Ursane-type Triterpene Glycosides from Rubus cochinchinensis Exhibited Insulin-Mimetic Activities in Differentiated 3T3-L1 Adipocytes

Diabetes mellitus is characterized by hyperglycemic due to impaired insulin secretion or resistance. In our search for anti-diabetic agents, we found that a 70% EtOH extract of Rubus cochinchinensis(Tratt) enhances glucose uptake in 3T3-L1 adipocytes. R. cochinchinensis is predominantly found in East Asia, particularly in Vietnam, Laos, Cambodia, and southern in China. Despite its widespread distribution, there have been few studies on its bioactivity or chemical constituents. In this study, activity-guided fractionation of 70% EtOH extract from the leaves of R. cochinchinensis resulted in the isolation of one new ursane-type glycoside, 3-O-β-acetyl-28-O-β-D-glucopyranosyl-rotundioic acid (1), along with four known compounds (2–5). The structures of these compounds were elucidated using 1D and 2D NMR and HRESIMS data. Notably, compound 4 significantly increased the uptake level of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) in differentiated 3T3-L1 adipocytes. This study suggests the potential of R. cochinchinensis as a promising medicinal plant for treating diabetes via glucose uptake.

Effects of Coumarins from Roots of Paramignya scandens (Griff.) Craib on LPS-induced IL-1β and IL-10 Cytokine Production in RAW 264.7 Macrophages

Based on our previous study, we evaluated the modulatory effects on LPS-induced IL-1β and IL-10 cytokine production in RAW 264.7 macrophages of several medicinal herbs, including P. scandens. The results showed that P. scandens extract showed significant effects on LPS-induced IL-1β and IL-10 cytokine production in RAW 264.7 macrophages. Therefore, in the current research, we focused on the P. scandens sample. Cytokine production effects bioassay-guided isolation of ethyl acetate fraction of 70% ethanol extract from roots of Paramignya scandens (XL) obtained seven coumarins (1–7). Their chemical structures were identified using spectroscopic methods (NMR and MS) and compared with those previously published data to be xanthyletin (1), luvangetin (2), clausenidin (3), nordentatin (4), dentatin (5), clausarin (6), and anisocoumarin E (7). This study represents the first report on the presence of compounds 3, 6, and 7 in the Paramignya genus and compounds 1 and 2 in XL. All isolates (1–7) exhibited significant inhibition of LPS-induced interleukin (IL)-1β production compared to the LPS 5 ng/mL control group, with IL-1β concentrations ranging from 42.77 to 69.76 pg/mL. Additionally, the IL-10 production induced by compounds 1‒7 in LPS-stimulated RAW 264.7 macrophages ranged from 175.98 to 321.56 pg/mL, demonstrating a marked increase as compared to the LPS 5 ng/mL control group. The stimulatory effect on IL-10 production and inhibitory effect on IL-1β production of compounds 1, 2, and 6 gradually increased with the test concentration in both RAW 264.7 macrophages and LPS-induced RAW 264.7 macrophages. Compounds 1, 2, and 6 inhibited IL-1β production in LPS-induced RAW 264.7 macrophages with IC 50 values of 10.70 ± 1.18 µM, 8.57 ± 1.05 µM, and 17.43 ± 1.05 µM, respectively. These findings highlight the potential of all the compounds derived from P. scandens roots in inducing IL-1β and IL-10 cytokines activity in LPS-stimulated RAW 264.7 macrophages. The results contributed to expanding the knowledge of the chemistry and bioactivities of P. scandens and provided valuable data for future investigations on this species.

Reserpine treatment activates AMP activated protein kinase (AMPK)

Reserpine is a well-known medicine for the treatment of hypertension, however the role of reserpine in cell signaling is not fully understood. Here, we report that reserpine treatment induces the phosphorylation of AMP activated protein kinase (AMPK) at threonine 172 (T172) in PC12 cells. Phosphorylation of AMPK T172 is regulated by upstream signaling molecules, and the increase of phospho-T172 indicates that AMPK is activated. When we examined the FOXO3a dependent transcription by using the FHRE-Luc reporter assay, reserpine treatment repressed the FHRE-Luc reporter activity in a dose dependent manner. Finally, we showed that reserpine treatment induced the phosphorylation of AMPK as well as cell death in MCF-7 cells. These results suggest that AMPK is a potential cellular target of reserpine.

