**1. Introduction**

To date there are about 100,000 fungal species, it is expected about one million species that are to be present. In spite of the fact that assessments for the quantity of fungi around 1.5 to more than 5 million, likely less than 10% of fungi have been identified till date. Marine derived fungi are rich in new metabolites [1, 2]. Marine derived fungi consists of secondary metabolites which acts a promising pharmacological and biological properties [3]. Fungi are significant parasites of nutrient cyclers and primary producers. These are tremendously understudied in the marine domain and information on their function is obliged by the fungal dispersion and drivers on worldwide scales [4]. Marine fungi are significant source of secondary metabolites. Despite the fact that marine parasites are less investigated in contrast, various valuable hits have been acquired from the drug discovery point of view adding to their significance in the product discovery [5, 6]. Source of drugs isolated from fungi are being used as camptothecin, torreyanic corrosive, vincristine and cytarabine and paclitaxel. Drug resistance towards diseases like tuberculosis, cancer and HIV-AIDS have been biological target with restricted accomplishment [7]. A few classes of particular metabolites from marine fungi have a wide scope of bio activities against various activities. From marine fungi, more than thousand metabolites have been accounted which can be possibly developed as drugs [8–10]. The source of these marine fungi metabolites is differed as their natural surroundings have been accounted from different sources, for example, algae, sponge, fungi and mangrove derived fungi from bottom residue [11]. Fungi can also be harnessed as sources of chemicals, food and biofuels when people exploit metabolism of fungi [12]. Secondary metabolites are produced by fungi for different purposes, including threat of different pathogens, iron chelation and microorganisms. These metabolites have been recognized from EDF [13]. Isolation of fungi from marine samples has regularly led to the recuperation of microorganisms, which are morphologically, trophically and ecologically like fungi yet are false organisms [14]. Fungi are generally conveyed in marine conditions from intense ocean to polar ice covers. They are found in a wide range of dead and living organic matter. Fungi have been made with those related with sediments, with explicit substrates like algae, driftwood, corals and specifically with sponges [15]. Reliably, fungi confined from sponges represent the biggest number (28%) of novel compounds revealed from marine fungi [16]. In spite of the fact that bio activities of secondary metabolites from marine fungi unveil clinical targets; they are not well constituted for pipelines of drugs and none of them right now is available [17]. To date, in excess of 180 bioactive secondary metabolites got from deep ocean fungi have been reported. These natural metabolites obtained are generally organic and compounds like Pencillium, Polyketides is largely discovered. These incorporate compounds with antimicrobial, anticancer, antiprotozoal, antifungal and antiviral activities [18]. Indeed, even in deep aqueous biological systems, an unsuspected high assorted variety of fungal species was discovered utilizing molecular approaches . At first samples are collected from the ocean. The next step is fungal cultures and sample preparation. In the lab, sterility was acquired by vertical laminar flow hood and bunsen burner. Cultures were allowed to grow aerobically at 25°C with atmospheric pressure and ambient temperature. GYPS medium is used for the growth of strains (1 g glucose, 1 g peptone, 1 g starch 1 g yeast and 30 g ocean salts). Then it is freeze-dried at 80°C. DNA is extracted by homogenizing each sample with sterile glass dabs at 30 rpm. DNA was removed from developed strains with a Fast DNA Spin pack. In Cloning and sequencing, the SSU rRNA qualities were amplified utilizing PCR (primers). Transfer DNA was amplified by PCR at 94°C for 1.30 minutes including 37 cycles of 94°C for 30 s, followed by 48°C for 1.25 min, and 72°C for 1.5 min. The PCR amplification with a last extension step and performed at 72°C for 10 min. The fragments were refined with a High Pure PCR kit (Roche) furthermore, were cloned in the DH5 equipped cells and pGEM-T vector. The two strands was determined utilizing Sequencher 4.6 (GeneCodes), A different grouping arrangement was developed for every phylum utilizing Clustal X 1.81 containing all the databases. After this protocol, 1733 sequences from Basidiomycota,, 4117 sequences from Ascomycota, 215 sequences from Chytridiomycota, 621 sequences from Glomeromycota and 292 sequences from Zygomycota is obtained from various branches of phylogenetic fungal species. Every phylum was then exposed to a numerous grouping arrangement methodology, trailed by neighbor-joining method. Phylogenetic trees were envisioned by utilizing Treeview. The phylogenetic neighbors nearest to the ecological sequence were chosen, and afterward phylogenetic analysis were performed. A different sequence arrangement methodology was performed utilizing CLUSTALX 1.81, and the arrangement was refined by eye. After these evaluation, phylotypes were indicated utilizing a cutoff of 98% (pairwise distance). Then qPCR analysis

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*Natural Medicinal Compounds from Marine Fungi towards Drug Discovery: A Review*

optimization of physicochemical characterization [21, 22].

**2. Secondary metabolites and bioactive compounds**

endophytic growth *Microsphaeropsis species* [29] (**Figure 1**).

