Kolaviron, Biflavonoid Complex from the Seed of Garcinia kola Attenuated Angiotensin II- and Lypopolysaccharide-induced Vascular Smooth Muscle Cell Proliferation and Nitric Oxide Production

INTRODUCTION: Kolaviron (KV), a biflavonoid extract from Garcinia kola seeds has been reported to possess anti-inflammatory, anti-oxidant, hepato-protective, cardio-protective, nephro-protective and other arrays of chemopreventive capabilities but the mechanism of action is still not completely understood. MATERIALS AND METHODS: In this study, we investigated the anti-proliferative, anti-inflammatory and anti-oxidative potential of KV in cultured Vascular Smooth Muscle Cells (VSMCs). Effects of KV (25-100 μg/mL) on VSMC proliferation alone or following treatments with mitogen and proinflammatory agents Angiotensin II (Ag II, 10(-6) M) and lipopolysaccharide (LPS, 100 μg/mL) and effects on NO production were determined. Cellular proliferations were determined by MTT assay, nitric oxide (NO) level was determined by Griess assay. KV dose-and time dependently attenuated VSMC growth. RESULTS: Treatment of VSMCs with Ag II and LPS significantly enhanced proliferation of the cell which was significantly attenuated by the treatment with KV. Treatment of VSMC with LPS significantly increased nitric oxide (NO) level in the media which was attenuated by KV. These results demonstrated anti-proliferative anti-inflammatory properties of KV as it clearly inhibited cellular proliferation induced by mitogens as well as LPS-induced inflammatory processes. CONCLUSION: Therefore, KV may mitigate cardiovascular conditions that involve cell proliferation, free radical generation and inflammatory processes such as hypertension, diabetes and stroke. However, the molecular mechanism of action of KV needs to be investigated. SUMMARY: Angiotensin-induced cell proliferation. Kolaviron mitigates angiotensin-induced cell proliferation. Kolaviron ameliorates nitric oxide production. Kolaviron offers antioxidant activity. Abbreviations Used: VSMCs: Vascular Smooth Muscle Cells, Ag II: Angiotensin II, KV: Kolaviron, LPS: lypopolysaccharide, NO: Nitric Oxide, DMEM: Dulbecco's modified Eagle's medium, MTT: (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide), DMSO: Dimethylsulfoxide, GB1: Garcinia kola biflavonoid-1, GB2: Garcinia kola biflavonoid-2, ROS: Reactive oxygen species, ET-1: Endothelin-1, NF-κB: Nuclear factor-kappa beta, COX-2: Cyclooxygenase-2