Effects of methanolic extract from leaves of Rubus imperialis in DSS-induced colitis in mice

Toxicological assessment of niga-ichigoside F1 and 2β,3β-19α-trihydroxyursolic acid derived from Rubus imperialis (Rosaceae): determining the safety using human peripheral blood mononuclear cells (PBMC)

Rubus imperialis Chum. Schl. (Rosaceae) is used in traditional medicine as a remedy to treat diabetes and other diseases. However, there are reports that the extract of this plant and others of the Rubus genus may produce cellular and/or genetic toxicity. Niga-ichigoside F1 (NIF1) and 2β,3β-19α-trihydroxyursolic acid (2B) are major compounds found in R. imperialis extract known to exert pharmacological effects which may be responsible for the observed toxicity. Thus, this study was aimed to examine the cytogenotoxic potential of NIF1 and 2B in human peripheral blood mononuclear cells (PBMC) following acute exposure. Cytotoxicity was determined by trypan blue staining and genotoxicity by micronucleus and comet assays. Data obtained showed that both compounds, at concentrations ranging from 0.1 and 20 µg/ml, did not markedly affect cell viability. In addition, genetic toxicity testing (comet assay) detected no evidence of DNA damage or chromosomal mutations by the micronucleus test. Under these experimental conditions and considering that both compounds exhibit biological effects at low concentrations, it may be concluded that NIF1 and 2B did not induce cytogenotoxic effects in primary human PBMC.

Risk assessment of 2β,3β-19α-trihydroxyursolic acid from Rubus imperialis (Rosaceae) in HepG2/C3A cells via genotoxicity, metabolism, and cell growth

Rubus imperialis (Rosaceae) is a Brazilian medicinal plant that already exhibited therapeutical perspectives. However, previous studies revealed cellular and/or genetic toxicity of extracts from aerial parts of this plant, as well as other species of the Rubus genus. Being 2β,3β-19α-trihydroxyursolic acid (2B) one of the major compounds of this plant, with proven pharmacological effect, it is important to investigate the biosafety of this isolated compound. Therefore, in the present study, (2B) was tested by several cytogenotoxic endpoints up to 20 μg/ml in human hepatoma HepG2/C3A cells. The test compound did not produce any decreased cell viability, DNA damage, chromosomal mutations, cell cycle changes, or apoptotic effects in the tested cells. Additionally, RT-qPCR analysis revealed the downregulation of CYP3A4 (metabolism), M-TOR (cell death), and CDKN1A (cell cycle) genes. Under the experimental conditions used, the 2B compound did not show cytogenotoxic activity after a single exposure to HepG2/C3A human cells.

Hydroalcoholic extract of Tagetes erecta L. flowers, rich in the carotenoid lutein, attenuates inflammatory cytokine secretion and improves the oxidative stress in an animal model of ulcerative colitis

Given the role of oxidative stress in ulcerative colitis (UC) etiology, and the amount of lutein (a carotenoid with antioxidant properties) in the dry hydroalcoholic extract of Tagetes erecta flowers (DHETE), this study investigated the intestinal anti-inflammatory properties of DHETE in an animal model of UC. The amount of lutein in the extract was determined by ¹H-nuclear magnetic resonance spectroscopy, and total phenols, radical scavenger capability, cytotoxicity, and effects on reactive oxygen species and nitric oxide production were evaluated in vitro. Experimental UC was established by adding 5% dextran sulfate sodium (DSS) to drinking water, with the effects of DHETE (30-300 mg/kg, once a day for 7 days) on the morphological (colon length and weight), clinical (disease activity index and body weight loss), microscopic (histological score and mucin levels), and biochemical parameters analyzed. The lutein concentration found in DHETE was 8.2%, and DHETE scavenged 2,2-diphenyl-1-picrylhydrazyl radicals at 1000 μg/mL The exposure of intestinal epithelial cells to DHETE did not change its viability but reduced reactive oxygen species and nitric oxide production after lipopolysaccharide stimulation. In vivo, DHETE (300 mg/kg) attenuated weight loss, disease activity index, colon shortening, and histopathological changes promoted by DSS intake. Moreover, DHETE increased mucin colonic staining. The treatment with DHETE decreased myeloperoxidase activity as well as tumor necrosis factor and interleukin-6 levels. The extract also increased reduced glutathione levels and catalase activity and normalized superoxide dismutase and glutathione-S-transferase activities. In conclusion, DHETE reduced colitis severity by attenuating inflammatory cytokine secretion and improved the endogenous antioxidant defense in DSS-induced UC in mice.