School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
Mar Drugs. 2010 Jul 20;8(7):2185-211. doi: 10.3390/md8072185.
Saxitoxin (STX) and its 57 analogs are a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs). PSTs are the causative agents of paralytic shellfish poisoning (PSP) and are mostly associated with marine dinoflagellates (eukaryotes) and freshwater cyanobacteria (prokaryotes), which form extensive blooms around the world. PST producing dinoflagellates belong to the genera Alexandrium, Gymnodinium and Pyrodinium whilst production has been identified in several cyanobacterial genera including Anabaena, Cylindrospermopsis, Aphanizomenon Planktothrix and Lyngbya. STX and its analogs can be structurally classified into several classes such as non-sulfated, mono-sulfated, di-sulfated, decarbamoylated and the recently discovered hydrophobic analogs--each with varying levels of toxicity. Biotransformation of the PSTs into other PST analogs has been identified within marine invertebrates, humans and bacteria. An improved understanding of PST transformation into less toxic analogs and degradation, both chemically or enzymatically, will be important for the development of methods for the detoxification of contaminated water supplies and of shellfish destined for consumption. Some PSTs also have demonstrated pharmaceutical potential as a long-term anesthetic in the treatment of anal fissures and for chronic tension-type headache. The recent elucidation of the saxitoxin biosynthetic gene cluster in cyanobacteria and the identification of new PST analogs will present opportunities to further explore the pharmaceutical potential of these intriguing alkaloids.
石房蛤毒素（STX）及其 57 种类似物是一大类天然神经毒素生物碱，通常被称为麻痹性贝类毒素（PSTs）。PSTs 是麻痹性贝类中毒（PSP）的病原体，主要与海洋甲藻（真核生物）和淡水蓝藻（原核生物）有关，这些生物在世界各地广泛繁殖。产生 PST 的甲藻属于亚历山大藻属、鳍藻属和短裸甲藻属，而几个蓝藻属包括鱼腥藻属、节旋藻属、鱼腥蓝藻属、束丝藻属和 Lyngbya 也被发现有 PST 产生。STX 及其类似物可根据结构分为几类，如非硫酸盐、单硫酸盐、二硫酸盐、脱羧酰胺化和最近发现的疏水性类似物——每一类都具有不同程度的毒性。在海洋无脊椎动物、人类和细菌中，已经确定 PST 会转化为其他 PST 类似物。了解 PST 转化为毒性较低的类似物以及化学或酶促降解的情况，对于开发净化受污染水源和供人类食用贝类的解毒方法非常重要。一些 PST 还具有作为治疗肛裂和慢性紧张型头痛的长期麻醉剂的药用潜力。蓝藻中石房蛤毒素生物合成基因簇的最近阐明以及新 PST 类似物的鉴定将为进一步探索这些有趣生物碱的药用潜力提供机会。
