hydrogen atom (H·) and electron (e). However, both donating hydrogen atom (H·) and electron (e) can result in the oxidation of xanthone to stable quinone form.