Two new metabolites, *carbonarones* A (1) and B (2), were acquired from the marine-fungi *Aspergillus carbonarius* detached from the marine residue gathered at Weizhou island of China. It indicated moderate cytotoxicity against K562 cells with IC50 estimations of 56.0 and 27.8 μg/ml, individually [23]. 14-norpseurotin A, 29-nordammarane triterpenoid 6β show noteworthy antimicrobial activity against *Bacillus subtilis*, *Escherichia coli* and *Micrococcus lysoleikticus* with MICs of 3.74, 14.97 μM [24]. From the fungi extracts *Ascochyta heteromorpha*, the agent of a foliar infection of oleander (*Nertum oleander*), another cytochalasin named ascochalasin was separated together with deoxaphomin and cytochalasins A and B. Cytochalasins are an enormous gathering of contagious metabolites created by a few genera of fungi which demonstrated diverse biological activities. These compound binds to actin filaments and block the polymerization and also involved in the elongation of actin [25–28]. Three new metabolites, microsphaeropsones A–C (1–3) with an interesting oxepino[2,3-b]chromen-6-one, were detached from the

A semisynthetic dihydrooxepino[2,3-b]chromen6-one 7 was set up by oxidation of the allylic alcohol 1 with manganese dioxide [29]. Marine-derived fungi *Aspergillus versicolor MF160003* for the pharmacologically dynamic secondary metabolites prompts the disclosure of another Xanthenone derivative, 3-hydroxy

were performed with 10-μl blends utilizing iQ SYBR green Supermix (Bio-Rad), which contained SYBR green PCR buffer, 2.7 μM dATP, 2.7 μM dGTP, 2.7 μM dCTP,2.7 μM dTTP, and 0.42 U of iTaq DNA polymerase (Bio-Rad). At that point 0.35 μM preliminary MH2 (5′TTCGATGGTAGGATAG3′) and 0.35 μM primer FungqPCR1 (5′TGTCGGGATTGGGTAATTT3′) were added to the blend. Reactions were carried out in optical tubes and were fixed with microseal film. All reactions performed with Chromo 4 thermocycler, utilizing an underlying denaturation at 94°C for 3 min to initiate the compound, trailed by 35 or 40 cycles of denaturation at 94°C for 30 s and furthermore expansion at 48°C for 45 s and afterward by plate perusing. The dissociation curve for temperatures from 65–95°C was estimated after the last qPCR cycle. All informations analyzed utilizing Opticon Monitor 3. Samples which showed the most grounded signals in two starter runs were compared at in a last run. Different plasmid concentrations were utilized to build a standard curve for supreme quantification. Using this formula, standards are found: molecules/ μl = a/(plasmid length × 660) × (6.022 × 10^23) where a is the plasmid of concentration in (μg/μl), 6.022 × 10^23 -molar constant, 660- avaerage molecular weight of one base pair [19]. The greater part of the work on secondary metabolites of marine organisms has concentrated on genera, mainly *Penicillium, Aspergillus* and additionally Fusarium and Cladosporium, moreover the less contemplated species merit extraordinary consideration [20]. Biological activity can also be identified using In Silico methods. It gives fast predictions for a large set of compounds in a high-throughput mode. The aim of target discovery is the validation and identification of suitable drug targets for therapeutic intervention and discovery of novel chemical molecules that acts on the most relevant targets for a disease under study. In silico methods include quantitative structure–activity relationships, databases, similarity searching, homology models, pharmacophores, and other molecular modeling, data mining, machine learning, data analysis and network analysis tools that use a computer. Such methods have seen frequent use in the discovery and

*DOI: http://dx.doi.org/10.5772/intechopen.94137*

#### *Natural Medicinal Compounds from Marine Fungi towards Drug Discovery: A Review DOI: http://dx.doi.org/10.5772/intechopen.94137*

were performed with 10-μl blends utilizing iQ SYBR green Supermix (Bio-Rad), which contained SYBR green PCR buffer, 2.7 μM dATP, 2.7 μM dGTP, 2.7 μM dCTP,2.7 μM dTTP, and 0.42 U of iTaq DNA polymerase (Bio-Rad). At that point 0.35 μM preliminary MH2 (5′TTCGATGGTAGGATAG3′) and 0.35 μM primer FungqPCR1 (5′TGTCGGGATTGGGTAATTT3′) were added to the blend. Reactions were carried out in optical tubes and were fixed with microseal film. All reactions performed with Chromo 4 thermocycler, utilizing an underlying denaturation at 94°C for 3 min to initiate the compound, trailed by 35 or 40 cycles of denaturation at 94°C for 30 s and furthermore expansion at 48°C for 45 s and afterward by plate perusing. The dissociation curve for temperatures from 65–95°C was estimated after the last qPCR cycle. All informations analyzed utilizing Opticon Monitor 3. Samples which showed the most grounded signals in two starter runs were compared at in a last run. Different plasmid concentrations were utilized to build a standard curve for supreme quantification. Using this formula, standards are found: molecules/ μl = a/(plasmid length × 660) × (6.022 × 10^23) where a is the plasmid of concentration in (μg/μl), 6.022 × 10^23 -molar constant, 660- avaerage molecular weight of one base pair [19]. The greater part of the work on secondary metabolites of marine organisms has concentrated on genera, mainly *Penicillium, Aspergillus* and additionally Fusarium and Cladosporium, moreover the less contemplated species merit extraordinary consideration [20]. Biological activity can also be identified using In Silico methods. It gives fast predictions for a large set of compounds in a high-throughput mode. The aim of target discovery is the validation and identification of suitable drug targets for therapeutic intervention and discovery of novel chemical molecules that acts on the most relevant targets for a disease under study. In silico methods include quantitative structure–activity relationships, databases, similarity searching, homology models, pharmacophores, and other molecular modeling, data mining, machine learning, data analysis and network analysis tools that use a computer. Such methods have seen frequent use in the discovery and optimization of physicochemical characterization [21, 22].
