Blechnum Orientale Linn - a fern with potential as antioxidant, anticancer and antibacterial agent

<p>Abstract</p> <p>Background</p> <p><it>Blechnum orientale </it>Linn. (<it>Blechnaceae</it>) is used ethnomedicinally for the treatment of various skin diseases, stomach pain, urinary bladder complaints and sterilization of women. The aim of the study was to evaluate antioxidant, anticancer and antibacterial activity of five solvent fractions obtained from the methanol extract of the leaves of <it>Blechnum orientale </it>Linn.</p> <p>Methods</p> <p>Five solvent fractions were obtained from the methanol extract of <it>B. orientale</it> through successive partitioning with petroleum ether, chloroform, ethyl acetate, butanol and water. Total phenolic content was assessed using Folin-Ciocalteu's method. The antioxidant activity was determined by measuring the scavenging activity of DPPH radicals. Cytotoxic activity was tested against four cancer cell lines and a non-malignant cell using MTT assay. Antibacterial activity was assessed using the disc diffusion and broth microdilution assays. Standard phytochemical screening tests for saponins, tannins, terpenoids, flavonoids and alkaloids were also conducted.</p> <p>Results</p> <p>The ethyl acetate, butanol and water fractions possessed strong radical scavenging activity (IC₅₀8.6-13.0 μg/ml) and cytotoxic activity towards human colon cancer cell HT-29 (IC₅₀27.5-42.8 μg/ml). The three extracts were also effective against all Gram-positive bacteria tested: <it>Bacillus cereus, Micrococcus luteus</it>, methicillin-susceptible <it>Staphylococcus aureus </it>(MSSA), methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) and <it>Stapylococcus epidermidis</it>(minimum inhibitory concentration MIC 15.6-250 μg/ml; minimum bactericidal concentration MBC 15.6-250 μg/ml). Phytochemical analysis revealed the presence of flavonoids, terpenoids and tannins. Ethyl acetate and butanol fractions showed highest total phenolic content (675-804 mg gallic acid equivalent/g).</p> <p>Conclusions</p> <p>The results indicate that this fern is a potential candidate to be used as an antioxidant agent, for colon cancer therapy and for treatment of MRSA infections and other MSSA/Gram-positive bacterial infectious diseases.</p

Evaluation of the antimicrobial activity of crude extracts and chromatographic fractions of Adenanthera pavonina Linn (Leguminosae) seeds

Most available reports on the biological activity of Adenanthera pavonina (AP) are on the bark or leaves and very few are on the seeds. In particular, there are no reports on the biological effects of the chromatographic fractions of A. pavonina seeds hence the present study aimed to evaluate the antimicrobial activity of the crude extract and chromatographic fractions of A. pavonina seeds. The methanolic extract was fractionated and all of the column chromatographic fractions as well as the crude extract were evaluated against different strains of Staphylococcus aureus. The methanolic extract (100 mg/ml) produced zones of inhibition on PHM 002 and PHM 005 while the 50 and 100 mg/ml of the hexane extract only produced inhibition on PHM 001. On the other hand, fractions ST 10-12 F exhibited activity PHM 002 at 50 and 100 mg/ml while fractions ST-13-15F exhibited activity at all concentrations (6.25, 12.5 25, 50 and 100 mg/ ml) against S. aureus PHM 002 strain from the skin. The study provides some justifications for the folkloric use of AP seed powder as an antiseptic paste and warrants further studies to determine the structure of the active compound in chromatographic fraction ST 13 -15F.Key words: Adenanthera pavonina, antimicrobial activity, chromatographic fractions, methanolic extract