Abstract
The extract of sea anemone Gyrostoma helianthus (Cnidaria, Anthozoa) has been reported as a source of neuroactive compounds. The current study was designed to explore biogenic monoamine effects of sea anemone crude extract in relation to histopathological changes in brain areas and plasma glutathione shuttling. Mouse bioassays were used to determine the dose response curve and behavioral neurotoxicity. Loss of balance, opaque eyes, tonic convulsions, paralysis, muscle flexing, and exophthalmia were the major behavioral changes observed. The LD50 in mice was identified as 29 mg/kg body weight after IP injection, which is calculated to be 20.3 mg/kg body weight in rats using a conversion table. Serotonin, dopamine, and norepinephrine were significantly increased in the cerebral cortex, cerebellum and pons plus medulla oblongata in rats in our 3-day study after a single IP injection of ½ LD50 of the crude extract. The greatest increases in serotonin, dopamine, and norepinephrine were attained in the cerebral cortex. Cells examined in the cerebral cortex and hippocampus showed necrosis, pyknosis, focal gliosis, and congestion of cerebral blood vessels as well as focal cerebral and hippocampus hemorrhage. At the tested dose, the extract caused significant decreases in plasma glutathione and G-reductase, while G-transferase levels were increased.
Highlights
In the field of natural products, marine organisms have a rich heritage as therapeutic resources that have been exploited for effective and beneficial use against many human diseases [1], and some have been used to investigate novel drugs [2]
The curve plateaued at the 6 mg.ml-1 dose with a response of 3.8 Mouse Units (MU)
Plate 2: Effect of sea anemone crude extract on cortical neurons of a male albino rat showing focal cerebral necrosis infiltrated with glia cells [A], focal gliosis [B], demyelination of nerve fibers [C], and focal cerebral necrosis [D]. [400X]
Summary
In the field of natural products, marine organisms have a rich heritage as therapeutic resources that have been exploited for effective and beneficial use against many human diseases [1], and some have been used to investigate novel drugs [2]. Sea anemones are one of the most ancient predatory marine animals. Pharmaceutical studies have demonstrated that the venom of several species of sea anemones produces different symptoms and modes of toxicity. Several studies have accumulated data attributing the effect to the diversity of polypeptide toxins [9]. It is increasingly recognized that many marine toxins interact with a large variety of excitable membranes, including myelinated and non-myelinated axons [10], neuronal cells [11] and nerve terminals [12]. Many have shown activity with diverse receptors and voltage-gated ion channels [9]. Other investigators have reported that sea anemones’ toxin provokes neurotransmitter release from synaptosomes, acts on different receptor structures in the membrane [13], and/or inhibits AChE activity [14]
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