Study on the Steroid Chemical Composition of Phyllospongia sp. from the South China Sea Cup Leaf Sponge
Sponges belong to the phylum Porifera, which is the most primitive lower multicellular animal. The diverse habitat and primitive evolutionary status of sponges enable them to produce and accumulate a large number of structurally novel secondary metabolites with different biological activities such as anti-tumor, antiparasitic, antiviral, antibacterial, anti-inflammatory, and immune regulation. They are the primary source of marine natural products. The South China Sea is vast and one of the areas where sponges are concentrated in the world. For many years, South China Sea sponges have been a hot topic in the study of marine natural product chemistry. As early as 1933, Professor Bergmann of Yale University in the United States began studying the chemical composition of sponges and obtained steroid components from them. In 1951, he isolated nucleoside compounds such as spongothymidine and spongouridine from the sponge Phyllospongia sp; The later antiviral drug adenosine and anticancer drug cytarabine are synthetic analogues of spongothimidine. Laulimalide, peloruside A, salicylihalimide A, variolins, and dictyodendrins obtained from sponge research have entered preclinical studies as anti-tumor drugs.
The research object of this article is Phyllospongia sp., a sponge belonging to the Demospongiae class, Dictyoceratida order, and Spongidae family. At present, many research groups at home and abroad have conducted a series of studies on this sponge, and have isolated many structurally novel secondary metabolites, including sesquiterpenes, steroids, diphenyl ethers, glycerolipids, and ceramides. Most of them contain unique tetracyclic or pentacyclic scalarane type sesquiterpenes and steroids. However, there are few reports on its biological activity. In order to better elucidate the bioactive components in Phyllosponia sp., various modern chromatographic and spectroscopic techniques were comprehensively used in this experiment to study the compounds isolated from the petroleum ether and ethyl acetate parts of the extract, and to screen for their cytotoxic activity. This enriched the composition of Phyllosponia sp. and laid the foundation for the development and utilization of active components in this sponge in the future.
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In this paper, the chemical constituents of Phyllospongia sp. collected from the the Xisha Islands in the South China Sea were studied. Eight steroids were isolated from petroleum ether and dichloromethane for the first time, and their cytotoxicity to MCF-7 (human breast cancer cells), HT-29 (human colon cancer cells) and Hep-2 (human laryngeal cancer epithelial cells) was tested by MTT method. Among them, compounds 1, 3, 4, 6, and 8 were weak against human colon cancer cells HT-29, with IC50 greater than 83 μ mol/L; Compounds 1, 2, and 7 showed significant cytotoxic activity against MCF-7 cells, with IC50 values of 8.8, 10.3, and 3.9 μ mol/L, respectively; Compound 2 exhibits good cytotoxic activity against Hep-2, with an IC50 of 10.6 μ mol/L. The experimental results showed that the cytotoxic activity of compound 7 was superior to the positive control drug cisplatin group. Due to the low content of this compound and the lack of literature reporting significant activity, it has the potential to develop into a new anti-tumor drug through structural modification or organic synthesis. These works further investigate and study the sponge resources and biological activities in the South China Sea and Xisha Islands, and provide reference for seeking new anti-tumor chemical structures and lead compounds with high efficiency and low toxicity.