chlorophyll-a and gramine

The effects of five natural products from Chinese herbs including evodiamine, curcumin, 4-methoxysalicylaldehyde, esculin hydrate, and gramine on the growth of Chattonella marina, one of the most noxious red tide algae, were observed. Among them, gramine exhibited the highest inhibitory rate with LC50, 96h of 0.51 mg/l. After exposure to gramine, the activities of superoxide dismutase (SOD) and catalase (CAT), and content of malondialdehyde (MDA) increased in C. marina, suggesting that gramine could induce microalgae oxidative stress. In addition, chlorophyll a and the maximum quantum yield of photosynthesis (Fv/Fm) decreased following exposure to gramine, indicating the inhibition of photosynthesis activity in the microalgae. Combined with the fast inhibition against the algal cells and environmentally friendly character of gramine, we proposed that gramine might be a potential algaecide against marine harmful algae and that the oxidative damage and photosynthesis inhibition might be responsible for the toxicity of gramine on harmful algae.

Topics: Alkaloids; Benzaldehydes; Biological Products; Catalase; Chlorophyll; Curcumin; Drugs, Chinese Herbal; Harmful Algal Bloom; Indole Alkaloids; Malondialdehyde; Microalgae; Oxidation-Reduction; Oxidative Stress; Photosynthesis; Quinazolines; Stramenopiles; Superoxide Dismutase

Allelochemical action against planktonic phototrophs is one central issue in freshwater ecology and quality management. To determine some basic mechanisms of this toxic action, we exposed the coccal green alga, Desmodesmus armatus, and the coccal cyanobacterium, Microcystis aeruginosa, in a batch culture well-supplied with carbon dioxide to increasing concentrations of the polyphenols tannic acid and gallic acid and the alkaloid gramine. The phototrophs were checked after 2d and at the end of the culture for biomass-based growth rates, cell volume, maximum quantum yield of photosystem II (ΦPSIImax), chlorophyll a content (chla) after 2d and at the end of the culture, and lipid peroxidation only at the end of the culture. During the culture, the pH rose from 7.64 to 10.95, a pH characteristic of eutrophic freshwater bodies during nuisance algal blooms. All xenobiotics reduced the growth rate, ΦPSIImax, and chla during the first 2d with M. aeruginosa being more sensitive to the polyphenols than D. armatus. The efficacy of the polyphenols declined with increasing pH, indicating potential polymerization and corresponding reduced bioavailability of the polyphenols. In contrast to the polyphenols, gramine increased its toxic action over time, independent of the prevailing pH. All exposures caused slight to severe lipid peroxidation (LPO) in the phototrophs. Hence, one mechanism of growth inhibition may be oxidative stress-mediated reduction in photosynthesis. The presented results suggest that in successful field trials with leachate, the prevailing environmental conditions may inactivate polyphenols and xenobiotics other than polyphenols may be more effective.

Topics: Alkaloids; Chlorophyll; Chlorophyll A; Cyanobacteria; Fresh Water; Gallic Acid; Indole Alkaloids; Microcystis; Oxidation-Reduction; Oxidative Stress; Photosynthesis; Photosystem II Protein Complex; Tannins; Xenobiotics