Protective effect of 2-dodecyl-6-methoxycyclohexa-2, 5-diene-1, 4-dione, isolated from Averrhoa carambola L., against Aß1-42-induced apoptosis in SH-SY5Y cells by reversing Bcl-2/Bax ratio.

BACKGROUND AND PURPOSE: Aß1-42-induced neurotoxicity has been considered as a possible mechanism to aggravate the onset and progression of Alzheimer's disease (AD). In this study, we aim to determine the protective effect of DMDD on the apoptosis of SH-SY5Y cells induced by Aß1-42 and elucidate potential mechanism of DMDD's protective function in apoptosis. EXPERIMENTAL APPROACH: CCK-8, AnnexinV-FITC/PI flow cytometry, and transmission electron microscopy analysis were used to determine the protection of DMDD on Aß1-42-evoked apoptosis of SH-SY5Y cells. Cytochrome c release, JC-1 staining, and measuring the protein of Bcl-2 family by Western blot were applied to elucidate the mechanism of DMDD's protective function in apoptosis. KEY RESULTS: Three concentration of DMDD (5 µmol/L, 10 µmol/L, and 20 µmol/L) rescues the cell viability loss and apoptosis of SH-SY5Y cells cultivated in Aß1-42. The expressions of cleaved Caspase-3, -8, -9, the cytochrome c release, and mitochondrial membrane potential loss were inhibited by DMDD in Aß1-42-insulted SH-SY5Y cells. The Western blot analysis showed that DMDD pretreatment clearly downregulated the protein of Bax and upregulated Bcl-2. Moreover, the Bcl-2/Bax ratio was obviously decreased in cells only exposed to Aß1-42, but, which was suppressed by treated with DMDD. CONCLUSION AND IMPLICATIONS: DMDD attenuated the apoptosis of SH-SY5Y cells induced by Aß1-42 through reversing the Bcl-2/Bax ratio.

Extract of Averrhoacarambola L. (Oxalidaceae) roots ameliorates carbon tetrachloride-induced hepatic fibrosis in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Averrhoa carambola L. (Oxalidaceae), a traditional Chinese medicine, was mainly used in ancient times in the treatment of urinary calculi, recurrent headache and joint pain. AIM OF THE STUDY: Our aims were to explore the potential therapeutic effect of the extract of Averrhoa carambola L. (Oxalidaceae) roots (EACR) against hepatic fibrosis in CCl4-treated rats and to understand the underlying molecular mechanism. MATERIALS AND METHODS: Six groups of male Sprague Dawley rats were treated as follows: vehicle (olive oil), CCl4 alone, CCl4+colchicine, CCl4+EACR 1.0 g/kg, CCl4+EACR 0.5 g/kg and CCl4+EACR 0.25 g/kg. At the end of the 12th week, biomarkers of liver function, liver fibrosis, hepatic oxidative stress and antioxidant status were assayed, and histopathological and immunohistochemical evaluation of liver tissue were conducted to investigate the liver damage and fibrosis degree. Furthermore, expressions of COL-1a1, α-SMA, TGF-ß1, Smad2, smad3, Smad4 and TIMP2 were examined by qPCR and/or western blot. The expressions of apoptosis-related proteins were also detected using western blot analysis. RESULTS: EACR treatment markedly reduced the CCl4-induced elevation of serum aminotransferase activities, liver fibrosis indexes, and the extent of oxidative stress. EACR treatment also significantly reduced the accumulation of collagen and the immunostaining of α-SMA, TGF-ß1 and Smad2, 4 and 7 in the liver of CCl4 treated rats. In addition, EACR treatment markedly reversed the CCl4-induced increase in mRNA expression of COL-1a1, α-SMA, TIMP2, TGF-ß1, Smad2 and Smad4 and suppressed the expressions of α-SMA, TIMP2, TGF-ß1, smad2, 3 and 4, BAX and cleaved caspase-3 proteins. Meanwhile, EACR treatment also significantly elevated the mRNA expression of Smad7 and the protein expression of Smad7 and Bcl-2. CONCLUSION: These results suggest that EACR has protective activity against liver fibrosis. The anti-fibrotic activity of EACR in vivo is associated with enhanced antioxidant, apoptosis-inhibition and increased MMP-2/TIMP-2 expression ratio, and with modulation of TGF-ß1/Smad signaling pathway.

2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione isolated from Averrhoa carambola L. root ameliorates diabetic nephropathy by inhibiting the TLR4/MyD88/NF-κB pathway.

BACKGROUND: Averrhoa carambola L. is a traditional medicinal herb that has long been used to treat diabetes. Our previous studies found that 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) isolated from A. carambola L. roots could ameliorate diabetic nephropathy (DN), but its exact mechanism remains unclear. METHODS: A DN model was established by streptozotocin (STZ, 100 mg/kg body weight) in TLR4 knockout (TLR4-/-, KO) mice and wild-type (WT) mice. Body weight and blood glucose were evaluated after oral administration of DMDD (12.5, 25, 50 mg/kg body weight/d) in diabetic mice. The levels of serum lipids, including TC, TG, HDL, and LDL and kidney function indexes Scr and BUN, were detected by biochemical equipment. The levels of inflammatory cytokines including IL-6 and TNF-α, were determined by ELISA kits. Furthermore, changes in renal ultrastructure were observed by electron microscopy. Western blot analysis and RT-PCR were used to assess the protein expression and mRNA levels of TLR4, MyD88 and NF-κB. RESULTS: DMDD treatment attenuated diabetic nephropathy, as a result of a decline in blood glucose, serum creatinine, and blood urine nitrogen levels and an increase in the quantity and density of podocytes, combined with improved dyslipidaemia. DMDD treatment inhibited the inflammatory response and downregulated the expression of the TLR4/MyD88/NF-κB pathway in diabetic mice, and these changes were significantly different in TLR4-/- mice. CONCLUSION: DMDD alleviates diabetic nephropathy by mitigating kidney damage and inflammation via the inhibition of the TLR4/MyD88/NF-κB signalling pathway.