Diarylbutane-type Lignans from Myristica fragrans (Nutmeg) show the Cytotoxicity against Breast Cancer Cells through Activation of AMP-activated Protein Kinase

In our program to search for new AMP-activated protein kinase (AMPK) activators from plants that exert potential anticancer property, we found that an EtOAc extract of Myristica fragrans (nutmeg) activated AMPK enzyme in human breast cancer MCF-7 cells. Two major diarylbutane-type lignans, macelignan and meso-dihydroguaiaretic acid (MDGA), were isolated as active principles from this extract. Treatment of breast cancer cells with two compounds induced cellular apoptosis, evidenced by cleavage of poly-(ADP-ribose) polymerase (PARP) and Ser 15 phosphorylation of p53. Moreover, macelignan and MDGA significantly inhibited the colony formation of MCF-7 breast cancer cells on soft agar. Intraperitoneal injection of macelignan and MDGA (20 mg/kg) suppressed the tumor growth of 4T1 mammary cancer cells. These results indicate that the chemopreventive effects of two major diarylbutane-type lignans from Myristica fragrans (nutmeg) may be associated with induction of apoptosis presumably through AMPK activation.

Desalinated underground seawater of Jeju Island (Korea) improves lipid metabolism in mice fed diets containing high fat and increases antioxidant potential in t-BHP treated HepG2 cells

This study was performed to investigate the effect of desalinated underground seawater (named as 'magma seawater', MSW) of Jeju Island in Korea on lipid metabolism and antioxidant activity. MSW was collected from underground of Han-Dong in Jeju Island, and freely given to high fat diet (HFD)-fed C57BL/6 mice for 10 weeks. Although there were no significant differences in the body weight changes and plasma lipid levels, hepatic triglyceride levels were significantly lower in the MSW group than in the normal tap water (TW)-drunken control group. Furthermore, the activity of fatty acid synthase (FAS) was significantly decreased and carnitine palmitoyltransferase (CPT) activity was increased in MSW group compared to TW group. Similarly, real-time PCR analysis revealed that mRNA expressions of lipogenic genes were lowered in MSW groups compared to the control group. In a morphometric observation on the liver tissue, accumulation of fats was remarkably reduced in MSW group. Meanwhile, in vitro assay, free radical scavenging activity measured by using diphenylpicrylhydrazyl (DPPH) was increased in MSW group. The 2'-7'-dichlorofluorescein diacetate (DCF-DA) staining followed with fluorescent microscopy showed a low intensity of fluorescence in MSW-treated HepG2 cells, compared to TW-treated HepG2 cells, which indicated that the production of reactive oxygen species by tert-butyl hydroperoxide (t-BHP) in HepG2 cells was decreased by MSW treatment. The antioxidant effect of MSW on t-BHP-induced oxidative stress in HepG2 cells was supported by the increased activities of intracellular antioxidant enzymes such as catalase and glutathione reductase. From these results, we speculate that MSW has an inhibitory effect on lipogenesis in liver and might play a protective role against cell damage by t-BHP-induced oxidative stress.

The Effect of Polygalasaponins in Polygalae Tenuifolia on Apomorphine-Induced Hyperlocomotions in Mice / 대한정신약물학회지

OBJECTIVE: This study was to investigate in vivo antidopaminergic activities of polygalasaponins which included in the roots of Polygalae tenuifolia, one of the natural plants prescribed to treat psychotic disorders in traditional medicine. METHODS: The chemical separations were conducted by chromatographies with various columns and the chemical structures were identified using spectroscopy, NMR and so on. The apomorphine-induced stereotyped behaviors and climbing behaviors in mice as animal models of psychotic disorders were applied to explore the antidopaminergic activity. RESULTS: The active compounds with antidopaminergic effects in the roots of Polygalae tenuifolia were identified as polygalasaponin A-D. The polygalasaponins showed to suppress the apomorphine-induced stereotyped behaviors and climbing behaviors in dose-related fashions. CONCLUSION: This study suggests that polygalasaponins might have antipsychotic activities. The natural products need to be explored extensively as sources of new medications in psychiatric fields. Further explorations for chemical and pharmacological properties of polygalasaponins are required.

Effects of Polygalae Radix on Apomorphine-Induced Stereotyped Behaviors in Mice / 신경정신의학

OBJECTIVES: This study was to investigate in vivo activities of Polygalae Radix, a natural plant including active components having affinities to central nervous system receptors, using an animal model for psychotic disorders in terms of behavioral psychopharmacology. METHODS: The extracts of Polygalae Radix in two concentrations of 5.0mg/g and 0..5mg/g were administered to mice in order to explore the suppression of apomorphine-induced stereotyped behaviors visually and to compare with the effects of haloperidol and control. 10 mice were tested in each groups. RESULTS: The capacities of suppressing the apomorphine-induced stereotyped behaviors were observed in decreasing order of haloperidol, Polygalae Radix 5.0mg/g, Polygalae Radix 0..5mg/g and control. The extracts of Polygalae Radix in both concentrations suppressed apomorphine- induced stereotyped behaviors significantly, and Polygalae Radix 5.0mg/g was as potent as haloperidol. CONCLUSION: This suggests that Polygalae Radix contain some effective ingredients to influence the central dopamine pathway in vivo. The identification of the chemical structures and the exploration of the biochemical and pharmacological characteristics of active components are to be required through further studies.