Cat's Whiskers Tea (Orthosiphon Stamineus) Extract Inhibits Growth of Colon Tumor in Nude Mice and Angiogenesis in Endothelial Cells via Suppressing VEGFR Phosphorylation

Abstract

Cat's whiskers (Orthosiphon stamineus) is commonly used as Java tea to treat kidney stones including a variety of angiogenesis-dependent diseases such as tumorous edema, rheumatism, diabetic blindness, and obesity. In the present study, antitumor potential of standardized 50% ethanol extract of O. stamineus leaves (EOS) was evaluated against colorectal tumor in athymic mice and antiangiogenic efficacy of EOS was investigated in human umbilical vein endothelial cells (HUVEC). EOS at 100 mg/kg caused 47.62 ± 6.4% suppression in tumor growth, while at 200 mg/kg it caused 83.39 ± 4.1% tumor regression. Tumor histology revealed significant reduction in extent of vascularization. Enzyme-linked immunosorbent assay showed EOS (200 mg/kg) significantly reduced the vascular endothelial growth factor (VEGF) level in vitro (211 ± 0.26 pg/ml cell lysate) as well as in vivo (90.9 ± 2 pg/g tissue homogenate) when compared to the control (378 ± 5 and 135.5 ± 4 pg, respectively). However, EOS was found to be noncytotoxic to colon cancer and endothelial cells. In vitro, EOS significantly inhibited the migration and tube formation of human umbilical vein endothelial cells (HUVECs). EOS suppressed VEGF-induced phosphorylation of VEGF receptor-2 in HUVECs. High performance liquid chromatography (HPLC) analysis of EOS showed high rosmarinic acid contents, whereas phytochemical analysis revealed high protein and phenolic contents. These results demonstrated that the antitumor activity of EOS may be due to its VEGF-targeted antiangiogenicity.

Proapoptotic and Antimetastatic Properties of Supercritical CO2 Extract of Nigella sativa Linn. Against Breast Cancer Cells

“…10,13 Phenolic compounds counteract cancer either by means of antioxidant effect or by inhibiting the formation of carcinogenic metabolites that damage the vital biomolecules. 33,34 Studies have shown that flavonoids have potent cytotoxic activities by induction of the apoptosis pathway. 35 In this study, the A3 extract was rich in total flavonoids and polyphenols, which might have contributed toward its overall anticancer effects observed in MCF-7 cells.…”

Anti-obesity Potential of Selected Tropical Plants via Pancreatic Lipase Inhibition

“…O. stamineus contains several chemically active constituents, but one of the most important classes of compounds is the phenolic group [70]. A study of 50% ethanol extract of O. stamineus leaves for its anti-tumor potential showed an ability to inhibit colon tumor in mice could be attributed mainly to its antioxidant-rich polyphenolic contents, the caffeic acid derivatives, polymethoxylated flavonoids and terpenes; particularly rosmarinic acid, eupatorin, sinensetin, 3′-hydroxy-5,6,7,4′-tetramethoxyflavone, and betulinic acid [71]. The authors found that flavonoids and phenolics in the extract possessed very promising antiangiogenic properties.…”

Use of Nigella sativa Linn. Supercritical Carbon Dioxide Extract for Targeting the Angiogenesis Cascade

“…Inhibitory effect of A3 and B3 on tube-like networks of HUVECs on matrigel matrix was investigated as previously described [35]. In brief, a layer of matrigel (150 μL/well) was added to 48 well plate and allowed to solidify for 45 min in an incubator at 37°C and 5% CO 2 .…”