The anti-inflammatory alkaloid aloperine in Chinese herbal medicine is potentially useful for management of pain and itch

Aloperine improves osteoporosis in ovariectomized mice by inhibiting RANKL-induced NF-κB, ERK and JNK approaches

Presently, postmenopausal osteoporosis mainly caused by excessive activation of in vivo osteoclasts has become a global public health burden. Natural compounds have gradually become the potential drugs for the treatment of postmenopausal osteoporosis. Aloperine is a new alkaloid extracted from the leaves and seeds of sophora bean. The current studies have proved that aloperine has many biological activities, including anti-inflammatory, antiviral and anticancer activities. This study shows that aloperine can inhibit activity and formation of osteoclast mediated by RANKL in a dose-dependent manner without affecting the activity of bone marrow macrophages (BMM). In addition, it is found that aloperine can inhibit the expression of osteoclast specific marker genes, including nuclear factor of activated T cells cytoplasmic 1 (NFATc1), tartrate resistant acid phosphatase (TRAcP), matrix metallopeptidase 9 (MMP9), cathepsin K (Ctsk), V-ATPase d2 and calcitonin receptor. The in vitro experiment of aloperine proved that aloperine can inhibit the degradation of IκBα and the phosphorylation of P65, ERK and JNK. Additionally, aloperine improves bone loss in ovariectomized (OVX) mice by inhibiting osteoclast activity. This project proved that aloperine can affect the formation of osteoclasts by inhibiting RANKL signaling channel, and it is indicated that aloperine has the potential to be developed as a new drug for the prevention and treatment of postmenopausal osteoporosis.

Aloperine protects human retinal pigment epithelial cells against hydrogen peroxide-induced oxidative stress and apoptosis through activation of Nrf2/HO-1 pathway

Age-related macular degeneration (AMD) is a complex multifactorial disease associated with the dysfunction of retinal pigment epithelium (RPE). Aloperine is a quinolizidine alkaloid that has been proven to possess broad pharmacological activities. However, the effects of aloperine on AMD remain unclear. In the present study, we used hydrogen peroxide (H₂O₂) to induce oxidative injury in human RPE cells (ARPE-19 cells). ARPE-19 cells were pretreated with different concentrations of aloperine for 2 h, followed by H₂O₂ exposure. Cell cytotoxicity was determined using lactate dehydrogenase (LDH) release assay. Cell viability was measured using Cell Counting Kit-8 (CCK-8) assay. The reactive oxygen species (ROS) generation, malondialdehyde (MDA) level, superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-PX) activity were detected to reflect oxidative status. Western blot was performed to detect the expressions of bcl-2, bax, nuclear factor-erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). The activity of caspase-3 was also assessed to indicate cell apoptosis. In addition, ARPE-19 cells were transfected with siNrf2 to knock down Nrf2. Our results showed that pretreatment with aloperine elevated the reduced cell viability of H₂O₂-induced ARPE-19 cells in a dose-dependent manner. Aloperine greatly decreased the production of ROS and MDA, and increased the activities of SOD and GSH-PX in H₂O₂-stimulated ARPE-19 cells. H₂O₂-caused a decrease in bcl-2 expression and increases in bax expression and caspase-3 activity were mitigated by aloperine. Moreover, aloperine treatment enhanced the expression levels of Nrf2 in nuclear fraction and the HO-1 expression in lysates. Knockdown of Nrf2 reversed the protective effects of aloperine on H₂O₂-induced ARPE-19 cells. In conclusion, these findings demonstrated that aloperine protected ARPE-19 cells from H₂O₂-induced oxidative stress and apoptosis in part via activating the Nrf2/HO-1 signaling pathway. The findings suggested a therapeutic potential of aloperine for the treatment of ADM.