Curcumolide reduces diabetic retinal vascular leukostasis and leakage partly via inhibition of the p38MAPK/NF-κ B signaling.

Retinal inflammation in a hyperglycemic condition is believed to play a crucial role in the development of diabetic retinopathy, and targeting inflammatory mediators is a promising strategy for the control of diabetic retinopathy. Curcumolide, a novel sesquiterpenoid with a unique 5/6/5 tricyclic skeleton, was isolated from Curcuma wenyujin. In this study, we demonstrate that treatment with curcumolide alleviated retinal inflammatory activities both in vitro and in vivo in a STZ-induced diabetic rat model and in TNF-α-stimulated HUVECs. Curcumolide alleviated retinal vascular permeability and leukostasis and attenuated the overexpression of TNF-α and ICAM-1 in diabetic retinas. Moreover, curcumolide also inhibited inducible p38 MAPK and NF-κB activation and the subsequent induction of proinflammatory mediators. These data suggest potential treatment strategies against diabetic retinopathy, particularly in the early stages of the disease.

Curcumolide, a unique sesquiterpenoid from Curcuma wenyujin displays anti-angiogenic activity and attenuates ischemia-induced retinal neovascularization.

BACKGROUND: Targeting vascular endothelial growth factor is a common treatment strategy for neovascular eye disease, a leading cause of visual impairment and blindness. However, these approaches are limited or carry various complications. Therefore, there is an urgent need for the development of unique therapeutic approaches. PURPOSE: To investigate the anti-angiogenic effects of curcumolide and its mechanism of action. METHODS /STUDY DESIGNS: In this study, we examine the effects of curcumolide on the process of vasculature formation, including cell proliferation, migration, tube formation and apoptosis in vitro using human umbilical vascular endothelial cells (HUVECs). We also assess the anti-angiogenic effects of curcumolide in vivo using a mouse model of oxygen induced retinopathy (OIR). The mechanism of anti-angiogenic effects was investigated by measuring the expression level of various signaling proteins and the molecular docking simulations. RESULTS: Intravitreal injection of curcumolide reduced the formation of retinal neovascular tufts and VEGFR2 phosphorylation in the murine OIR model at concentrations administered without definite cellular and retinal toxicities. Curcumolide suppressed VEGF-induced HRMECs proliferation, migration and tube formation in a dose-dependent manner. Meanwhile, it promoted caspase-dependent apoptosis. Curcumolide also inhibited VEGF-induced phosphorylation of VEGFR-2 tyrosine kinase, and suppressed downstream protein kinases of VEGFR2, including Src, FAK, ERK, AKT, and mTOR in HRMECs. In silico study revealed that curcumolide bound with ATP-binding sites of the VEGFR2 kinase unit by the formation of a hydrogen bond and hydrophobic interactions. CONCLUSION: Curcumolide has anti-angiogenic activity in HUVECs and in a murine OIR model of ischemia-induced retinal neovascularization, and it might be a potential drug candidate for the treatment of proliferative diabetic retinopathy.

Substolides A-G, germacrane sesquiterpenoids from Salvia substolonifera.

Chemical investigation of the whole plants of Salvia substolonifera E.Peter yielded seven germacrane sesquiterpenoids, substolides A-G (1-7), an ethoxylated artifact (8), and two known analogues, 6ß-tigloyloxyglechomafuran (9) and castanin F (10). Four germacrane 8-acetylation derivatives (1a-4a) were obtained by chemical transformation. Their structures and relative or absolute configurations were elucidated by intensive spectroscopic methods, and single-crystal X-ray diffraction analysis. Compounds 1a-4a, and 5-10 were evaluated for their in vitro anti-angiogenic effects. Compounds 7 and 9 significantly inhibited VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation in vitro, with IC50 values of 16.15 ± 0.19, and 4.03 ± 0.26 µM, respectively. The structure activity relationship of these compounds is discussed.