The anticancer activity of visnagin, isolated from Ammi visnaga L., against the human malignant melanoma cell lines, HT 144.

Melanoma is a cancer of melanocyte cells and has the highest global incidence. There is a need to develop new drugs for the treatment of this deadly cancer, which is resistant to currently used treatment modalities. We investigated the anticancer activity of visnagin, a natural furanochromone derivative, isolated from Ammi visnaga L., against malignant melanoma (HT 144) cell lines. The singlet oxygen production capacity of visnagin was determined by the RNO bleaching method while cytotoxic activity by the MTT assay. Further, HT 144 cells treated with visnagin were also exposed to visible light (λ ≥ 400 nm) for 25 min to examine the illumination cytotoxic activity. The apoptosis was measured by flow cytometry with annexin V/PI dual staining technique. The effect of TNF-α secretion on apoptosis was also investigated. In standard MTT assay, visnagin (100 µg/mL) exhibited 80.93% inhibitory activity against HT 144 cancer cell lines, while in illuminated MTT assay at same concentration it showed lesser inhibitory activity (63.19%). Visnagin was induced apoptosis due to the intracellular generation of reactive oxygen species (ROS) and showed an apoptotic effect against HT 144 cell lines by 25.88%. However, it has no effect on TNF-α secretion. Our study indicates that visnagin can inhibit the proliferation of malignant melanoma, apparently by inducing the intracellular oxidative stress.

Khellin and visnagin in different organs of Ammi visnaga and Ammi majus.

Ammi visnaga and Ammi majus are plants that have long been used in traditional medicine. Nowadays, both herbs are commercially marketed as alternative medicines in different formulations. The main active ingredients of A. visnaga are known as khellin and visnagin. Information on the quantitative amounts of both bioactive substances in the different organs of the plant is lacking. This study aims to determine the amounts of these two active substances in the five organs of both plants from Turkey and provide information to the pharmaceutical industry. For this purpose, a fast and reliable micellar electrokinetic chromatography method was applied. It was found that Ammi visnaga, flowers, seeds, and leaves are good sources of both khellin and visnagin. Ammi majus only contains khellin in its seeds and flowers.

Synthesis, characterization and antioxidant activity of chitosan Schiff base derivatives bearing (-)-gossypol.

In this work, two new chitosan-Schiff base derivatives (HCS-GSP and LCS-GSP) were synthesized by the condensation reaction of high molecular weight chitosan (HCS) and low molecular weight chitosan (LCS) with (-)-gossypol (GSP), respectively. For this purpose, racemic gossypol was isolated from cotton seeds and it was further enantiomerically purified by diastereomeric resolution technique using l-tryptophan methyl ester hydrochloride. Then, chitosan polymers were derivatized with (-)-gossypol by the condensation reaction. The isolated and synthesized coumpounds were characterized by physical measurements and spectroscopic methods (elemental analysis C,H,N, Uv-vis, FT-IR, 1H&13C NMR and TG/DTG/DTA). The antioxidant activity of high molecular weight chitosan (HCS), low molecular weight chitosan (LCS) and their gossypol derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-gossypol derivatives (HCS-GSP and LCS-GSP) had a better ability to scavenging DPPH radical (IC50, 12 µg/mL and 16 µg/mL, respectively) than its unmodified chitosan.

Synthesis, characterization and antioxidant activity of chitosan-chromone derivatives.

In this study, a new chromone-functionalized chitosan Schiff base and its cross-linked derivative were synthesized and characterized by FT-IR, UV-vis, 13C CP/MAS solid-state NMR, TGA, XRD-powder and SEM measurements and elemental analysis data. Degrees of substitution (DS) were determined from the elemental analysis by using the C/N ratios. The in vitro antioxidant activity of high molecular chitosan and its chromone derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-chromone derivatives have good antioxidant potential which might be due to the phenolic group introduced after chemical modification of chitosan with a chromone derivative. Chromone-chitosan Schiff base (CSCH) had a better ability to scavenging DPPH radical (IC50, 0.88mg/mL) than that of its cross-linked derivative (CSCH-TP) obtained by using terephthalaldehyde (IC50, 1.32mg/mL).

The chemical investigations on the ripe fruits of Ammi visnaga (Lam.) Lamarck growing in Turkey.

Two furanochromones and one furanochromone glycoside were isolated from the fruits of Ammi visnaga (L.) Lam. They were identified as khellin, visnagin, and khellol glycoside by interpretation of spectral analyses. Quantitative determination of furanochromones in A. visnaga (L.) ripe fruits from Hatay region (Turkey) was carried out by ultraviolet spectrophotometry and gas chromatography. In addition, photochemical properties of furanochromones and chemical composition of essential oil were determined.