Cardioprotective Effects of Vitex negundo: A Review of Bioactive Extracts and Compounds.

There has been accumulating interest in the application of medicinal plants as alternative medicine to treat various diseases and/or to develop modern medicines. Vitex negundo is one of such medicinal plants that has been of interest to many researchers and has been of use in traditional medicine. V. negundo is found in Sri Lanka, Madagascar, Malaysia, India, China, The Philippines and East Africa. Therapeutic properties of V. negundo have previously been reviewed. Different parts, preparations and bioactive components of V. negundo possess potential protective and therapeutic effects against cardiovascular disease and related conditions as demonstrated in previous studies. We review the present state of scientific knowledge on the potential use of V. negundo and some of its bioactive components in protecting against cardiovascular diseases and related pathologies. Previous studies in animal and non-animal experimental models, although limited in number and vary in design, seem to support the cardioprotective effect of V. negundo and some of its active components. However, there is need for further preclinical and clinical studies to validate the use of V. negundo and its active constituents in protection and treatment of cardiovascular diseases. Additionally, since only a few V. negundo compounds have been evaluated, specific cardioprotective effects or mechanisms and possible side effects of other V. negundo compounds need to be extensively evaluated.

Anti-inflammatory effect of leaves of Vernonia zeylanica in lipopolysaccharide-stimulated RAW 264.7 macrophages and carrageenan-induced rat paw-edema model.

ETHNOPHARMACOLOGICAL RELEVANCE: Vernonia zeylanica (L.) Less (Family: Compositae) is a medicinal plant used as external applications for boils, bone fractures, eczema and internally for asthma in traditional medicine in Sri Lanka. Anti-nociceptive, anti-bacterial and anti-proliferative activities have been reported previously. AIM OF THE STUDY: To investigate the anti-inflammatory activity of methanol/dichloromethane extract (MDE) of leaves of V. zeylanica by assessing in vivo inhibition of rat paw-edema, in vitro inhibition of the production of nitric oxide (NO) and superoxide and inhibitory effect on inducible nitric oxide synthase (iNOS) gene expression. MATERIALS AND METHODS: In vivo anti-inflammatory activity of MDE was tested at the dose of 1500 mg/kg using rat paw-edema model. Indomethacin and Gum acacia was used as the positive and vehicle control respectively. In vitro NO inhibitory activity of 7.8-250 µg/ml MDE was tested using lipopolysaccharide (LPS)-stimulated (1 µg/ml) mouse macrophages (RAW264.7 cells) and rat peritoneal cells (RPC) obtained following carrageenan-induction (5 mg/Kg). Griess method was used to quantify the nitrite levels in culture supernatants. In vitro inhibition of superoxide production of Phorbal 12-myristate 13-acetate (PMA)-stimulated RAW cells was determined by quantitative Nitroblue Tetrazolium (NBT) assay. N-monomethyl-L-arginine acetate (NMMA) (1 mM) and Diphenyleneiodonium chloride (DPI) (10 µM) were used as the positive controls for inhibitory activity of NO and superoxide production respectively. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis was carried out to test the inhibitory effect on mRNA expression of iNOS gene. RESULTS: Treatment with MDE of V. zeylanica at 1500 mg/kg showed significant inhibition of paw-edema from 1st-5th hour (P < 0.01) compared with the control. The reference drug, indomethacin showed a biphasic pattern and its highest inhibition was (98.3 ± 7.1%) at 4th h (P < 0.01). MDE of V. zeylanica showed similar inhibition of paw-edema with highest inhibition recorded as 94.5 ± 5.28%, at 5th h (P < 0.01). The inhibitory concentration (IC50) of MDE for in vitro NO inhibitory activity was 105 µg/ml for RAW cells and 80 µg/ml for RPCs. Both NO inhibitory activities showed significant dose-dependency (r = 0.998 and r = 0.915 respectively; p < 0.05). MDE concentration of 250 µg/ml showed 55% inhibition of ROS production in RAW cells. NMMA showed 78% and 70.1% inhibition of NO production with RAW cells and RPCs whereas DPI showed 61% superoxide inhibitory activity with RAW cells. NO inhibitory activity of MDE on RAW cells was confirmed by the significant reduction (99.1%) in iNOS gene expression. CONCLUSION: These results demonstrated potent anti-inflammatory activity of MDE of V. zeylanica reflected by its significant in vivo inhibition of rat paw-edema, in vitro inhibition of NO and superoxide production, and the reduction of iNOS gene expression. Thus, further purification and isolation of bioactive compounds from V. zeylanica are emphasized.