# Marine-Originated Materials and Their Potential Use in Biomedicine
## 3 Marine Sponge-Originated Components
### Biomedical Applications of Marine Sponge-Originated Components  
Marine sponges are rich in secondary metabolites of pharmaceutical significance. Most of them are microbial origins, which symbiotically exist due to sponges [52]. Terpenes, alkaloids, and peptides are among the main metabolites produced by marine sponges. [PERSON] et al. have isolated manoalide from sponge _L. variabilis_ in Palau [53]. This compound exhibited antibacterial activity against _Streptomyces pyogenes_ and _S. aureus_. Manoalide, according to [PERSON] et al., could inhibit the activity of the phospholipase A2 (PLA2) enzyme that provides a substrate of pro-inflammatory mediators [54]. Isomalabaricanes are triterpenes found in marine sponges. They can be classified into stelletiins, stelliferins, and globostellatic acids [12]. [PERSON] et al. have indicated that stelletins from _J. stellifera_ and _Stelleta tenuis_ are cytotoxic to murine leukemia P388 cells [55]. Manzamine A, an alkaloid isolated from _Haliclona_ sp., has shown cytotoxic, anti-malarial, and antibacterial activity [56]. Discodermin A, a peptide detected in Discodermin kiensis (and in discodermins B, C, and D) has exhibited antibacterial potential, inhibiting PLA2 [57]. Clathric acid from Clathria compressa [58] and motualevic acid from _Siliquariaspongia_ sp. [59] could inhibit the growth of methicillin-resistant _S. aureus_. Metachromin A from _Dactylospongia metachromia_ inhibited Hepatitis B viral production [60]. Xestodecalactone B isolated from Xestospongia exigua could inhibit the growth of _C. albicans_[61]. [PERSON] et al. isolated from _Aspergillus_ sp. Misszrtine A, an alkaloid with anticancer effects on HL-60 and LNCaP cells [62]. Also, gracilosulfates A, B, C, D, E, F, and G, which are steroids found in _Haliclona gracilis_, has shown anti-tumor activity in human prostate cancer [63]. Monacolin X, a polyketide isolated from _Monascus_ sp., showed a significant anti-proliferative and anti-migratory effect on human breast cancer cells [64]. Silicon dioxide (SiO\({}_{2}\)) or silica can be synthesized by marine sponges to form their skeletal elements. Thus, this type of silica is widely known as biosilica (biogenously formed polymeric silica) [65]. Biosilica has numerous areas of application, such as in sensoring, coating, and the development of hybrid materials and drug delivery systems [66]. Also, it can be used with positive effects on cartilage and bone healing; thus, it can be used in tissue engineering to form scaffolds [67]. Polphosphates are inorganic compounds that are produced from various animals and are also present in the skeletons of marine sponges. According to various studies, this substance has an osteogenic role. [PERSON] et al. have shown that polyphosphates enhanced the mineralization of osteoblast-like SaOS-2 cells [68]. [PERSON] et al. indicated that polyphosphates upregulated collagen type I and II levels in osteogenic and chondrogenic cells [69]. Thus, polyphosphates should be used in regenerative medicine, and mainly in bone repair and bone therapies, due to biomimetic behavior. Collagen-like protein (spongin) can be extracted from marine sponges, such as _Axinella cannabina_ and _Suberites carnosus_[70]. Spongin has ideal properties, regarding porosity, thermostability, and mechanical strength, and, hence, it can be used in tissue engineering [71]. Spongin-based scaffolds have been isolated from _Demosopage Hippocampia_ communis andused as a template for the hydrothermal deposition of crystalline titanium dioxide, with potential use in biomedicine [72]. Chitin is a very famous biopolymer present in many organisms, including marine sponges and arthropods [73]. Thermostability, biocompatibility, and biodegradation, in parallel with good mechanical properties, are the major advantages of chitin to be used in applications, such as drug delivery system development and tissue engineering (wound healing, scaffolds, etc.) [74].