Antimicrobial, antiparasitic, anti-inflammatory, and cytotoxic activities of Lopezia racemosa

Abstract

The present study investigates the potential benefits of the Mexican medicinal plant Lopezia racemosa (Onagraceae). Extracts and fractions from aerial parts of this plant were assessed to determine their antibacterial, antifungal, antiparasitic, anti-inflammatory and cytotoxic activities in vitro. Aerial parts of the plant were extracted with various solvents and fractionated accordingly. Extracts and fractions were tested against a panel of nine bacterial and four fungal species. The antiparasitic activity was tested against Leishmania donovani, whereas the anti-inflammatory activity of the compounds was determined by measuring the secretion of interleukin-6 from human-derived macrophages. The same macrophage cell line was used to investigate the cytotoxicity of the compounds. Various extracts and fractions showed antibacterial, antifungal, antiparasitic, and anti-inflammatory activities. The hexanic fraction HF 11-14b was the most interesting fraction with antimicrobial, and anti-inflammatory activities. The benefit of L. racemosa as a traditional medicinal plant was confirmed as shown by its antibacterial, antifungal and anti-inflammatory activities. To the best of our knowledge, this is the first study reporting the biological activities of L. racemosa, including antiparasitic and anti-inflammatory activities.

Figure 1

Antiparasitic activity exhibited by fractions of Lopezia racemosa. Leishmania donovani promastigote growth inhibition was evaluated after incubation of the parasites with extracts and fractions. Untreated promastigotes and DMSO were used as negative controls. Shown is the mean ± SE of three independent experiments. *P value < 0.05. CE, chloroform extract; HF and MF represent hexanic and methanolic fractions, respectively.

Figure 2

Cytotoxic effects of extracts and fractions of Lopezia racemosa. Human macrophages (THP-1 cells) were used to assess the cytotoxic effects of bioactive compounds using propidium iodide staining. Dashed lines represent treatment with 5% H₂O₂ (upper line) (positive control), and untreated cells (lower line) (negative control). Shown is the mean ± SE of three independent experiments. *P value < 0.05. HE, CE, and ME are hexane, chloroform, and methanol extracts, respectively. HF, CF, and MF represent hexanic, chloroformic, and methanolic fractions, respectively.

Figure 3

Anti-inflammatory activity of extracts and fractions from Lopezia racemosa. An inflammatory process was elicited by exposing macrophages to LPS. Extracts and fractions were exposed overnight to macrophages prior to the addition of LPS. The anti-inflammatory process was evaluated by measuring the secretion of IL-6 into the supernatant. Shown is the mean ± SE of three independent experiments. *P value < 0.05. HF, methanolic fraction.